Django Tweepy can't access Amazon S3 file - django

Question

I'm using Tweepy, a tweeting python library, django-storages and boto. I have a custom manage.py command that works correctly locally, it gets an image from the filesystem and tweets that image. If I change the storage to Amazon S3, however, I can't access the file. It gives me this error:
raise TweepError('Unable to access file: %s' % e.strerror)
I tried making the images in the bucket "public". Didn't work. This is the code (it works without S3):
filename = model_object.image.file.url
media_ids = api.media_upload(filename=filename) # ERROR
params = {'status': tweet_text, 'media_ids': [media_ids.media_id_string]}
api.update_status(**params)
This line:
model_object.image.file.url
Gives me the complete url of the image I want to tweet, something like this:
https://criptolibertad.s3.amazonaws.com/OrillaLibertaria/195.jpg?Signature=xxxExpires=1467645897&AWSAccessKeyId=yyy
I also tried constructing the url manually, since it is a public image stored in my bucket, like this:
filename = "https://criptolibertad.s3.amazonaws.com/OrillaLibertaria/195.jpg"
But it doesn't work.
¿Why do I get the Unable to access file error?
The source code from tweepy looks like this:
def media_upload(self, filename, *args, **kwargs):
""" :reference: https://dev.twitter.com/rest/reference/post/media/upload
:allowed_param:
"""
f = kwargs.pop('file', None)
headers, post_data = API._pack_image(filename, 3072, form_field='media', f=f) # ERROR
kwargs.update({'headers': headers, 'post_data': post_data})
def _pack_image(filename, max_size, form_field="image", f=None):
"""Pack image from file into multipart-formdata post body"""
# image must be less than 700kb in size
if f is None:
try:
if os.path.getsize(filename) > (max_size * 1024):
raise TweepError('File is too big, must be less than %skb.' % max_size)
except os.error as e:
raise TweepError('Unable to access file: %s' % e.strerror)
Looks like Tweepy can't get the image from the Amazon S3 bucket, but how can I make it work? Any advice will help.

Answer 1

The issue occurs when tweepy attempts to get file size in _pack_image:
if os.path.getsize(filename) > (max_size * 1024):
The function os.path.getsize assumes it is given a file path on disk; however, in your case it is given a URL. Naturally, the file is not found on disk and os.error is raised. For example:
# The following raises OSError on my machine
os.path.getsize('https://criptolibertad.s3.amazonaws.com/OrillaLibertaria/195.jpg')
What you could do is to fetch the file content, temporarily save it locally and then tweet it:
import tempfile
with tempfile.NamedTemporaryFile(delete=True) as f:
name = model_object.image.file.name
f.write(model_object.image.read())
media_ids = api.media_upload(filename=name, f=f)
params = dict(status='test media', media_ids=[media_ids.media_id_string])
api.update_status(**params)
For your convenience, I published a fully working example here: https://github.com/izzysoftware/so38134984