Markdown preview through AJAX (/ajax/preview)

app/controllers/ajax/question_controller.rb

@@ -46,4 +46,20 @@ class Ajax::QuestionController < ApplicationController
     @message = "Question asked successfully."
     @success = true
   end
+
+  def preview
+    params.require :md
+
+    @message = "Failed to render markdown."
+    begin
+      @markdown = markdown(params[:md], Time.new)
+      @message = "Successfully rendered markdown."
+    rescue
+      @status = :fail
+      @success = false
+      return
+    end
+    @status = :okay
+    @success = true
+  end
 end

app/views/ajax/question/preview.json.jbuilder

@@ -0,0 +1,2 @@
+json.partial! 'ajax/shared/status'
+json.markdown @markdown if @markdown

config/routes.rb

@@ -81,6 +81,7 @@ Rails.application.routes.draw do
     match '/create_group', to: 'group#create', via: :post, as: :create_group
     match '/destroy_group', to: 'group#destroy', via: :post, as: :destroy_group
     match '/group_membership', to: 'group#membership', via: :post, as: :group_membership
+    match '/preview', to: "question#preview", via: :post, as: :preview
   end
 
   match '/public', to: 'public#index', via: :get, as: :public_timeline
@@ -89,7 +90,7 @@ Rails.application.routes.draw do
   match '/notifications(/:type)', to: 'notifications#index', via: :get, as: :notifications, defaults: {type: 'all'}
 
   match '/inbox', to: 'inbox#show', via: 'get'
-  
+
   match '/user/:username(/p/:page)', to: 'user#show', via: 'get', defaults: {page: 1}
   match '/@:username(/p/:page)', to: 'user#show', via: 'get', as: :show_user_profile_alt, defaults: {page: 1}
   match '/@:username/a/:id', to: 'answer#show', via: 'get', as: :show_user_answer_alt