H5页面获取微信用户openid极简攻略

背景

之前每次写到获取openid 就觉得特别麻烦，网上很多代码段会把一部分功能分开写，确实相对合理，但是对于复制粘贴代码来说依赖越少越方便，所以根据自己的经验做了一个极简的复用代码。

前置条件

1.公众号已认证，否则会出现“Scope 参数错误或没有 Scope 权限”
2.公众号后台设置安全域名
【公众号设置】=》【功能设置】=》【JS接口安全域名】&【网页授权域名】

前端

getUrlParam(name){
  return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.href) || [, ""])[1].replace(/\+/g, '%20')) || null
}

getOpenId(){
  let ua = navigator.userAgent.toLowerCase();
        if (/micromessenger/.test(ua)) {
            if (!localStorage.getItem('wxOpenid')) {
                const code = getUrlParam('code'); // 截取路径中的code,
                if (code == null || code === '' || code === false) {
                    const local = location.href;
                    let appid = 'xxxxxxx';
                    window.location.href =
                        'https://open.weixin.qq.com/connect/oauth2/authorize?appid=' +
                        appid +
                        '&redirect_uri=' +
                        encodeURIComponent(local) +
                        '&response_type=code&scope=snsapi_base&state=1#wechat_redirect';
                } else {
                    this.$axios.post('/index/index/getWxOpenid?code=' + code).then(res => {
                        const openid = res.data.data.openid;
                        if (openid) {
                            localStorage.setItem('wxOpenid', openid);
                        } else {
                            location.href = '/';
                        }
                    });
                }
            }
        }
}

后端

如果只是需要获取到openid,不需要其他信息

public function getOpenid(){
  $appid = '<公众号appid>';
  $secret = '<公众号secret>';
  $code = $_GET["code"];
  $url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=" . $appid . "&secret=" . $secret. "&code=" . $code . "&grant_type=authorization_code";
  $weixin = file_get_contents($url);
  $jsondecode = json_decode($weixin);
  return result(1, $jsondecode, '成功');
  }

如果需要根据openid进一步获取用户信息

public function getUserInfo(){
    $appid = '<公众号appid>';
    $secret = '<公众号secret>';
    $code = $_GET["code"];
    $get_token_url = 'https://api.weixin.qq.com/sns/oauth2/access_token?appid='.$appid.'&secret='.$secret.'&code='.$code.'&grant_type=authorization_code';
    $ch = curl_init();
    curl_setopt($ch,CURLOPT_URL,$get_token_url);
    curl_setopt($ch,CURLOPT_HEADER,0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1 );
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10);
    $res = curl_exec($ch);
    curl_close($ch);
    $json_obj = json_decode($res,true);
    $access_token = $json_obj['access_token'];
    $openid = $json_obj['openid'];
    $get_user_info_url = 'https://api.weixin.qq.com/sns/userinfo?access_token='.$access_token.'&openid='.$openid.'&lang=zh_CN';
    $ch = curl_init();
    curl_setopt($ch,CURLOPT_URL,$get_user_info_url);
    curl_setopt($ch,CURLOPT_HEADER,0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1 );
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10);
    $res = curl_exec($ch);
    curl_close($ch);
    $user_obj = json_decode($res,true);
    $_SESSION['user'] = $user_obj;
    return json($user_obj);
}