Create a cloud function to generate HTML diffs for Phabricator revisions (#3494)

2023-06-02 10:02:11 -04:00 · 2023-06-02 10:02:11 -04:00 · 3032922276
--- a/functions/diff2html-revision/index.js
+++ b/functions/diff2html-revision/index.js
@ -0,0 +1,88 @@
+const https = require("https");
+const functions = require("@google-cloud/functions-framework");
+const Diff2html = require("diff2html");
+
+const agent = new https.Agent({ keepAlive: true });
+const headers = new Headers({
+  "User-Agent": "bugbug-diff2html",
+});
+const configuration = {
+  // Diff2Html Configuration
+  outputFormat: "line-by-line",
+  matching: "lines",
+  renderNothingWhenEmpty: false,
+  diffStyle: "word",
+  // Diff2HtmlUI Configuration
+  synchronisedScroll: true,
+  highlight: true,
+  fileListToggle: true,
+  fileListStartVisible: false,
+  fileContentToggle: true,
+  stickyFileHeaders: true,
+};
+
+/**
+ * Responds to any HTTP request.
+ *
+ * @param {!express:Request} req HTTP request context.
+ * @param {!express:Response} res HTTP response context.
+ */
+functions.http("revisionDiff2html", (req, res) => {
+  res.set("Access-Control-Allow-Origin", "*");
+
+  let revision_id = req.query.revision_id;
+  let diff_id = req.query.diff_id;
+  let enableJS = req.query.format !== "html";
+
+  if (isNaN(revision_id) || isNaN(diff_id)) {
+    res.status(400).send("Invalid IDs");
+    return;
+  }
+
+  const url = `https://phabricator.services.mozilla.com/D${revision_id}?id=${diff_id}&download=true`;
+  fetch(url, { agent, headers })
+    .then((res) => res.text())
+    .then((text) => strDiff2Html(text, enableJS))
+    .then((output) => res.status(200).send(output))
+    .catch((err) => res.status(500).send(`Error: ${err.message}`));
+});
+
+const jsTemplate = `
+<meta charset="utf-8" />
+<link
+  rel="stylesheet"
+  href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/10.7.1/styles/github.min.css"
+/>
+<script
+  type="text/javascript"
+  src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js"
+></script>
+<script>
+  document.addEventListener("DOMContentLoaded", () => {
+    const targetElement = document.getElementById("diff");
+    const diff2htmlUi = new Diff2HtmlUI(targetElement);
+    diff2htmlUi.fileListToggle(false);
+    diff2htmlUi.fileContentToggle();
+    diff2htmlUi.synchronisedScroll();
+    diff2htmlUi.highlightCode();
+  });
+</script>
+`;
+
+function strDiff2Html(strDiff, enableJS) {
+  const diffHtml = Diff2html.html(strDiff, configuration);
+  return `<!DOCTYPE html>
+<html lang="en-us">
+  <head>${enableJS ? jsTemplate : ""}
+    <link
+      rel="stylesheet"
+      type="text/css"
+      href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css"
+    />
+  </head>
+  <body>
+    <div id="diff">${diffHtml}</div>
+  </body>
+</html>
+`;
+}
--- a/functions/diff2html-revision/package.json
+++ b/functions/diff2html-revision/package.json
@ -0,0 +1,7 @@
+{
+  "name": "diff2html-revision",
+  "dependencies": {
+    "@google-cloud/functions-framework": "^3.1.2",
+    "diff2html": "3.4.35"
+  }
+}