feat(backend): Initial support for open graph images

artwork/og/template.svg

@@ -403,7 +403,7 @@
          id="tspan1657"
          sodipodi:role="line"><tspan
            style="font-size:8.46666622px;fill:#a3a3a3;fill-opacity:0.53472218"
-           id="tspan1665">sub_1 | sub_2</tspan></tspan></text>
+           id="tspan1665">sub_1 sub_2</tspan></tspan></text>
     <text
        xml:space="preserve"
        style="font-style:normal;font-weight:normal;font-size:13.63457108px;line-height:1.25;font-family:sans-serif;letter-spacing:0px;word-spacing:0px;fill:#fdf4ff;fill-opacity:1;stroke:none;stroke-width:0.34086427"

packages/backend/package.json

@@ -59,10 +59,12 @@
     "passport-jwt": "4.0.0",
     "query-string": "6.2.0",
     "remark": "13",
+    "remark-frontmatter": "^4.0.1",
     "remark-parse": "^9.0.0",
     "remark-plain-text": "^0.2.0",
     "rimraf": "2.6.2",
-    "sharp": "^0.29.3"
+    "sharp": "^0.29.3",
+    "yaml": "^1.10.2"
   },
   "devDependencies": {
     "backpack-core": "0.7.0"

packages/backend/src/controllers/og.js

@@ -1,13 +1,15 @@
 import config from "../config";
-import { log } from "../utils";
+import { capitalize, log } from "../utils";
 import sharp from 'sharp';
 import fs from "fs";
 import path from "path";
 import axios from 'axios'
 import remark from 'remark'
 import remarkParse from 'remark-parse'
+import remarkFrontmatter from 'remark-frontmatter'
 import toString from 'mdast-util-to-string'
 import { Buffer } from 'buffer'
+import yaml from 'yaml'
 
 // Sites for which we generate images
 const sites = ['dev', 'org']
@@ -20,9 +22,8 @@ const template = fs.readFileSync(
   'utf-8'
 )
 
-/* Turns markdown into a syntax tree */
-/* Helper method to extract intro from markdown */
-const introFromMarkdown = async (md, slug) => {
+/* Helper method to extract intro from strapi markdown */
+const introFromStrapiMarkdown = async (md, slug) => {
   const tree = await remark().use(remarkParse).parse(md)
   if (tree.children[0].type !== 'paragraph')
     console.log('Markdown does not start with paragraph', slug)
@@ -30,6 +31,23 @@ const introFromMarkdown = async (md, slug) => {
   return toString(tree.children[0])
 }
 
+/* Helper method to extract title from markdown frontmatter */
+const titleAndIntroFromLocalMarkdown = async (md, slug) => {
+  const tree = await remark()
+    .use(remarkParse)
+    .use(remarkFrontmatter, ['yaml'])
+    .parse(md)
+
+  if (tree.children[0].type !== 'yaml')
+    console.log('Markdown does not start with frontmatter', slug)
+  else return {
+    title: titleAsLines(yaml.parse(tree.children[0].value).title),
+    intro: introAsLines(toString(tree.children.slice(1, 2)))
+  }
+
+  return false
+}
+
 /* Helper method to load dev blog post */
 const loadDevBlogPost = async (slug) => {
   const result = await axios.get(
@@ -37,7 +55,7 @@ const loadDevBlogPost = async (slug) => {
   )
   if (result.data) return {
     title: titleAsLines(result.data[0].title),
-    intro: introAsLines(await introFromMarkdown(result.data[0].body, slug)),
+    intro: introAsLines(await introFromStrapiMarkdown(result.data[0].body, slug)),
     sub: [
       result.data[0].author.displayname,
       new Date(result.data[0].published_at).toString().split(' ').slice(0,4).join(' '),
@@ -48,6 +66,22 @@ const loadDevBlogPost = async (slug) => {
   return false
 }
 
+/* Helper method to load markdown file from disk */
+const loadMarkdownFile = async (page, site, lang) => fs.promises.readFile(
+  path.resolve('..', '..', 'markdown', site, ...page.split('/'), `${lang}.md`),
+  'utf-8'
+).then(async (md) => md
+  ? {
+    ...((await titleAndIntroFromLocalMarkdown(md, page))),
+    sub: [
+      'freesewing.dev',
+      page
+    ],
+    lead: capitalize(page.split('/').shift())
+  }
+  : false
+)
+
 /* Find longest possible place to split a string */
 const splitLine = (line, chars) => {
   const words = line.split(' ')
@@ -84,28 +118,43 @@ const introAsLines = intro => {
   // Two lines it is
   return splitLine(intro, config.og.chars.intro)
 }
+
 // Get title and intro
 const getMetaData = {
   dev: async (page) => {
     const data = {}
     const chunks = page.split('/')
+    // Home page
     if (chunks.length === 0) return {
       title: 'FreeSewing FIXME',
       intro: "FreeSewing's fixme",
       sub: ['freesewing.dev', '/fixme'],
     }
-    if (chunks.length === 1) {
-      if (chunks[0] === 'blog') return {
-        title: titleAsLines('FreeSewing Development Blog'),
-        intro: introAsLines("FreeSewing's blog for developers and contributors"),
-        sub: ['freesewing.dev', '/blog'],
-      }
+    // Blog index page
+    if (chunks.length === 1 && chunks[0] === 'blog') return {
+      title: titleAsLines('FreeSewing Developer Blog'),
+      intro: introAsLines("Contains no sewing news whatsover. Only posts for (aspiring) developers :)"),
+      sub: ['freesewing.dev', '/blog'],
+      lead: 'Developer Blog',
     }
+    // Blog post
     if (chunks.length === 2 && chunks[0] === 'blog') {
       return await loadDevBlogPost(chunks[1])
     }
+    // Other (MDX) page
+    const md = await loadMarkdownFile(page, 'dev', 'en')
+
+    // Return markdown info or default generic data
+    return md
+      ? md
+      : {
+      title: titleAsLines('FreeSewing.dev'),
+      intro: introAsLines('Documentation, guides, and howtos for contributors and developers alike'),
+      sub: ['https://freesewing.dev/', '<== Check it out'],
+      lead: 'freesewing.dev'
+    }
   },
-  org: page => ({})
+  org: async (page, site, lang) => ({})
 }
 
 /* Hide unused placeholders */
@@ -169,7 +218,7 @@ OgController.prototype.image = async function (req, res) {
   if (languages.indexOf(lang) === -1) return res.send({error: 'sorry'})
 
   // Load meta data
-  const data = await getMetaData[site](page)
+  const data = await getMetaData[site](page, site, lang)
   // Inject into SVG
   const svg = decorateSvg(data)
   // Turn into PNG

packages/backend/src/utils/index.js

@@ -12,6 +12,8 @@ import sharp from "sharp";
 export const email = mailer;
 export const log = logger;
 
+export const capitalize = string => string.charAt(0).toUpperCase() + string.slice(1);
+
 export const getHash = (email) => {
   let hash = crypto.createHash("sha256");
   hash.update(clean(email));