获取openid

公众号设置授权回调页面域名: example.com
example.com/get_openid.php

$appid, 'secret'=>$appsecret, 'code'=>$code, 'grant_type'=>'authorization_code' ];
    $result = do_get( $url, $params );
    $result =  json_decode( $result, true );

    $redirect_uri_web =  str_replace( '@@@', '&', $_GET[ 'redirect_uri_web' ] );
    $redirect_uri_web = $redirect_uri_web. ( strchr( $redirect_uri_web, '?' )? '&':'?' ) .'openid='.$result[ 'openid' ];

    header( "Location:  $redirect_uri_web" );
    exit();
}

function do_get( $url, $params ) {
    $url = "{$url}?" . http_build_query ( $params );
    $ch = curl_init ();

    curl_setopt ( $ch, CURLOPT_URL, $url );

    curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, 1 );

    curl_setopt ( $ch, CURLOPT_CUSTOMREQUEST, 'GET' );

    curl_setopt ( $ch, CURLOPT_TIMEOUT, 60 );

    curl_setopt ( $ch, CURLOPT_POSTFIELDS, $params );
    $result = curl_exec ( $ch );

    curl_close ( $ch );
    return $result;

}

使用: