john
69 lines
2.4 KiB
JavaScript
69 lines
2.4 KiB
JavaScript
import crypto from 'node:crypto';
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import { injectBeforeDocumentClosingBody } from './html-document-injection.mjs';
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/**
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* Public MindSpace pages (workspace `/MindSpace/<userId>/public/*.html`) reference images via
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* `/api/mindspace/v1/assets/:id/download`, which is authorized per-request (owner cookie, signed
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* `public_token`, or `/public/` referrer). Right after an agent generates a page, the very first
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* image request can occasionally race asset materialization and return a transient 401/404/5xx.
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*
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* Generated pages usually ship a page-specific `onerror` fallback that permanently swaps the
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* `<img>` for a static placeholder — so a single transient failure becomes a permanent "broken
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* image" until the visitor manually reloads. This script intercepts image load failures for
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* MindSpace asset URLs (any page, any author) and retries a few times with backoff BEFORE the
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* page's own `onerror` gets a chance to run; only once retries are exhausted does it let the
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* original fallback take over.
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*/
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const IMAGE_RETRY_SCRIPT = `(function(){
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var MAX_RETRIES=3;
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var BASE_DELAY_MS=900;
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var ASSET_PATTERN=/\\/api\\/mindspace\\/v1\\/assets\\/[^/]+\\/download/;
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var retries=new WeakMap();
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document.addEventListener('error',function(event){
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var img=event.target;
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if(!img||img.tagName!=='IMG')return;
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var src=img.getAttribute('src')||'';
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if(!ASSET_PATTERN.test(src))return;
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var count=retries.get(img)||0;
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if(count>=MAX_RETRIES)return;
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event.stopImmediatePropagation();
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retries.set(img,count+1);
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setTimeout(function(){
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try{
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var url=new URL(src,location.href);
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url.searchParams.set('_retry',String(count+1));
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img.src=url.toString();
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}catch(e){
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img.src=src;
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}
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},BASE_DELAY_MS*(count+1));
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},true);
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})();`;
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const IMAGE_RETRY_SCRIPT_HASH = crypto.createHash('sha256').update(IMAGE_RETRY_SCRIPT).digest('base64');
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const MARKER_ATTR = 'data-mindspace-image-retry';
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export function injectPublicImageRetryScript(html) {
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const source = String(html ?? '');
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if (!source || source.includes(MARKER_ATTR)) {
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return { html: source, scriptHashes: [] };
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}
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const markup = `<script ${MARKER_ATTR}="1">${IMAGE_RETRY_SCRIPT}</script>`;
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if (/<\/body>/i.test(source)) {
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return {
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html: injectBeforeDocumentClosingBody(source, markup),
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scriptHashes: [IMAGE_RETRY_SCRIPT_HASH],
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};
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}
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return {
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html: `${source}${markup}`,
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scriptHashes: [IMAGE_RETRY_SCRIPT_HASH],
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};
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}
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export const publicImageRetryInternals = {
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IMAGE_RETRY_SCRIPT_HASH,
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MARKER_ATTR,
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};
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