Upload Files To Google Cloud Storage With Google App Engine (Python)

Question

I'm trying to set up a basic python-based google app engine site that allows users to upload files to google cloud storage (mostly images)

I've been going through the documentation for the JSON API and the GCS client library overview (as well as blobstore etc) and still don't have a good handle on which is the best method and how they are related. Would be great if someone could give an overview of this or point me to some resources I can check out

Also, any sample code that's relevant would be really helpful. I've been able to run the upload samples here but not sure if they're useful for an app engine setup: https://github.com/GoogleCloudPlatform/storage-file-transfer-json-python

Thanks!!

Answer 1

Google Cloud Storage has two APIs -- the XML API and the JSON API. The XML API is XML based and very like the Amazon S3 API. The JSON API is similar to many other Google APIs, and it works with the standard Google API client libraries (for example, the Google API Python library). Both of these APIs can be used from anywhere, with or without App Engine, and are based on RESTful HTTP calls.

App Engine provides a couple of standard ways to access Google Cloud Storage. The first is built into App Engine's API as a feature called the "Google Cloud Storage Python API". This does not directly use either the XML or the JSON API. It's deprecated and no longer recommended.

The second App Engine library is called the "Google Cloud Storage Python Client Library" and is not part of the core App Engine API. Instead, it's a Python library put out by Google that you can download and add to your application like any other library. This library happens to be implemented using the XML API. It provides a few extra features that are useful for App Engine users, such as the ability to serialize an upload while it's in progress. There's an example of using this library included as part of the download, in the python/demo directory. You can also see it online.

Equivalents of these tools also exist in Java and Go.

There's no need for users to use the App Engine-specific libraries unless they find them to be useful. The standard Python library or even just hand-written HTTP calls using urlfetch will work just as well. The App Engine library merely provides some useful extras for App Engine users.

App Engine also have a "Blobstore Python API". This is a feature specific to App Engine and distinct from Google Cloud Storage, except that it provides a few hooks into Google Cloud Storage, such as the ability to store files in Google Cloud Storage using the Blobstore API.