Add JSON endpoint to get simple blob viewer

app/controllers/concerns/renders_blob.rb

+module RendersBlob
+  extend ActiveSupport::Concern
+
+  def render_blob_json(blob)
+    viewer =
+      if params[:viewer] == 'rich'
+        blob.rich_viewer
+      else
+        blob.simple_viewer
+      end
+    return render_404 unless viewer
+
+    render json: {
+      html: view_to_html_string("projects/blob/_viewer", viewer: viewer)
+    }
+  end
+end

app/controllers/projects/blob_controller.rb

@@ -2,6 +2,7 @@
 class Projects::BlobController < Projects::ApplicationController
   include ExtractsPath
   include CreatesCommit
+  include RendersBlob
   include ActionView::Helpers::SanitizeHelper
 
   # Raised when given an invalid file path
@@ -34,8 +35,18 @@ class Projects::BlobController < Projects::ApplicationController
   end
 
   def show
-    environment_params = @repository.branch_exists?(@ref) ? { ref: @ref } : { commit: @commit }
-    @environment = EnvironmentsFinder.new(@project, current_user, environment_params).execute.last
+    respond_to do |format|
+      format.html do
+        environment_params = @repository.branch_exists?(@ref) ? { ref: @ref } : { commit: @commit }
+        @environment = EnvironmentsFinder.new(@project, current_user, environment_params).execute.last
+
+        render 'show'
+      end
+
+      format.json do
+        render_blob_json(@blob)
+      end
+    end
   end
 
   def edit