Support StackBlitz embed

Author: tsuzuki-takaaki

lib/qiita/markdown.rb

@@ -18,6 +18,7 @@
 require "qiita/markdown/embed/speeker_deck"
 require "qiita/markdown/embed/docswell"
 require "qiita/markdown/embed/figma"
+require "qiita/markdown/embed/stack_blitz"
 require "qiita/markdown/transformers/filter_attributes"
 require "qiita/markdown/transformers/filter_script"
 require "qiita/markdown/transformers/filter_iframe"

lib/qiita/markdown/embed/stack_blitz.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Qiita
+  module Markdown
+    module Embed
+      module StackBlitz
+        SCRIPT_HOST = "stackblitz.com"
+      end
+    end
+  end
+end

lib/qiita/markdown/transformers/filter_iframe.rb

@@ -11,6 +11,7 @@ class FilterIframe
           Embed::Docswell::SCRIPT_HOSTS,
           Embed::Figma::SCRIPT_HOST,
           Embed::GoogleDrive::SCRIPT_HOST,
+          Embed::StackBlitz::SCRIPT_HOST,
         ].flatten.freeze
 
         def self.call(**args)

spec/qiita/markdown/processor_spec.rb

@@ -1747,6 +1747,43 @@
         end
       end
 
+      context "with HTML embed code for StackBlitz" do
+        shared_examples "embed code stackblitz example" do
+          let(:markdown) do
+            <<~MARKDOWN
+              <iframe src="#{url}" width="800" height="600" frameborder="0" allowfullscreen="true"></iframe>
+            MARKDOWN
+          end
+          let(:url) { "#{scheme}//stackblitz.com/embed/example" }
+
+          if allowed
+            it "does not sanitize embed code" do
+              should eq <<~HTML
+                <iframe src="#{url}" width="800" height="600" frameborder="0" allowfullscreen="true"></iframe>
+              HTML
+            end
+          else
+            it "forces width attribute on iframe" do
+              should eq <<~HTML
+                <iframe src="#{url}" width="100%" height="600" frameborder="0" allowfullscreen="true"></iframe>
+              HTML
+            end
+          end
+        end
+
+        context "with scheme" do
+          let(:scheme) { "https:" }
+
+          include_examples "embed code stackblitz example"
+        end
+
+        context "without scheme" do
+          let(:scheme) { "" }
+
+          include_examples "embed code stackblitz example"
+        end
+      end
+
       context "with embed code for Tweet" do
         let(:markdown) do
           <<-MARKDOWN.strip_heredoc