We can use See also the full update documentation in raw mongo DB: There you will find more information on modifier operations and everything that was briefly covered here. In App Engine, the local filesystem that your application is deployed to is not writeable.
For details about this file write option, see Allowing Users to Upload Files For information about reading files from Google Cloud Storage, see Providing Public Access to Files You need to activate Google Cloud Storage and create a bucket. Many of the commonly used PHP file functions are supported, along with file information and directory functions.
For a complete list of supported PHP functions, see PHP filesystem functions support.
Because of this, the For very large files, you may not be able to write directly from your app, because of the requirement for all app requests to complete within 60 seconds.
So, for very large files, you may need to upload the file directly, not write it from the app.
For details on how revisions are retained, see the Drive Help Center.