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quak/test/cli/metadata-exif.test.ts
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exif(): read HEIF/HEIC originals with exifreader (closes #145)
`photo.exif()` and `quak backup-metadata --exif` now read EXIF through `exifreader`. HEIC/HEIF originals get EXIF, including a live photo's image, as do the other formats `exifreader` reads. It replaces `exif-reader` and the hand-written JPEG scan. `PhotoExif` is unchanged.

The `backup-metadata` dump now holds `exifreader`'s tag output, with unnamed tags keyed `undefined-` plus their number. GPS altitude without a reference counts as above sea level. A latitude or longitude without its hemisphere tag, an unreadable text tag, and a date the parser rejects each give no field.

Licence: `exifreader` is MPL-2.0, used unmodified.

Model: opus-5-5
2026-10-01 22:34:09 +02:00

239 lines
9.4 KiB
TypeScript

/**
* Tests for reading EXIF (`src/exif.ts`) and the image metadata
* `quak backup-metadata --exif` records.
*
* The originals come from users' libraries, so a truncated or corrupt file
* must neither hang the read nor throw out of it: `readPhotoExif` gives `{}`,
* and `backup-metadata` tells an EXIF block it cannot read apart from a file
* that simply has no EXIF, carrying the reason in `exifError`. Each JPEG below
* is a short hand-built byte array; the HEIC is a real file.
*/
import { describe, expect, it } from "vitest";
import { readPhotoExif } from "../../src/exif.js";
import { extractImageMetadata } from "../../src/metadata-backup.js";
import { HEIC_WITH_EXIF } from "../exif-heic.js";
const SOI = [0xff, 0xd8]; // start of image
const SOS = [0xff, 0xda, 0x00, 0x02]; // start of scan
const EXIF_HEADER = [0x45, 0x78, 0x69, 0x66, 0x00, 0x00]; // "Exif\0\0"
const APP0 = [0xff, 0xe0, 0x00, 0x04, 0x00, 0x00];
const ZERO_LENGTH_APP0 = [0xff, 0xe0, 0x00, 0x00];
// A big-endian TIFF block with one IFD entry: Orientation (0x0112), SHORT, 6.
const TIFF_ORIENTATION_6 = [
0x4d, 0x4d, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x08, 0x00, 0x01, 0x01, 0x12,
0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00,
];
// A big-endian TIFF block holding Orientation 6 and DateTimeOriginal
// "0000:00:00 00:00:00", which a camera with an unset clock writes.
const TIFF_UNSET_DATE = [
...[0x4d, 0x4d, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x08], // the first IFD at 8
// The first IFD, at 8: two entries, then no next IFD.
...[0x00, 0x02],
// Orientation (0x0112), SHORT, 6.
...[0x01, 0x12, 0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x06, 0x00, 0x00],
// The Exif IFD's offset (0x8769), LONG, 38.
...[0x87, 0x69, 0x00, 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x26],
...[0x00, 0x00, 0x00, 0x00],
// The Exif IFD, at 38: one entry, then no next IFD.
...[0x00, 0x01],
// DateTimeOriginal (0x9003), 20 ASCII bytes at 56.
...[0x90, 0x03, 0x00, 0x02, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x38],
...[0x00, 0x00, 0x00, 0x00],
...new TextEncoder().encode("0000:00:00 00:00:00\0"), // at 56
];
// A big-endian TIFF block holding a GPSAltitude of 12.5 m and no
// GPSAltitudeRef.
const TIFF_ALTITUDE_WITHOUT_REF = [
...[0x4d, 0x4d, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x08], // the first IFD at 8
// The first IFD, at 8: one entry, then no next IFD.
...[0x00, 0x01],
// The GPS IFD's offset (0x8825), LONG, 26.
...[0x88, 0x25, 0x00, 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x1a],
...[0x00, 0x00, 0x00, 0x00],
// The GPS IFD, at 26: one entry, then no next IFD.
...[0x00, 0x01],
// GPSAltitude (0x0006), one RATIONAL at 44.
...[0x00, 0x06, 0x00, 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x2c],
...[0x00, 0x00, 0x00, 0x00],
...[0x00, 0x00, 0x00, 0x19, 0x00, 0x00, 0x00, 0x02], // 25/2, at 44
];
// A big-endian TIFF block holding Orientation 6 and a Make whose value lies
// past the end of the file.
const TIFF_MAKE_PAST_END = [
...[0x4d, 0x4d, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x08], // the first IFD at 8
// The first IFD, at 8: two entries, then no next IFD.
...[0x00, 0x02],
// Make (0x010f), 6 ASCII bytes at 4096.
...[0x01, 0x0f, 0x00, 0x02, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x10, 0x00],
// Orientation (0x0112), SHORT, 6.
...[0x01, 0x12, 0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x06, 0x00, 0x00],
...[0x00, 0x00, 0x00, 0x00],
];
// A big-endian TIFF block with one IFD entry that exifreader has no name for:
// tag 0xc000 (49152), SHORT, 7.
const TIFF_UNNAMED_TAG = [
...[0x4d, 0x4d, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x08], // the first IFD at 8
// The first IFD, at 8: one entry, then no next IFD.
...[0x00, 0x01],
// Tag 0xc000, SHORT, 7.
...[0xc0, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x07, 0x00, 0x00],
...[0x00, 0x00, 0x00, 0x00],
];
// An APP1 segment whose length field matches its data.
const app1 = (data: number[]): number[] => {
const len = data.length + 2;
return [0xff, 0xe1, len >> 8, len & 0xff, ...data];
};
const bytes = (...parts: number[][]): Uint8Array =>
new Uint8Array(parts.flat());
describe("readPhotoExif", () => {
it("reads the common fields of a valid JPEG", () => {
const data = [...EXIF_HEADER, ...TIFF_ORIENTATION_6];
expect(readPhotoExif(bytes(SOI, app1(data), SOS))).toStrictEqual({
orientation: 6,
});
});
it("gives no dateTimeOriginal for a DateTimeOriginal of 0000:00:00 00:00:00", () => {
const data = [...EXIF_HEADER, ...TIFF_UNSET_DATE];
expect(readPhotoExif(bytes(SOI, app1(data), SOS))).toStrictEqual({
orientation: 6,
});
});
it("reads a GPSAltitude without GPSAltitudeRef as above sea level", () => {
const data = [...EXIF_HEADER, ...TIFF_ALTITUDE_WITHOUT_REF];
expect(readPhotoExif(bytes(SOI, app1(data), SOS))).toStrictEqual({
gpsAltitude: 12.5,
});
});
it("gives no make for a Make whose value lies past the end of the file", () => {
const data = [...EXIF_HEADER, ...TIFF_MAKE_PAST_END];
expect(readPhotoExif(bytes(SOI, app1(data), SOS))).toStrictEqual({
orientation: 6,
});
});
it.each([
[
"a file that is not an image",
new TextEncoder().encode("just some text, not an image"),
],
[
"a PNG without EXIF",
bytes([0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]),
],
["a JPEG without EXIF", bytes(SOI, APP0, SOS)],
// A length under 8 cannot hold the six-byte "Exif\0\0" header. This one
// has length 7 and holds only "Exif\0", so a read past its end would
// take the next segment's bytes as EXIF.
[
"an APP1 segment too short to hold the Exif header",
bytes(SOI, app1(EXIF_HEADER.slice(0, 5)), SOS),
],
[
"an APP1 segment holding just the Exif header",
bytes(SOI, app1(EXIF_HEADER), SOS),
],
[
"a JPEG truncated inside a segment header",
bytes(SOI, [0xff, 0xe1, 0x00]),
],
["a JPEG that ends before the image data", bytes(SOI, APP0)],
// A length of 0 would step a scan by 2 bytes at a time through the
// rest of the file, reading garbage as markers.
[
"a zero-length segment",
bytes(
SOI,
ZERO_LENGTH_APP0,
ZERO_LENGTH_APP0,
ZERO_LENGTH_APP0,
ZERO_LENGTH_APP0,
SOS,
),
],
["a segment length of 1", bytes(SOI, [0xff, 0xe0, 0x00, 0x01], SOS)],
// APP1 claims 0x4000 bytes but only the "Exif\0\0" header follows.
[
"a segment length that runs past the end of the file",
bytes(SOI, [0xff, 0xe1, 0x40, 0x00], EXIF_HEADER),
],
// "XX" where the TIFF byte order belongs.
[
"an EXIF block that cannot be parsed",
bytes(SOI, app1([...EXIF_HEADER, 0x58, 0x58]), SOS),
],
])("returns no fields for %s", (_, input) => {
expect(readPhotoExif(input)).toStrictEqual({});
});
});
describe("extractImageMetadata", () => {
it("parses EXIF from a valid JPEG", () => {
const meta = extractImageMetadata(
bytes(SOI, app1([...EXIF_HEADER, ...TIFF_ORIENTATION_6]), SOS),
);
expect(meta?.exifError).toBeUndefined();
expect(meta?.exif).toMatchObject({ Orientation: { value: 6 } });
});
it("parses EXIF from a HEIC", () => {
const meta = extractImageMetadata(HEIC_WITH_EXIF);
expect(meta?.exifError).toBeUndefined();
expect(meta?.exif).toMatchObject({
Make: { value: ["Canon"] },
Model: { value: ["EOS R5"] },
DateTimeOriginal: { value: ["2021:07:15 14:30:00"] },
Orientation: { value: 6 },
GPSLatitudeRef: { value: ["N"] },
});
});
it("keys a tag exifreader has no name for by its number", () => {
const meta = extractImageMetadata(
bytes(SOI, app1([...EXIF_HEADER, ...TIFF_UNNAMED_TAG]), SOS),
);
expect(meta?.exifError).toBeUndefined();
expect(meta?.exif).toMatchObject({ "undefined-49152": { value: 7 } });
});
it("returns nothing for a file that is not an image", () => {
const text = new TextEncoder().encode("just some text, not an image");
expect(extractImageMetadata(text)).toBeUndefined();
});
it("records the reason when the JPEG is malformed", () => {
const meta = extractImageMetadata(
bytes(SOI, [0xff, 0xe1, 0x40, 0x00], EXIF_HEADER),
);
expect(meta?.exif).toBeUndefined();
expect(meta?.exifError).toBe(
"no tag could be read from the EXIF block",
);
});
it("keeps the raw bytes and the reason when EXIF cannot be parsed", () => {
// The raw bytes are the whole EXIF block as exifreader finds it: for a
// JPEG, the APP1 segment, marker and length included.
const segment = app1([...EXIF_HEADER, 0x58, 0x58]);
const meta = extractImageMetadata(bytes(SOI, segment, SOS));
expect(meta?.exif).toBeUndefined();
expect(meta?.exifRaw).toBe(Buffer.from(segment).toString("base64"));
expect(meta?.exifError).toBe(
"no tag could be read from the EXIF block",
);
});
});