fix(content-blog): temporarily swallow feed mdxToHtml errors + feed refactor (#5753)

packages/docusaurus-plugin-content-blog/src/feed.ts

@@ -0,0 +1,129 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {Feed, Author as FeedAuthor} from 'feed';
+import {PluginOptions, Author, BlogPost, FeedType} from './types';
+import {normalizeUrl, mdxToHtml} from '@docusaurus/utils';
+import {DocusaurusConfig} from '@docusaurus/types';
+import path from 'path';
+import fs from 'fs-extra';
+
+// TODO this is temporary until we handle mdxToHtml better
+// It's hard to convert reliably JSX/require calls  to an html feed content
+// See https://github.com/facebook/docusaurus/issues/5664
+function mdxToFeedContent(mdxContent: string): string | undefined {
+  try {
+    return mdxToHtml(mdxContent);
+  } catch (e) {
+    // TODO will we need a plugin option to configure how to handle such an error
+    // Swallow the error on purpose for now, until we understand better the problem space
+    return undefined;
+  }
+}
+
+export async function generateBlogFeed({
+  blogPosts,
+  options,
+  siteConfig,
+}: {
+  blogPosts: BlogPost[];
+  options: PluginOptions;
+  siteConfig: DocusaurusConfig;
+}): Promise<Feed | null> {
+  if (!blogPosts.length) {
+    return null;
+  }
+
+  const {feedOptions, routeBasePath} = options;
+  const {url: siteUrl, baseUrl, title, favicon} = siteConfig;
+  const blogBaseUrl = normalizeUrl([siteUrl, baseUrl, routeBasePath]);
+
+  const updated =
+    (blogPosts[0] && blogPosts[0].metadata.date) ||
+    new Date('2015-10-25T16:29:00.000-07:00'); // weird legacy magic date
+
+  const feed = new Feed({
+    id: blogBaseUrl,
+    title: feedOptions.title || `${title} Blog`,
+    updated,
+    language: feedOptions.language,
+    link: blogBaseUrl,
+    description: feedOptions.description || `${siteConfig.title} Blog`,
+    favicon: favicon ? normalizeUrl([siteUrl, baseUrl, favicon]) : undefined,
+    copyright: feedOptions.copyright,
+  });
+
+  function toFeedAuthor(author: Author): FeedAuthor {
+    // TODO ask author emails?
+    // RSS feed requires email to render authors
+    return {name: author.name, link: author.url};
+  }
+
+  blogPosts.forEach((post) => {
+    const {
+      id,
+      metadata: {title: metadataTitle, permalink, date, description, authors},
+    } = post;
+    feed.addItem({
+      title: metadataTitle,
+      id,
+      link: normalizeUrl([siteUrl, permalink]),
+      date,
+      description,
+      content: mdxToFeedContent(post.content),
+      author: authors.map(toFeedAuthor),
+    });
+  });
+
+  return feed;
+}
+
+async function createBlogFeedFile({
+  feed,
+  feedType,
+  filePath,
+}: {
+  feed: Feed;
+  feedType: FeedType;
+  filePath: string;
+}) {
+  const feedContent = feedType === 'rss' ? feed.rss2() : feed.atom1();
+  try {
+    await fs.outputFile(filePath, feedContent);
+  } catch (err) {
+    throw new Error(`Generating ${feedType} feed failed: ${err}.`);
+  }
+}
+
+export async function createBlogFeedFiles({
+  blogPosts,
+  options,
+  siteConfig,
+  outDir,
+}: {
+  blogPosts: BlogPost[];
+  options: PluginOptions;
+  siteConfig: DocusaurusConfig;
+  outDir: string;
+}): Promise<void> {
+  const feed = await generateBlogFeed({blogPosts, options, siteConfig});
+
+  const feedTypes = options.feedOptions.type;
+  if (!feed || !feedTypes) {
+    return;
+  }
+
+  await Promise.all(
+    feedTypes.map(async function (feedType) {
+      await createBlogFeedFile({
+        feed,
+        feedType,
+        filePath: path.join(outDir, options.routeBasePath, `${feedType}.xml`),
+      });
+    }),
+  );
+}