quak logout ends the session on the server (closes #108)

logout now calls POST /users/logout with the saved token through the new
Client.logoutOnServer(), then deletes session.json even when that call
fails; in that case it says the server session could not be ended and
exits 1. It prints the account's cache directory and says it still holds
decrypted data. The default cache path moves into
defaultCacheDirectory(), shared with Library.open, so both name the same
directory.

Model: opus-5-5

README.md

@@ -318,6 +318,7 @@ Endpoints used:
   encrypted token plus key attributes.
 - `POST /users/ott` and `POST /users/verify-email`: email OTP fallback path.
 - `POST /users/two-factor/verify`: TOTP second factor.
+- `POST /users/logout`: end the calling token's session (`quak logout`).
 - `GET /collections/v2?sinceTime=<usec>`: list collections changed since
   microsecond timestamp; pass 0 for a full enumeration.
 - `GET /collections/v2/diff?collectionID=<id>&sinceTime=<usec>`: list files in a
@@ -432,7 +433,9 @@ whatever else fits their use case. `Client.fromJSON(snapshot)` restores a
 working client from that snapshot without re-authenticating; it checks every
 field and each key's length first, and throws an error naming the bad field.
 `client.logout()` clears the token and zeroes the key buffers in place; every
-later call on that client throws.
+later call on that client throws. It does not contact the server, so the token
+stays valid there and in any saved snapshot; `await client.logoutOnServer()`
+first ends the session on the server (`POST /users/logout`).
 
 The CLI stores the snapshot at the platform-appropriate data directory via
 `env-paths`: `~/Library/Application Support/quak/session.json` on macOS,
@@ -442,13 +445,21 @@ you would treat the password itself. A missing file is reported as "not logged
 in"; a file that exists but is corrupt is reported as such, naming the bad
 field. Both exit with status 1.
 
+`quak logout` ends the session on the server, so the token in `session.json`
+stops working even in a copy of the file, and then deletes the file. If the
+server call fails (or the file is corrupt), the file is still deleted, the
+command says the server session could not be ended, and it exits with status 1.
+It does not delete the cache: it prints the account's cache directory and says
+it still holds decrypted data (file keys in `metadata.json`, cached originals
+and thumbnails), for the user to delete if they want it gone.
+
 ### CLI surface
 
 ```
 quak [--cache-dir <path>] <command>             global: local metadata/content cache location
 quak login                                      interactive or QUAK_EMAIL/QUAK_PASSWORD
 quak whoami                                     print logged-in account as JSON
-quak logout                                     delete saved session
+quak logout                                     end the session, delete it
 quak collections [--json]                       list all collections
 quak files --collection <id> [--json]           list files in a collection
 quak get <fileID> [--out path] [--collection]   download and decrypt a file

TODO.md

@@ -18,6 +18,13 @@ Tag v1.0.0.
 
 # Completed Steps
 
+- 2026-09-23: `quak logout` ends the session on the server (issue 108). It calls
+  `POST /users/logout` through the new `Client.logoutOnServer()`, then deletes
+  `session.json` even when that call fails, says so and exits 1. It prints the
+  account's cache directory and says it still holds decrypted data. The default
+  cache path is now `defaultCacheDirectory()` in the library, shared with
+  `Library.open`.
+
 - 2026-09-23: `backup-metadata` no longer stops on one failed ML data request
   (issue 101). Each request of up to 200 files is tried on its own; a failed one
   is logged, its files are written with the reason in `mlDataError`, and the

bin/quak.ts

@@ -73,7 +73,7 @@ program
 
 program
     .command("logout")
-    .description("Delete the saved session")
+    .description("End the session on the server and delete the saved session")
     .action(() => run(logoutCommand(context())));
 
 program

src/cli-commands.ts

@@ -17,7 +17,11 @@ import {
 import { join } from "node:path";
 import { Client, type ClientSnapshot } from "./client.js";
 import { init } from "./crypto/index.js";
-import { Library, type LibraryClient } from "./library/index.js";
+import {
+    defaultCacheDirectory,
+    Library,
+    type LibraryClient,
+} from "./library/index.js";
 import {
     fileListRow,
     fileListLine,
@@ -146,14 +150,43 @@ export const whoamiCommand = async (ctx: CliContext): Promise<number> => {
     return 0;
 };
 
+// Ends the session on the server, then deletes the session file even when that
+// failed, and exits 1 if it did. The cache is left in place; the user is told
+// where it is.
 export const logoutCommand = async (ctx: CliContext): Promise<number> => {
-    if (existsSync(sessionPath(ctx))) {
-        unlinkSync(sessionPath(ctx));
-        ctx.stderr.write("Session deleted.\n");
-    } else {
+    const path = sessionPath(ctx);
+    if (!existsSync(path)) {
         ctx.stderr.write("No session found.\n");
+        return 0;
     }
-    return 0;
+    await init();
+    let cacheDir = ctx.cacheDir;
+    let failure: string | undefined;
+    try {
+        const client = ctx.loadSession(path);
+        if (client) {
+            cacheDir ??= defaultCacheDirectory(client.whoami().userID);
+            await client.logoutOnServer();
+            client.logout();
+        }
+    } catch (err) {
+        failure = err instanceof Error ? err.message : String(err);
+    }
+    unlinkSync(path);
+    if (failure === undefined) {
+        ctx.stderr.write("Session ended on the server.\n");
+    } else {
+        ctx.stderr.write(
+            `Could not end the session on the server: ${failure}\n`,
+        );
+    }
+    ctx.stderr.write("Session deleted.\n");
+    if (cacheDir !== undefined) {
+        ctx.stderr.write(
+            `Cache directory ${cacheDir} still holds decrypted data; delete it to remove that data.\n`,
+        );
+    }
+    return failure === undefined ? 0 : 1;
 };
 
 export const collectionsCommand = async (

src/client.ts

@@ -217,6 +217,14 @@ export class Client {
         };
     }
 
+    // Ends this client's session on the server (`POST /users/logout`), so the
+    // token stops working everywhere, including in any saved copy of it. This
+    // client is left as it was; call `logout()` to clear it.
+    async logoutOnServer(): Promise<void> {
+        this.assertLoggedIn();
+        await this.api.postJSON("/users/logout", {});
+    }
+
     // Zeroes the key buffers in place, so any copy of the reference held
     // elsewhere is wiped too. Every method checks `assertLoggedIn` before
     // touching the keys, so nothing decrypts with the zeroed keys.

src/library/index.ts

@@ -97,6 +97,11 @@ export {
 
 export const DEFAULT_REFRESH_INTERVAL_SECONDS = 3;
 
+// The account's cache directory when `cacheDirectory` is not given: the
+// env-paths cache directory plus the user id, so each account has its own.
+export const defaultCacheDirectory = (userID: number): string =>
+    join(envPaths("quak", { suffix: "" }).cache, String(userID));
+
 // Project a metadata store into by-id records, filling each record's cache
 // paths from the content cache when one is given. Shared by the live read
 // projection and the precache's initial seeding at open().
@@ -343,8 +348,7 @@ export class Library {
     static async open(opts: LibraryOptions): Promise<Library> {
         const { userID } = opts.client.whoami();
         const cacheDirectory =
-            opts.cacheDirectory ??
-            join(envPaths("quak", { suffix: "" }).cache, String(userID));
+            opts.cacheDirectory ?? defaultCacheDirectory(userID);
         const store = await MetadataStore.load(
             join(cacheDirectory, "metadata.json"),
         );

test/cli/commands.test.ts

@@ -38,7 +38,8 @@ import { loadSession } from "../../src/cli-session.js";
 import type { Client, ClientSnapshot } from "../../src/client.js";
 import type { ContentSource } from "../../src/library/content.js";
 import type { Collection, EnteFile } from "../../src/model/types.js";
-import { init } from "../../src/crypto/index.js";
+import { init, toBase64 } from "../../src/crypto/index.js";
+import { defaultCacheDirectory } from "../../src/library/index.js";
 
 const USER_ID = 42;
 
@@ -176,19 +177,6 @@ describe("session file", () => {
         expect(JSON.parse(readFileSync(path, "utf-8"))).toEqual(snapshot);
     });
 
-    it("is removed by logout", async () => {
-        const ctx = context();
-        saveSession(ctx.sessionDir, snapshot);
-        expect(await logoutCommand(ctx)).toBe(0);
-        expect(existsSync(join(ctx.sessionDir, "session.json"))).toBe(false);
-        expect(stderr.text).toBe("Session deleted.\n");
-    });
-
-    it("logout without a session says so and exits 0", async () => {
-        expect(await logoutCommand(context())).toBe(0);
-        expect(stderr.text).toBe("No session found.\n");
-    });
-
     it("a missing session exits 1 with 'Not logged in'", async () => {
         const ctx = { ...context(), loadSession };
         expect(await whoamiCommand(ctx)).toBe(1);
@@ -211,6 +199,85 @@ describe("session file", () => {
     });
 });
 
+// These use a real client read from the session file, over a fake API that
+// records each request and answers with `status`.
+describe("logout", () => {
+    const snapshot: ClientSnapshot = {
+        email: "cli@example.com",
+        userID: USER_ID,
+        token: "saved-token",
+        masterKey: toBase64(new Uint8Array(32)),
+        secretKey: toBase64(new Uint8Array(32)),
+        publicKey: toBase64(new Uint8Array(32)),
+    };
+
+    const requests: Request[] = [];
+
+    const logoutContext = (status: number): CliContext => ({
+        ...context(),
+        loadSession: (path) =>
+            loadSession(path, {
+                fetch: async (url, init) => {
+                    requests.push(new Request(url, init));
+                    return new Response(JSON.stringify({}), {
+                        status,
+                        headers: { "content-type": "application/json" },
+                    });
+                },
+            }),
+    });
+
+    beforeEach(() => {
+        requests.length = 0;
+    });
+
+    it("ends the session on the server, then deletes the file", async () => {
+        const ctx = logoutContext(200);
+        saveSession(ctx.sessionDir, snapshot);
+        expect(await logoutCommand(ctx)).toBe(0);
+
+        expect(requests).toHaveLength(1);
+        expect(requests[0]!.method).toBe("POST");
+        expect(new URL(requests[0]!.url).pathname).toBe("/users/logout");
+        expect(requests[0]!.headers.get("X-Auth-Token")).toBe("saved-token");
+        expect(existsSync(join(ctx.sessionDir, "session.json"))).toBe(false);
+        expect(stderr.text).toBe(
+            "Session ended on the server.\n" +
+                "Session deleted.\n" +
+                `Cache directory ${ctx.cacheDir} still holds decrypted data; delete it to remove that data.\n`,
+        );
+    });
+
+    it("still deletes the file when the server call fails, and says so", async () => {
+        const ctx = logoutContext(500);
+        saveSession(ctx.sessionDir, snapshot);
+        expect(await logoutCommand(ctx)).toBe(1);
+
+        expect(requests).toHaveLength(1);
+        expect(existsSync(join(ctx.sessionDir, "session.json"))).toBe(false);
+        expect(stderr.text).toBe(
+            "Could not end the session on the server: HTTP 500\n" +
+                "Session deleted.\n" +
+                `Cache directory ${ctx.cacheDir} still holds decrypted data; delete it to remove that data.\n`,
+        );
+    });
+
+    it("names the account's default cache directory without --cache-dir", async () => {
+        const ctx = { ...logoutContext(200), cacheDir: undefined };
+        saveSession(ctx.sessionDir, snapshot);
+        expect(await logoutCommand(ctx)).toBe(0);
+        expect(stderr.text).toContain(
+            `Cache directory ${defaultCacheDirectory(USER_ID)} still holds decrypted data`,
+        );
+    });
+
+    it("without a session says so, calls nothing and exits 0", async () => {
+        expect(await logoutCommand(logoutContext(200))).toBe(0);
+        expect(requests).toHaveLength(0);
+        expect(stderr.text).toBe("No session found.\n");
+    });
+});
+
 describe("whoami", () => {
     it("prints the account as one line of JSON", async () => {
         expect(await whoamiCommand(context())).toBe(0);