I need to upload and process a CSV file from a form in a Google App Engine application based on Webapp2 (Python) I understand I could use blobstore to temporary store the file but I am curious to know if there is a way to process the file without having to store it at all.
The content of uploaded files is in self.request.POST in your handler, so you can get that content (assuming e.g the field for the uploaded file is named 'foo') with e.g
content = self.request.POST.multi['foo'].file.read()
So now you have the content as a string -- process it as you wish. This does of course assume the thing will fit in memory (no multi-megabyte uploads!-)...