自定义分享

分享的时候，网站可以指定用户分享的内容和图片，叫做自定义分享，根据微信提供的jsapi，我们可以实现网页的分享标题，描述，图片和链接的指定分享。

使用条件

要想使用微信分享，需要满足以下几个条件。

• 在微信中访问网页
• 在微信公众号中申请认证
• 配置域名ip白名单

分享配置

1. 引入官方最新版分享js的sdk.

   <script src="http://res.wx.qq.com/open/js/jweixin-1.6.0.js"></script>

2. 后台引入sdk,生成签名等信息。

   <?php
   
   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;
     }
   }
     $url = 'http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
   $jssdk = new JSSDK("公众号ID", "公众号密钥",$url);//按照自己的公众号填写
   $signPackage = $jssdk->GetSignPackage();
   $data=json_encode(array ('appId'=>$signPackage["appId"],'timestamp'=>$signPackage["timestamp"],'nonceStr'=>$signPackage["nonceStr"],'signature'=>$signPackage["signature"],'url'=>$signPackage["url"]));
   $this->assign('data',$data);
   exit;
   ?>

3. 页面设置配置

   <script>
   wx.config({
   　　　　 debug: true, // 开启调试模式,调用的所有api的返回值会在客户端alert出来，若要查看传入的参数，可以在pc端打开，参数信息会通过log打出，仅在pc端时才会打印
   　　　　 appId: data.appId,
   　　　　 timestamp: data.timestamp,
   　　　　 nonceStr: data.nonceStr,
   　　　　 signature: data.signature,
   　　　　 jsApiList: [
          　　"onMenuShareTimeline", //分享给好友
          　　"onMenuShareAppMessage", //分享到朋友圈
          　　"onMenuShareQQ",  //分享到QQ
          　　"onMenuShareWeibo" //分享到微博
   ]
   });
   </script> 

4. 设置分享配置

   <script>
   wx.ready(function (){
     var shareData = {
     title: '标题',
     desc: '简介',//这里请特别注意是要去除html
     link: '链接',
     imgUrl: '标题图'
     };
     wx.onMenuShareAppMessage(shareData);
     wx.onMenuShareTimeline(shareData);
     wx.onMenuShareQQ(shareData);
     wx.onMenuShareWeibo(shareData);
   });
   </script>

注意事项

• 公众号需要认证
• 静态页面需要使用ajax来动态获取签名等信息
• 分享链接注意转义
• 调试的时候开启debug
• 注意js可能存在的报错