Files
hyperframes/packages/cli/src/capture/htmlExtractor.ts
Miguel Ángel 7a07ea9ac3 fix(cli): fetch a page's assets as the same agent that loaded the page (#3726)
A capture is one session with two halves: Chrome navigates the page with a
browser User-Agent, then Node fetches the assets that page referenced. Those
halves sent three different identities — "HyperFrames/1.0" from the asset and
media downloaders, a bare "Mozilla/5.0" from the stylesheet inliner, and the
real Chrome UA from the navigation itself.

An origin is free to answer those differently, and anti-bot edges do. Capturing
one large site, GET /favicon.svg answers 403 text/html to "HyperFrames/1.0" and
200 image/svg+xml to the UA the very same capture had just navigated with. The
favicon ranker had already picked that SVG as the best declared icon; the 403
discarded it and the downloader fell through to the next candidate, so the icon
written to assets/ was chosen by the CDN's bot rules rather than by the ranker.
The capture reported it as one "unavailable" drop and carried on.

Hoist the navigation UA into CAPTURE_USER_AGENT and use it for every
out-of-band fetch the capture makes: favicons, images, og:image, fonts,
stylesheets, Lottie JSON and videos. One constant is what stops the two halves
drifting apart again.

Verified end to end against that site: before, assets/favicon.png (the
apple-touch icon) plus one unavailable drop; after, assets/favicon.svg, byte
identical to the file the site itself serves.
2026-09-05 22:20:15 -04:00

237 lines
9.1 KiB
TypeScript

/**
* Extract full-page HTML from a website using Puppeteer CDP.
*
* All page.evaluate() calls use string expressions to avoid
* tsx/esbuild __name injection (see esbuild issue #1031).
*/
import type { Page } from "puppeteer-core";
import type { ExtractedHtml } from "./types.js";
import { isPrivateUrl } from "./assetDownloader.js";
import { CAPTURE_USER_AGENT } from "./userAgent.js";
const DEFAULT_SETTLE_TIME = 3000;
// Pre-existing capture pipeline size — surfaced by a one-line escape fix, not new logic.
// fallow-ignore-next-line complexity
export async function extractHtml(
page: Page,
opts: { settleTime?: number } = {},
): Promise<ExtractedHtml> {
const settleTime = opts.settleTime ?? DEFAULT_SETTLE_TIME;
// Lazy-load scroll removed — index.ts already scrolls before calling extractHtml.
// Images are loaded by the time we get here.
// Settle wait kept as buffer before DOM extraction.
await new Promise((r) => setTimeout(r, settleTime));
// Step 2: Inline external stylesheets
// Fetch CSS from Node.js (bypasses CORS) then inject into page
const stylesheetUrls = (await page.evaluate(`(() => {
return Array.from(document.querySelectorAll('link[rel="stylesheet"][href]')).map(function(l) { return l.href; });
})()`)) as string[];
for (const href of stylesheetUrls) {
try {
if (isPrivateUrl(href)) continue;
const res = await fetch(href, {
signal: AbortSignal.timeout(10000),
headers: { "User-Agent": CAPTURE_USER_AGENT },
});
if (!res.ok) continue;
let css = await res.text();
// Fix relative url() references
// fallow-ignore-next-line complexity
css = css.replace(/url\(\s*['"]?([^'")\s]+)['"]?\s*\)/g, (match: string, url: string) => {
if (url.startsWith("data:") || url.startsWith("http") || url.startsWith("//")) return match;
try {
return `url('${new URL(url, href).href}')`;
} catch {
return match;
}
});
// Add the CSS as a <style> tag in <head> via Puppeteer's addStyleTag
await page.addStyleTag({ content: css });
// Remove the original <link> tag (use parameterized evaluate to avoid injection)
await page.evaluate((targetHref: string) => {
const links = document.querySelectorAll('link[rel="stylesheet"]');
for (const link of links) {
if ((link as HTMLLinkElement).href === targetHref) {
link.remove();
break;
}
}
}, href);
} catch {
/* network error — skip */
}
}
// Step 3: Make URLs absolute and fix HTML entity encoding in src attributes
await page.evaluate(`(() => {
document.querySelectorAll("img[src]").forEach(function(el) {
try {
// getAttribute returns the raw HTML attribute (with &amp;)
// .src returns the resolved URL (with &) — use .src for the correct value
var resolved = el.src;
if (resolved) el.setAttribute("src", resolved);
} catch(e) {}
});
// Fix srcset attributes too (Next.js image optimization)
document.querySelectorAll("img[srcset]").forEach(function(el) {
try {
var srcset = el.getAttribute("srcset") || "";
// Decode &amp; entities in srcset
srcset = srcset.replace(/&amp;/g, "&");
el.setAttribute("srcset", srcset);
} catch(e) {}
});
document.querySelectorAll('[style*="url("]').forEach(function(el) {
el.style.cssText = el.style.cssText.replace(/url\\(['"]?([^'"\\)\\s]+)['"]?\\)/g, function(_, url) {
try { return "url('" + new URL(url, location.href).href + "')"; } catch(e) { return "url('" + url + "')"; }
});
});
})()`);
// Step 3b: Convert cross-origin images to data URLs
// Some CDNs (Contentful, etc.) block direct access but images are already
// loaded in the browser. We convert loaded images to data URLs via canvas.
await page.evaluate(`(async () => {
var imgs = Array.from(document.querySelectorAll("img"));
for (var i = 0; i < imgs.length; i++) {
var img = imgs[i];
try {
if (!img.src || img.src.startsWith("data:")) continue;
if (img.naturalWidth < 10 || img.naturalHeight < 10) continue;
// Only convert cross-origin images (same-origin ones will load fine)
var imgUrl = new URL(img.src);
if (imgUrl.origin === location.origin) continue;
// Try to draw to canvas — will fail if CORS blocks it
var canvas = document.createElement("canvas");
canvas.width = img.naturalWidth;
canvas.height = img.naturalHeight;
var ctx = canvas.getContext("2d");
ctx.drawImage(img, 0, 0);
var dataUrl = canvas.toDataURL("image/png");
if (dataUrl.length > 100) {
img.setAttribute("src", dataUrl);
img.removeAttribute("srcset");
}
} catch(e) {
// Canvas CORS failed — try fetch + blob as fallback
try {
var resp = await fetch(img.src, { mode: "cors" });
if (resp.ok) {
var blob = await resp.blob();
var reader = new FileReader();
var dataUrl2 = await new Promise(function(resolve) {
reader.onloadend = function() { resolve(reader.result); };
reader.readAsDataURL(blob);
});
if (dataUrl2 && typeof dataUrl2 === "string" && dataUrl2.length > 100) {
img.setAttribute("src", dataUrl2);
img.removeAttribute("srcset");
}
}
} catch(e2) {
// Both methods failed — image stays as original URL
}
}
}
})()`);
// Step 4: Extract everything
const result = (await page.evaluate(`(() => {
// Capture styles AND scripts from head separately then combine
// Scripts include Three.js, animation libraries that we want to preserve
var styles = Array.from(document.head.querySelectorAll("style")).map(function(s) { return s.outerHTML; }).join("\\n");
var scripts = Array.from(document.head.querySelectorAll("script")).map(function(s) { return s.outerHTML; }).join("\\n");
var headHtml = styles + "\\n" + scripts;
var bodyHtml = document.body.innerHTML;
var cssomRules = [];
for (var i = 0; i < document.styleSheets.length; i++) {
var sheet = document.styleSheets[i];
try {
var ownerNode = sheet.ownerNode;
if (ownerNode && ownerNode.textContent && ownerNode.textContent.trim()) continue;
if (sheet.href) continue;
for (var j = 0; j < sheet.cssRules.length; j++) {
cssomRules.push(sheet.cssRules[j].cssText);
}
} catch(e) {}
}
var htmlEl = document.documentElement;
var attrParts = [];
for (var i = 0; i < htmlEl.attributes.length; i++) {
var attr = htmlEl.attributes[i];
if (attr.name === "lang" || attr.name === "class" || attr.name === "style" || attr.name === "dir" || attr.name.startsWith("data-")) {
attrParts.push(attr.name + '="' + attr.value.replace(/&/g, "&amp;").replace(/"/g, "&quot;") + '"');
}
}
return {
headHtml: headHtml,
bodyHtml: bodyHtml,
cssomRules: cssomRules.join("\\n"),
htmlAttrs: attrParts.join(" "),
viewportWidth: Math.max(window.innerWidth, document.documentElement.scrollWidth),
viewportHeight: window.innerHeight,
fullPageHeight: document.body.scrollHeight
};
})()`)) as ExtractedHtml;
// Post-process in Node.js (more reliable than browser-side fixing):
// 1. Decode &amp; in image src/srcset attributes
// 2. Make relative image URLs absolute using the page's origin
const pageOrigin = new URL(page.url()).origin;
// fallow-ignore-next-line code-duplication
result.bodyHtml = result.bodyHtml.replace(
/(<img\b[^>]*\bsrc=")([^"]*?)(")/g,
(_match: string, pre: string, url: string, post: string) => {
let fixed = url.replace(/&amp;/g, "&");
// Make relative URLs absolute
if (fixed.startsWith("/") && !fixed.startsWith("//")) {
fixed = pageOrigin + fixed;
}
return pre + fixed + post;
},
);
result.bodyHtml = result.bodyHtml.replace(
/(<img\b[^>]*\bsrcset=")([^"]*?)(")/g,
(_match: string, pre: string, urls: string, post: string) => {
const fixed = urls
.replace(/&amp;/g, "&")
.replace(
/(^|,\s*)(\/[^\s,]+)/g,
(_m: string, sep: string, path: string) => sep + pageOrigin + path,
);
return pre + fixed + post;
},
);
// Also fix video src/poster URLs
// fallow-ignore-next-line code-duplication
result.bodyHtml = result.bodyHtml.replace(
/(<video\b[^>]*\bsrc=")([^"]*?)(")/g,
(_match: string, pre: string, url: string, post: string) => {
let fixed = url.replace(/&amp;/g, "&");
if (fixed.startsWith("/") && !fixed.startsWith("//")) fixed = pageOrigin + fixed;
return pre + fixed + post;
},
);
// fallow-ignore-next-line code-duplication
result.bodyHtml = result.bodyHtml.replace(
/(<video\b[^>]*\bposter=")([^"]*?)(")/g,
(_match: string, pre: string, url: string, post: string) => {
let fixed = url.replace(/&amp;/g, "&");
if (fixed.startsWith("/") && !fixed.startsWith("//")) fixed = pageOrigin + fixed;
return pre + fixed + post;
},
);
return result;
}