Google Drive API文件监听未触发新增文件通知的原因排查

问题背景 #

为「我的云端硬盘」中的某一共享文件夹配置了Google Drive API变更通知，指定了对应文件夹的folderId，修改文件夹名称时可正常收到通知，但新增文件时无通知推送。

初始配置代码 #

$client = new Google_Client();
$client->setApplicationName('Some Name');
$client->setAuthConfig( __DIR__  . '/service_account.json');
$client->setScopes(Google_Service_Drive::DRIVE);
$client->fetchAccessTokenWithAssertion();
$token = $client->getAccessToken();
$service = new Google\Service\Drive($client);
$httpclient = new \GuzzleHttp\Client();
$folderid = $someid;
$body = [
    'kind' => "api#channel",
    'id' => uniqid(),
    'type' => 'web_hook',
    'resourceId' => $folderid,
    'resourceUri' => 'https://www.googleapis.com/drive/v3/files/'.$folderid,
    'address' => 'myendpoint'
];

$apiendpoint = 'https://www.googleapis.com/drive/v3/files/' . $folderid . '/watch';
$result = $httpclient->post($apiendpoint, [
    'headers' => ['Content-Type' => 'application/json', 'Authorization' => "Bearer {$token['access_token']}"],
    'body' => json_encode($body),
    "http_errors" => false]);

配置后接口返回成功，通道立即向接收端点发送了sync消息，端点代码如下：

function myendpoint (WP_REST_Request $request) {
    $headers= getallheaders();
    write_log('in google drive webhook with headers '.print_r($headers, true));
    $body = $request->get_body();
    write_log('in google drive webhook with body '.print_r($body, true));
    global $wpdb;
    return http_response_code(200);
}

日志打印的sync通知头信息如下：

[07-Nov-2021 12:52:35 UTC] in google drive webhook with headers Array
(
    [Host] => courses-test.com
    [User-Agent] => APIs-Google; (+https://developers.google.com/webmasters/APIs-Google.html)
    [Content-Length] => 0
    [Accept] => */*
    [Accept-Encoding] => gzip, deflate, br
    [X-Forwarded-For] => 66.102.8.121
    [X-Forwarded-Proto] => https
    [X-Goog-Channel-Expiration] => Sun, 07 Nov 2021 13:51:26 GMT
    [X-Goog-Channel-Id] => 6187cbc82a08e
    [X-Goog-Message-Number] => 1
    [X-Goog-Resource-Id] => resid
    [X-Goog-Resource-State] => sync
    [X-Goog-Resource-Uri] => https://www.googleapis.com/drive/v3/files/folderid?acknowledgeAbuse=false&supportsAllDrives=false&supportsTeamDrives=false&alt=json
    [X-Original-Host] => mydomain
)

已确认返回200状态码符合响应要求，端点响应速度正常不会触发重试机制，权限也正常，可通过listFiles接口正常列出该文件夹下的文件：

$optParams = array(
    'pageSize' => 10,
    'fields' => 'nextPageToken, files(id, name)'
);
$results = $service->files->listFiles($optParams);

但向配置了监听的文件夹内新增、编辑文件时，均无法收到通知。该文件夹为共享文件夹，但不属于共享盘，按照官方文档说明，文件夹资源的监听应该支持add新增事件。 #

问题解决更新 #

未触发通知的原因是初始Guzzle请求错误传入了kind、resourceId（resourceId与folderId并非同一值）等多余参数，被Google服务端限制了通知推送。
修改方案为将Guzzle发起POST请求的方式替换为官方SDK的watch方法，仅传入id、address、type三个参数即可正常运行，代码如下：

$channel->setId(uniqid());
$channel->setAddress($body['address']);
$channel->setType('web_hook');
$test = $service->files->watch($folderid, $channel);

修改后新增文件时，端点可收到如下请求头：

(
    [Host] => courses-test.com
    [User-Agent] => APIs-Google; (+https://developers.google.com/webmasters/APIs-Google.html)
    [Content-Length] => 0
    [Accept] => */*
    [Accept-Encoding] => gzip, deflate, br
    [X-Forwarded-For] => someip
    [X-Forwarded-Proto] => https
    [X-Goog-Changed] => children
    [X-Goog-Channel-Expiration] => Mon, 08 Nov 2021 09:46:10 GMT
    [X-Goog-Channel-Id] => chanid
    [X-Goog-Message-Number] => num
    [X-Goog-Resource-Id] => someid
    [X-Goog-Resource-State] => update
    [X-Goog-Resource-Uri] => https://www.googleapis.com/drive/v3/files/folderid?acknowledgeAbuse=false&supportsAllDrives=false&supportsTeamDrives=false&alt=json
    [X-Original-Host] => mydomain
)

疑问解答 #

1. 是否可以通过fields查询参数直接获取新增文件ID？ #

不可以。Google Drive API的推送通知本身返回体为空，不会携带任何变更内容，fields参数仅作用于主动调用接口时指定返回字段，无法配置到推送通知的返回内容中。
你可以在收到X-Goog-Changed: children的update事件后，调用files.list接口，使用筛选条件'[你的文件夹ID]' in parents and createdTime > [上次同步的时间戳]，同时指定fields=files(id,name)即可直接拉取到新增的文件列表，不需要全量比对，效率更高。

2. 官方提到的add事件是否仅适用于Google Cloudbuckets？ #

情况属实。Google Drive API v3的推送通知没有add类型的X-Goog-Resource-State值，Drive的资源变更全部通过update状态配合X-Goog-Changed的不同值来区分变更类型，值为children时对应子文件/文件夹的新增、删除、移动等变更。add事件是Google Cloud Storage（GCS）的对象变更通知特有的事件类型，不适用于Google Drive API。 #

内容的提问来源于stack exchange，提问作者Brian