84 lines
2.1 KiB
TypeScript
84 lines
2.1 KiB
TypeScript
import { rgbaToThumbHash } from "thumbhash";
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import ExifReader from "exifreader";
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import type { ImageMetadata } from "astro";
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import { readFile } from "node:fs/promises";
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import sharp from "sharp";
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export async function generateThumbHash(
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buffer: ArrayBuffer,
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): Promise<string | undefined> {
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if (!buffer) return;
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const sp = sharp(buffer);
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const meta = await sp.metadata();
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const scaleFactor = 100 / Math.max(meta.width, meta.height);
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const smallWidth = Math.floor(meta.width * scaleFactor);
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const smallHeight = Math.floor(meta.height * scaleFactor);
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const smallImg = await sp
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.resize(smallWidth, smallHeight)
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.withMetadata()
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.raw()
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.ensureAlpha()
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.toBuffer();
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const hashBuffer = rgbaToThumbHash(smallWidth, smallHeight, smallImg);
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return Buffer.from(hashBuffer).toString("base64");
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}
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const allowedExif = [
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"ApertureValue",
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"DateTimeOriginal",
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"ShutterSpeedValue",
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"ExposureTime",
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"ApertureValue",
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"FNumber",
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"FocalLength",
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"GPSLatitude",
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"GPSLongitude",
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"GPSAltitude",
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"IsoSpeedRatings",
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"Make",
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"Model",
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];
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export async function getImageBuffer(
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image: ImageMetadata,
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): Promise<ArrayBuffer> {
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if (image.format === "svg") return undefined; // SVGs don't have EXIF data
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const imagePath = (image as ImageMetadata & { fsPath: string }).fsPath ??
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image.src;
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if (!imagePath) return undefined;
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try {
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if (imagePath.startsWith("https://") || imagePath.startsWith("http://")) {
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const res = await fetch(imagePath, { signal: AbortSignal.timeout(5000) });
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return await res.arrayBuffer();
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} else {
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const b = await readFile(imagePath);
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return b.buffer as ArrayBuffer;
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}
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} catch (err) {
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return undefined;
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}
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}
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export async function getExifData(buffer: ArrayBuffer) {
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if (!buffer) return undefined;
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const tags = await ExifReader.load(buffer, { async: true });
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const out: Record<string, unknown> = {};
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let hasExif = false;
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for (const key of allowedExif) {
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if (!tags[key]) continue;
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hasExif = true;
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out[key] = tags[key]?.description;
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}
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return hasExif ? out : undefined;
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}
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