FEATURE: support markdown rendering for embedded posts

app/models/topic_embed.rb

@@ -48,11 +48,17 @@ class TopicEmbed < ActiveRecord::Base
       Topic.transaction do
         eh = EmbeddableHost.record_for_url(url)
 
+        cook_method = if SiteSetting.embed_support_markdown
+          Post.cook_methods[:regular]
+        else
+          Post.cook_methods[:raw_html]
+        end
+
         creator = PostCreator.new(user,
                                   title: title,
                                   raw: absolutize_urls(url, contents),
                                   skip_validations: true,
-                                  cook_method: Post.cook_methods[:raw_html],
+                                  cook_method: cook_method,
                                   category: eh.try(:category_id))
         post = creator.create
         if post.present?

config/locales/server.en.yml

@@ -1558,6 +1558,7 @@ en:
     highlighted_languages: "Included syntax highlighting rules. (Warning: including too many languages may impact performance) see: https://highlightjs.org/static/demo/ for a demo"
 
     embed_truncate: "Truncate the embedded posts."
+    embed_support_markdown: "Support Markdown formatting for embedded posts."
     allowed_href_schemes: "Schemes allowed in links in addition to http and https."
     embed_post_limit: "Maximum number of posts to embed."
     embed_username_required: "The username for topic creation is required."

config/site_settings.yml

@@ -656,6 +656,8 @@ posting:
      - code-fences
   embed_truncate:
     default: true
+  embed_support_markdown:
+    default: false
   allowed_href_schemes:
     client: true
     default: ''

spec/models/topic_embed_spec.rb

@@ -58,6 +58,19 @@ describe TopicEmbed do
       end
     end
 
+    context "post creation supports markdown rendering" do
+      before do
+        SiteSetting.embed_support_markdown = true
+      end
+
+      it "works as expected" do
+        post = TopicEmbed.import(user, url, title, "some random content")
+        expect(post).to be_present
+
+        # It uses regular rendering
+        expect(post.cook_method).to eq(Post.cook_methods[:regular])
+      end
+    end
   end
 
   context '.topic_id_for_embed' do