API request not returning expected data - PHP

Question

My code has service account credentials but it not returning expected data - anyone spot any issues with it? It is returning an empty object - am I not accessing the right part of the $file when I try to return the data? The example at https://developers.google.com/drive/api/guides/folder#php_2 to move folders notes this line:

        $file = $driveService->files->get($fileId, array('fields' => 'parents'));

But when I use that the response is an error exception and the file is not found. The file id and folder id are both correct.

$fileId = '{myfileid}'; //image file id
$folderId = '{myFolderId}'; //folder to move into

use Google\Client;
use Google\Service\Drive;
use Google\Service\Drive\DriveFile;

function moveFileToFolder($fileId, $folderId)
{
try {
    $client = new Client();
    putenv('GOOGLE_APPLICATION_CREDENTIALS=/var/www/https/html/googleapis/drive/service_credentials.json');
    $client->useApplicationDefaultCredentials();
    $client->addScope(Drive::DRIVE);
    $driveService = new Drive($client);
    $emptyFileMetadata = new DriveFile();
    // Retrieve the existing parents to remove
    $file = $driveService->files->get($fileId, [
        'fields' => 'parents',
        'alt' => 'media'
    ]);

    echo json_encode($file);

    // // Access the parent information
    // $parents = $file->getParents();
    // foreach ($parents as $parent) {
    //     echo 'Parent ID: ' . $parent . '<br>';
    // }

    $previousParents = join(',', $file->parents);

    // Move the file to the new folder
    $file = $driveService->files->update($fileId, $emptyFileMetadata, array(
        'addParents' => $folderId,
        'removeParents' => $previousParents,
        'supportsAllDrives' => true,
        'fields' => 'id, parents'
    ));
    return $file->parents;
} catch (Exception $e) {
    echo "Error Message: " . $e;
}
}

moveFileToFolder($fileId, $folderId);

I have used the same setup for other successful requests bar the line:

        $emptyFileMetadata = new DriveFile();

and is subsequent use.

Answer 1

I believe your goal is as follows.

• You want to retrieve the parent folder ID of the file on the shared drive using googleapis for php with the service account.
• Your service account has permission to read the file on the shared drive.

In this case, how about the following answer?

When 'alt' => 'media' is used to $driveService->files->get(), the file content is retrieved instead of the file metadata. So, I think that fields is not used.

I guessed that in your situation, you might have wanted to retrieve the parent folder ID of the file of $fileId on the shared drive. If my understanding is correct, how about the following modification?

From:

$file = $driveService->files->get($fileId, array('fields' => 'parents'));

To:

$file = $driveService->files->get($fileId, array('fields' => 'parents', 'supportsAllDrives' => true));

By this modification, the file metadata of $fileId on the shared drive is retrieved.

Reference:

• Method: files.get