Facebook SDK for PHP 5:返回一个错误:No URL set - Facebook SDK for PHP 5: returned an error: No URL set

Facebook SDK for PHP 5: returned an error: No URL set

我正在遵循Facebook的SDK，但我收到以下错误:

没有URL集。

代码如下:

<?php
    require_once __DIR__ . '/src/autoload.php';
    session_start();
    $fb = new Facebook'Facebook([
        'app_id' => '',
        'app_secret' => '',
        'default_graph_version' => 'v2.2',
    ]);
    // Use one of the helper classes to get a Facebook'Authentication'AccessToken entity.
    $helper = $fb->getRedirectLoginHelper();
    //$helper = $fb->getJavaScriptHelper();
    //$helper = $fb->getCanvasHelper();
    //$helper = $fb->getPageTabHelper();
    try {
        // Get the Facebook'GraphNodes'GraphUser object for the current user.
        // If you provided a 'default_access_token', the '{access-token}' is optional.
        $response = $fb->get('/me', '{access-token}');
    } catch(Facebook'Exceptions'FacebookResponseException $e) {
        // When Graph returns an error
        echo 'Graph returned an error: ' . $e->getMessage();
        exit;
    } catch(Facebook'Exceptions'FacebookSDKException $e) {
        // When validation fails or other local issues
        echo 'Facebook SDK returned an error: ' . $e->getMessage();
        exit;
    }
    $me = $response->getGraphUser();
    echo 'Logged in as ' . $me->getName();
?>

为什么我收到这个错误?

可能您没有重定向到正确的登录url

$fb = new Facebook'Facebook([
    'app_id' => '',
    'app_secret' => '',
    'default_graph_version' => 'v2.2',
]);
$helper = $fb->getRedirectLoginHelper();
$permissions = ['email', 'public_profile'];
$callback = 'http://yoursite.com/callbackscript.php < your file';
$loginUrl = $helper->getLoginUrl($callback, $permissions);
<a href="<?= $loginUrl; ?>">Login with Facebook!</a>

请确保php.ini中启用了php_curl.dll扩展