Parse image file info if available

src/utils/parse-iptc.ts

@@ -0,0 +1,56 @@
+const IPTC_ENTRY_TYPES = new Map([
+	[0x78, 'caption'],
+	[0x6e, 'credit'],
+	[0x19, 'keywords'],
+	[0x37, 'dateCreated'],
+	[0x50, 'byline'],
+	[0x55, 'bylineTitle'],
+	[0x7a, 'captionWriter'],
+	[0x69, 'headline'],
+	[0x74, 'copyright'],
+	[0x0f, 'category'],
+]);
+
+const IPTC_ENTRY_MARKER = Buffer.from([0x1c, 0x02]);
+
+export default function parseIPTC(buffer: Buffer) {
+	if (!Buffer.isBuffer(buffer)) return {};
+
+	let iptc = {};
+	let lastIptcEntryPos = buffer.indexOf(IPTC_ENTRY_MARKER);
+
+	while (lastIptcEntryPos !== -1) {
+		lastIptcEntryPos = buffer.indexOf(
+			IPTC_ENTRY_MARKER,
+			lastIptcEntryPos + IPTC_ENTRY_MARKER.byteLength
+		);
+
+		let iptcBlockTypePos = lastIptcEntryPos + IPTC_ENTRY_MARKER.byteLength;
+		let iptcBlockSizePos = iptcBlockTypePos + 1;
+		let iptcBlockDataPos = iptcBlockSizePos + 2;
+
+		let iptcBlockType = buffer.readUInt8(iptcBlockTypePos);
+		let iptcBlockSize = buffer.readUInt16BE(iptcBlockSizePos);
+
+		if (!IPTC_ENTRY_TYPES.has(iptcBlockType)) {
+			continue;
+		}
+
+		// if (iptcBlockSize > buffer.length - (iptcBlockDataPos + iptcBlockSize)) {
+		// 	throw new Error('Invalid IPTC directory');
+		// }
+
+		let iptcBlockTypeId = IPTC_ENTRY_TYPES.get(iptcBlockType);
+		let iptcData = buffer.slice(iptcBlockDataPos, iptcBlockDataPos + iptcBlockSize).toString();
+
+		if (iptc[iptcBlockTypeId] == null) {
+			iptc[iptcBlockTypeId] = iptcData;
+		} else if (Array.isArray(iptc[iptcBlockTypeId])) {
+			iptc[iptcBlockTypeId].push(iptcData);
+		} else {
+			iptc[iptcBlockTypeId] = [iptc[iptcBlockTypeId], iptcData];
+		}
+	}
+
+	return iptc;
+}