controller.rb

require 'mini_magick'

class CustomAdmin::MiniCaptchaController < CustomAdmin::ApplicationController

 

  before_filter :clear_captcha_session, :only => :mini_captcha

 

  def mini_captcha

    send_data(
    
    generate_mini_captcha_image,
    
    :type => 'image/jpeg',
    
    :disposition => 'inline',
    
    :filename => 'mini_captcha.jpg')
  
  end

 

  private

 

  # TODO: 在内存中生成验证码图片

  def generate_mini_captcha_image(opts = {})

    label = SecureRandom.hex(3)
    
    session[:captcha] = label
    
    image = MiniMagick::Image.new('mini_captcha.jpg')
    
    image.run_command("convert -pointsize 16 -kerning 1 +noise Laplacian -undercolor lightgrey label:#{label} mini_captcha.jpg")
    
    image.to_blob

  end

 

 

 

end

helper.rb

module CustomAdmin

  module ApplicationHelper
  
 

    def show_mini_captcha
  
      raw "<img src='mini_captcha?v=#{Time.now.to_i}'/>"
  
    end

 

 

  end

end

routes.rb

map.namespace :custom_admin do |custom_admin|

  custom_admin.mini_captcha 'mini_captcha', :controller => 'mini_captcha', :action => 'mini_captcha'

end