feat(website): create RSS feed for releases

Author: strager

website/public/releases/feed.ejs.xml

@@ -0,0 +1,63 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2020  Matthew "strager" Glazar -->
+<!-- See end of file for extended copyright information. -->
+<rss version="2.0">
+  <%
+    let fs = await import("fs");
+    let url = await import("url");
+    let { datestampToRFC822 } = await importFileAsync("../../src/timestamp.mjs");
+    let { parseReleaseVersionsFromMarkdown } = await importFileAsync("../../src/release-documentation.mjs");
+
+    let releaseVersions = parseReleaseVersionsFromMarkdown(await fs.promises.readFile(absoluteFilePath("../../../docs/CHANGELOG.md"), "utf-8"));
+  %>
+
+  <channel>
+    <title>quick-lint-js releases</title>
+    <link>https://quick-lint-js.com/releases/</link>
+    <description>Change log and release notes for new quick-lint-js versions.</description>
+
+    <language>en-US</language>
+    <copyright>Copyright (C) 2020  Matthew "strager" Glazar</copyright> 
+    <managingEditor>[email protected] (strager)</managingEditor>
+    <webMaster>[email protected] (strager)</webMaster>
+
+    <image>
+      <url>https://quick-lint-js.com/dusty-right-256x256.png</url>
+      <title>Dusty, the quick-lint-js mascot</title>
+      <description>Dusty, the quick-lint-js mascot</description>
+      <link>https://quick-lint-js.com/releases/</link>
+      <!-- FIXME(strager): These numbers are out of spec. -->
+      <width>256</width>
+      <height>256</height>
+    </image>
+
+    <% for (let versionInfo of releaseVersions) { %>
+      <item>
+        <title>quick-lint-js release: version <%= versionInfo.version %></title>
+        <link>https://quick-lint-js.com/releases/#<%= versionInfo.version %></link>
+        <author>strager.nds@gmail.com (strager)</author>
+        <pubDate><%= datestampToRFC822(versionInfo.date) %></pubDate>
+      </item>
+    <% } %>
+  </channel>
+</rss>
+
+<!--
+quick-lint-js finds bugs in JavaScript programs.
+Copyright (C) 2020  Matthew "strager" Glazar
+
+This file is part of quick-lint-js.
+
+quick-lint-js is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+quick-lint-js is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with quick-lint-js.  If not, see <https://www.gnu.org/licenses/>.
+-->

website/public/releases/index.ejs.html

@@ -20,6 +20,12 @@
       //%>
     </script>
     <link href="../main.css" rel="stylesheet" />
+    <link
+      rel="alternate"
+      type="application/rss+xml"
+      href="<%= makeRelativeURI('/releases/feed.xml') %>"
+      title="quick-lint-js releases"
+    />
     <style>
       /* Clearly separate releases. */
       h3 {

website/public/releases/index.mjs

@@ -0,0 +1,28 @@
+// Copyright (C) 2020  Matthew "strager" Glazar
+// See end of file for extended copyright information.
+
+export let routes = {
+  "/releases/feed.xml": {
+    type: "build-ejs",
+    path: "releases/feed.ejs.xml",
+    contentType: "application/rss+xml",
+  },
+};
+
+// quick-lint-js finds bugs in JavaScript programs.
+// Copyright (C) 2020  Matthew "strager" Glazar
+//
+// This file is part of quick-lint-js.
+//
+// quick-lint-js is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// quick-lint-js is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with quick-lint-js.  If not, see <https://www.gnu.org/licenses/>.

website/src/release-documentation.mjs

@@ -21,6 +21,24 @@ export function releasesMarkdownToHTML(releasesMarkdown) {
   return html;
 }
 
+export function parseReleaseVersionsFromMarkdown(releasesMarkdown) {
+  let env = {};
+  let tokens = markdownParser.parse(releasesMarkdown, env);
+
+  let versionHeadingSpanIndexes = getVersionHeadingSpans(tokens, "h2");
+  let versions = [];
+  for (let [headingBeginIndex, headingEndIndex] of versionHeadingSpanIndexes) {
+    let textTokens = tokens.slice(headingBeginIndex + 1, headingEndIndex);
+    let text = textTokens.map((token) => token.content).join("");
+    let versionInfo = extractVersionInfoFromHeadingText(text);
+    if (versionInfo === null) {
+      continue;
+    }
+    versions.push(versionInfo);
+  }
+  return versions;
+}
+
 function removeTitle(markdownTokens) {
   let filteredTokens = [];
   let inTitle = false;
@@ -56,23 +74,26 @@ function demoteHeadings(markdownTokens) {
   });
 }
 
-function linkifyVersions(markdownTokens) {
-  markdownTokens = [...markdownTokens];
-
-  // @type Array<[number, number]>
-  let versionHeadingSpanIndexes = [];
+// @returns Array<[number, number]>
+function getVersionHeadingSpans(markdownTokens, headingTag) {
+  let spans = [];
   for (let i = 0; i < markdownTokens.length; ++i) {
     let token = markdownTokens[i];
-    if (token.tag === "h3") {
+    if (token.tag === headingTag) {
       if (token.type === "heading_open") {
-        versionHeadingSpanIndexes.push([i]);
+        spans.push([i]);
       }
       if (token.type === "heading_close") {
-        versionHeadingSpanIndexes[versionHeadingSpanIndexes.length - 1].push(i);
+        spans[spans.length - 1].push(i);
       }
     }
   }
+  return spans;
+}
 
+function linkifyVersions(markdownTokens) {
+  markdownTokens = [...markdownTokens];
+  let versionHeadingSpanIndexes = getVersionHeadingSpans(markdownTokens, "h3");
   versionHeadingSpanIndexes.reverse();
   for (let [headingBeginIndex, headingEndIndex] of versionHeadingSpanIndexes) {
     let textTokens = markdownTokens.slice(

website/src/timestamp.mjs

@@ -38,6 +38,20 @@ export function parseTimestamp(timestamp) {
   };
 }
 
+// Parses a subset of ISO 8601 datestamps.
+//
+// Example: "2022-05-25"
+export function datestampToRFC822(datestamp) {
+  let match = datestamp.match(/^(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})$/);
+  if (!match) {
+    throw new Error(`failed to parse timestamp: ${datestamp}`);
+  }
+  let { year, month, day } = match.groups;
+  let monthNumber = parseInt(month, 10);
+  // See: https://www.w3.org/Protocols/rfc822/#z28
+  return `${day} ${rfc822Months[monthNumber - 1]} ${year} 00:00:00 Z`;
+}
+
 // quick-lint-js finds bugs in JavaScript programs.
 // Copyright (C) 2020  Matthew "strager" Glazar
 //

website/test/test-timestamp.mjs

@@ -1,7 +1,7 @@
 // Copyright (C) 2020  Matthew "strager" Glazar
 // See end of file for extended copyright information.
 
-import { parseTimestamp } from "../src/timestamp.mjs";
+import { datestampToRFC822, parseTimestamp } from "../src/timestamp.mjs";
 
 describe("parse timestamp", () => {
   it("gives date in local timezone", () => {
@@ -19,6 +19,12 @@ describe("parse timestamp", () => {
   });
 });
 
+describe("datestampToRFC822", () => {
+  it("converts date to RFC 822 format in UTC timezone without day of week", () => {
+    expect(datestampToRFC822("2022-05-25")).toEqual("25 May 2022 00:00:00 Z");
+  });
+});
+
 // quick-lint-js finds bugs in JavaScript programs.
 // Copyright (C) 2020  Matthew "strager" Glazar
 //