Google Drive PHP API library example to download a spreadsheet file

gdrive-example.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

class DriveFile
{
    private $service = null;
    private $client = null;

    private $auth;
    private $serviceEmail = '';
    private $serviceKeyFilename = '';
    private $userEmail = '';

    /**
     * Constructor, initialize with service email and name of private key file.
     *
     * @param string $serviceEmail
     * @param string $serviceKeyFilename
     * @param string $userEmail
     */
    public function __construct($serviceEmail = '', $serviceKeyFilename = '', $userEmail='')
    {
        $this->serviceEmail = $serviceEmail;
        $this->serviceKeyFilename = $serviceKeyFilename;
        $this->userEmail = $userEmail;
    }

    /**
     * Build Drive API authenticatioin and access service.
     * We assume that nothing will go wrong.
     */
    public function buildService()
    {
        $key = file_get_contents($this->serviceKeyFilename);
        $this->auth = new Google_Auth_AssertionCredentials(
            $this->serviceEmail,
            array('https://www.googleapis.com/auth/drive'),
            $key);
        $this->auth->sub = $this->userEmail;
        $this->client = new Google_Client();
        $this->client->setAssertionCredentials($this->auth);
        $this->service = new Google_Service_Drive($this->client);
    }

    /**
     * Search for file by title and retrieve a list of File resources.
     *
     * @param string $title
     * @return Array List of Google_DriveFile resources.
     */
    public function searchFile($title='')
    {
        if (!$this->service) {
            $this->buildService();
        }
        $query = "title='" . $title . "'";
        $result = array();
        $pageToken = null;
        do {
            try {
                $parameters = array();
                if ($pageToken) {
                    $parameters['pageToken'] = $pageToken;
                }
                if ($query) {
                    $parameters['q'] = $query;
                }
               $files = $this->service->files->listFiles($parameters);
                $result = array_merge($result, $files->getItems());
                $pageToken = $files->getNextPageToken();
            } catch (Exception $e) {
                print "An error occurred: " . $e->getMessage();
                $pageToken = null;
            }
        } while ($pageToken);
        return $result;
    }

    /**
     * Returns meta data by file id
     *
     * @param Google_Service_Drive_DriveFile file object to print metadata for.
     * @return array of meta data
     */
    public function getMetadata(Google_Service_Drive_DriveFile $file)
    {
        try {
            return array('title' => $file->getTitle(),
            'description' => $file->getDescription(),
            'mime_type' => $file->getMimeType()
            );
        } catch (Exception $e) {
            print "An error occurred: " . $e->getMessage();
        }
    }

    /**
     * Return downloaded file by file object and mime type
     *
     * @param File $file Drive File instance.
     * @return String The file's content if successful, null otherwise.
     * @param string $fileMimeType, default spreadsheet as example
     */
    public function getFile(Google_Service_Drive_DriveFile $file, $fileMimeType='')
    {
        if (!$this->service) {
            $this->buildService();
        }
        $downloadUrl = $file->getExportLinks()[$fileMimeType];

        if ($downloadUrl) {
            $request = new Google_Http_Request($downloadUrl, 'GET', null, null);

            // use authentication parameter to login with previously created credentials
            // and request the file
            $client = new Google_Client();
            $client->setAssertionCredentials($this->auth);
            $client->getAuth()->sign($request);

            $io = $client->getIo();
            $httpRequest = $io->makeRequest($request);

            if ($httpRequest->getResponseHttpCode() == 200) {
                return $httpRequest->getResponseBody();
            } else {
                // An error occurred. Maybe throw some exception?
                return null;
            }
        } else {
            // The file doesn't have any content stored on Drive.

            return null;
        }
    }

    /**
     * Shortcut method for getting spreadsheet file content
     *
     * @param Google_Service_Drive_DriveFile $file
     * @return String
     */
    public function getSpreadsheetFile(Google_Service_Drive_DriveFile $file)
    {
        return $this->getFile( $file, 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    }
}


// example client code

$driveFile = new DriveFile('<your-access-address_will_be_created_by_google>@developer.gserviceaccount.com',
    __DIR__ . '/google-privatekey.p12',
    '<[email protected]');

$files = $driveFile->searchFile('my-spreadsheet-title');

if (isset($files[0])) {
    $file = $files[0];
    echo "file id: " . $file->id . "\n";
    $meta = $driveFile->getMetadata( $file);
    echo "meta data: \n";
    print_r($meta);

    if ($content = $driveFile->getSpreadsheetFile($file)) {
        file_put_contents('spreadsheet.xlsx',$content);
    }
    else {
        echo "An error occurred.";
    }

}

echo "\n";