CODEWITHSUNDEEP
pythongoogle-app-engine
LA_
LA_

Reputation: 20429

How to return image with GAE?

Each time user accesses http://www.example.com/some-random-symbols-1x1.png, I should return transparent image 1x1px. I've created according file, but how should I read it in my code to return to the user? I know how to display the image from the datastore or blobstore. But have no idea how to read and return binary file.

It can not be static file due to the following reasons:

  1. url will contain some-random-symbols;
  2. once url is accessed, prior to displaying images, I would like to log that somebody accessed the file.

Upvotes: 0

Views: 273

Answers (2)

Dave W. Smith
Dave W. Smith

Reputation: 24966

A 1x1 transparent PNG (or GIF) is small enough that you can hard-code the base64 representation directly and emit it directly via self.response.write() (after decoding).

Reading from disk every time is relatively expensive. If you want to go that route, lazily initialize a global variable.

Upvotes: 3

Greg
Greg

Reputation: 10360

In a more general case, I'd use the blobstore and the BlobstoreDownloadHandler, but for a tiny gif that will definitely fit into memory, something like this to read the file's content: 

with open('path/to/file.gif') as f:
  img_content = f.read()

I'd put this outside of my handler, so it was done once per instance. If you're using 2.5, then you'll need to import 'with' from future, or open and close the file yourself.

then in your handler, assuming webapp2:

self.response.content_type = 'image/gif'
self.response.write(img_content)

Upvotes: 2

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