tjh.dev
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tangled.org/core
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avatar: use cf workers image resizing api to serve tiny imgs
Signed-off-by: Anirudh Oppiliappan <anirudh@tangled.sh>
anirudh.fi
+90
-69
avatar/src/index.js
+90
-69
avatar/src/index.js
···
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export default {
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async fetch(request, env) {
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const url = new URL(request.url);
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const { pathname } = url;
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async fetch(request, env) {
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const url = new URL(request.url);
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const { pathname, searchParams } = url;
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if (!pathname || pathname === '/') {
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return new Response(`This is Tangled's avatar service. It fetches your pretty avatar from Bluesky and caches it on Cloudflare.
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You can't use this directly unforunately since all requests are signed and may only originate from the appview.`);
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}
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if (!pathname || pathname === "/") {
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return new Response(`This is Tangled's avatar service. It fetches your pretty avatar from Bluesky and caches it on Cloudflare.
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You can't use this directly unfortunately since all requests are signed and may only originate from the appview.`);
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}
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const cache = caches.default;
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const size = searchParams.get("size");
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const resizeToTiny = size === "tiny";
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let cacheKey = request.url;
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let response = await cache.match(cacheKey);
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if (response) {
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return response;
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}
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const cache = caches.default;
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let cacheKey = request.url;
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let response = await cache.match(cacheKey);
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if (response) return response;
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const pathParts = pathname.slice(1).split('/');
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if (pathParts.length < 2) {
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return new Response('Bad URL', { status: 400 });
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}
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const pathParts = pathname.slice(1).split("/");
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if (pathParts.length < 2) {
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return new Response("Bad URL", { status: 400 });
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}
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const [signatureHex, actor] = pathParts;
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const [signatureHex, actor] = pathParts;
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const actorBytes = new TextEncoder().encode(actor);
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const actorBytes = new TextEncoder().encode(actor);
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const key = await crypto.subtle.importKey(
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"raw",
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new TextEncoder().encode(env.AVATAR_SHARED_SECRET),
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{ name: "HMAC", hash: "SHA-256" },
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false,
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["sign", "verify"],
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);
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const key = await crypto.subtle.importKey(
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'raw',
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new TextEncoder().encode(env.AVATAR_SHARED_SECRET),
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{ name: 'HMAC', hash: 'SHA-256' },
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false,
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['sign', 'verify'],
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);
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const computedSigBuffer = await crypto.subtle.sign("HMAC", key, actorBytes);
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const computedSig = Array.from(new Uint8Array(computedSigBuffer))
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.map((b) => b.toString(16).padStart(2, "0"))
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.join("");
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const computedSigBuffer = await crypto.subtle.sign('HMAC', key, actorBytes);
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const computedSig = Array.from(new Uint8Array(computedSigBuffer))
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.map((b) => b.toString(16).padStart(2, '0'))
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.join('');
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console.log({
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level: "debug",
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message: "avatar request for: " + actor,
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computedSignature: computedSig,
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providedSignature: signatureHex,
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});
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console.log({
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level: 'debug',
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message: 'avatar request for: ' + actor,
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computedSignature: computedSig,
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providedSignature: signatureHex,
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});
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const sigBytes = Uint8Array.from(
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signatureHex.match(/.{2}/g).map((b) => parseInt(b, 16)),
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);
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const valid = await crypto.subtle.verify("HMAC", key, sigBytes, actorBytes);
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const sigBytes = Uint8Array.from(signatureHex.match(/.{2}/g).map((b) => parseInt(b, 16)));
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const valid = await crypto.subtle.verify('HMAC', key, sigBytes, actorBytes);
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if (!valid) {
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return new Response("Invalid signature", { status: 403 });
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}
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if (!valid) {
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return new Response('Invalid signature', { status: 403 });
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}
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try {
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const profileResponse = await fetch(
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`https://public.api.bsky.app/xrpc/app.bsky.actor.getProfile?actor=${actor}`,
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);
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const profile = await profileResponse.json();
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const avatar = profile.avatar;
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try {
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const profileResponse = await fetch(`https://public.api.bsky.app/xrpc/app.bsky.actor.getProfile?actor=${actor}`, { method: 'GET' });
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const profile = await profileResponse.json();
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const avatar = profile.avatar;
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if (!avatar) {
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return new Response(`avatar not found for ${actor}.`, { status: 404 });
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}
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if (!avatar) {
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return new Response(`avatar not found for ${actor}.`, { status: 404 });
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}
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// Resize if requested
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let avatarResponse;
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if (resizeToTiny) {
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avatarResponse = await fetch(avatar, {
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cf: {
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image: {
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width: 32,
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height: 32,
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fit: "cover",
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format: "webp",
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},
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},
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});
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} else {
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avatarResponse = await fetch(avatar);
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}
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// fetch the actual avatar image
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const avatarResponse = await fetch(avatar);
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if (!avatarResponse.ok) {
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return new Response(`failed to fetch avatar for ${actor}.`, { status: avatarResponse.status });
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}
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if (!avatarResponse.ok) {
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return new Response(`failed to fetch avatar for ${actor}.`, {
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status: avatarResponse.status,
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});
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}
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const avatarData = await avatarResponse.arrayBuffer();
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const contentType = avatarResponse.headers.get('content-type') || 'image/jpeg';
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const avatarData = await avatarResponse.arrayBuffer();
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const contentType =
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avatarResponse.headers.get("content-type") || "image/jpeg";
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response = new Response(avatarData, {
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headers: {
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'Content-Type': contentType,
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'Cache-Control': 'public, max-age=43200', // 12 h
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},
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});
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response = new Response(avatarData, {
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headers: {
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"Content-Type": contentType,
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"Cache-Control": "public, max-age=43200",
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},
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});
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// cache it in cf using request.url as the key
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await cache.put(cacheKey, response.clone());
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return response;
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} catch (error) {
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return new Response(`error fetching avatar: ${error.message}`, { status: 500 });
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}
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},
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await cache.put(cacheKey, response.clone());
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return response;
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} catch (error) {
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return new Response(`error fetching avatar: ${error.message}`, {
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status: 500,
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});
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}
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},
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};