app.php

App\Providers\GoogleDriveServiceProvider::class,

filesystems.php

    'disks' => [

        'local' => [
            'driver' => 'local',
            'root' => storage_path('app'),
        ],

        'public' => [
            'driver' => 'local',
            'root' => storage_path('app/public'),
            'url' => env('APP_URL').'/storage',
            'visibility' => 'public',
        ],

        's3' => [
            'driver' => 's3',
            'key' => env('AWS_KEY'),
            'secret' => env('AWS_SECRET'),
            'region' => env('AWS_REGION'),
            'bucket' => env('AWS_BUCKET'),
        ],

        'google' => [
	        'driver' => 'google',
	        'clientId' => env('GOOGLE_DRIVE_CLIENT_ID'),
	        'clientSecret' => env('GOOGLE_DRIVE_CLIENT_SECRET'),
	        'refreshToken' => env('GOOGLE_DRIVE_REFRESH_TOKEN'),
	        'folderId' => env('GOOGLE_DRIVE_FOLDER_ID'),
        ],
    ],

GoogleDriveAdapter.php

<?php

namespace App\Providers;

class GoogleDriveAdapter extends \Hypweb\Flysystem\GoogleDrive\GoogleDriveAdapter
{
    public function getService()
    {
            return $this->service;
    }
}

GoogleDriveApiController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class GoogleDriveApiController extends Controller
{
	public function getApi() {
		$filename = 'namefile.txt';
		$dir = '/';
		$recursive = false;
		$contents = collect(Storage::cloud()->listContents($dir, $recursive));
		$file = $contents
			->where('type', '=', 'file')
			->where('filename', '=', pathinfo($filename, PATHINFO_FILENAME))
			->where('extension', '=', pathinfo($filename, PATHINFO_EXTENSION))
			->first();
		$rawData = Storage::cloud()->get($file['path']);
		return response($rawData, 200)
			->header('ContentType', $file['mimetype'])
			->header('Content-Disposition', "attachment; filename='$filename'");
    }
}

script.js

$(window).on('load', function(){
    $.ajax({
        headers: {
            'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content'),
            'charset': 'utf-8'
        },

        type: 'GET',
        url: 'getApi',

        success: function(data) {
            console.log(data);
        },
        error: function (data) {
            console.log('Doh! : ', data);
        }
    });
});

web.php

Route::get('getApi', 'GoogleDriveApiController@getApi');