FCM 仅通过使用 PHP 的 Google 客户端 API 为 iOS 设备返回 401 未经授权的错误

Question

I am using FCM HTTP v1 API for sending notifications to mobile devices. The backend is written using PHP and I am using Google API client library and using a service account to authorize my requests to FCM. But I am facing some weird issues like notifications are being sent to all Android devices, but fcm returns 401 unauthorized error for iOS devices. Also, I have tested using my own iOS device but fcm always returns 200 OK when I am using my own iOS device. I am so confused whether the issue is with my code or some configuration on the mobile device. Here is how I am sending the notifications.

$client = new Google_Client();
$client->useApplicationDefaultCredentials(); 
$client->addScope('https://www.googleapis.com/auth/firebase.messaging');
$httpClient = $client->authorize();
$message = [
    "message" => 
    [
        "token" => $device_token,
        "notification" => 
        [
            "body" => $body,
            "title" => "xxxxx"
        ],
        "apns" => 
        [
            "payload" =>
            [
                "aps" => 
                [
                  "category" =>  "NEW_MESSAGE_CATEGORY",
                  "alert" =>  [
                     "body" =>  $body
                  ],
                  "badge" =>  3,
                  "sound" =>  "default",
                  "chat" => 2

                ]
            ]  
        ]
    ]
];
$response = $httpClient->post("https://fcm.googleapis.com/v1/projects/xxxx-123/messages:send", ['json' => $message]);

What am I doing wrong in authorization? Please help. Service account file is already added in GOOGLE_APPLICATION_CREDENTIALS env variable.

Answer 1

FCM uses APNS (Apple Push Notification Service) to delivery messages to iOS devices, in order to do it, FCM need to connect to Apple server.
So we need to configure APNS credentials in firebase console. If there is any error in this configuration, FCM can't connect to Apple server, and return 401 error.

So check all configs in Settings -> Project Configuration -> Cloud Messaging -> iOS Configuration -> APNS Authentication Key In special, check if the " key code " are correct.

More info about this configs can be found at:

https://firebase.google.com/docs/cloud-messaging/ios/client#upload_your_apns_authentication_key

https://firebase.google.com/docs/cloud-messaging/ios/certs

Regards