feat: move embedding config to a yaml file (#11611)

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

config/markdown_embeds.yml

@@ -0,0 +1,132 @@
+# Markdown Embed Configuration
+#
+# This file defines patterns and templates for converting URLs into embedded content
+# in markdown rendering. Each embed type has:
+#   - regex: Pattern with named capture groups (?<name>...)
+#   - template: HTML template with %{capture_group_name} placeholders
+#
+# To add a new embed type:
+# 1. Add a new top-level key
+# 2. Define the regex pattern with named capture groups: (?<name>pattern)
+# 3. Create an HTML template using %{name} placeholders matching the capture groups
+
+youtube:
+  regex: 'https?://(?:www\.)?(?:youtube\.com/watch\?v=|youtu\.be/)(?<video_id>[^&/]+)'
+  template: |
+    <div style="position: relative; padding-bottom: 62.5%; height: 0;">
+     <iframe
+      src="https://www.youtube-nocookie.com/embed/%{video_id}"
+      frameborder="0"
+      style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"
+      allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
+      allowfullscreen></iframe>
+    </div>
+
+loom:
+  regex: 'https?://(?:www\.)?loom\.com/share/(?<video_id>[^&/]+)'
+  template: |
+    <div style="position: relative; padding-bottom: 62.5%; height: 0;">
+      <iframe
+       src="https://www.loom.com/embed/%{video_id}"
+       frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen
+       style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
+    </div>
+
+vimeo:
+  regex: 'https?://(?:www\.)?vimeo\.com/(?<video_id>\d+)'
+  template: |
+    <div style="position: relative; padding-bottom: 62.5%; height: 0;">
+     <iframe
+      src="https://player.vimeo.com/video/%{video_id}?dnt=true"
+      frameborder="0"
+      allow="autoplay; fullscreen; picture-in-picture"
+      allowfullscreen
+      style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
+     </div>
+
+mp4:
+  regex: '(?<link_url>https?://(?:www\.)?.+\.mp4)'
+  template: |
+    <video width="640" height="360" controls>
+      <source src="%{link_url}" type="video/mp4">
+      Your browser does not support the video tag.
+    </video>
+
+arcade:
+  regex: 'https?://(?:www\.)?app\.arcade\.software/share/(?<video_id>[^&/]+)'
+  template: |
+    <div style="position: relative; padding-bottom: 62.5%; height: 0;">
+      <iframe
+        src="https://app.arcade.software/embed/%{video_id}"
+        frameborder="0"
+        webkitallowfullscreen
+        mozallowfullscreen
+        allowfullscreen
+        allow="fullscreen"
+        style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;">
+      </iframe>
+    </div>
+
+wistia:
+  regex: 'https?://(?:www\.)?[^/]+\.wistia\.com/medias/(?<video_id>[^&/]+)'
+  template: |
+    <div style="position: relative; padding-bottom: 56.25%; height: 0;">
+      <script src="https://fast.wistia.com/player.js" async></script>
+      <script src="https://fast.wistia.com/embed/%{video_id}.js" async type="module"></script>
+      <style>
+        wistia-player[media-id='%{video_id}']:not(:defined) {
+          background: center / contain no-repeat url('https://fast.wistia.com/embed/medias/%{video_id}/swatch');
+          display: block;
+          filter: blur(5px);
+          padding-top:56.25%;
+        }
+      </style>
+      <wistia-player
+        media-id="%{video_id}"
+        aspect="1.7777777777777777"
+        style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;">
+      </wistia-player>
+    </div>
+
+bunny:
+  regex: 'https?://iframe\.mediadelivery\.net/play/(?<library_id>\d+)/(?<video_id>[^&/?]+)'
+  template: |
+    <div style="position: relative; padding-top: 56.25%;">
+      <iframe
+        src="https://iframe.mediadelivery.net/embed/%{library_id}/%{video_id}?autoplay=false&loop=false&muted=false&preload=true&responsive=true"
+        title="Bunny video player"
+        loading="lazy"
+        style="border: 0; position: absolute; top: 0; height: 100%; width: 100%;"
+        allow="accelerometer; gyroscope; autoplay; encrypted-media; picture-in-picture;"
+        allowfullscreen>
+      </iframe>
+    </div>
+
+codepen:
+  regex: 'https?://(?:www\.)?codepen\.io/(?<user>[^/]+)/pen/(?<pen_id>[^/?]+)'
+  template: |
+    <div style="height: 400px; box-sizing: border-box; display: flex; align-items: center; justify-content: center;">
+      <iframe
+        height="400"
+        style="width: 100%;"
+        scrolling="no"
+        title="CodePen Embed"
+        src="https://codepen.io/%{user}/embed/%{pen_id}?default-tab=result"
+        frameborder="no"
+        loading="lazy"
+        allowtransparency="true"
+        allowfullscreen="true">
+      </iframe>
+    </div>
+
+github_gist:
+  regex: 'https?://gist\.github\.com/(?<username>[^/]+)/(?<gist_id>[a-f0-9]+)'
+  template: |
+    <script src="https://gist.github.com/%{username}/%{gist_id}.js"></script>
+    <noscript>
+      <div style="border: 1px solid #d1d9e0; border-radius: 6px; padding: 16px; margin: 16px 0; background: #f6f8fa;">
+        <a href="https://gist.github.com/%{username}/%{gist_id}" target="_blank" style="color: #0969da; text-decoration: none;">
+          View this gist on GitHub
+        </a>
+      </div>
+    </noscript>

lib/custom_markdown_renderer.rb

@@ -1,13 +1,13 @@
 class CustomMarkdownRenderer < CommonMarker::HtmlRenderer
-  # TODO: let move this regex from here to a config file where we can update this list much more easily
+  CONFIG_PATH = Rails.root.join('config/markdown_embeds.yml')
-  # the config file will also have the matching embed template as well.
+
-  YOUTUBE_REGEX = %r{https?://(?:www\.)?(?:youtube\.com/watch\?v=|youtu\.be/)([^&/]+)}
+  def self.config
-  LOOM_REGEX = %r{https?://(?:www\.)?loom\.com/share/([^&/]+)}
+    @config ||= YAML.load_file(CONFIG_PATH)
-  VIMEO_REGEX = %r{https?://(?:www\.)?vimeo\.com/(\d+)}
+  end
-  MP4_REGEX = %r{https?://(?:www\.)?.+\.(mp4)}
+
-  ARCADE_REGEX = %r{https?://(?:www\.)?app\.arcade\.software/share/([^&/]+)}
+  def self.embed_regexes
-  WISTIA_REGEX = %r{https?://(?:www\.)?([^/]+)\.wistia\.com/medias/([^&/]+)}
+    @embed_regexes ||= config.transform_values { |embed_config| Regexp.new(embed_config['regex']) }
-  BUNNY_REGEX = %r{https?://iframe\.mediadelivery\.net/play/(\d+)/([^&/?]+)}
+  end
 
   def text(node)
     content = node.string_content
@@ -23,7 +23,7 @@ class CustomMarkdownRenderer < CommonMarker::HtmlRenderer
   def link(node)
     return if surrounded_by_empty_lines?(node) && render_embedded_content(node)
 
-    # If it's not YouTube or Vimeo link, render normally
+    # If it's not a supported embed link, render normally
     super
   end
 
@@ -47,25 +47,35 @@ class CustomMarkdownRenderer < CommonMarker::HtmlRenderer
 
   def render_embedded_content(node)
     link_url = node.url
-    embedding_methods = {
+    embed_html = find_matching_embed(link_url)
-      YOUTUBE_REGEX => :make_youtube_embed,
-      VIMEO_REGEX => :make_vimeo_embed,
-      MP4_REGEX => :make_video_embed,
-      LOOM_REGEX => :make_loom_embed,
-      ARCADE_REGEX => :make_arcade_embed,
-      WISTIA_REGEX => :make_wistia_embed,
-      BUNNY_REGEX => :make_bunny_embed
-    }
 
-    embedding_methods.each do |regex, method|
+    return false unless embed_html
+
+    out(embed_html)
+    true
+  end
+
+  def find_matching_embed(link_url)
+    self.class.embed_regexes.each do |embed_key, regex|
       match = link_url.match(regex)
-      if match
+      next unless match
-        out(send(method, match))
+
-        return true
+      return render_embed_from_match(embed_key, match)
-      end
     end
 
-    false
+    nil
+  end
+
+  def render_embed_from_match(embed_key, match_data)
+    embed_config = self.class.config[embed_key]
+    return nil unless embed_config
+
+    template = embed_config['template']
+    # Use Ruby's built-in named captures with gsub to handle CSS % values
+    match_data.named_captures.each do |var_name, value|
+      template = template.gsub("%{#{var_name}}", value)
+    end
+    template
   end
 
   def parse_sup(content)
@@ -77,39 +87,4 @@ class CustomMarkdownRenderer < CommonMarker::HtmlRenderer
       end
     end
   end
-
-  def make_youtube_embed(youtube_match)
-    video_id = youtube_match[1]
-    EmbedRenderer.youtube(video_id)
-  end
-
-  def make_loom_embed(loom_match)
-    video_id = loom_match[1]
-    EmbedRenderer.loom(video_id)
-  end
-
-  def make_vimeo_embed(vimeo_match)
-    video_id = vimeo_match[1]
-    EmbedRenderer.vimeo(video_id)
-  end
-
-  def make_video_embed(link_url)
-    EmbedRenderer.video(link_url)
-  end
-
-  def make_wistia_embed(wistia_match)
-    video_id = wistia_match[2]
-    EmbedRenderer.wistia(video_id)
-  end
-
-  def make_arcade_embed(arcade_match)
-    video_id = arcade_match[1]
-    EmbedRenderer.arcade(video_id)
-  end
-
-  def make_bunny_embed(bunny_match)
-    library_id = bunny_match[1]
-    video_id = bunny_match[2]
-    EmbedRenderer.bunny(library_id, video_id)
-  end
 end

lib/embed_renderer.rb

@@ -1,102 +0,0 @@
-module EmbedRenderer
-  def self.youtube(video_id)
-    %(
-      <div style="position: relative; padding-bottom: 62.5%; height: 0;">
-       <iframe
-        src="https://www.youtube-nocookie.com/embed/#{video_id}"
-        frameborder="0"
-        style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"
-        allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
-        allowfullscreen></iframe>
-      </div>
-    )
-  end
-
-  def self.loom(video_id)
-    %(
-      <div style="position: relative; padding-bottom: 62.5%; height: 0;">
-        <iframe
-         src="https://www.loom.com/embed/#{video_id}"
-         frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen
-         style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
-      </div>
-    )
-  end
-
-  def self.vimeo(video_id)
-    %(
-      <div style="position: relative; padding-bottom: 62.5%; height: 0;">
-       <iframe
-        src="https://player.vimeo.com/video/#{video_id}?dnt=true"
-        frameborder="0"
-        allow="autoplay; fullscreen; picture-in-picture"
-        allowfullscreen
-        style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
-       </div>
-    )
-  end
-
-  def self.video(link_url)
-    %(
-      <video width="640" height="360" controls>
-        <source src="#{link_url}" type="video/mp4">
-        Your browser does not support the video tag.
-      </video>
-    )
-  end
-
-  # Generates an HTML embed for a Wistia video.
-  # @param wistia_match [MatchData] A match object from the WISTIA_REGEX regex, where wistia_match[2] contains the video ID.
-  def self.wistia(video_id)
-    %(
-      <div style="position: relative; padding-bottom: 56.25%; height: 0;">
-        <script src="https://fast.wistia.com/player.js" async></script>
-        <script src="https://fast.wistia.com/embed/#{video_id}.js" async type="module"></script>
-        <style>
-          wistia-player[media-id='#{video_id}']:not(:defined) {
-            background: center / contain no-repeat url('https://fast.wistia.com/embed/medias/#{video_id}/swatch');
-            display: block;
-            filter: blur(5px);
-            padding-top:56.25%;
-          }
-        </style>
-        <wistia-player
-          media-id="#{video_id}"
-          aspect="1.7777777777777777"
-          style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;">
-        </wistia-player>
-      </div>
-    )
-  end
-
-  def self.arcade(video_id)
-    %(
-    <div style="position: relative; padding-bottom: 62.5%; height: 0;">
-      <iframe
-        src="https://app.arcade.software/embed/#{video_id}"
-        frameborder="0"
-        webkitallowfullscreen
-        mozallowfullscreen
-        allowfullscreen
-        allow="fullscreen"
-        style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;">
-      </iframe>
-    </div>
-  )
-  end
-
-  def self.bunny(library_id, video_id)
-    %(
-      <div style="position: relative; padding-top: 56.25%;">
-        <iframe
-          src="https://iframe.mediadelivery.net/embed/#{library_id}/#{video_id}?autoplay=false&loop=false&muted=false&preload=true&responsive=true"
-          title="Bunny video player"
-          loading="lazy"
-          style="border: 0; position: absolute; top: 0; height: 100%; width: 100%;"
-          allow="accelerometer; gyroscope; autoplay; encrypted-media; picture-in-picture;"
-          allowfullscreen>
-        </iframe>
-      </div>
-    )
-  end
-end

spec/config/markdown_embeds_spec.rb

@@ -0,0 +1,103 @@
+require 'rails_helper'
+
+# rubocop:disable RSpec/DescribeClass
+describe 'Markdown Embeds Configuration' do
+  # rubocop:enable RSpec/DescribeClass
+  let(:config) { YAML.load_file(Rails.root.join('config/markdown_embeds.yml')) }
+
+  describe 'YAML structure' do
+    it 'loads valid YAML' do
+      expect(config).to be_a(Hash)
+      expect(config).not_to be_empty
+    end
+
+    it 'has required keys for each embed type' do
+      config.each do |embed_type, embed_config|
+        expect(embed_config).to have_key('regex'), "#{embed_type} missing regex"
+        expect(embed_config).to have_key('template'), "#{embed_type} missing template"
+        expect(embed_config['regex']).to be_a(String), "#{embed_type} regex should be string"
+        expect(embed_config['template']).to be_a(String), "#{embed_type} template should be string"
+      end
+    end
+
+    it 'contains expected embed types' do
+      expected_types = %w[youtube loom vimeo mp4 arcade wistia bunny codepen github_gist]
+      expect(config.keys).to match_array(expected_types)
+    end
+  end
+
+  describe 'regex patterns and named capture groups' do
+    let(:test_cases) do
+      {
+        'youtube' => [
+          { url: 'https://www.youtube.com/watch?v=dQw4w9WgXcQ', expected: { 'video_id' => 'dQw4w9WgXcQ' } },
+          { url: 'https://youtu.be/dQw4w9WgXcQ', expected: { 'video_id' => 'dQw4w9WgXcQ' } },
+          { url: 'https://youtube.com/watch?v=abc123XYZ', expected: { 'video_id' => 'abc123XYZ' } }
+        ],
+        'loom' => [
+          { url: 'https://www.loom.com/share/abc123def456', expected: { 'video_id' => 'abc123def456' } },
+          { url: 'https://loom.com/share/xyz789', expected: { 'video_id' => 'xyz789' } }
+        ],
+        'vimeo' => [
+          { url: 'https://vimeo.com/123456789', expected: { 'video_id' => '123456789' } },
+          { url: 'https://www.vimeo.com/987654321', expected: { 'video_id' => '987654321' } }
+        ],
+        'mp4' => [
+          { url: 'https://example.com/video.mp4', expected: { 'link_url' => 'https://example.com/video.mp4' } },
+          { url: 'https://www.test.com/path/to/movie.mp4', expected: { 'link_url' => 'https://www.test.com/path/to/movie.mp4' } }
+        ],
+        'arcade' => [
+          { url: 'https://app.arcade.software/share/arcade123', expected: { 'video_id' => 'arcade123' } },
+          { url: 'https://www.app.arcade.software/share/demo456', expected: { 'video_id' => 'demo456' } }
+        ],
+        'wistia' => [
+          { url: 'https://chatwoot.wistia.com/medias/kjwjeq6f9i', expected: { 'video_id' => 'kjwjeq6f9i' } },
+          { url: 'https://www.company.wistia.com/medias/abc123def', expected: { 'video_id' => 'abc123def' } }
+        ],
+        'bunny' => [
+          { url: 'https://iframe.mediadelivery.net/play/431789/1f105841-cad9-46fe-a70e-b7623c60797c',
+            expected: { 'library_id' => '431789', 'video_id' => '1f105841-cad9-46fe-a70e-b7623c60797c' } },
+          { url: 'https://iframe.mediadelivery.net/play/12345/abcdef-ghijkl', expected: { 'library_id' => '12345', 'video_id' => 'abcdef-ghijkl' } }
+        ],
+        'codepen' => [
+          { url: 'https://codepen.io/username/pen/abcdef', expected: { 'user' => 'username', 'pen_id' => 'abcdef' } },
+          { url: 'https://www.codepen.io/testuser/pen/xyz123', expected: { 'user' => 'testuser', 'pen_id' => 'xyz123' } }
+        ],
+        'github_gist' => [
+          { url: 'https://gist.github.com/username/1234567890abcdef1234567890abcdef',
+            expected: { 'username' => 'username', 'gist_id' => '1234567890abcdef1234567890abcdef' } },
+          { url: 'https://gist.github.com/testuser/fedcba0987654321fedcba0987654321', expected: { 'username' => 'testuser', 'gist_id' => 'fedcba0987654321fedcba0987654321' } }
+        ]
+      }
+    end
+
+    it 'correctly captures named groups for all embed types' do
+      test_cases.each do |embed_type, cases|
+        regex = Regexp.new(config[embed_type]['regex'])
+
+        cases.each do |test_case|
+          match = regex.match(test_case[:url])
+          expect(match).not_to be_nil, "#{embed_type} regex failed to match URL: #{test_case[:url]}"
+          expect(match.named_captures).to eq(test_case[:expected]),
+                                          "#{embed_type} captured groups don't match expected for URL: #{test_case[:url]}"
+        end
+      end
+    end
+
+    it 'validates that template variables match capture group names' do
+      config.each do |embed_type, embed_config|
+        regex = Regexp.new(embed_config['regex'])
+        template = embed_config['template']
+
+        # Extract template variables like %{video_id}
+        template_vars = template.scan(/%\{(\w+)\}/).flatten.uniq
+
+        # Get named capture groups from regex
+        capture_names = regex.names
+
+        expect(capture_names).to match_array(template_vars),
+                                 "#{embed_type}: Template variables #{template_vars} don't match capture groups #{capture_names}"
+      end
+    end
+  end
+end