feat: siteConfig.markdown.parseFrontMatter hook (#9624)

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

@@ -8,6 +8,7 @@
 import {jest} from '@jest/globals';
 import path from 'path';
 import fs from 'fs-extra';
+import {DEFAULT_PARSE_FRONT_MATTER} from '@docusaurus/utils';
 import {DEFAULT_OPTIONS} from '../options';
 import {generateBlogPosts} from '../blogUtils';
 import {createBlogFeedFiles} from '../feed';
@@ -31,6 +32,8 @@ const DefaultI18N: I18n = {
   },
 };
 
+const markdown = {parseFrontMatter: DEFAULT_PARSE_FRONT_MATTER};
+
 function getBlogContentPaths(siteDir: string): BlogContentPaths {
   return {
     contentPath: path.resolve(siteDir, 'blog'),
@@ -72,6 +75,7 @@ describe.each(['atom', 'rss', 'json'])('%s', (feedType) => {
       baseUrl: '/',
       url: 'https://docusaurus.io',
       favicon: 'image/favicon.ico',
+      markdown,
     };
     const outDir = path.join(siteDir, 'build-snap');
 
@@ -110,6 +114,7 @@ describe.each(['atom', 'rss', 'json'])('%s', (feedType) => {
       baseUrl: '/myBaseUrl/',
       url: 'https://docusaurus.io',
       favicon: 'image/favicon.ico',
+      markdown,
     };
 
     // Build is quite difficult to mock, so we built the blog beforehand and
@@ -152,6 +157,7 @@ describe.each(['atom', 'rss', 'json'])('%s', (feedType) => {
       baseUrl: '/myBaseUrl/',
       url: 'https://docusaurus.io',
       favicon: 'image/favicon.ico',
+      markdown,
     };
 
     // Build is quite difficult to mock, so we built the blog beforehand and
@@ -204,6 +210,7 @@ describe.each(['atom', 'rss', 'json'])('%s', (feedType) => {
       baseUrl: '/myBaseUrl/',
       url: 'https://docusaurus.io',
       favicon: 'image/favicon.ico',
+      markdown,
     };
 
     // Build is quite difficult to mock, so we built the blog beforehand and

packages/docusaurus-plugin-content-blog/src/__tests__/index.test.ts

@@ -16,6 +16,7 @@ import type {
   LoadContext,
   I18n,
   Validate,
+  MarkdownConfig,
 } from '@docusaurus/types';
 import type {
   BlogPost,
@@ -24,6 +25,24 @@ import type {
   EditUrlFunction,
 } from '@docusaurus/plugin-content-blog';
 
+const markdown: MarkdownConfig = {
+  format: 'mdx',
+  mermaid: true,
+  mdx1Compat: {
+    comments: true,
+    headingIds: true,
+    admonitions: true,
+  },
+  parseFrontMatter: async (params) => {
+    // Reuse the default parser
+    const result = await params.defaultParseFrontMatter(params);
+    if (result.frontMatter.title === 'Complex Slug') {
+      result.frontMatter.custom_frontMatter = 'added by parseFrontMatter';
+    }
+    return result;
+  },
+};
+
 function findByTitle(
   blogPosts: BlogPost[],
   title: string,
@@ -81,6 +100,7 @@ const getPlugin = async (
     title: 'Hello',
     baseUrl: '/',
     url: 'https://docusaurus.io',
+    markdown,
   } as DocusaurusConfig;
   return pluginContentBlog(
     {
@@ -242,6 +262,7 @@ describe('blog plugin', () => {
         slug: '/hey/my super path/héllô',
         title: 'Complex Slug',
         tags: ['date', 'complex'],
+        custom_frontMatter: 'added by parseFrontMatter',
       },
       tags: [
         {

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

@@ -11,7 +11,7 @@ import _ from 'lodash';
 import logger from '@docusaurus/logger';
 import readingTime from 'reading-time';
 import {
-  parseMarkdownString,
+  parseMarkdownFile,
   normalizeUrl,
   aliasedSitePath,
   getEditUrl,
@@ -29,7 +29,7 @@ import {
 } from '@docusaurus/utils';
 import {validateBlogPostFrontMatter} from './frontMatter';
 import {type AuthorsMap, getAuthorsMap, getBlogPostAuthors} from './authors';
-import type {LoadContext} from '@docusaurus/types';
+import type {LoadContext, ParseFrontMatter} from '@docusaurus/types';
 import type {
   PluginOptions,
   ReadingTimeFunction,
@@ -180,10 +180,19 @@ function formatBlogPostDate(
   }
 }
 
-async function parseBlogPostMarkdownFile(blogSourceAbsolute: string) {
-  const markdownString = await fs.readFile(blogSourceAbsolute, 'utf-8');
+async function parseBlogPostMarkdownFile({
+  filePath,
+  parseFrontMatter,
+}: {
+  filePath: string;
+  parseFrontMatter: ParseFrontMatter;
+}) {
+  const fileContent = await fs.readFile(filePath, 'utf-8');
   try {
-    const result = parseMarkdownString(markdownString, {
+    const result = await parseMarkdownFile({
+      filePath,
+      fileContent,
+      parseFrontMatter,
       removeContentTitle: true,
     });
     return {
@@ -191,7 +200,7 @@ async function parseBlogPostMarkdownFile(blogSourceAbsolute: string) {
       frontMatter: validateBlogPostFrontMatter(result.frontMatter),
     };
   } catch (err) {
-    logger.error`Error while parsing blog post file path=${blogSourceAbsolute}.`;
+    logger.error`Error while parsing blog post file path=${filePath}.`;
     throw err;
   }
 }
@@ -207,7 +216,10 @@ async function processBlogSourceFile(
   authorsMap?: AuthorsMap,
 ): Promise<BlogPost | undefined> {
   const {
-    siteConfig: {baseUrl},
+    siteConfig: {
+      baseUrl,
+      markdown: {parseFrontMatter},
+    },
     siteDir,
     i18n,
   } = context;
@@ -228,7 +240,10 @@ async function processBlogSourceFile(
   const blogSourceAbsolute = path.join(blogDirPath, blogSourceRelative);
 
   const {frontMatter, content, contentTitle, excerpt} =
-    await parseBlogPostMarkdownFile(blogSourceAbsolute);
+    await parseBlogPostMarkdownFile({
+      filePath: blogSourceAbsolute,
+      parseFrontMatter,
+    });
 
   const aliasedSource = aliasedSitePath(blogSourceAbsolute, siteDir);