What would cause a zip file to not be recognized on Google App Engine's when it reads properly in my local GAE sdk

Question

My code executes successfully when I run it locally, but when I upload it to GAE and attempt to run it throws me a BadZipfile: File is not a zip file, or ends with a comment

raw_file = urllib2.urlopen(url)
buffer = cStringIO.StringIO(raw_file.read())
z = zipfile.ZipFile(buffer)

zipped file size is 2.5 mb unzipped size is 14 mb

What is the difference in the two environments that is causing this error?

Answer 1

The maximum size you can fetch using urlfetch (App Engine's API for making HTTP requests to other sites) is 1MB, so your file is getting truncated. The dev_appserver doesn't enforce the 1MB limit.