微信扫码登陆获取unionid

1.准备工作 登陆微信开放平台，申请对应的应用，获取AppID，AppSecret；

index.php

//设置redirect_uri
$backUrl=urlEncode("http://www.baidu.com/index.php?act=check");
$smarty->assign('backUrl',$backUrl);
$smarty->display('index.html');

$action=$_REQUEST['act']?$_REQUEST['act']:'';           
           
if ($action == 'check'){
    $code=$_GET['code'];
    $unionid=checkUid($code);
}
             
 //获取unionid    
function checkUid($code){
    $data=file_get_contents("https://api.weixin.qq.com/sns/oauth2/access_token?appid=wxc7ce8558&secret=87b630c82952rtr2t1ret535807&code=". $code . "&grant_type=authorization_code");
    $data=json_decode($data,true);
    $unionid=$data['unionid'];
    return $unionid;
}

index.html

<a href="https://open.weixin.qq.com/connect/qrconnect?appid=wxc7ce8558&redirect_uri={$backUrl}&response_type=code&scope=snsapi_login&state=STATE#wechat_redirect"  style="margin-left:15px;" >
   <img src="static/picture/Wechat.png" alt="微信登录" style="width: 25px; height: 25px; vertical-align: middle;">
</a>