Pillow/docs/releasenotes/2.8.0.rst

2.8.0
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Open HTTP response objects with Image.open
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HTTP response objects returned from `urllib2.urlopen(url)` or `requests.get(url, stream=True).raw` are 'file-like' but do not support `.seek()` operations. As a result PIL was unable to open them as images, requiring a wrap in `cStringIO` or `BytesIO`.

Now new functionality has been added to `Image.open()` by way of an `.seek(0)` check and catch on exception `AttributeError` or `io.UnsupportedOperation`. If this is caught we attempt to wrap the object using `io.BytesIO` (which will only work on buffer-file-like objects).

This allows opening of files using both `urllib2` and `requests`, e.g.::

    Image.open(urllib2.urlopen(url))
    Image.open(requests.get(url, stream=True).raw)

If the response uses content-encoding (compression, either gzip or deflate) then this will fail as both the urllib2 and requests raw file object will produce compressed data in that case. Using Content-Encoding on images is rather non-sensical as most images are already compressed, but it can still happen.

For requests the work-around is to set the decode_content attribute on the raw object to True::

    response = requests.get(url, stream=True)
    response.raw.decode_content = True
    image = Image.open(response.raw)