I am having a Trouble to check if that param is empty or not on ruby on rails -

i trying check if user_avatar present or not form(submitted user).if select different image update need go cropping otherwise redirect edit page.

but if run bellow code on controller directly redirecting edit page if select , send image also.

controller

if @user.update(user_params)       if((@user.user_avatar.present?) && (!params[:user_avatar].blank?) )        format.html { render :action => 'crop'}       else         format.html { redirect_to edit_user_path, notice: 'user updated.' }        format.json { head :no_content }      end  else     format.html { render action: 'edit' }     format.json { render json: @user.errors, status: :unprocessable_entity } 

end

def user_params params.require(:user).permit(:user, :crop_x, :crop_y, :crop_w, :crop_h,  :user_avatar, :fname, :lname,  :city_id, :location_id, :email, :password, :course, :phone_no) end 

in rails can use has_key? method returns true or false, rewriting above if condition

if @user.user_avatar.present? , params[:user].has_key?(:user_avatar)   # code end