README.md

@@ -470,10 +470,14 @@ cache lives; without it each account gets its own directory under the per-user
 cache path.
 
 `get` and `get-thumb` resolve the file by ID directly, so `--collection` is
-accepted for backward compatibility but ignored. `backup-metadata --exif` (alias
+accepted for backward compatibility but ignored. For a live photo, `get` writes
-`--all`) additionally downloads each file to extract full EXIF/IPTC/XMP
+its image and its video, each named after the title with its own extension, as
-metadata. The listing and backup commands support `--json` for machine-readable
+Ente's clients name them (`IMG_0001.heic` and `IMG_0001.mov`). With
-output.
+`--out PATH`, the image is written to `PATH` and the video beside it, with
+`PATH`'s name and the video's extension; a `PATH` with the video's extension is
+refused. `backup-metadata --exif` (alias `--all`) additionally downloads each
+file to extract full EXIF/IPTC/XMP metadata. The listing and backup commands
+support `--json` for machine-readable output.
 
 `backup-metadata` fetches ML data in requests of up to 200 files. When a request
 still fails after its retries, the error is logged, each of its files is written
@@ -499,8 +503,10 @@ the smallest does not.
 ```
 <dir>/
     originals/
-        <fileID>.<ext>          actual file content (one per unique file)
+        <fileID>.<ext>          actual file content (one per unique file,
+                                two for a live photo: see below)
         <fileID>.json           all decrypted metadata for that file
+        <fileID>.livephoto.json which of a live photo's two files is which
     collections/
         <name>/
             <title> -> ../../originals/<fileID>.<ext>   (symlink)
@@ -516,12 +522,22 @@ library's `lib.backup({ includeThumbnails: true })` also writes
 
 A collection's directory and JSON are named after the collection, and a symlink
 after the file's title, both with unsafe characters replaced. When two
-collections would get the same name, or two files in one collection the same
+collections would get the same name, or two symlinks in one collection the same
-title (ignoring case in both), each of them gets its ID added: two albums named
+name (ignoring case in both), each of them gets its ID added: two albums named
 `Trip` become `Trip (10)/` and `Trip (11)/`, and two files titled `IMG_0001.JPG`
 become `IMG_0001 (12345).JPG` and `IMG_0001 (12346).JPG`. IDs never change, so a
 name stays the same from run to run until such a clash appears or goes away.
 
+A live photo, which Ente stores as one ZIP of its image and its video, is stored
+as those two files, which a photo viewer can open: each is
+`originals/<fileID>.<ext>` with the extension it has inside the ZIP (for example
+`12345.heic` and `12345.mov`), and `<fileID>.livephoto.json` names the two. The
+live photo counts as stored only when both files are present and not empty. Its
+album folder links both, each named after the title with that file's extension
+(`IMG_0001.heic` and `IMG_0001.mov`). A live photo that an earlier version of
+quak stored as the ZIP, under the image's name, is replaced by its two files on
+the next run, and the ZIP and its link are removed.
+
 Each run removes the symlinks into `originals/` that no longer belong in their
 collection's directory, and the directories (and JSON) of collections that were
 deleted or renamed. Nothing else in `collections/` is touched: a file or a
@@ -555,9 +571,9 @@ temporary file's permissions, not those of the file it replaced.
       errors
 - [x] Update the API reference section below to match the current implementation
 - [x] `make docker` green
-- [ ] Store live photos in a form a photo viewer can open
+- [x] Store live photos in a form a photo viewer can open
-      (https://git.eeqj.de/sneak/quak/issues/107), once sneak has chosen between
+      (https://git.eeqj.de/sneak/quak/issues/107): unpacked into the image and
-      keeping the ZIP and unpacking it
+      the video
 
 Tagging and releases are decided by sneak alone, and happen only when he
 declares one.
@@ -649,7 +665,9 @@ An `Album` exposes its record fields and `album.photos.list()` → `Photo[]`
 (newest first). A `Photo` exposes its record fields, `photo.record()` →
 `PhotoRecord`, and two content methods:
 
-- `await photo.original(opts?)` → `{ path, bytes }` — the full-resolution file.
+- `await photo.original(opts?)` → `{ path, bytes, videoPath? }` — the
+  full-resolution file. For a live photo, `path` and `bytes` are its image's and
+  `videoPath` is its video.
 - `await photo.thumbnail(opts?)` → `{ path, bytes }`.
 
 Both serve from the on-disk content cache when the bytes are present and
@@ -669,7 +687,7 @@ The GUI-facing records hold no key material and no binary, so they survive
 - `PhotoRecord`: `fileID`, `albumIDs`, `title`, `takenAt` (milliseconds),
   `fileType`, optional `caption` / `width` / `height` / `latitude` /
   `longitude`, `isArchived`, `isHidden`, and `thumbnailPath` / `originalPath`
-  once the bytes are cached.
+  once the bytes are cached (for a live photo, `originalPath` is its image).
 - `AlbumRecord`: `collectionID`, `name`, `type`, `isShared`, `updationTime`, and
   `fileIDs` (newest first).
 - `LibrarySnapshot`: `{ albums, photos, takenAt }`.
@@ -720,6 +738,8 @@ Under `cacheDirectory`:
 <cacheDirectory>/
     metadata.json                 decrypted account state + refresh cursor
     originals/<fileID>.<ext>      cached full-resolution files
+    originals/<fileID>.livephoto.json
+                                  which of a live photo's two files is which
     thumbnails/<fileID>.jpg       cached thumbnails
     mldata/
         <fileID>.json             one decrypted ML payload per file
@@ -732,14 +752,21 @@ When `metadata.json` belongs to a different account than the client's,
 originals and thumbnails are kept; they are reached only through the files the
 current account's records name.
 
+A live photo's original is cached as in the backup: its image and its video,
+each `originals/<fileID>.<ext>` with its own extension, and
+`originals/<fileID>.livephoto.json` naming them; the two are evicted together. A
+live photo that an earlier version cached as its ZIP is not served, and is
+replaced by its two files the next time it is read.
+
 A stored file appears only via an atomic temp-then-rename, so its presence means
 it is complete. Every downloaded original (by `quak get`, the cache, or
 `backup`) whose metadata records a content hash (`FileMetadata.hash`) is hashed
-as it is written: unkeyed BLAKE2b with a 64-byte output, standard base64. For a
+as it is written: unkeyed BLAKE2b with a 64-byte output, standard base64. A live
-live photo, which is stored as a ZIP, the image and the video are hashed
+photo arrives as a ZIP and is unpacked as it is written; its image and its video
-separately and joined as `<imageHash>:<videoHash>`. A mismatch stores nothing
+are hashed separately and joined as `<imageHash>:<videoHash>`, and neither is
-and fails the download with an error naming the file ID. An original with no
+stored unless both are complete and match. A mismatch stores nothing and fails
-recorded hash, from a very old client, is stored unchecked.
+the download with an error naming the file ID. An original with no recorded
+hash, from a very old client, is stored unchecked.
 
 ### Key types by source file
 

TODO.md

@@ -14,15 +14,25 @@ pre-1.0
 
 # Next Step
 
-Store live photos in a form a photo viewer can open
+None: every issue still open is done on `next` or `next2` and waits for it to
-(https://git.eeqj.de/sneak/quak/issues/107). This waits on sneak's choice
+reach `main`.
-between keeping the ZIP and unpacking it into the image and the video.
 
 Tagging and releases are decided by sneak alone, and happen only when he
 declares one.
 
 # Completed Steps
 
+- 2026-09-23: Live photos are stored as their image and their video (issue 107).
+  A live photo, which Ente stores as one ZIP, is unpacked as it downloads into
+  `<fileID>.<ext>` for the image and for the video, each with its extension from
+  the ZIP, beside `<fileID>.livephoto.json`, which names the two. Both are
+  checked against the recorded hash and renamed into place only when both are
+  complete. The backup and the content cache count the live photo as stored only
+  with both files, the album folder links both, `quak get` writes both, and the
+  content result gives the video as `videoPath`. A ZIP an earlier version stored
+  is replaced on the next backup run, and in the cache when the photo is next
+  read.
+
 - 2026-09-23: Settled the package metadata (issue 6). quak is not published, so
   `package.json` is marked `"private": true` and the `files` field is gone.
   `engines.node` is `>=22`, the major version `script/bootstrap` and the

src/backup.ts

@@ -5,7 +5,7 @@
 // gets its original bytes onto disk under `downloadDirectory` and rebuilds the
 // derived views (per-file sidecars, per-collection symlink trees,
 // per-collection JSON) from the model. The on-disk layout is the historical
-// one, unchanged:
+// one:
 //
 //     <downloadDirectory>/
 //         originals/<fileID>.<ext>     the decrypted bytes
@@ -14,6 +14,10 @@
 //         collections/<name>.json      per-collection metadata
 //         failures.json                durable ledger of unresolved failures
 //
+// A live photo's original is its image and its video, `<fileID>.<ext>` each
+// with its own extension, and `originals/<fileID>.livephoto.json` naming them;
+// its album folders link both.
+//
 // Crash-safety rests on two properties. Bytes are present-means-complete: an
 // original appears under `originals/` only via the content layer's atomic
 // temp-then-rename, so a file that exists is whole and is never re-fetched — an
@@ -48,7 +52,12 @@ import { copyFile, rename, rm } from "node:fs/promises";
 import { basename, dirname, extname, join, relative } from "node:path";
 
 import { fsyncPath, removeLeftoverTempFiles } from "./download/index.js";
-import { safeExtension, sanitizeFileName } from "./filename.js";
+import { sanitizeFileName, withExtension } from "./filename.js";
+import {
+    originalName,
+    storedOriginal,
+    writeLivePhoto,
+} from "./library/content.js";
 import type { Collection, EnteFile } from "./model/types.js";
 
 export type ProgressCallback = (message: string) => void;
@@ -98,8 +107,13 @@ export interface BackupLibrary {
     listFiles(collectionID: number): EnteFile[];
     // Get an original's bytes onto disk through the content cache/pools,
     // returning where they landed: `destination` when they were fetched now,
-    // otherwise wherever they already were (the cache, or a prior backup).
+    // otherwise wherever they already were (the cache, or a prior backup). A
-    original(fileID: number, destination: string): Promise<{ path: string }>;
+    // live photo lands as its image and its video, fetched now beside
+    // `destination`.
+    original(
+        fileID: number,
+        destination: string,
+    ): Promise<{ path: string; videoPath?: string }>;
     thumbnail(fileID: number): Promise<{ path: string }>;
 }
 
@@ -116,12 +130,6 @@ interface FailureEntry {
 
 const LEDGER_VERSION = 1;
 
-// The originals/ filename for a file: `<id><ext>`, the extension taken from the
-// title (or `.bin`). Matches the content cache's own naming so a present check
-// lines up with what a fetch would write.
-const originalName = (file: EnteFile): string =>
-    `${file.id}${safeExtension(file.metadata.title)}`;
-
 // A regular file with content is treated as complete. A zero-byte file is not:
 // it is the shape an aborted write leaves and must be re-fetched.
 const isPresent = (path: string): boolean => {
@@ -187,6 +195,31 @@ const copyAtomic = async (src: string, dest: string): Promise<void> => {
     }
 };
 
+// Put an original the library returned at `dest` in originals/, where a fresh
+// fetch already wrote it. A live photo's image and video go beside `dest`: when
+// they came from the cache they are copied, after removing whatever was at
+// `dest` (an earlier version's ZIP of the two). Then the JSON file naming them
+// is written, which is what makes the live photo count as stored.
+const placeOriginal = async (
+    file: EnteFile,
+    dest: string,
+    got: { path: string; videoPath?: string },
+): Promise<void> => {
+    if (got.videoPath === undefined) {
+        await copyAtomic(got.path, dest);
+        return;
+    }
+    const originalsDir = dirname(dest);
+    const path = join(originalsDir, basename(got.path));
+    const videoPath = join(originalsDir, basename(got.videoPath));
+    if (got.path !== path) {
+        await rm(dest, { force: true });
+        await copyAtomic(got.path, path);
+        await copyAtomic(got.videoPath, videoPath);
+    }
+    await writeLivePhoto(originalsDir, file.id, { path, videoPath });
+};
+
 // Ensure `linkPath` is a symlink to `target`, rebuilding a missing, wrong, or
 // non-symlink entry. Throws on failure (a directory in the way, no permission)
 // so the caller records it and moves on rather than aborting the run.
@@ -203,43 +236,61 @@ const rebuildSymlink = (linkPath: string, target: string): void => {
     symlinkSync(target, linkPath);
 };
 
-// The on-disk names for the entries of one directory, keyed by ID. Each name
+// The on-disk names for the entries of one directory, in entry order. Each
-// is used as is unless another entry would get the same name, ignoring case
+// name is used as is unless another entry would get the same name, ignoring
-// (two names that differ only in case are one entry on a case-insensitive
+// case (two names that differ only in case are one entry on a case-insensitive
 // file system); then every entry sharing it gets ` (<id>)`, before the
 // extension when `beforeExtension` is set. A name with an ID added can match
 // another entry's own name (`IMG (6).JPG`), so this repeats until no name is
 // shared. IDs are stable, so the names are too.
-const namesByID = (
+const uniqueNames = (
     entries: { id: number; name: string }[],
     beforeExtension: boolean,
-): Map<number, string> => {
+): string[] => {
     const withID = (id: number, name: string): string => {
         const ext = beforeExtension ? extname(name) : "";
         const stem = name.slice(0, name.length - ext.length);
         return `${stem} (${id})${ext}`;
     };
-    const names = new Map<number, string>();
+    const names = entries.map((e) => e.name);
-    for (const { id, name } of entries) names.set(id, name);
     const suffixed = new Set<number>();
     for (;;) {
         const counts = new Map<string, number>();
-        for (const name of names.values()) {
+        for (const name of names) {
             const key = name.toLowerCase();
             counts.set(key, (counts.get(key) ?? 0) + 1);
         }
         let changed = false;
-        for (const { id, name } of entries) {
+        for (const [i, { id, name }] of entries.entries()) {
-            if (suffixed.has(id)) continue;
+            if (suffixed.has(i)) continue;
             if (counts.get(name.toLowerCase()) === 1) continue;
-            names.set(id, withID(id, name));
+            names[i] = withID(id, name);
-            suffixed.add(id);
+            suffixed.add(i);
             changed = true;
         }
         if (!changed) return names;
     }
 };
 
+// The links a file gets in its album's folder: one named after its title, to
+// its original if that is stored. A stored live photo gets two, to its image
+// and its video, each named after the title with that file's extension.
+const linksFor = (
+    file: EnteFile,
+    stored: { path: string; videoPath?: string } | undefined,
+): { id: number; name: string; file: EnteFile; target?: string }[] => {
+    const name = sanitizeFileName(file.metadata.title, `file-${file.id}`);
+    if (stored?.videoPath === undefined) {
+        return [{ id: file.id, name, file, target: stored?.path }];
+    }
+    return [stored.path, stored.videoPath].map((target) => ({
+        id: file.id,
+        name: withExtension(name, extname(target)),
+        file,
+        target,
+    }));
+};
+
 // Remove the symlinks in the album directory `dir` that point into
 // `originalsDir` and are not named in `keep`. Nothing else in the directory
 // is touched: anything else there was put there by the user.
@@ -419,17 +470,21 @@ export const runBackup = async (
     // tree; a present file is left as is.
     if (includeOriginals) {
         for (const [fileID, file] of distinct) {
-            const dest = join(originalsDir, originalName(file));
+            if (storedOriginal(originalsDir, file) !== undefined) {
-            if (isPresent(dest)) {
                 skipped++;
                 continue;
             }
+            const dest = join(originalsDir, originalName(file));
             try {
                 log(`Fetching original ${file.metadata.title} (${fileID})...`);
-                // A fetched original is written straight to `dest`; only one
+                // A fetched original is written straight to `dest` (a live
-                // that was already cached elsewhere is copied.
+                // photo beside it); only one that was already cached elsewhere
-                const { path } = await lib.original(fileID, dest);
+                // is copied.
-                await copyAtomic(path, dest);
+                await placeOriginal(
+                    file,
+                    dest,
+                    await lib.original(fileID, dest),
+                );
                 downloaded++;
             } catch (err) {
                 log(
@@ -465,8 +520,7 @@ export const runBackup = async (
     // every present original (this repairs stale ones).
     if (includeOriginals) {
         for (const [fileID, file] of distinct) {
-            const orig = join(originalsDir, originalName(file));
+            if (storedOriginal(originalsDir, file) !== undefined) {
-            if (isPresent(orig)) {
                 writeSidecar(join(originalsDir, `${fileID}.json`), file);
             }
         }
@@ -478,19 +532,18 @@ export const runBackup = async (
     // an album it skipped. Stale entries are removed before anything is
     // rebuilt, so on a case-insensitive file system removing an old name can
     // never remove the new one.
-    const albumDirNames = namesByID(
+    const dirNames = uniqueNames(
         allCollections.map((c) => ({
             id: c.id,
             name: sanitizeFileName(c.name, `collection-${c.id}`),
         })),
         false,
     );
-    try {
+    const albumDirNames = new Map(
-        removeStaleAlbumDirs(
+        allCollections.map((c, i) => [c.id, dirNames[i]!]),
-            collectionsDir,
-            new Set(albumDirNames.values()),
-            originalsDir,
     );
+    try {
+        removeStaleAlbumDirs(collectionsDir, new Set(dirNames), originalsDir);
     } catch (err) {
         log(`FAILED removing old album directories: ${errorMessage(err)}`);
     }
@@ -501,34 +554,33 @@ export const runBackup = async (
         mkdirSync(colDir, { recursive: true });
 
         const files = filesByCollection.get(c.id) ?? [];
-        const linkNames = namesByID(
+        const links = files.flatMap((f) =>
-            files.map((f) => ({
+            linksFor(f, storedOriginal(originalsDir, f)),
-                id: f.id,
-                name: sanitizeFileName(f.metadata.title, `file-${f.id}`),
-            })),
-            true,
         );
+        const linkNames = uniqueNames(links, true);
         try {
-            removeStaleLinks(colDir, new Set(linkNames.values()), originalsDir);
+            removeStaleLinks(colDir, new Set(linkNames), originalsDir);
         } catch (err) {
             log(`FAILED removing old links in ${c.name}: ${errorMessage(err)}`);
         }
 
-        const metaFiles: { id: number; metadata: EnteFile["metadata"] }[] = [];
+        const metaFiles = files.map((f) => ({
-        for (const file of files) {
+            id: f.id,
-            metaFiles.push({ id: file.id, metadata: file.metadata });
+            metadata: f.metadata,
-            if (!includeOriginals) continue;
+        }));
-            const orig = join(originalsDir, originalName(file));
+        for (const [i, link] of links.entries()) {
-            if (!isPresent(orig)) continue;
+            if (!includeOriginals || link.target === undefined) continue;
-            const linkName = linkNames.get(file.id)!;
+            const linkName = linkNames[i]!;
-            const linkPath = join(colDir, linkName);
             try {
-                rebuildSymlink(linkPath, relative(colDir, orig));
+                rebuildSymlink(
+                    join(colDir, linkName),
+                    relative(colDir, link.target),
+                );
             } catch (err) {
                 log(
                     `FAILED symlink ${c.name}/${linkName}: ${errorMessage(err)}`,
                 );
-                recordFailure(file, c.name, err);
+                recordFailure(link.file, c.name, err);
             }
         }
 

src/cli-commands.ts

@@ -10,10 +10,11 @@ import {
     copyFileSync,
     existsSync,
     mkdirSync,
+    statSync,
     unlinkSync,
     writeFileSync,
 } from "node:fs";
-import { join } from "node:path";
+import { extname, join } from "node:path";
 import {
     type Client,
     type ClientSnapshot,
@@ -32,6 +33,7 @@ import {
     thumbnailName,
 } from "./cli-output.js";
 import { freshCollections, freshFiles, freshFile } from "./cli-read.js";
+import { withExtension } from "./filename.js";
 import { runMetadataBackup } from "./metadata-backup.js";
 import { listMissingThumbnails, fixMissingThumbnails } from "./thumbnails.js";
 
@@ -305,9 +307,30 @@ export const getCommand = async (
         // Default name is the file's own title, as the pre-library CLI used
         // (not the editedName-preferring projection title) (issue #52).
         const outPath = opts.out ?? originalName(file);
+        if (result.videoPath === undefined) {
             copyFileSync(result.path, outPath);
             ctx.stderr.write(`${result.bytes} bytes -> ${outPath}\n`);
             return 0;
+        }
+        // A live photo is written as its image and its video, each named after
+        // the title with its own extension, as Ente's clients name them. With
+        // --out, the image goes there and the video beside it.
+        const imageOut =
+            opts.out ?? withExtension(outPath, extname(result.path));
+        const videoOut = withExtension(outPath, extname(result.videoPath));
+        if (imageOut.toLowerCase() === videoOut.toLowerCase()) {
+            ctx.stderr.write(
+                `File ${fileID} is a live photo, and its video would also be written to ${imageOut}\n`,
+            );
+            return 1;
+        }
+        copyFileSync(result.path, imageOut);
+        copyFileSync(result.videoPath, videoOut);
+        ctx.stderr.write(
+            `${result.bytes} bytes -> ${imageOut}\n` +
+                `${statSync(videoOut).size} bytes -> ${videoOut}\n`,
+        );
+        return 0;
     } finally {
         await lib.close();
     }

src/download/index.ts

@@ -16,14 +16,18 @@ import {
     streamTagFinal,
 } from "../crypto/index.js";
 import { TruncatedStreamError } from "../errors.js";
-import { sanitizeFileName } from "../filename.js";
+import { safeExtension, sanitizeFileName, withExtension } from "../filename.js";
 import { withRetry } from "../retry.js";
 import type { ApiClient } from "../api/client.js";
 import type { EnteFile } from "../model/types.js";
 
 export interface DownloadResult {
+    // Where the file was written. A live photo is written as two files, its
+    // image here and its video at `videoPath` (see `decryptLivePhoto`).
     path: string;
+    // The decrypted length; for a live photo, that of the ZIP it arrives as.
     bytesWritten: number;
+    videoPath?: string;
 }
 
 // Fired as decrypted plaintext accumulates, with the running total of
@@ -45,9 +49,9 @@ const ENC_CHUNK_SIZE = STREAM_CHUNK_SIZE + STREAM_CHUNK_OVERHEAD;
 // new: a body cut short still decrypts and authenticates up to its last whole
 // chunk, so the absence of TAG_FINAL is the sole evidence it was cut short, and
 // this throws rather than let a caller keep a short file. The sink has already
-// seen those chunks by then; the caller (`decryptToTemp`) stages them in a temp
+// seen those chunks by then; the callers (`decryptToTemp`, `decryptLivePhoto`)
-// file that is renamed into place only on a clean return, so a throw leaves
+// stage them in temp files that are renamed into place only on a clean return,
-// nothing on disk.
+// so a throw leaves nothing on disk.
 const streamDecrypt = async (
     stream: ReadableStream<Uint8Array>,
     header: Uint8Array,
@@ -213,6 +217,13 @@ export const removeLeftoverTempFiles = (dir: string): void => {
     }
 };
 
+// A new temp file name in `dir`. The random suffix keeps concurrent downloads
+// of the same destination from stepping on each other's temporary file; the
+// process ID lets `removeLeftoverTempFiles` tell a leftover from a write in
+// progress.
+const tempPathIn = (dir: string): string =>
+    join(dir, `.quak-${process.pid}-${randomBytes(16).toString("hex")}.tmp`);
+
 // Stage a write to `destination` atomically and durably, then rename it into
 // place. `fill` writes the contents into the open temp file handle — either the
 // whole buffer at once (`writeAtomic`) or chunk by chunk as they decrypt
@@ -237,13 +248,7 @@ const stageAtomic = async (
     fill: (handle: FileHandle) => Promise<void>,
 ): Promise<void> => {
     const dir = dirname(destination);
-    // The random suffix keeps concurrent downloads of the same destination
+    const tmpPath = tempPathIn(dir);
-    // from stepping on each other's temporary file; the process ID lets
-    // `removeLeftoverTempFiles` tell a leftover from a write in progress.
-    const tmpPath = join(
-        dir,
-        `.quak-${process.pid}-${randomBytes(16).toString("hex")}.tmp`,
-    );
     try {
         const handle = await open(tmpPath, "w");
         try {
@@ -278,81 +283,14 @@ export const writeAtomic = async (
 ): Promise<void> =>
     stageAtomic(destination, (handle) => handle.writeFile(plaintext));
 
-// Hashes an original's bytes as they are decrypted, for comparison with the
+// Refuse an original whose bytes do not hash to what its uploader recorded.
-// hash its uploader recorded.
+// The error is not retried.
-interface ContentHasher {
+const checkHash = (file: EnteFile, actual: string): void => {
-    update: (plaintext: Uint8Array) => void;
+    if (actual !== file.metadata.hash) {
-    digest: () => string;
+        throw new Error(
-}
+            `download: file ${file.id}: content hash ${actual} does not match the hash its uploader recorded, ${file.metadata.hash}`,
-
-const fileHasher = (): ContentHasher => {
-    const state = chunkHashInit();
-    return {
-        update: (plaintext) => chunkHashUpdate(state, plaintext),
-        digest: () => chunkHashFinal(state),
-    };
-};
-
-// A live photo is stored as a ZIP of its image and its video, and its recorded
-// hash is `<imageHash>:<videoHash>`, each over that part's own bytes. Like the
-// upstream client's decoder, this takes the first entries whose names start
-// with `image` and `video`.
-//
-// The ZIP is chosen by its uploader and may expand enormously, so entries are
-// hashed as they decompress and never held. fflate's `Unzip` inflates each
-// push in one piece, and deflate expands at most about 1000-fold, so the ZIP
-// is pushed in 4 KiB slices to keep each decompressed piece near 4 MiB, one
-// plaintext chunk. Every entry is started, even one that is not hashed,
-// because fflate keeps an unstarted entry's data in memory.
-const livePhotoHasher = (fileID: number): ContentHasher => {
-    const sliceSize = 4096;
-    const fail = (message: string, cause?: unknown): Error =>
-        new Error(`download: file ${fileID}: ${message}`, { cause });
-    const claimed = new Set<string>();
-    const hashes = new Map<string, string>();
-    const unzip = new Unzip((entry) => {
-        const part = ["image", "video"].find((p) => entry.name.startsWith(p));
-        const target =
-            part === undefined || claimed.has(part)
-                ? undefined
-                : { part, state: chunkHashInit() };
-        if (target !== undefined) claimed.add(target.part);
-        entry.ondata = (err, data, final) => {
-            if (err) throw err;
-            if (target === undefined) return;
-            chunkHashUpdate(target.state, data);
-            if (final) hashes.set(target.part, chunkHashFinal(target.state));
-        };
-        entry.start();
-    });
-    unzip.register(UnzipInflate);
-    // fflate reports a bad ZIP by throwing, sometimes a TypeError, which the
-    // retry would take for a network failure; a bad ZIP is never retried.
-    const push = (data: Uint8Array, final: boolean): void => {
-        try {
-            unzip.push(data, final);
-        } catch (err) {
-            throw fail("live photo is not a readable ZIP", err);
-        }
-    };
-    return {
-        update: (plaintext) => {
-            for (let i = 0; i < plaintext.length; i += sliceSize) {
-                push(plaintext.subarray(i, i + sliceSize), false);
-            }
-        },
-        digest: () => {
-            push(new Uint8Array(0), true);
-            const image = hashes.get("image");
-            const video = hashes.get("video");
-            if (image === undefined || video === undefined) {
-                throw fail(
-                    "live photo ZIP does not hold both an image and a video",
         );
     }
-            return `${image}:${video}`;
-        },
-    };
 };
 
 // Decrypt `stream` straight to `destination`, one plaintext chunk at a time,
@@ -363,9 +301,8 @@ const livePhotoHasher = (fileID: number): ContentHasher => {
 // Returns the plaintext length written.
 //
 // `original` is the file whose original this is (none for a thumbnail, which
-// has no recorded hash). When its metadata has a hash, the decrypted bytes
+// has no recorded hash). When its metadata has a hash, the decrypted bytes are
-// must match it or nothing is stored. Both a plain file and a live photo's
+// hashed as they stream and must match it, or nothing is stored.
-// parts are hashed as they stream. The mismatch error is not retried.
 const decryptToTemp = async (
     destination: string,
     stream: ReadableStream<Uint8Array>,
@@ -374,44 +311,173 @@ const decryptToTemp = async (
     onProgress?: ProgressCallback,
     original?: EnteFile,
 ): Promise<number> => {
-    const expected = original?.metadata.hash;
+    const hash =
-    const hasher =
+        original?.metadata.hash === undefined ? undefined : chunkHashInit();
-        original === undefined || expected === undefined
-            ? undefined
-            : original.metadata.fileType === "livePhoto"
-              ? livePhotoHasher(original.id)
-              : fileHasher();
     let bytesWritten = 0;
-    try {
     await stageAtomic(destination, async (handle) => {
         bytesWritten = await streamDecrypt(
             stream,
             header,
             key,
             async (plaintext) => {
-                    hasher?.update(plaintext);
+                if (hash !== undefined) chunkHashUpdate(hash, plaintext);
                 await handle.write(plaintext);
             },
             onProgress,
         );
-            if (original === undefined || hasher === undefined) return;
+        if (original !== undefined && hash !== undefined) {
-            const actual = hasher.digest();
+            checkHash(original, chunkHashFinal(hash));
-            if (actual !== expected) {
-                throw new Error(
-                    `download: file ${original.id}: content hash ${actual} does not match the hash its uploader recorded, ${expected}`,
-                );
         }
     });
+    return bytesWritten;
+};
+
+// One of the two parts of a live photo being unpacked: the ZIP entry whose
+// name starts with `kind`, written to its own temp file.
+interface LivePhotoPart {
+    kind: "image" | "video";
+    tmpPath: string;
+    handle: FileHandle;
+    hash: ReturnType<typeof chunkHashInit>;
+    // Decompressed bytes not yet written.
+    pending: Uint8Array[];
+    // The entry's extension, set once all of the entry has been read.
+    ext?: string;
+}
+
+const openPart = async (
+    kind: "image" | "video",
+    dir: string,
+): Promise<LivePhotoPart> => {
+    const tmpPath = tempPathIn(dir);
+    const handle = await open(tmpPath, "w");
+    return { kind, tmpPath, handle, hash: chunkHashInit(), pending: [] };
+};
+
+// A live photo arrives as a ZIP of its image and its video. Ente's clients
+// name the entries `image.<ext>` and `video.<ext>`, and like the upstream
+// client's decoder this takes the first entries whose names start with `image`
+// and `video`. It is written unpacked: each part is named `destination` with
+// the extension replaced by its own entry's, and the two must differ ignoring
+// case. When the file records a hash, `<imageHash>:<videoHash>` must match it,
+// each over that part's own bytes. Only then is whatever was at `destination`
+// removed and the image, then the video, renamed into place; on any failure
+// neither is stored.
+//
+// The ZIP is chosen by its uploader and may expand enormously, so each part is
+// written as it decompresses and never held. fflate's `Unzip` inflates each
+// push in one piece before `push` returns, and deflate expands at most about
+// 1000-fold, so the ZIP is pushed in 4 KiB slices, keeping each decompressed
+// piece near 4 MiB, one plaintext chunk, and each piece is written before the
+// next slice is pushed. Every entry is started, even one that is not kept,
+// because fflate keeps an unstarted entry's data in memory.
+const decryptLivePhoto = async (
+    destination: string,
+    stream: ReadableStream<Uint8Array>,
+    header: Uint8Array,
+    key: Uint8Array,
+    onProgress: ProgressCallback | undefined,
+    file: EnteFile,
+): Promise<DownloadResult> => {
+    const sliceSize = 4096;
+    const dir = dirname(destination);
+    const fail = (message: string, cause?: unknown): Error =>
+        new Error(`download: file ${file.id}: ${message}`, { cause });
+    const parts: LivePhotoPart[] = [];
+    try {
+        const image = await openPart("image", dir);
+        parts.push(image);
+        const video = await openPart("video", dir);
+        parts.push(video);
+
+        const claimed = new Set<LivePhotoPart>();
+        const unzip = new Unzip((entry) => {
+            const part = parts.find(
+                (p) => !claimed.has(p) && entry.name.startsWith(p.kind),
+            );
+            if (part !== undefined) claimed.add(part);
+            entry.ondata = (err, data, final) => {
+                if (err) throw err;
+                if (part === undefined) return;
+                chunkHashUpdate(part.hash, data);
+                part.pending.push(data);
+                if (final) part.ext = safeExtension(entry.name);
+            };
+            entry.start();
+        });
+        unzip.register(UnzipInflate);
+        const push = async (
+            data: Uint8Array,
+            final: boolean,
+        ): Promise<void> => {
+            // fflate reports a bad ZIP by throwing, sometimes a TypeError,
+            // which the retry would take for a network failure; a bad ZIP is
+            // never retried.
+            try {
+                unzip.push(data, final);
             } catch (err) {
-        // Cancel the body so its connection is closed now rather than held
+                throw fail("live photo is not a readable ZIP", err);
-        // until the stream is garbage collected. A backup run carries on past
+            }
-        // a failed file, so without this every failure would hold a socket.
+            for (const part of parts) {
-        // This covers every failure, including a temp file that cannot be
+                for (const piece of part.pending)
-        // opened and a header that is rejected before the body is read.
+                    await part.handle.write(piece);
-        await stream.cancel(err).catch(() => undefined);
+                part.pending = [];
+            }
+        };
+
+        const bytesWritten = await streamDecrypt(
+            stream,
+            header,
+            key,
+            async (plaintext) => {
+                for (let i = 0; i < plaintext.length; i += sliceSize) {
+                    await push(plaintext.subarray(i, i + sliceSize), false);
+                }
+            },
+            onProgress,
+        );
+        await push(new Uint8Array(0), true);
+
+        if (image.ext === undefined || video.ext === undefined) {
+            throw fail(
+                "live photo ZIP does not hold both an image and a video",
+            );
+        }
+        if (file.metadata.hash !== undefined) {
+            checkHash(
+                file,
+                `${chunkHashFinal(image.hash)}:${chunkHashFinal(video.hash)}`,
+            );
+        }
+        if (image.ext.toLowerCase() === video.ext.toLowerCase()) {
+            throw fail(
+                `live photo's image and video have the same extension, ${video.ext}`,
+            );
+        }
+        const path = withExtension(destination, image.ext);
+        const videoPath = withExtension(destination, video.ext);
+        for (const part of parts) {
+            await part.handle.sync();
+            await part.handle.close();
+        }
+        await rm(destination, { force: true });
+        await rename(image.tmpPath, path);
+        try {
+            await rename(video.tmpPath, videoPath);
+        } catch (err) {
+            await rm(path, { force: true }).catch(() => undefined);
+            throw err;
+        }
+        await fsyncPath(dir);
+        return { path, bytesWritten, videoPath };
+    } catch (err) {
+        // Best-effort cleanup, as in `stageAtomic`.
+        for (const part of parts) {
+            await part.handle.close().catch(() => undefined);
+            await rm(part.tmpPath, { force: true }).catch(() => undefined);
+        }
         throw err;
     }
-    return bytesWritten;
 };
 
 // Fetch a stream and decrypt it to `destination`, retrying the whole sequence.
@@ -442,10 +508,12 @@ const fetchAndDecrypt = async (
     destination: string,
     onProgress?: ProgressCallback,
     original?: EnteFile,
-): Promise<number> =>
+): Promise<DownloadResult> =>
     withRetry(async () => {
         const stream = await openStream();
-        return decryptToTemp(
+        try {
+            if (original?.metadata.fileType === "livePhoto") {
+                return await decryptLivePhoto(
                     destination,
                     stream,
                     header,
@@ -453,8 +521,31 @@ const fetchAndDecrypt = async (
                     onProgress,
                     original,
                 );
+            }
+            const bytesWritten = await decryptToTemp(
+                destination,
+                stream,
+                header,
+                key,
+                onProgress,
+                original,
+            );
+            return { path: destination, bytesWritten };
+        } catch (err) {
+            // Cancel the body so its connection is closed now rather than held
+            // until the stream is garbage collected. A backup run carries on
+            // past a failed file, so without this every failure would hold a
+            // socket. This covers every failure, including a temp file that
+            // cannot be opened and a header that is rejected before the body
+            // is read.
+            await stream.cancel(err).catch(() => undefined);
+            throw err;
+        }
     }, api.getRetryOptions());
 
+// Write `file`'s original to `outPath`. A live photo is written as its image
+// and its video beside `outPath` instead, and whatever was at `outPath` is
+// removed (see `decryptLivePhoto`).
 export const downloadFile = async (
     api: ApiClient,
     file: EnteFile,
@@ -466,7 +557,7 @@ export const downloadFile = async (
     const resolvedPath =
         outPath ?? sanitizeFileName(file.metadata.title, `file-${file.id}`);
     const header = fromBase64(file.file.decryptionHeader);
-    const bytesWritten = await fetchAndDecrypt(
+    return fetchAndDecrypt(
         api,
         () => api.getFileStream(file.id, { retry: false }),
         header,
@@ -475,7 +566,6 @@ export const downloadFile = async (
         onProgress,
         file,
     );
-    return { path: resolvedPath, bytesWritten };
 };
 
 export const downloadThumbnail = async (
@@ -488,7 +578,7 @@ export const downloadThumbnail = async (
         outPath ??
         `thumb_${sanitizeFileName(file.metadata.title, `file-${file.id}`)}`;
     const header = fromBase64(file.thumbnail.decryptionHeader);
-    const bytesWritten = await fetchAndDecrypt(
+    return fetchAndDecrypt(
         api,
         () => api.getThumbnailStream(file.id, { retry: false }),
         header,
@@ -496,5 +586,4 @@ export const downloadThumbnail = async (
         resolvedPath,
         onProgress,
     );
-    return { path: resolvedPath, bytesWritten };
 };

src/filename.ts

@@ -35,3 +35,7 @@ export const safeExtension = (title: string): string => {
     const ext = extname(title);
     return /^\.[A-Za-z0-9]+$/.test(ext) ? ext : ".bin";
 };
+
+// `name` with its extension, if it has one, replaced by `ext` (".mov").
+export const withExtension = (name: string, ext: string): string =>
+    name.slice(0, name.length - extname(name).length) + ext;

src/library/content.ts

@@ -1,11 +1,13 @@
 // The on-disk content and thumbnail cache keyed by fileID (issue #46).
 //
 // Layout under `cacheDirectory`: `originals/<fileID>.<ext>` and
-// `thumbnails/<fileID>.<ext>`, flat directories at 0700 with files at 0600.
+// `thumbnails/<fileID>.<ext>`, flat directories at 0700 with files at 0600. A
-// Content appears only by the streaming atomic writer's rename (the download
+// live photo's original is two files, its image and its video, with
-// layer, #40), so a file that exists is whole — "present means complete". The
+// `originals/<fileID>.livephoto.json` naming them. Content appears only by the
-// directory listing taken at `open()` is the record of what is cached, and the
+// streaming atomic writer's rename (the download layer, #40), so a file that
-// orphan temp files a crashed write may have left are reaped there.
+// exists is whole — "present means complete". The directory listing taken at
+// `open()` is the record of what is cached, and the orphan temp files a crashed
+// write may have left are reaped there.
 //
 // A fetch goes through the shared request pools (#45): the content pool for
 // originals, the thumbnail pool for thumbnails. The pool limits concurrency,
@@ -22,7 +24,7 @@
 // does; thumbnails have none. On top of that this module refuses to record a
 // stored file that came out empty.
 
-import { existsSync, statSync } from "node:fs";
+import { existsSync, readFileSync, statSync } from "node:fs";
 import {
     chmod,
     mkdir,
@@ -32,7 +34,7 @@ import {
     statfs,
     utimes,
 } from "node:fs/promises";
-import { dirname, extname, join } from "node:path";
+import { basename, dirname, extname, join } from "node:path";
 
 import type { ApiClient } from "../api/client.js";
 import {
@@ -40,6 +42,7 @@ import {
     downloadThumbnail,
     type ProgressCallback,
     removeLeftoverTempFiles,
+    writeAtomic,
 } from "../download/index.js";
 import { safeExtension } from "../filename.js";
 import type { EnteFile } from "../model/types.js";
@@ -77,6 +80,8 @@ const poolPriorityOf = (priority: ThumbnailPriority): Priority =>
 export interface ContentResult {
     path: string;
     bytes: number;
+    // A live photo's video. `path` and `bytes` are then its image's.
+    videoPath?: string;
 }
 
 // Progress for a single `original`/`thumbnail` call. A present file emits one
@@ -127,11 +132,14 @@ export interface ThumbnailsAPI {
 // stand-in so the cache logic runs with no crypto and no network. Pool routing,
 // dedup, present-checks and integrity live in the cache, not here.
 export interface ContentSource {
+    // Writes the original at `destination`. A live photo is written beside it
+    // as its image and its video instead, and their paths are returned, as
+    // `downloadFile` does.
     original(args: {
         file: EnteFile;
         destination: string;
         onProgress?: ProgressCallback;
-    }): Promise<{ bytesWritten: number }>;
+    }): Promise<{ bytesWritten: number; path?: string; videoPath?: string }>;
     thumbnail(args: {
         file: EnteFile;
         destination: string;
@@ -209,7 +217,9 @@ class AbortDrop extends Error {
     }
 }
 
-const originalName = (file: EnteFile): string =>
+// The originals/ name for a file: `<fileID><ext>`, the extension taken from the
+// title (or `.bin`). A backup names its originals the same way.
+export const originalName = (file: EnteFile): string =>
     `${file.id}${safeExtension(file.metadata.title)}`;
 
 // The fileID a cache filename encodes, or undefined when the name is not one
@@ -231,6 +241,73 @@ const fileSize = (path: string): number | undefined => {
     }
 };
 
+// Whether `path` is a regular file with content. A zero-byte file is the shape
+// an aborted write leaves, so it does not count.
+const hasContent = (path: string | undefined): boolean =>
+    path !== undefined && (fileSize(path) ?? 0) > 0;
+
+// A live photo's image and video are named with the extensions from inside its
+// ZIP, so their names alone do not say which is which. Wherever the cache or a
+// backup stores one, this JSON file beside them names both.
+const livePhotoFileName = (fileID: number): string =>
+    `${fileID}.livephoto.json`;
+
+// The image and video that the live photo's JSON file in `dir` names, or
+// undefined when there is none. Only names of the form the cache writes are
+// taken, so the file cannot point outside `dir`.
+const readLivePhoto = (
+    dir: string,
+    fileID: number,
+): { path: string; videoPath: string } | undefined => {
+    const valid = (name: unknown): name is string =>
+        typeof name === "string" && name === `${fileID}${safeExtension(name)}`;
+    try {
+        const { image, video } = JSON.parse(
+            readFileSync(join(dir, livePhotoFileName(fileID)), "utf-8"),
+        );
+        if (valid(image) && valid(video)) {
+            return { path: join(dir, image), videoPath: join(dir, video) };
+        }
+    } catch {
+        // No such file, or not one the cache wrote.
+    }
+    return undefined;
+};
+
+// Write the JSON file naming a live photo's image and video, both in `dir`.
+export const writeLivePhoto = (
+    dir: string,
+    fileID: number,
+    stored: { path: string; videoPath: string },
+): Promise<void> =>
+    writeAtomic(
+        join(dir, livePhotoFileName(fileID)),
+        new TextEncoder().encode(
+            JSON.stringify({
+                image: basename(stored.path),
+                video: basename(stored.videoPath),
+            }),
+        ),
+    );
+
+// The original of `file` as the cache or a backup stored it in `dir`, when all
+// of it is there: `<fileID><ext>`, or a live photo's image and video.
+export const storedOriginal = (
+    dir: string,
+    file: EnteFile,
+): { path: string; videoPath?: string } | undefined => {
+    if (file.metadata.fileType !== "livePhoto") {
+        const path = join(dir, originalName(file));
+        return hasContent(path) ? { path } : undefined;
+    }
+    const stored = readLivePhoto(dir, file.id);
+    return stored !== undefined &&
+        hasContent(stored.path) &&
+        hasContent(stored.videoPath)
+        ? stored
+        : undefined;
+};
+
 export class ContentCache implements PhotoContent, ThumbnailsAPI {
     private readonly pools: RequestPools;
     private readonly source: ContentSource;
@@ -238,10 +315,17 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
     private readonly getFile: (fileID: number) => EnteFile | undefined;
     private readonly originalsDir: string;
     private readonly thumbnailsDir: string;
-    // fileID -> absolute path of the cached bytes, seeded from the directory
+    // fileID -> absolute path of the cached bytes, and for a live photo's
-    // listing at open() and extended as fetches store new files.
+    // original its video's, seeded from the directory listing at open() and
-    private readonly originals = new Map<number, string>();
+    // extended as fetches store new files.
-    private readonly thumbnails = new Map<number, string>();
+    private readonly originals = new Map<
+        number,
+        { path: string; videoPath?: string }
+    >();
+    private readonly thumbnails = new Map<
+        number,
+        { path: string; videoPath?: string }
+    >();
     private readonly maxOriginalsBytes: number;
     private readonly freeBelowBytes: number;
     private readonly isPinned: (fileID: number) => boolean;
@@ -301,9 +385,9 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
     pathsFor(fileID: number): CachedPaths {
         const out: CachedPaths = {};
         const original = this.originals.get(fileID);
-        if (original !== undefined) out.originalPath = original;
+        if (original !== undefined) out.originalPath = original.path;
         const thumbnail = this.thumbnails.get(fileID);
-        if (thumbnail !== undefined) out.thumbnailPath = thumbnail;
+        if (thumbnail !== undefined) out.thumbnailPath = thumbnail.path;
         return out;
     }
 
@@ -335,7 +419,11 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
             undefined,
             { destination },
         );
-        return { path: result.path, bytes: result.bytes };
+        return {
+            path: result.path,
+            bytes: result.bytes,
+            videoPath: result.videoPath,
+        };
     }
 
     async ensure(args: EnsureOptions): Promise<EnsureResult[]> {
@@ -434,52 +522,72 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
                 ? { status: "skipped", bytes: result.bytes }
                 : { status: "done", bytes: result.bytes },
         );
-        return { path: result.path, bytes: result.bytes };
+        return {
+            path: result.path,
+            bytes: result.bytes,
+            videoPath: result.videoPath,
+        };
     }
 
     // The core: return the cached path if present, else fetch through the pool,
     // store, and return it. `cached` distinguishes a present hit (no network,
     // no download event) from a fresh fetch. A fetched original is stored at
-    // `opts.destination` when given, instead of in `originalsDir`.
+    // `opts.destination` when given, instead of in `originalsDir`. A live
+    // photo's original is present only with its video, and is returned with
+    // it.
     private async acquire(
         fileID: number,
         kind: Kind,
         priority: Priority,
         signal: AbortSignal | undefined,
         opts?: { onByte?: ProgressCallback; destination?: string },
-    ): Promise<{ path: string; bytes: number; cached: boolean }> {
+    ): Promise<{
+        path: string;
+        bytes: number;
+        videoPath?: string;
+        cached: boolean;
+    }> {
         const file = this.getFile(fileID);
         if (!file) throw new Error(`content cache: unknown file ${fileID}`);
+        const isLivePhoto =
+            kind === "original" && file.metadata.fileType === "livePhoto";
 
         const known = kind === "original" ? this.originals : this.thumbnails;
         const cached = known.get(fileID);
         if (cached !== undefined) {
-            const size = fileSize(cached);
+            const size = fileSize(cached.path);
-            if (size !== undefined && size > 0) {
+            if (
+                size !== undefined &&
+                size > 0 &&
+                (!isLivePhoto || hasContent(cached.videoPath))
+            ) {
                 // Returning an original's path is a use: bump its mtime so LRU
                 // order reflects it and survives a restart with no ledger.
                 if (
                     kind === "original" &&
-                    dirname(cached) === this.originalsDir
+                    dirname(cached.path) === this.originalsDir
                 )
-                    await this.touch(cached);
+                    await this.touch(cached.path);
-                return { path: cached, bytes: size, cached: true };
+                return { ...cached, bytes: size, cached: true };
             }
-            // A recorded file that has since gone re-fetches below.
+            // A recorded file that has since gone, or a live photo an earlier
+            // version stored as one ZIP, re-fetches below.
             known.delete(fileID);
         }
 
         // An original a backup already stored counts as present.
         if (kind === "original" && this.downloadDirectory !== undefined) {
-            const backupPath = join(
+            const stored = storedOriginal(
-                this.downloadDirectory,
+                join(this.downloadDirectory, "originals"),
-                "originals",
+                file,
-                originalName(file),
             );
-            const size = fileSize(backupPath);
+            if (stored !== undefined) {
-            if (size !== undefined && size > 0) {
+                this.originals.set(fileID, stored);
-                this.originals.set(fileID, backupPath);
+                return {
-                return { path: backupPath, bytes: size, cached: true };
+                    ...stored,
+                    bytes: fileSize(stored.path) ?? 0,
+                    cached: true,
+                };
             }
         }
 
@@ -508,21 +616,39 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
                         ? this.beginOriginalWrite(fileID)
                         : null;
                 try {
-                    await this.download(file, dest, kind, opts?.onByte);
+                    const stored = await this.download(
-                    await chmod(dest, FILE_MODE);
+                        file,
-                    const size = (await stat(dest)).size;
+                        dest,
-                    if (size === 0) {
+                        kind,
+                        opts?.onByte,
+                    );
+                    for (const path of [stored.path, stored.videoPath]) {
+                        if (path === undefined) continue;
+                        await chmod(path, FILE_MODE);
+                        if ((await stat(path)).size === 0) {
                             throw new Error(
                                 `content cache: ${kind} ${fileID} stored empty`,
                             );
                         }
-                    known.set(fileID, dest);
+                    }
+                    // A backup records its own live photos.
+                    if (
+                        stored.videoPath !== undefined &&
+                        opts?.destination === undefined
+                    ) {
+                        await writeLivePhoto(dir, fileID, {
+                            path: stored.path,
+                            videoPath: stored.videoPath,
+                        });
+                    }
+                    known.set(fileID, stored);
                     // A fresh original may have crossed the limit; make room by
                     // evicting least-recently-used originals. An over-budget
                     // fetch keeps the file it returns, and no overlapping
                     // sibling is evicted. Thumbnails are never bounded.
                     if (write) await this.enforceOriginalsLimit(write);
-                    return { path: dest, bytes: size, cached: false };
+                    const size = (await stat(stored.path)).size;
+                    return { ...stored, bytes: size, cached: false };
                 } finally {
                     if (write) this.inFlightOriginals.delete(write);
                 }
@@ -531,18 +657,24 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
         );
     }
 
+    // Fetch into `destination`, returning where the bytes landed: there, or
+    // for a live photo, its image and video beside it.
     private async download(
         file: EnteFile,
         destination: string,
         kind: Kind,
         onProgress: ProgressCallback | undefined,
-    ): Promise<number> {
+    ): Promise<{ path: string; videoPath?: string }> {
         const args = { file, destination, onProgress };
-        const result =
+        if (kind === "thumbnail") {
-            kind === "original"
+            await this.source.thumbnail(args);
-                ? await this.source.original(args)
+            return { path: destination };
-                : await this.source.thumbnail(args);
+        }
-        return result.bytesWritten;
+        const result = await this.source.original(args);
+        return {
+            path: result.path ?? destination,
+            videoPath: result.videoPath,
+        };
     }
 
     // Best-effort bump of a file's mtime to now; a failed touch must never fail
@@ -553,13 +685,14 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
     }
 
     // Every stored original that lives under `originalsDir` (a backup-directory
-    // hit recorded in the map is excluded), with its size and mtime. Entries
+    // hit recorded in the map is excluded), with its size and mtime; a live
-    // whose file has vanished are dropped from the map. Backups and thumbnails
+    // photo's size includes its video. Entries whose file has vanished are
-    // are never counted.
+    // dropped from the map. Backups and thumbnails are never counted.
     private async measureOriginals(): Promise<{
         entries: {
             fileID: number;
             path: string;
+            videoPath?: string;
             size: number;
             mtimeMs: number;
         }[];
@@ -568,21 +701,28 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
         const entries: {
             fileID: number;
             path: string;
+            videoPath?: string;
             size: number;
             mtimeMs: number;
         }[] = [];
         let used = 0;
-        for (const [fileID, path] of this.originals) {
+        for (const [fileID, { path, videoPath }] of this.originals) {
             if (dirname(path) !== this.originalsDir) continue;
             try {
                 const s = await stat(path);
+                const size =
+                    s.size +
+                    (videoPath === undefined
+                        ? 0
+                        : (await stat(videoPath)).size);
                 entries.push({
                     fileID,
                     path,
-                    size: s.size,
+                    videoPath,
+                    size,
                     mtimeMs: s.mtimeMs,
                 });
-                used += s.size;
+                used += size;
             } catch {
                 this.originals.delete(fileID);
             }
@@ -646,6 +786,18 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
                 for (const e of evictable) {
                     if (remaining <= limit) break;
                     await rm(e.path, { force: true });
+                    // A live photo goes whole: its video and the JSON file
+                    // naming the two go with its image.
+                    if (e.videoPath !== undefined) {
+                        await rm(e.videoPath, { force: true });
+                        await rm(
+                            join(
+                                this.originalsDir,
+                                livePhotoFileName(e.fileID),
+                            ),
+                            { force: true },
+                        );
+                    }
                     this.originals.delete(e.fileID);
                     remaining -= e.size;
                 }
@@ -670,7 +822,10 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
         await chmod(dir, DIR_MODE);
     }
 
-    private async scan(dir: string, into: Map<number, string>): Promise<void> {
+    private async scan(
+        dir: string,
+        into: Map<number, { path: string; videoPath?: string }>,
+    ): Promise<void> {
         // Another process sharing this cache may still be writing its temp
         // files, so only those whose process has exited are removed.
         removeLeftoverTempFiles(dir);
@@ -680,10 +835,17 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
         } catch {
             return;
         }
+        const names = new Set(entries);
         for (const name of entries) {
             const id = fileIDFromName(name);
             const path = join(dir, name);
-            if (id !== undefined && existsSync(path)) into.set(id, path);
+            if (id === undefined || !existsSync(path)) continue;
+            // A live photo's image and video are one entry, as the JSON file
+            // beside them names them.
+            const livePhoto = names.has(livePhotoFileName(id))
+                ? readLivePhoto(dir, id)
+                : undefined;
+            into.set(id, livePhoto ?? { path });
         }
     }
 }

src/library/read.ts

@@ -80,7 +80,8 @@ export class Photo {
     }
 
     // Fetch and cache the full-resolution original, returning its on-disk path
-    // and byte length. Served from the cache (or the backup download directory)
+    // and byte length; for a live photo, its image's, and its video's path as
+    // `videoPath`. Served from the cache (or the backup download directory)
     // when already present, otherwise fetched through the content pool.
     async original(opts?: ContentOptions): Promise<ContentResult> {
         return this.contentOrThrow().original(this.rec.fileID, opts);

src/library/records.ts

@@ -42,6 +42,7 @@ export interface PhotoRecord {
     isArchived: boolean;
     isHidden: boolean;
     // Local cache paths, set once a later phase caches the bytes; unset here.
+    // A live photo's `originalPath` is its image.
     thumbnailPath?: string;
     originalPath?: string;
 }

src/metadata-backup.ts

@@ -128,7 +128,8 @@ export const extractImageMetadata = (
 // Read a file's original bytes through the library's content cache and extract
 // its embedded image metadata. The bytes come from `photo.original()` — the
 // same on-disk cache the rest of the library fills — rather than a fresh
-// per-call download to a throwaway temp file.
+// per-call download to a throwaway temp file. For a live photo, its `path` is
+// the image.
 const extractExif = async (
     photo: Photo,
 ): Promise<Record<string, unknown> | undefined> => {

test/cli/backup.test.ts

@@ -53,6 +53,13 @@ import { Library } from "../../src/library/index.js";
 import type { ContentSource } from "../../src/library/content.js";
 import type { CollectionsPage, FilesPage } from "../../src/client.js";
 import type { Collection, EnteFile } from "../../src/model/types.js";
+import {
+    asLivePhoto,
+    cdnSource,
+    IMAGE,
+    livePhotoZip,
+    VIDEO,
+} from "../live-photo.js";
 
 // `open` and `rename` are wrapped to record, in order, every fsync and rename,
 // so a test can pin the sequence "fsync the temp file, rename, fsync the
@@ -740,6 +747,28 @@ describe("the refresh before a backup", () => {
     });
 });
 
+// Every entry under collections/, one level of directories deep, with each
+// symlink's target.
+const tree = (outDir: string): string[] => {
+    const lines: string[] = [];
+    const list = (dir: string, prefix: string): void => {
+        for (const name of readdirSync(dir).sort()) {
+            const path = join(dir, name);
+            const st = lstatSync(path);
+            if (st.isSymbolicLink()) {
+                lines.push(`${prefix}${name} -> ${readlinkSync(path)}`);
+            } else if (st.isDirectory() && prefix === "") {
+                lines.push(`${name}/`);
+                list(path, `${name}/`);
+            } else {
+                lines.push(`${prefix}${name}`);
+            }
+        }
+    };
+    list(join(outDir, "collections"), "");
+    return lines;
+};
+
 // The album folders under collections/, driven through `runBackup` with a
 // stand-in library whose albums a test changes between runs.
 describe("backup album folders", () => {
@@ -763,28 +792,6 @@ describe("backup album folders", () => {
         },
     });
 
-    // Every entry under collections/, one level of directories deep, with each
-    // symlink's target.
-    const tree = (outDir: string): string[] => {
-        const lines: string[] = [];
-        const list = (dir: string, prefix: string): void => {
-            for (const name of readdirSync(dir).sort()) {
-                const path = join(dir, name);
-                const st = lstatSync(path);
-                if (st.isSymbolicLink()) {
-                    lines.push(`${prefix}${name} -> ${readlinkSync(path)}`);
-                } else if (st.isDirectory() && prefix === "") {
-                    lines.push(`${name}/`);
-                    list(path, `${name}/`);
-                } else {
-                    lines.push(`${prefix}${name}`);
-                }
-            }
-        };
-        list(join(outDir, "collections"), "");
-        return lines;
-    };
-
     const albumID = (outDir: string, jsonName: string): number =>
         JSON.parse(readFileSync(join(outDir, "collections", jsonName), "utf-8"))
             .id;
@@ -1054,3 +1061,190 @@ describe("backup album folders", () => {
         ).toBe(json);
     });
 });
+
+// A live photo, which Ente stores as one ZIP, is backed up as its image and
+// its video, which a photo viewer can open, beside a JSON file naming them,
+// and its album folder links both. These tests download a live photo ZIP
+// through the real download layer (test/live-photo.ts).
+describe("backup of live photos", () => {
+    // An account of one album, Trip (10), holding `files`.
+    class TripClient extends MockClient {
+        constructor(private readonly files: EnteFile[]) {
+            super();
+        }
+        override async collectionsSince(): Promise<CollectionsPage> {
+            return {
+                collections: [collection(10, "Trip")],
+                deleted: [],
+                cursor: 1,
+            };
+        }
+        override async filesSince(): Promise<FilesPage> {
+            return { files: this.files, deleted: [], cursor: 1 };
+        }
+    }
+
+    const open = (files: EnteFile[], bodies: Map<number, Uint8Array>) =>
+        openLibrary(cdnSource(bodies), new TripClient(files));
+
+    // What an earlier version stored for live photo 500: the ZIP under the
+    // image's name, and its link.
+    const earlierZIP = (outDir: string): void => {
+        mkdirSync(join(outDir, "originals"), { recursive: true });
+        mkdirSync(join(outDir, "collections", "Trip"), { recursive: true });
+        writeFileSync(join(outDir, "originals", "500.HEIC"), livePhotoZip());
+        symlinkSync(
+            "../../originals/500.HEIC",
+            join(outDir, "collections", "Trip", "IMG_0500.HEIC"),
+        );
+    };
+
+    const stored = ["500.heic", "500.json", "500.livephoto.json", "500.mov"];
+    const linked = [
+        "Trip/",
+        "Trip/IMG_0500.heic -> ../../originals/500.heic",
+        "Trip/IMG_0500.mov -> ../../originals/500.mov",
+        "Trip.json",
+    ];
+
+    it("stores a live photo as its image and its video and links both", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(500, 10, "IMG_0500.HEIC"),
+        );
+        const lib = await open([live], new Map([[500, body]]));
+        const outDir = join(root, "backup");
+        const originals = join(outDir, "originals");
+
+        const result = await lib.backup({ downloadDirectory: outDir });
+
+        expect(result).toMatchObject({ downloaded: 1, failed: 0 });
+        expect(readdirSync(originals).sort()).toEqual(stored);
+        expect(readFileSync(join(originals, "500.heic"))).toEqual(
+            Buffer.from(IMAGE),
+        );
+        expect(readFileSync(join(originals, "500.mov"))).toEqual(
+            Buffer.from(VIDEO),
+        );
+        expect(tree(outDir)).toEqual(linked);
+
+        // Both parts are there, so the next run fetches nothing.
+        const second = await lib.backup({ downloadDirectory: outDir });
+        expect(second).toMatchObject({ downloaded: 0, skipped: 1, failed: 0 });
+        await lib.close();
+    });
+
+    it("gives both links of each live photo their own names when titles clash", async () => {
+        const a = await asLivePhoto(file(500, 10, "IMG_0001.HEIC"));
+        const b = await asLivePhoto(file(501, 10, "IMG_0001.HEIC"));
+        const lib = await open(
+            [a.file, b.file],
+            new Map([
+                [500, a.body],
+                [501, b.body],
+            ]),
+        );
+        const outDir = join(root, "backup");
+
+        await lib.backup({ downloadDirectory: outDir });
+
+        expect(tree(outDir)).toEqual([
+            "Trip/",
+            "Trip/IMG_0001 (500).heic -> ../../originals/500.heic",
+            "Trip/IMG_0001 (500).mov -> ../../originals/500.mov",
+            "Trip/IMG_0001 (501).heic -> ../../originals/501.heic",
+            "Trip/IMG_0001 (501).mov -> ../../originals/501.mov",
+            "Trip.json",
+        ]);
+        await lib.close();
+    });
+
+    it("replaces the ZIP an earlier version stored, and its link", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(500, 10, "IMG_0500.HEIC"),
+        );
+        const outDir = join(root, "backup");
+        earlierZIP(outDir);
+        const lib = await open([live], new Map([[500, body]]));
+
+        const result = await lib.backup({ downloadDirectory: outDir });
+
+        expect(result).toMatchObject({ downloaded: 1, failed: 0 });
+        expect(readdirSync(join(outDir, "originals")).sort()).toEqual(stored);
+        expect(tree(outDir)).toEqual(linked);
+        await lib.close();
+    });
+
+    it("stores nothing for a live photo that fails its hash, and keeps what was there", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(500, 10, "IMG_0500.HEIC"),
+            livePhotoZip(),
+            "not:the recorded hash",
+        );
+        const outDir = join(root, "backup");
+        earlierZIP(outDir);
+        const lib = await open([live], new Map([[500, body]]));
+
+        const result = await lib.backup({ downloadDirectory: outDir });
+
+        expect(result).toMatchObject({ downloaded: 0, failed: 1 });
+        expect(result.errors.map((e) => e.fileID)).toEqual([500]);
+        expect(Object.keys(readLedger(outDir).files)).toEqual(["500"]);
+        expect(readdirSync(join(outDir, "originals"))).toEqual(["500.HEIC"]);
+        expect(tree(outDir)).toEqual([
+            "Trip/",
+            "Trip/IMG_0500.HEIC -> ../../originals/500.HEIC",
+            "Trip.json",
+        ]);
+        await lib.close();
+    });
+
+    it("copies both parts of a live photo the cache already holds", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(500, 10, "IMG_0500.HEIC"),
+        );
+        const lib = await open([live], new Map([[500, body]]));
+        const cached = await lib.photos.byID({ fileID: 500 })!.original();
+        const outDir = join(root, "backup");
+
+        const result = await lib.backup({ downloadDirectory: outDir });
+
+        expect(result).toMatchObject({ downloaded: 1, failed: 0 });
+        expect(readdirSync(join(outDir, "originals")).sort()).toEqual(stored);
+        expect(readFileSync(join(outDir, "originals", "500.mov"))).toEqual(
+            Buffer.from(VIDEO),
+        );
+        expect(tree(outDir)).toEqual(linked);
+        // The cache keeps its own copy.
+        expect(existsSync(cached.videoPath!)).toBe(true);
+        await lib.close();
+    });
+
+    it("serves a live photo the backup stored to a library reading the backup", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(500, 10, "IMG_0500.HEIC"),
+        );
+        const lib = await open([live], new Map([[500, body]]));
+        const outDir = join(root, "backup");
+        await lib.backup({ downloadDirectory: outDir });
+        await lib.close();
+
+        // Another cache over the same backup, whose server has nothing.
+        const reader = await Library.open({
+            client: new TripClient([live]),
+            cacheDirectory: join(root, "other-cache"),
+            downloadDirectory: outDir,
+            contentSource: cdnSource(new Map()),
+            refreshIntervalSeconds: 3600,
+            precacheThumbnails: false,
+            precacheOriginals: false,
+        });
+        const read = await reader.photos.byID({ fileID: 500 })!.original();
+
+        expect(read).toEqual({
+            path: join(outDir, "originals", "500.heic"),
+            videoPath: join(outDir, "originals", "500.mov"),
+            bytes: IMAGE.length,
+        });
+        await reader.close();
+    });
+});

test/cli/commands.test.ts

@@ -12,6 +12,7 @@
 
 import {
     existsSync,
+    mkdirSync,
     mkdtempSync,
     readdirSync,
     readFileSync,
@@ -22,6 +23,7 @@ import {
 import { join } from "node:path";
 import { tmpdir } from "node:os";
 import { PassThrough } from "node:stream";
+import * as jpegJs from "jpeg-js";
 import {
     describe,
     it,
@@ -54,6 +56,14 @@ import type { ContentSource } from "../../src/library/content.js";
 import type { Collection, EnteFile } from "../../src/model/types.js";
 import { init, toBase64 } from "../../src/crypto/index.js";
 import { defaultCacheDirectory } from "../../src/library/index.js";
+import {
+    asLivePhoto,
+    cdnSource,
+    IMAGE,
+    livePhotoHash,
+    livePhotoZip,
+    VIDEO,
+} from "../live-photo.js";
 
 const USER_ID = 42;
 
@@ -531,6 +541,120 @@ describe("get and get-thumb", () => {
     });
 });
 
+// A live photo, which Ente stores as one ZIP, is written as its image and its
+// video, which a photo viewer can open. The account here is Vacation holding
+// one live photo, 300, downloaded through the real download layer
+// (test/live-photo.ts).
+describe("a live photo", () => {
+    const livePhotoClient = async (image = IMAGE): Promise<Client> => {
+        const { file: live, body } = await asLivePhoto(
+            file(300, 1, "IMG_0300.HEIC"),
+            livePhotoZip({ "image.heic": image, "video.mov": VIDEO }),
+            livePhotoHash(image, VIDEO),
+        );
+        const fake = {
+            whoami: () => ({ email: "cli@example.com", userID: USER_ID }),
+            collectionsSince: async () => ({
+                collections: [collection(1, "Vacation")],
+                deleted: [],
+                cursor: 1,
+            }),
+            filesSince: async () => ({ files: [live], deleted: [], cursor: 1 }),
+            contentSource: () => cdnSource(new Map([[300, body]])),
+            // The ML data request of `backup-metadata`: no file has any.
+            getApiClient: () => ({ postJSON: async () => ({ data: [] }) }),
+        };
+        return fake as unknown as Client;
+    };
+
+    it("get writes its image and video, named after the title with their own extensions", async () => {
+        const ctx = context(await livePhotoClient());
+        const dir = join(root, "cwd");
+        mkdirSync(dir);
+        const previous = process.cwd();
+        process.chdir(dir);
+        try {
+            expect(await getCommand(ctx, "300", {})).toBe(0);
+        } finally {
+            process.chdir(previous);
+        }
+
+        expect(readdirSync(dir).sort()).toEqual([
+            "IMG_0300.heic",
+            "IMG_0300.mov",
+        ]);
+        expect(readFileSync(join(dir, "IMG_0300.heic"))).toEqual(
+            Buffer.from(IMAGE),
+        );
+        expect(readFileSync(join(dir, "IMG_0300.mov"))).toEqual(
+            Buffer.from(VIDEO),
+        );
+        expect(stderr.text).toBe(
+            `${IMAGE.length} bytes -> IMG_0300.heic\n` +
+                `${VIDEO.length} bytes -> IMG_0300.mov\n`,
+        );
+    });
+
+    it("get --out writes the image there and the video beside it", async () => {
+        const out = join(root, "photo.jpg");
+        const video = join(root, "photo.mov");
+
+        expect(
+            await getCommand(context(await livePhotoClient()), "300", { out }),
+        ).toBe(0);
+
+        expect(readFileSync(out)).toEqual(Buffer.from(IMAGE));
+        expect(readFileSync(video)).toEqual(Buffer.from(VIDEO));
+        expect(stderr.text).toBe(
+            `${IMAGE.length} bytes -> ${out}\n${VIDEO.length} bytes -> ${video}\n`,
+        );
+    });
+
+    it("get exits 1 and writes nothing when --out has the video's extension", async () => {
+        const out = join(root, "photo.MOV");
+
+        expect(
+            await getCommand(context(await livePhotoClient()), "300", { out }),
+        ).toBe(1);
+
+        expect(existsSync(out)).toBe(false);
+        expect(existsSync(join(root, "photo.mov"))).toBe(false);
+        expect(stderr.text).toBe(
+            `File 300 is a live photo, and its video would also be written to ${out}\n`,
+        );
+    });
+
+    it("backup-metadata --exif reads its image", async () => {
+        // A 4x4 JPEG, whose size can only come from reading the image; the
+        // ZIP and the video are not JPEGs.
+        const jpeg = jpegJs.encode(
+            { data: new Uint8Array(4 * 4 * 4), width: 4, height: 4 },
+            50,
+        ).data;
+        const dir = join(root, "dump");
+
+        expect(
+            await backupMetadataCommand(
+                context(await livePhotoClient(new Uint8Array(jpeg))),
+                dir,
+                { exif: true },
+            ),
+        ).toBe(0);
+
+        const record = JSON.parse(
+            readFileSync(
+                join(dir, "collections", "1-Vacation", "300.json"),
+                "utf-8",
+            ),
+        );
+        expect(record.imageMetadata).toMatchObject({
+            format: "jpeg",
+            width: 4,
+            height: 4,
+        });
+    });
+});
+
 describe("backup", () => {
     it("exits 0 and prints a summary when every file is saved", async () => {
         const dir = join(root, "backup");

test/download/download.test.ts

@@ -55,6 +55,7 @@ import {
     readFileSync,
     rmSync,
     mkdtempSync,
+    statSync,
     writeFileSync,
 } from "node:fs";
 import { dirname, join } from "node:path";
@@ -81,6 +82,7 @@ import {
     writeAtomic,
 } from "../../src/download/index.js";
 import type { EnteFile, FileMetadata } from "../../src/model/types.js";
+import { IMAGE, livePhotoHash, livePhotoZip, VIDEO } from "../live-photo.js";
 
 // ---------------------------------------------------------------------------
 // Test helpers
@@ -106,6 +108,8 @@ import type { EnteFile, FileMetadata } from "../../src/model/types.js";
 const renameHook = vi.hoisted(() => ({
     calls: [] as { from: string; to: string; sourceExisted: boolean }[],
     failWith: null as Error | null,
+    // When set, only a rename to this path fails.
+    failTo: null as string | null,
 }));
 
 /**
@@ -181,7 +185,10 @@ vi.mock("node:fs/promises", async (importOriginal) => {
                 sourceExisted: sourceExists(from),
             });
             durabilityHook.events.push(`rename:${to}`);
-            if (renameHook.failWith !== null) {
+            if (
+                renameHook.failWith !== null &&
+                (renameHook.failTo === null || renameHook.failTo === to)
+            ) {
                 throw renameHook.failWith;
             }
             await actual.rename(from, to);
@@ -216,6 +223,7 @@ beforeEach(() => {
     hashHook.lengths.length = 0;
     renameHook.calls.length = 0;
     renameHook.failWith = null;
+    renameHook.failTo = null;
     durabilityHook.events.length = 0;
     writeHook.writes.length = 0;
 });
@@ -1642,15 +1650,15 @@ describe.each(entryPoints)("$name progress", ({ name, download }) => {
     });
 });
 
-describe("downloadFile content hash", () => {
+// Node's own BLAKE2b-512 is the reference, so the tests below do not depend on
-    // Node's own BLAKE2b-512 is the reference, so these tests do not depend
+// the code under test to compute what they expect.
-    // on the code under test to compute what they expect.
+const blake2b = (bytes: Uint8Array): string =>
-    const blake2b = (bytes: Uint8Array): string =>
     createHash("blake2b512").update(bytes).digest("base64");
 
-    // Serve `plaintext` encrypted as file 999 with the given metadata. Four
+// Serve `plaintext` encrypted as file 999 with the given metadata, to be
-    // responses are scripted so a retried mismatch would show in `requests`.
+// written to `f.bin` in a fresh directory. Four responses are scripted so a
-    const setup = (plaintext: Uint8Array, metadata: Partial<FileMetadata>) => {
+// retried failure would show in `requests`.
+const setup = (plaintext: Uint8Array, metadata: Partial<FileMetadata>) => {
     const key = sodium.crypto_secretstream_xchacha20poly1305_keygen();
     const { header, ciphertext } = encryptFileBody(plaintext, key);
     const file = buildMockEnteFile(key, header, header);
@@ -1662,18 +1670,15 @@ describe("downloadFile content hash", () => {
     const outPath = join(dir, "f.bin");
     return {
         run: () => downloadFile(api, file, outPath),
+        api,
+        file,
         dir,
         outPath,
         requests,
     };
-    };
+};
-
-    const livePhotoZip = zipSync({
-        "image.heic": patternBytes(500, 81),
-        "video.mov": patternBytes(900, 82),
-    });
-    const livePhotoHash = `${blake2b(patternBytes(500, 81))}:${blake2b(patternBytes(900, 82))}`;
 
+describe("downloadFile content hash", () => {
     it("stores a file whose hash matches", async () => {
         const plaintext = patternBytes(700, 80);
         const t = setup(plaintext, { hash: blake2b(plaintext) });
@@ -1706,17 +1711,18 @@ describe("downloadFile content hash", () => {
     });
 
     it("stores a live photo whose image and video hashes match", async () => {
-        const t = setup(livePhotoZip, {
+        const t = setup(livePhotoZip(), {
             fileType: "livePhoto",
-            hash: livePhotoHash,
+            hash: livePhotoHash(),
         });
 
         await t.run();
 
-        expectSameBytes(readFileSync(t.outPath), livePhotoZip);
+        expect(readFileSync(join(t.dir, "f.heic"))).toEqual(Buffer.from(IMAGE));
+        expect(readFileSync(join(t.dir, "f.mov"))).toEqual(Buffer.from(VIDEO));
     });
 
-    it("hashes a large live photo entry as it decompresses, never whole", async () => {
+    it("writes a large live photo entry as it decompresses, never whole", async () => {
         // 64 MiB of zeros deflates to a few kilobytes, the shape of a ZIP
         // that would exhaust memory if expanded whole.
         const image = new Uint8Array(64 * 1024 * 1024);
@@ -1724,40 +1730,45 @@ describe("downloadFile content hash", () => {
         const zip = zipSync({ "image.heic": image, "video.mov": video });
         const t = setup(zip, {
             fileType: "livePhoto",
-            hash: `${blake2b(image)}:${blake2b(video)}`,
+            hash: livePhotoHash(image, video),
         });
 
         await t.run();
 
-        expectSameBytes(readFileSync(t.outPath), zip);
+        expect(statSync(join(t.dir, "f.heic")).size).toBe(image.length);
+        expectSameBytes(readFileSync(join(t.dir, "f.mov")), video);
         const hashed = hashHook.lengths.reduce((a, b) => a + b, 0);
         expect(hashed).toBe(image.length + video.length);
         expect(Math.max(...hashHook.lengths)).toBeLessThanOrEqual(
             2 * STREAM_CHUNK_SIZE,
         );
+        const written = writeHook.writes.filter((w) => w.path.endsWith(".tmp"));
+        expect(Math.max(...written.map((w) => w.length))).toBeLessThanOrEqual(
+            2 * STREAM_CHUNK_SIZE,
+        );
     });
 
-    it("rejects a live photo whose hash does not match", async () => {
+    it("rejects a live photo whose hash does not match, keeping what was there", async () => {
         // The whole ZIP's hash is not the recorded one: each part is hashed.
-        const t = setup(livePhotoZip, {
+        const zip = livePhotoZip();
-            fileType: "livePhoto",
+        const t = setup(zip, { fileType: "livePhoto", hash: blake2b(zip) });
-            hash: blake2b(livePhotoZip),
+        writeFileSync(t.outPath, "an earlier download");
-        });
 
         await expect(t.run()).rejects.toThrow(
             /file 999: content hash .* does not match/,
         );
 
-        expect(readdirSync(t.dir)).toEqual([]);
+        expect(readdirSync(t.dir)).toEqual(["f.bin"]);
+        expect(readFileSync(t.outPath, "utf-8")).toBe("an earlier download");
     });
 
     it("rejects a live photo that is not a readable ZIP and does not retry", async () => {
         // Bytes 8-9 of a ZIP entry's local header name its compression
         // method; 99 is one no reader knows, so the entry cannot be read.
-        const zip = livePhotoZip.slice();
+        const zip = livePhotoZip();
         zip[8] = 99;
         zip[9] = 0;
-        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash });
+        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash() });
 
         await expect(t.run()).rejects.toThrow(
             /file 999: live photo is not a readable ZIP/,
@@ -1768,8 +1779,8 @@ describe("downloadFile content hash", () => {
     });
 
     it("rejects a live photo ZIP with no image entry", async () => {
-        const zip = zipSync({ "video.mov": patternBytes(900, 82) });
+        const zip = livePhotoZip({ "video.mov": VIDEO });
-        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash });
+        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash() });
 
         await expect(t.run()).rejects.toThrow(
             /file 999: live photo ZIP does not hold both an image and a video/,
@@ -1779,8 +1790,8 @@ describe("downloadFile content hash", () => {
     });
 
     it("rejects a live photo ZIP with no video entry", async () => {
-        const zip = zipSync({ "image.heic": patternBytes(500, 81) });
+        const zip = livePhotoZip({ "image.heic": IMAGE });
-        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash });
+        const t = setup(zip, { fileType: "livePhoto", hash: livePhotoHash() });
 
         await expect(t.run()).rejects.toThrow(
             /file 999: live photo ZIP does not hold both an image and a video/,
@@ -1789,3 +1800,99 @@ describe("downloadFile content hash", () => {
         expect(readdirSync(t.dir)).toEqual([]);
     });
 });
+
+// ---------------------------------------------------------------------------
+// Live photos
+//
+// A live photo arrives as a ZIP of its image and its video. It is written as
+// those two files, which a photo viewer can open, each named after the
+// destination with its own extension from the ZIP, the way Ente's clients name
+// them when they save one.
+// ---------------------------------------------------------------------------
+
+describe("downloadFile live photos", () => {
+    const livePhoto = { fileType: "livePhoto", hash: livePhotoHash() } as const;
+
+    it("names the image and the video after the title when no outPath is given", async () => {
+        const t = setup(livePhotoZip(), {
+            ...livePhoto,
+            title: "IMG_1234.HEIC",
+        });
+
+        const result = await inDirectory(t.dir, () =>
+            downloadFile(t.api, t.file),
+        );
+
+        // `bytesWritten` is the length of the decrypted ZIP.
+        expect(result).toEqual({
+            path: "IMG_1234.heic",
+            videoPath: "IMG_1234.mov",
+            bytesWritten: livePhotoZip().length,
+        });
+        expect(readdirSync(t.dir).sort()).toEqual([
+            "IMG_1234.heic",
+            "IMG_1234.mov",
+        ]);
+    });
+
+    it("gives each part its own extension from the ZIP, letters and digits only", async () => {
+        const zip = livePhotoZip({ "image.JPG": IMAGE, "video.m-4v": VIDEO });
+        const t = setup(zip, livePhoto);
+
+        const result = await downloadFile(t.api, t.file, join(t.dir, "f.HEIC"));
+
+        expect(result.path).toBe(join(t.dir, "f.JPG"));
+        expect(result.videoPath).toBe(join(t.dir, "f.bin"));
+        expect(readdirSync(t.dir).sort()).toEqual(["f.JPG", "f.bin"]);
+    });
+
+    it("replaces what was at the destination, such as an earlier ZIP of the two", async () => {
+        const t = setup(livePhotoZip(), livePhoto);
+        writeFileSync(t.outPath, livePhotoZip());
+
+        await t.run();
+
+        expect(readdirSync(t.dir).sort()).toEqual(["f.heic", "f.mov"]);
+    });
+
+    it("renames the image and then the video into place, each from its own temp file", async () => {
+        const t = setup(livePhotoZip(), livePhoto);
+
+        await t.run();
+
+        expect(
+            renameHook.calls.map((c) => [
+                dirname(c.from),
+                c.to,
+                c.sourceExisted,
+            ]),
+        ).toEqual([
+            [t.dir, join(t.dir, "f.heic"), true],
+            [t.dir, join(t.dir, "f.mov"), true],
+        ]);
+    });
+
+    it("stores neither part when the video cannot be renamed into place", async () => {
+        const t = setup(livePhotoZip(), livePhoto);
+        renameHook.failWith = new Error("simulated rename failure");
+        renameHook.failTo = join(t.dir, "f.mov");
+
+        await expect(t.run()).rejects.toThrow("simulated rename failure");
+
+        expect(readdirSync(t.dir)).toEqual([]);
+    });
+
+    it("refuses an image and a video with the same extension, storing nothing", async () => {
+        // On a file system that ignores case, the two would be one file.
+        const zip = livePhotoZip({ "image.mov": IMAGE, "video.MOV": VIDEO });
+        const t = setup(zip, livePhoto);
+        writeFileSync(t.outPath, "an earlier download");
+
+        await expect(t.run()).rejects.toThrow(
+            /file 999: live photo's image and video have the same extension/,
+        );
+
+        expect(readdirSync(t.dir)).toEqual(["f.bin"]);
+        expect(t.requests()).toBe(1);
+    });
+});

test/library/content.test.ts

@@ -31,6 +31,8 @@ import {
     existsSync,
     writeFileSync,
     mkdirSync,
+    readdirSync,
+    readFileSync,
     statSync,
 } from "node:fs";
 import { spawnSync } from "node:child_process";
@@ -44,6 +46,13 @@ import {
 } from "../../src/library/content.js";
 import { RequestPools } from "../../src/library/pools.js";
 import type { EnteFile } from "../../src/model/types.js";
+import {
+    asLivePhoto,
+    cdnSource,
+    IMAGE,
+    livePhotoZip,
+    VIDEO,
+} from "../live-photo.js";
 
 const file = (id: number, title = `file-${id}.jpg`): EnteFile => ({
     id,
@@ -458,3 +467,125 @@ describe("ContentCache.ensureThumbnails", () => {
         expect(results[1]?.error).toMatch(/unknown file/i);
     });
 });
+
+// A live photo's original is two files, its image and its video, which a
+// photo viewer can open, and a JSON file naming them: the two are named with
+// the extensions from inside the ZIP, so the names alone do not say which is
+// which. These tests download a live photo ZIP through the real download
+// layer (test/live-photo.ts).
+describe("ContentCache live photos", () => {
+    const originals = (): string => join(cacheDir, "originals");
+
+    // A cache over the stand-in server, which holds `bodies` by file ID.
+    const cacheOf = (
+        files: EnteFile[],
+        bodies: Map<number, Uint8Array>,
+    ): ContentCache => buildCache({ files, source: cdnSource(bodies) }).cache;
+
+    it("stores a live photo as its image and its video and a JSON file naming them", async () => {
+        const { file: live, body } = await asLivePhoto(file(5, "IMG_5.HEIC"));
+        const cache = cacheOf([live], new Map([[5, body]]));
+        await cache.open();
+
+        const result = await cache.original(5);
+
+        expect(result).toEqual({
+            path: join(originals(), "5.heic"),
+            videoPath: join(originals(), "5.mov"),
+            bytes: IMAGE.length,
+        });
+        expect(readFileSync(result.path)).toEqual(Buffer.from(IMAGE));
+        expect(readFileSync(result.videoPath!)).toEqual(Buffer.from(VIDEO));
+        expect(statSync(result.videoPath!).mode & 0o777).toBe(0o600);
+        expect(
+            JSON.parse(
+                readFileSync(join(originals(), "5.livephoto.json"), "utf-8"),
+            ),
+        ).toEqual({ image: "5.heic", video: "5.mov" });
+        expect(cache.pathsFor(5)).toEqual({ originalPath: result.path });
+    });
+
+    it("serves a stored live photo from disk after the cache is opened again", async () => {
+        const { file: live, body } = await asLivePhoto(file(5, "IMG_5.HEIC"));
+        const first = cacheOf([live], new Map([[5, body]]));
+        await first.open();
+        const stored = await first.original(5);
+
+        // This server has nothing, so a fetch would fail.
+        const second = cacheOf([live], new Map());
+        await second.open();
+        const events: string[] = [];
+        const served = await second.original(5, {
+            onProgress: (e) => events.push(e.status),
+        });
+
+        expect(served).toEqual(stored);
+        expect(events).toEqual(["skipped"]);
+    });
+
+    it("replaces a live photo an earlier version stored as a ZIP under the image's name", async () => {
+        const { file: live, body } = await asLivePhoto(file(5, "IMG_5.HEIC"));
+        mkdirSync(originals(), { recursive: true });
+        writeFileSync(join(originals(), "5.HEIC"), livePhotoZip());
+        const cache = cacheOf([live], new Map([[5, body]]));
+        await cache.open();
+
+        const result = await cache.original(5);
+
+        expect(result.videoPath).toBe(join(originals(), "5.mov"));
+        expect(readdirSync(originals()).sort()).toEqual([
+            "5.heic",
+            "5.livephoto.json",
+            "5.mov",
+        ]);
+    });
+
+    it("evicts a live photo's image, video and JSON file together", async () => {
+        const a = await asLivePhoto(file(5, "a.HEIC"));
+        const b = await asLivePhoto(file(6, "b.HEIC"));
+        const size = IMAGE.length + VIDEO.length;
+        const cache = new ContentCache({
+            pools: new RequestPools(),
+            source: cdnSource(
+                new Map([
+                    [5, a.body],
+                    [6, b.body],
+                ]),
+            ),
+            cacheDirectory: cacheDir,
+            getFile: (id) => [a.file, b.file].find((f) => f.id === id),
+            // Room for one live photo, on a disk with plenty free.
+            cacheOriginalsMaxBytes: size,
+            freeBelowBytes: 0,
+            statfs: async () => ({ bsize: 1, bavail: 1e12 }),
+        });
+        await cache.open();
+
+        await cache.original(5);
+        await cache.original(6);
+
+        expect(readdirSync(originals()).sort()).toEqual([
+            "6.heic",
+            "6.livephoto.json",
+            "6.mov",
+        ]);
+        expect(cache.originalsStatus().usedBytes).toBe(size);
+    });
+
+    it("stores nothing when a live photo does not match its recorded hash", async () => {
+        const { file: live, body } = await asLivePhoto(
+            file(5, "IMG_5.HEIC"),
+            livePhotoZip(),
+            "not:the recorded hash",
+        );
+        const cache = cacheOf([live], new Map([[5, body]]));
+        await cache.open();
+
+        await expect(cache.original(5)).rejects.toThrow(
+            /file 5: content hash .* does not match/,
+        );
+
+        expect(readdirSync(originals())).toEqual([]);
+        expect(cache.pathsFor(5)).toEqual({});
+    });
+});

test/live-photo.ts

@@ -0,0 +1,77 @@
+/**
+ * Live photo fixtures for the download, content cache, backup and CLI tests.
+ *
+ * Ente stores a live photo as one ZIP holding its image and its video, which
+ * Ente's clients name `image.<ext>` and `video.<ext>`. The ZIP is built here
+ * with fflate from small fixed bytes and encrypted the way the server serves a
+ * file under 4 MiB, as one secretstream chunk. `cdnSource` serves it to the
+ * real download layer, so a test checks what quak stores for a real one.
+ */
+
+import { createHash } from "node:crypto";
+import { zipSync } from "fflate";
+
+import { ApiClient } from "../src/api/client.js";
+import { encryptBlob, init, toBase64 } from "../src/crypto/index.js";
+import {
+    makeDownloadContentSource,
+    type ContentSource,
+} from "../src/library/content.js";
+import type { EnteFile } from "../src/model/types.js";
+
+export const IMAGE = new TextEncoder().encode("the still image");
+export const VIDEO = new TextEncoder().encode("the few seconds of video");
+
+// A live photo's ZIP; by default the entries an iPhone's live photo gets.
+export const livePhotoZip = (
+    entries: Record<string, Uint8Array> = {
+        "image.heic": IMAGE,
+        "video.mov": VIDEO,
+    },
+): Uint8Array => zipSync(entries);
+
+const blake2b = (bytes: Uint8Array): string =>
+    createHash("blake2b512").update(bytes).digest("base64");
+
+// The hash Ente's clients record for a live photo: the unkeyed BLAKE2b-512 of
+// the image and of the video, each in standard base64, joined by a colon.
+export const livePhotoHash = (image = IMAGE, video = VIDEO): string =>
+    `${blake2b(image)}:${blake2b(video)}`;
+
+// `file` as a live photo whose original is `zip` and whose recorded hash is
+// `hash`, and `body`, what the server serves for it: `zip` encrypted under the
+// file's key and header.
+export const asLivePhoto = async (
+    file: EnteFile,
+    zip = livePhotoZip(),
+    hash = livePhotoHash(),
+): Promise<{ file: EnteFile; body: Uint8Array }> => {
+    await init();
+    const key = new Uint8Array(32).fill(file.id & 0xff);
+    const { header, ciphertext } = encryptBlob(zip, key);
+    return {
+        file: {
+            ...file,
+            key,
+            metadata: { ...file.metadata, fileType: "livePhoto", hash },
+            file: { decryptionHeader: toBase64(header) },
+        },
+        body: ciphertext,
+    };
+};
+
+// A content source that downloads through the real download layer from a
+// stand-in server, which serves `bodies` by file ID and a 404 for any other.
+export const cdnSource = (bodies: Map<number, Uint8Array>): ContentSource =>
+    makeDownloadContentSource(
+        new ApiClient({
+            fetch: (async (url: string | URL) => {
+                const fileID = new URL(String(url)).searchParams.get("fileID");
+                const body = bodies.get(Number(fileID));
+                return body === undefined
+                    ? new Response("not found", { status: 404 })
+                    : new Response(body);
+            }) as typeof globalThis.fetch,
+            retry: { attempts: 1 },
+        }),
+    );