微信jssdk分享功能开发及解决ajax跨域的问题

1月9日,腾讯正式面向开发者开放微信内网页开发工具包(微信JS-SDK)，造成以前用js写的微信分享功能都失效了。只好对对着jssdk说明文档重新开发。

微信JS-SDK说明文档

微信JS-SDK Demo

我所要实现的分享功能要求：只要提供一段js代码给前端美工放置在静态页面等就可以实现分享功能。

js代码如下：

<script>

 url=location.href;

url = url.replace("&","55555");

//为了解决微信客户端会在你的链接末尾加入其它参数，如果不是动态获取当前链接，将导致分享后的页面签名失败问题。把链接地址中出现的&替换临时字符。否则后台处理就得不到完整的地址链接了。

  $.ajax({

    type : "get",

    url : "http://域名/wx/test/jssdk.php?url="+url,

    dataType : "jsonp",

    jsonp: "callback",

    jsonpCallback:"success_jsonpCallback",

    success : function(data){

        wx.config({
appId: data.appId,
timestamp: data.timestamp,
nonceStr: data.nonceStr,
signature: data.signature,
jsApiList: [
"onMenuShareTimeline",
"onMenuShareAppMessage"
]
});
},

                error:function(data){

                    alert("连接失败！");

                }

});

  wx.ready(function (){
 var shareData = {
title: '霾黄色预警昨发布 冷空气昨夜到温 雾霾可能消散',
desc: '在长大的过程中，我才慢慢发现，我身边的所有事，别人跟我说的所有事，那些所谓本来如此，注定如此的事，它们其实没有非得如此，事情是可以改变的。更重要的是，有些事既然错了，那就该做出改变。',
link: 'http://news.wendu.cn/2015/0127/482049.shtml',
imgUrl: 'http://upload.wendu.cn/2015/0127/1422306020538.jpg'
};
wx.onMenuShareAppMessage(shareData);
wx.onMenuShareTimeline(shareData);

    });

</script>

为了便于在不同的域名下面页面调用，用了jsonp（json的一种使用模式）来解决跨域数据访问的问题。

 url=location.href;获取当前网址，以参数的方式传给jssdk.php进行签名验证。 
url : "http://域名/wx/test/jssdk.php?url="+url

jssdk.php是在微信JS-SDK　DEMO的基础上进行了修改。代码如下：

<?php

 $url = $_GET['url'];

 $url = str_replace("55555","&",$url);

//上面JS里&被替换的，在这里要替换回去。

class JSSDK {

  private $appId;

  private $appSecret;

  private $url;

  public function __construct($appId, $appSecret,$url) {

    $this->appId = $appId;

    $this->appSecret = $appSecret;
$this->url = $url;

  }

  public function getSignPackage() {

    $jsapiTicket = $this->getJsApiTicket();

    $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";

   // $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$url =$this->url;

    $timestamp = time();

    $nonceStr = $this->createNonceStr();

    // 这里参数的顺序要按照 key 值 ASCII 码升序排序

    $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr×tamp=$timestamp&url=$url";

    $signature = sha1($string);

    $signPackage = array(

      "appId"     => $this->appId,

      "nonceStr"  => $nonceStr,

      "timestamp" => $timestamp,

      "url"       => $url,

      "signature" => $signature,

      "rawString" => $string

    );

    return $signPackage; 

  }

  private function createNonceStr($length = 16) {

    $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

    $str = "";

    for ($i = 0; $i < $length; $i++) {

      $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);

    }

    return $str;

  }

  private function getJsApiTicket() {

    // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例

    $data = json_decode(file_get_contents("jsapi_ticket.json"));

    if ($data->expire_time < time()) {

      $accessToken = $this->getAccessToken();

      // 如果是企业号用以下 URL 获取 ticket

      // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi
4000
_ticket?access_token=$accessToken";

      $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";

      $res = json_decode($this->httpGet($url));

      $ticket = $res->ticket;

      if ($ticket) {

        $data->expire_time = time() + 7000;

        $data->jsapi_ticket = $ticket;

        $fp = fopen("jsapi_ticket.json", "w");

        fwrite($fp, json_encode($data));

        fclose($fp);

      }

    } else {

      $ticket = $data->jsapi_ticket;

    }

    return $ticket;

  }

  private function getAccessToken() {

    // access_token 应该全局存储与更新，以下代码以写入到文件中做示例

    $data = json_decode(file_get_contents("access_token.json"));

    if ($data->expire_time < time()) {

      // 如果是企业号用以下URL获取access_token

      // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";

      $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";

      $res = json_decode($this->httpGet($url));

      $access_token = $res->access_token;

      if ($access_token) {

        $data->expire_time = time() + 7000;

        $data->access_token = $access_token;

        $fp = fopen("access_token.json", "w");

        fwrite($fp, json_encode($data));

        fclose($fp);

      }

    } else {

      $access_token = $data->access_token;

    }

    return $access_token;

  }

  private function httpGet($url) {

    $curl = curl_init();

    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

    curl_setopt($curl, CURLOPT_TIMEOUT, 500);

    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);

    curl_setopt($curl, CURLOPT_URL, $url);

    $res = curl_exec($curl);

    curl_close($curl);

    return $res;

  }

}

$jssdk = new JSSDK("公众号", "公众号密钥",$url);

$signPackage = $jssdk->GetSignPackage();

$tmp=json_encode(array ('appId'=>$signPackage["appId"],'timestamp'=>$signPackage["timestamp"],'nonceStr'=>$signPackage["nonceStr"],'signature'=>$signPackage["signature"],'url'=>$signPackage["url"]));

$callback = $_GET['callback'];

echo $callback.'('.$tmp.')';

exit;

?>