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;
  $.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'];
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=$nonceStr&timestamp=$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
      // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$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;
?>