FEATURE: Show more context in Discourse topic oneboxes

Currently when generating a onebox for Discourse topics, some important
context is missing such as categories and tags.

This patch addresses this issue by introducing a new onebox engine
dedicated to display this information when available. Indeed to get this
new information, categories and tags are exposed in the topic metadata
as opengraph tags.

app/assets/stylesheets/common/base/onebox.scss

@@ -738,7 +738,8 @@ aside.onebox.xkcd .onebox-body img {
 
 // allowlistedgeneric twitter labels
 .onebox.allowlistedgeneric,
-.onebox.whitelistedgeneric {
+.onebox.whitelistedgeneric,
+.onebox.discoursetopic {
   .label1,
   .label2 {
     color: var(--primary-med-or-secondary-med);
@@ -754,6 +755,7 @@ aside.onebox.xkcd .onebox-body img {
 .onebox {
   &.allowlistedgeneric,
   &.whitelistedgeneric,
+  &.discoursetopic,
   &.gfycat,
   &.githubfolder {
     .site-icon {
@@ -769,6 +771,24 @@ aside.onebox.xkcd .onebox-body img {
   }
 }
 
+.onebox.discoursetopic {
+  h3 {
+    width: 100%;
+    margin-bottom: 0.2rem !important;
+  }
+
+  .d-icon-tag {
+    width: 0.75rem;
+    padding-top: 0.3rem;
+    position: absolute;
+    color: var(--primary-medium);
+  }
+
+  .discourse-tags .discourse-tag:first-of-type {
+    padding-left: 1rem;
+  }
+}
+
 .onebox.gfycat p {
   span.label1 a {
     white-space: nowrap;

app/assets/stylesheets/common/base/tagging.scss

@@ -131,7 +131,8 @@
 .discourse-tags {
   display: inline-flex;
   flex-wrap: wrap;
-  a {
+  a,
+  span {
     margin-right: 0.25em;
   }
 }

app/helpers/application_helper.rb

@@ -311,6 +311,15 @@ module ApplicationHelper
         result << tag(:meta, { name: "twitter:#{property}", content: content }, nil, true)
       end
     end
+    Array
+      .wrap(opts[:breadcrumbs])
+      .each do |breadcrumb|
+        result << tag(:meta, property: "og:article:section", content: breadcrumb[:name])
+        result << tag(:meta, property: "og:article:section:color", content: breadcrumb[:color])
+      end
+    Array
+      .wrap(opts[:tags])
+      .each { |tag_name| result << tag(:meta, property: "og:article:tag", content: tag_name) }
 
     if opts[:read_time] && opts[:read_time] > 0 && opts[:like_count] && opts[:like_count] > 0
       result << tag(:meta, name: "twitter:label1", value: I18n.t("reading_time"))

app/views/topics/show.html.erb

@@ -132,7 +132,7 @@
 
   <% content_for :head do %>
     <%= auto_discovery_link_tag(@topic_view, {action: :feed, slug: @topic_view.topic.slug, topic_id: @topic_view.topic.id}, rel: 'alternate nofollow', title: t('rss_posts_in_topic', topic: @topic_view.title), type: 'application/rss+xml') %>
-    <%= raw crawlable_meta_data(title: @topic_view.title, description: @topic_view.summary(strip_images: true), image: @topic_view.image_url, read_time: @topic_view.read_time, like_count: @topic_view.like_count, ignore_canonical: true, published_time: @topic_view.published_time) %>
+    <%= raw crawlable_meta_data(title: @topic_view.title, description: @topic_view.summary(strip_images: true), image: @topic_view.image_url, read_time: @topic_view.read_time, like_count: @topic_view.like_count, ignore_canonical: true, published_time: @topic_view.published_time, breadcrumbs: @breadcrumbs, tags: @topic_view.tags) %>
 
     <% if @topic_view.prev_page || @topic_view.next_page %>
       <% if @topic_view.prev_page %>

lib/cooked_processor_mixin.rb

@@ -70,7 +70,7 @@ module CookedProcessorMixin
           found = false
           parent = img
           while parent = parent.parent
-            if parent["class"] && parent["class"].include?("allowlistedgeneric")
+            if parent["class"] && parent["class"].match?(/\b(allowlistedgeneric|discoursetopic)\b/)
               found = true
               break
             end

lib/onebox/engine/discourse_topic_onebox.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module Onebox
+  module Engine
+    class DiscourseTopicOnebox
+      include Engine
+      include StandardEmbed
+      include LayoutSupport
+
+      matches_regexp(%r{/t/.*(/\d+)?})
+
+      def data
+        @data ||= {
+          categories: categories,
+          link: link,
+          article_published_time: published_time.strftime("%-d %b %y"),
+          article_published_time_title: published_time.strftime("%I:%M%p - %d %B %Y"),
+          domain: html_entities.decode(raw[:site_name].truncate(80, separator: " ")),
+          description: html_entities.decode(raw[:description].truncate(250, separator: " ")),
+          title: html_entities.decode(raw[:title].truncate(80, separator: " ")),
+          image: image,
+          render_tags?: render_tags?,
+          render_category_block?: render_category_block?,
+        }.reverse_merge(raw)
+      end
+      alias verified_data data
+
+      private
+
+      def categories
+        Array
+          .wrap(raw[:article_sections])
+          .map
+          .with_index { |name, index| { name: name, color: raw[:article_section_colors][index] } }
+      end
+
+      def published_time
+        @published_time ||= Time.parse(raw[:published_time])
+      end
+
+      def html_entities
+        @html_entities ||= HTMLEntities.new
+      end
+
+      def image
+        image = Onebox::Helpers.get_absolute_image_url(raw[:image], @url)
+        Onebox::Helpers.normalize_url_for_output(html_entities.decode(image))
+      end
+
+      def render_tags?
+        raw[:article_tags].present?
+      end
+
+      def render_category_block?
+        render_tags? || categories.present?
+      end
+    end
+  end
+end

lib/onebox/normalizer.rb

@@ -4,19 +4,11 @@ module Onebox
   class Normalizer
     attr_reader :data
 
-    def get(attr, length = nil, sanitize = true)
+    def get(attr, *args)
-      return nil if Onebox::Helpers.blank?(data)
-
       value = data[attr]
-
+      return if value.blank?
-      return nil if Onebox::Helpers.blank?(value)
+      return value.map { |v| sanitize_value(v, *args) } if value.is_a?(Array)
-
+      sanitize_value(value, *args)
-      value = html_entities.decode(value)
-      value = Sanitize.fragment(value) if sanitize
-      value.strip!
-      value = Onebox::Helpers.truncate(value, length) unless length.nil?
-
-      value
     end
 
     def method_missing(attr, *args, &block)
@@ -48,5 +40,13 @@ module Onebox
     def html_entities
       @html_entities ||= HTMLEntities.new
     end
+
+    def sanitize_value(value, length = nil, sanitize = true)
+      value = html_entities.decode(value)
+      value = Sanitize.fragment(value) if sanitize
+      value.strip!
+      value = Onebox::Helpers.truncate(value, length) if length
+      value
+    end
   end
 end

lib/onebox/open_graph.rb

@@ -22,6 +22,8 @@ module Onebox
 
     private
 
+    COLLECTIONS = %i[article_section article_section_color article_tag]
+
     def extract(doc)
       return {} if Onebox::Helpers.blank?(doc)
 
@@ -33,7 +35,14 @@ module Onebox
           if (m["property"] && m["property"][/^(?:og|article|product):(.+)$/i]) ||
                (m["name"] && m["name"][/^(?:og|article|product):(.+)$/i])
             value = (m["content"] || m["value"]).to_s
-            data[$1.tr("-:", "_").to_sym] ||= value unless Onebox::Helpers.blank?(value)
+            next if Onebox::Helpers.blank?(value)
+            key = $1.tr("-:", "_").to_sym
+            data[key] ||= value
+            if key.in?(COLLECTIONS)
+              collection_name = "#{key}s".to_sym
+              data[collection_name] ||= []
+              data[collection_name] << value
+            end
           end
         end
 

lib/onebox/sanitize_config.rb

@@ -10,7 +10,7 @@ module Onebox
           Sanitize::Config::RELAXED,
           elements:
             Sanitize::Config::RELAXED[:elements] +
-              %w[audio details embed iframe source video svg path],
+              %w[audio details embed iframe source video svg path use],
           attributes: {
             "a" => Sanitize::Config::RELAXED[:attributes]["a"] + %w[target],
             "audio" => %w[controls controlslist],
@@ -40,7 +40,8 @@ module Onebox
             "path" => %w[d fill-rule],
             "svg" => %w[aria-hidden width height viewbox],
             "div" => [:data], # any data-* attributes,
-            "span" => [:data], # any data-* attributes
+            "span" => [:data], # any data-* attributes,
+            "use" => %w[href],
           },
           add_attributes: {
             "iframe" => {
@@ -89,6 +90,9 @@ module Onebox
             "source" => {
               "src" => HTTP_PROTOCOLS,
             },
+            "use" => {
+              "href" => [:relative],
+            },
           },
           css: {
             properties: Sanitize::Config::RELAXED[:css][:properties] + %w[--aspect-ratio],

lib/onebox/templates/discoursetopic.mustache

@@ -0,0 +1,42 @@
+{{#image}}<img src="{{image}}" class="thumbnail"/>{{/image}}
+
+<div class="title-wrapper">
+  <h3><a href="{{link}}" target="_blank" rel="noopener">{{title}}</a></h3>
+  {{#render_category_block?}}
+  <div class="topic-category">
+    {{#categories}}
+      <span class="badge-wrapper bullet">
+        <span class="badge-category-bg" style="background-color: #{{color}};"></span>
+        <span class="badge-category clear-badge">
+          <span class="category-name">{{name}}</span>
+        </span>
+      </span>
+    {{/categories}}
+    {{#render_tags?}}
+    <div class="topic-header-extra">
+      <div class="list-tags">
+        <div class="discourse-tags">
+          <svg class="fa d-icon d-icon-tag svg-icon svg-string" xmlns="http://www.w3.org/2000/svg"><use href="#tag" /></svg>
+          {{#article_tags}}
+            <span class="discourse-tag simple">{{.}}</span>
+          {{/article_tags}}
+        </div>
+      </div>
+    </div>
+    {{/render_tags?}}
+  </div>
+  {{/render_category_block?}}
+</div>
+
+{{#description}}
+  <p>{{description}}</p>
+{{/description}}
+
+{{#data1}}
+  <p>
+    <span class="label1">{{label1}}: {{data1}}</span>
+    {{#data2}}
+      <span class="label2">{{label2}}: {{data2}}</span>
+    {{/data2}}
+  </p>
+{{/data1}}

lib/topic_view.rb

@@ -713,6 +713,10 @@ class TopicView
     @mentioned_users = mentioned_users.to_h { |u| [u.username, u] }
   end
 
+  def tags
+    @topic.tags.map(&:name)
+  end
+
   protected
 
   def read_posts_set
@@ -814,13 +818,9 @@ class TopicView
   end
 
   def find_topic(topic_or_topic_id)
-    if topic_or_topic_id.is_a?(Topic)
+    return topic_or_topic_id if topic_or_topic_id.is_a?(Topic)
-      topic_or_topic_id
+    # with_deleted covered in #check_and_raise_exceptions
-    else
+    Topic.with_deleted.includes(:category, :tags).find_by(id: topic_or_topic_id)
-      # with_deleted covered in #check_and_raise_exceptions
-      finder = Topic.with_deleted.where(id: topic_or_topic_id).includes(:category)
-      finder.first
-    end
   end
 
   def unfiltered_posts

spec/fixtures/onebox/discourse_topic.response

@@ -194,6 +194,10 @@ And that too in just over an year, way to go! [boom]">
 <meta name="twitter:data2" value="9 ❤" />
 <meta property="article:published_time" content="2014-02-06T04:55:19+00:00" />
 <meta property="og:ignore_canonical" content="true" />
+<meta property="og:article:section" content="praise" />
+<meta property="og:article:section:color" content="9EB83B" />
+<meta property="og:article:tag" content="how-to" />
+<meta property="og:article:tag" content="sso" />
 
 
 

spec/helpers/application_helper_spec.rb

@@ -640,6 +640,38 @@ RSpec.describe ApplicationHelper do
         expect(helper.crawlable_meta_data).not_to include("twitter:image")
       end
     end
+
+    context "with breadcrumbs" do
+      subject(:metadata) { helper.crawlable_meta_data(breadcrumbs: breadcrumbs) }
+
+      let(:breadcrumbs) do
+        [{ name: "section1", color: "ff0000" }, { name: "section2", color: "0000ff" }]
+      end
+      let(:tags) { <<~HTML.strip }
+        <meta property="og:article:section" content="section1" />
+        <meta property="og:article:section:color" content="ff0000" />
+        <meta property="og:article:section" content="section2" />
+        <meta property="og:article:section:color" content="0000ff" />
+        HTML
+
+      it "generates section and color tags" do
+        expect(metadata).to include tags
+      end
+    end
+
+    context "with tags" do
+      subject(:metadata) { helper.crawlable_meta_data(tags: tags) }
+
+      let(:tags) { %w[tag1 tag2] }
+      let(:output_tags) { <<~HTML.strip }
+        <meta property="og:article:tag" content="tag1" />
+        <meta property="og:article:tag" content="tag2" />
+        HTML
+
+      it "generates tag tags" do
+        expect(metadata).to include output_tags
+      end
+    end
   end
 
   describe "discourse_color_scheme_stylesheets" do

spec/lib/onebox/engine/discourse_topic_onebox_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+RSpec.describe Onebox::Engine::DiscourseTopicOnebox do
+  subject(:onebox) { described_class.new(url) }
+
+  describe "#data" do
+    subject(:data) { onebox.data }
+
+    let(:url) do
+      "https://meta.discourse.org/t/congratulations-most-stars-in-2013-github-octoverse/12483"
+    end
+    let(:expected_data) do
+      {
+        article_published_time: "6 Feb 14",
+        article_published_time_title: "04:55AM - 06 February 2014",
+        article_tags: %w[how-to sso],
+        card: "summary",
+        categories: [{ name: "praise", color: "9EB83B" }],
+        data1: "1 mins 🕑",
+        data2: "9 ❤",
+        description:
+          "Congratulations Discourse for qualifying Repositories with the most stars on GitHub Octoverse.     And that too in just over an year, way to go! 💥",
+        domain: "Discourse Meta",
+        favicon:
+          "https://d11a6trkgmumsb.cloudfront.net/optimized/3X/b/3/b33be9538df3547fcf9d1a51a4637d77392ac6f9_2_32x32.png",
+        ignore_canonical: "true",
+        image:
+          "https://d11a6trkgmumsb.cloudfront.net/optimized/2X/d/d063b3b0807377d98695ee08042a9ba0a8c593bd_2_690x362.png",
+        label1: "Reading time",
+        label2: "Likes",
+        link:
+          "https://meta.discourse.org/t/congratulations-most-stars-in-2013-github-octoverse/12483",
+        published_time: "2014-02-06T04:55:19+00:00",
+        render_category_block?: true,
+        render_tags?: true,
+        site_name: "Discourse Meta",
+        title: "Congratulations, most stars in 2013 GitHub Octoverse!",
+        url:
+          "https://meta.discourse.org/t/congratulations-most-stars-in-2013-github-octoverse/12483",
+      }
+    end
+
+    before do
+      stub_request(:get, url).to_return(status: 200, body: onebox_response("discourse_topic"))
+    end
+
+    it "returns the expected data" do
+      expect(data).to include expected_data
+    end
+  end
+end

spec/lib/onebox/open_graph_spec.rb

@@ -24,4 +24,32 @@ RSpec.describe Onebox::OpenGraph do
     og = described_class.new(doc)
     expect(og.image).to eq("http://test.com/test'ing.mp3")
   end
+
+  describe "Collections" do
+    subject(:graph) { described_class.new(doc) }
+
+    let(:doc) { Nokogiri.HTML(<<-HTML) }
+      <html>
+        <title>test</title>
+        <meta property="og:article:tag" content="&lt;b&gt;tag1&lt;/b&gt;" />
+        <meta property="og:article:tag" content="tag2" />
+        <meta property="og:article:section" content="category1" />
+        <meta property="og:article:section" content="category2" />
+        <meta property="og:article:section:color" content="ff0000" />
+        <meta property="og:article:section:color" content="0000ff" />
+      </html>
+      HTML
+
+    it "handles multiple article:tag tags" do
+      expect(graph.article_tags).to eq %w[tag1 tag2]
+    end
+
+    it "handles multiple article:section tags" do
+      expect(graph.article_sections).to eq %w[category1 category2]
+    end
+
+    it "handles multiple article:section:color tags" do
+      expect(graph.article_section_colors).to eq %w[ff0000 0000ff]
+    end
+  end
 end

spec/lib/topic_view_spec.rb

@@ -1072,4 +1072,17 @@ RSpec.describe TopicView do
       end
     end
   end
+
+  describe "#tags" do
+    subject(:topic_view_tags) { topic_view.tags }
+
+    let(:topic_view) { described_class.new(topic, user) }
+    let(:topic) { Fabricate.build(:topic, tags: tags) }
+    let(:tags) { Fabricate.build_times(2, :tag) }
+    let(:user) { Fabricate(:user) }
+
+    it "returns the tags names" do
+      expect(topic_view_tags).to match tags.map(&:name)
+    end
+  end
 end