Google Drive APIでファイルアップロード(PHP)

自動でGoogle Driveにファイルをアップしたかったので。

# 参考文献
* [Google Drive REST API](https://developers.google.com/drive/v3/web/about-sdk)
  - [PHP Quickstart](https://developers.google.com/drive/v3/web/quickstart/php)と[Uploading Files](https://developers.google.com/drive/v3/web/manage-uploads)を参考にした。

# 手順 
## チュートリアルを進める
- [ウィザード](https://console.developers.google.com/start/api?id=drive)からAPI有効化
- `client_secret.json`を落としてきてプロジェクトの直下に配置
-  composerインストール

```bash
$ curl -sS https://getcomposer.org/installer | php
$ php composer.phar require google/apiclient:^2.0
```

## サンプルソースをいじる
```php:upload.php
<?php
require_once __DIR__ . '/vendor/autoload.php';


define('APPLICATION_NAME', 'Drive API PHP Quickstart');
define('CREDENTIALS_PATH', '~/.credentials/drive-php-quickstart.json');
define('CLIENT_SECRET_PATH', __DIR__ . '/client_secret.json');
define('FOLDER_ID', 'ここにフォルダIDを入れる');
// If modifying these scopes, delete your previously saved credentials
// at ~/.credentials/drive-php-quickstart.json
define('SCOPES', implode(' ', array(
        Google_Service_Drive::DRIVE)
));

if (php_sapi_name() != 'cli') {
    throw new Exception('This application must be run on the command line.');
}

/**
 * Returns an authorized API client.
 * @return Google_Client the authorized client object
 */
function getClient() {
    $client = new Google_Client();
    $client->setApplicationName(APPLICATION_NAME);
    $client->setScopes(SCOPES);
    $client->setAuthConfig(CLIENT_SECRET_PATH);
    $client->setAccessType('offline');

    // Load previously authorized credentials from a file.
    $credentialsPath = expandHomeDirectory(CREDENTIALS_PATH);
    if (file_exists($credentialsPath)) {
        $accessToken = json_decode(file_get_contents($credentialsPath), true);
    } else {
        // Request authorization from the user.
        $authUrl = $client->createAuthUrl();
        printf("Open the following link in your browser:\n%s\n", $authUrl);
        print 'Enter verification code: ';
        $authCode = trim(fgets(STDIN));

        // Exchange authorization code for an access token.
        $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);

        // Store the credentials to disk.
        if(!file_exists(dirname($credentialsPath))) {
            mkdir(dirname($credentialsPath), 0700, true);
        }
        file_put_contents($credentialsPath, json_encode($accessToken));
        printf("Credentials saved to %s\n", $credentialsPath);
    }
    $client->setAccessToken($accessToken);

    // Refresh the token if it's expired.
    if ($client->isAccessTokenExpired()) {
        $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
        file_put_contents($credentialsPath, json_encode($client->getAccessToken()));
    }
    return $client;
}

/**
 * Expands the home directory alias '~' to the full path.
 * @param string $path the path to expand.
 * @return string the expanded path.
 */
function expandHomeDirectory($path) {
    $homeDirectory = getenv('HOME');
    if (empty($homeDirectory)) {
        $homeDirectory = getenv('HOMEDRIVE') . getenv('HOMEPATH');
    }
    return str_replace('~', realpath($homeDirectory), $path);
}

// Get the API client and construct the service object.
$client = getClient();
$service = new Google_Service_Drive($client);

$fileMetadata = new Google_Service_Drive_DriveFile(array(
    'name' => 'photo.jpg',
    'parents' => array(FOLDER_ID),
));

$content = file_get_contents('files/photo.jpg');

$file = $service->files->create($fileMetadata, array(
    'data' => $content,
    'mimeType' => 'image/jpeg',
    'uploadType' => 'multipart',
    'fields' => 'id'));
printf("File ID: %s\n", $file->id);
```

`files/photo.jpg`を`FOLDER_ID`で指定したフォルダにアップロード。