Why are the properties of Google_Service_Drive files only returning null?

Question

I want to list all files in a folder shared with my Service Account. I'm trying to figure out what files have a 'parent' attribute set to the folder ID or folder name. However, all the objects that I output show "NULL" for nearly all fields. I've searched through the Google Drive API v3 and I can't even find the listFiles() function in it. Additionally, the documentation recommends using the Files.list function for outputting a list of files but when I use the Files.list function, I get an error as if the method doesn't exist. So I went back to using listFiles()... My code looks like this:

public function getTitlesAndIDs($folderID)
{

    // $capabilities = new \Google_Service_Drive_DriveFileCapabilities();
    // $capabilities->canListChildren = true;
    $files = $this->driveService->files->listFiles();

    var_dump($files);
}

Trying to add capabilities just returns NULL as well. When I run listFiles() I get output like this:

["files"]=>
  array(100) {
    [0]=>
    object(Google_Service_Drive_DriveFile)#77 (65) {
      ["collection_key":protected]=>
      string(6) "spaces"
      ["appProperties"]=>
      NULL
      ["capabilitiesType":protected]=>
      string(42) "Google_Service_Drive_DriveFileCapabilities"
      ["capabilitiesDataType":protected]=>
      string(0) ""
      ["contentHintsType":protected]=>
      string(42) "Google_Service_Drive_DriveFileContentHints"
      ["contentHintsDataType":protected]=>
      string(0) ""
      ["createdTime"]=>
      NULL
      ["description"]=>
      NULL
      ["explicitlyTrashed"]=>
      NULL
      ["fileExtension"]=>
      NULL
      ["folderColorRgb"]=>
...

Why are the values all coming back as NULL and how do I fix this so I can search by parent folders? Is there a php equivalent to the Files.list function? Thanks in advance.

Answer 1

First you need to make sure that there are files that the service account has access to. Once you have done so this should be able to list the files.

$service = new Google_Service_Drive($client);

// Print the names and IDs for up to 10 files.
$optParams = array(
  'pageSize' => 10,
  'fields' => 'nextPageToken, files(id, name)'
);
$results = $service->files->listFiles($optParams);

if (count($results->getFiles()) == 0) {
  print "No files found.\n";
} else {
  print "Files:\n";
  foreach ($results->getFiles() as $file) {
    printf("%s (%s)\n", $file->getName(), $file->getId());
  }
}

Code ripped from PHP Quickstart

Answer 2

除了@DalmTo 所说的之外，还有一件重要的事情要明确指出：您几乎所有字段都收到NULL ，因为您没有提供字段列表， 'fields'作为可选参数。

Answer 3

In addition to Google Drive API V3 properties such as id, name, kind and description , there are custom file attributes available to the developer via properties and appProperties .

https://developers.google.com/drive/api/v3/properties

Google Drive properties key / value pairs are controlled and manipulated by your application.

Throughout Google Drive V3 documentation, the term "properties" also refers to metadata . I found this very confusing. https://developers.google.com/drive/api/v3/reference/files

In Google Drive V2, there are copious examples of how to manipulate key / value properties using PHP, but in Google Drive V3 the properties API was significantly changed, and PHP code examples are very sparse.

By modifying the example code above, I was able to retrieve my customized properties.

$service = new Google_Service_Drive($client);

// Print the names, IDs and properties for up to 10 files.
$optParams = array(
  'pageSize' => 10,
  'fields' => 'nextPageToken, files(id, name, properties)'
);
$results = $service->files->listFiles($optParams);

if (count($results->getFiles()) == 0) {
  print "No files found.\n";
} else {
  print "Files:\n";
  foreach ($results->getFiles() as $file) {
    printf("%s (%s)\n", "name: ".$file->getName(), "ID: ".$file->getId());
      foreach ($file->getProperties() as $key => $value) {
        printf("%s%s\n","-key: ".$key,", value: ".$value);
    }
  }
}

I wanted to share my extension of the original answer for those developers who land on this page looking for a PHP example of manipulating properties and appProperties in Google Drive V3.