Empty response body when downloading file via Google Drive API despite 200 status code

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1

I’m new to working with the Google Drive API and I’m facing a puzzling issue. I’ve set up a PHP server to handle file operations for our Android and iOS apps, and while uploading and deleting files work fine, downloading them is a problem.

When I try to download a file, the server responds with a 200 status code and the headers seem right, but the body is completely empty. I don’t understand why this is happening.

Below is a revised snippet of my code:

function getFileContent($fileId) {
  $driveFile = $this->driveService->files->get($fileId);
  $downloadLink = $driveFile->getDownloadUrl();

  if ($downloadLink) {
    $request = new CustomHttpRequest($downloadLink, 'GET');
    $response = $this->client->sendAuthenticatedRequest($request);

    if ($response->getStatusCode() == 200) {
      return $response->getBody();
    }
  }

  return null;
}

Has anyone encountered this issue or have any suggestions on how to fix the empty response body problem?

2

hey, i’ve dealt with this before. make sure you’re using the right scope for downloading. try adding ‘https://www.googleapis.com/auth/drive.readonly’ to your scopes. also, check if the file is actually downloadable - some google docs aren’t. if that doesn’t work, try using the exportLinks property for google docs instead of downloadUrl.

3

I’ve encountered a similar issue when working with the Google Drive API. The problem might be related to how the response stream is being handled. Instead of directly returning the body, you could try reading the response content in chunks to ensure that the entire stream is processed.

Here’s a modification you could try:

$content = '';
$stream = $response->getBody();
while (!$stream->eof()) {
    $content .= $stream->read(8192);
}
return $content;

This approach ensures that the complete response is retrieved, especially with larger files. Also, double-check that your authentication is correct and that you have the necessary permissions to access the file. If the issue persists, reviewing the raw response headers might provide further insights.

4

Having worked extensively with the Google Drive API, I can share some insights that might help resolve your issue. One common pitfall I’ve encountered is assuming that the file content is immediately available in the response body. In reality, for larger files especially, you often need to follow a redirection.

Try modifying your code to handle redirects:

$client = new GuzzleHttp\Client(['allow_redirects' => true]);
$response = $client->get($downloadLink, [
    'headers' => $this->client->getAuthorizationHeaders()
]);

return $response->getBody()->getContents();

This approach has worked well for me in the past. Also, ensure you’re using the latest version of the Google API client library, as older versions sometimes had issues with certain file types. If problems persist, enable verbose logging to see what’s happening behind the scenes during the API calls.