Question

I would like to create an app using python on google app engine to handle file upload and store them into the blobstore.

However, currently blobstore requires the use of blobstore.create_upload_url to create the url for the file upload form post. Since I am uploading from another server, my question is, is it possible to upload file to gae blobstore without using that dynamic url from blobstore.create_upload_url?

FYI, it is ok that I request a upload URL from the python script before I upload from another server but this creates extra latency and that is not what I want. Also I read that using the so called “file-like API” from http://code.google.com/intl/en/appengine/docs/python/blobstore/overview.html#Writing_Files_to_the_Blobstore but the documentation didn’t seem to cover the part on uploading.

Also, previously I tried to use datastore for file upload, but the max file size is 1MB which is not enough for my case. Please kindly advise, thanks.

Answer 1

There are exactly two ways to write files to the blobstore: 1) using create_upload_url, and posting a form with a file attachment to it, 2) writing to the blobstore directly using an API (with a solution here for large files).

If you want a remote server to be able to upload, you have the same two choices:

1) The remote server firsts requests a URL. You have a handler that’s just is only to return such a URL. With this URL, the remote server crafts a properly-encoded POST message and posts it to the URL.

2) You send the file data as an HTTP parameter to a handler to your app engine server, which uses the blobstore write API to then write the file directly. Request size is limited to 32MB, so the maximum file size you can write using this method will be slightly under that.