Use ThinkPHP as the backend for WeChat login

login: function(e) {
        var that = this;
        wx.login({
          success: function(res){
            var code = res.code;  //获取code
            wx.getUserInfo({  //得到rawData, signatrue, encryptData
              success: function(data){
                var rawData = data.rawData;
                var signature = data.signature;
                var encryptedData = data.encryptedData; 
                var iv = data.iv;
                wx.request({
                  url: '你自己的后台地址',
                  data: {
                    "code" : code,
                    "rawData" : rawData,
                    "signature" : signature,
                    'iv' : iv,
                    'encryptedData': encryptedData
                  },
                  method: 'GET', 
                  success: function(info){
                    console.log(info);
                  }
                })
              }
            })
          },
        })
    }

//开发者使用登陆凭证 code 获取 session_key 和 openid
$APPID = '';
$AppSecret = '';
$code = I('get.code');
$url="https://api.weixin.qq.com/sns/jscode2session?appid=".$APPID."&secret=".$AppSecret."&js_code=".$code."&grant_type=authorization_code";
$arr = vget($url);  // 一个使用curl实现的get方法请求
$arr = json_decode($arr,true);
$openid = $arr['openid'];
$session_key = $arr['session_key'];

// 数据签名校验
$signature = I('get.signature');
$signature2 = sha1($_GET['rawData'].$session_key);  //记住不应该用TP中的I方法，会过滤掉必要的数据
if ($signature != $signature2) {
    echo '数据签名验证失败！';die;
}

//开发者如需要获取敏感数据，需要对接口返回的加密数据( encryptedData )进行对称解密
Vendor("PHP.wxBizDataCrypt");  //加载解密文件，在官方有下载
$encryptedData = $_GET['encryptedData'];
$iv = $_GET['iv'];
$pc = new \WXBizDataCrypt($APPID, $session_key);
$errCode = $pc->decryptData($encryptedData, $iv, $data);  //其中$data包含用户的所有数据
if ($errCode != 0) {
    echo '解密数据失败！';die;
}

//生成第三方3rd_session
$session3rd  = null;
$strPol = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
$max = strlen($strPol)-1;
for($i=0;$i<16;$i++){
    $session3rd .=$strPol[rand(0,$max)];
}
echo $session3rd;

public function vget($url){
    $info=curl_init();
    curl_setopt($info,CURLOPT_RETURNTRANSFER,true);
    curl_setopt($info,CURLOPT_HEADER,0);
    curl_setopt($info,CURLOPT_NOBODY,0);
    curl_setopt($info,CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($info,CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($info,CURLOPT_URL,$url);
    $output= curl_exec($info);
    curl_close($info);
    return $output;
}