json - Rails: Calling Model methods in to_json(:methods => [:model_method]) -

i've defined 2 methods in model image_url & thumb_urlto absolute url of images , thumbs , calling them in controller .to_json() method.

when view json response shows image_url not thumb_url please guide me doing wrong here.

model :

class post < activerecord::base   include rails.application.routes.url_helpers      validates :image, presence: true        has_attached_file :image, styles: { :medium => "640x", thumb: "100x100#" } # # means crop image         validates_attachment_content_type :image, :content_type => /\aimage\/.*\z/    def image_url    relative_path =  image.url(:medium)    self.add_host_prefix relative_path   end   def thumb_url    relative_path = image.url(:thumb)    self.add_host_prefix relative_path  end    def add_host_prefix(url)     uri.join(root_url, url).to_s   end end 

controller :

class api::imagescontroller < applicationcontroller    def index     @posts =  post.all.order(id: :desc)     paginated_records = @posts.paginate(:page => params[:page], :per_page => params[:per_page])     @posts = with_pagination_info( paginated_records )     render :json => @posts.to_json(:methods => [:thumb_url], :methods =>[:image_url])   end end 

here json response:

"data": [{ "id": 23, "caption": "world top view", "created_at": "2015-09-17t14:10:57.278z", "updated_at": "2015-09-17t14:10:57.278z", "image_file_name": "world.topo.bathy.200401.3x21600x10800.jpg", "image_content_type": "image/jpeg", "image_file_size": 29698041, "image_updated_at": "2015-09-17t14:10:36.975z", "image_url": "http://localhost:3000/system/posts/images/000/000/023/medium/world.topo.bathy.200401.3x21600x10800.jpg?1442499036"} 

you can't pass 2 :methods keys hash, last key used. remember key hash has unique. if want mulitiple methods, should do...

render :json => @posts.to_json(:methods => [:thumb_url, :image_url])