验证码之google的reCAPTCHA使用

天热了，各种选秀节目不断，互联网活动上的各种选秀节目也不少。有了选秀，就会有投票，票数的多少导致的名次先后之争直接牵扯到选手的利益。于是，各种刷票产业应运而生。

笔者用过各种防刷票的方法来杜绝，基本都无用。每次活动经历刷票工具的攻城拔寨后，票数暴涨。

最近采用了google的reCAPTCHA验证码机制，刷票基本杜绝。具体使用方法记录如下，已被后用。

1、首先申请API Keys

URL: https://www.google.com/recaptcha/admin/create

2、非插件方式

页面端代码方式一：直接页面显示

页面端代码方式二：AJAX

用户输入验证：ajax请求

URL: http://www.google.com/recaptcha/api/verify

Parameters (sent via POST)
privatekey (required)	Your private key
remoteip (required)	The IP address of the user who solved the CAPTCHA.
challenge (required)	The value of "recaptcha_challenge_field" sent via the form
response (required)	The value of "recaptcha_response_field" sent via the form

Recaptcha.get_challenge() 获取challenge;

Recaptcha.get_response() 获取 response.

返回：

Line 1

"true" or "false". True if the reCAPTCHA was successful

Line 2

if Line 1 is false, then this string will be an error code. reCAPTCHA can display the error to the user (through theerror parameter of www.google.com/recaptcha/api/challenge). Implementations should not depend on error code names, as they may change in the future. Example: If your response looks like this: false incorrect-captcha-sol ... you can add '&error=incorrect-captcha-sol' to the challenge request URL, and the user will get an error code.

3、使用PHP的插件方式

客户端：

服务器端：

is_valid) {
    // What happens when the CAPTCHA was entered incorrectly
    die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." .
         "(reCAPTCHA said: " . $resp->error . ")");
  } else {
    // Your code here to handle a successful verification
  }
?>

文档地址：https://developers.google.com/recaptcha/intro?hl=zh-CN