def clean_image(self):
"""Check the image is of a supported type.
"""
image = self.cleaned_data.get('image')
if image and not image.content_type in ALLOWED_MIMETYPES:
types = "/".join([x for x in ALLOWED_MIMETYPES.itervalues()])
error = "Image is not of an allowed type: %s." % types
raise forms.ValidationError(error)
return image
def download_and_validate_image(url, temp_folder=None):
"""Tries to download and save a given URL to a temporary
location, checking it is a valid image using PIL. For
small images we simply save to a memory buffer, for
larger images, we take the safe option of saving them
to disk first.
"""
ret_dict = {'image': '',
'filetype': '',
'mimetype': '',
'message': ''}
if temp_folder is None:
temp_folder = settings.FILE_UPLOAD_TEMP_DIR
req = requests.get(url)
if not req.ok:
error_messages = {404: "The image could not be found.",
410: "The server says the image has been removed.",
500: "There was an error with the remote server."}
msg = error_messages.get(req.status_code, "An unknown error occured.")
ret_dict['message'] = "Sorry, the image retrieval failed. %s" % msg
return ret_dict
mimetype = req.headers['content-type']
if mimetype not in ALLOWED_MIMETYPES:
ret_dict['message'] = "Image is not of an allowed type: %s." % \
"/".join([x for x in ALLOWED_MIMETYPES.itervalues()])
return ret_dict
if len(req.content) > UPLOAD_MAX_SIZE:
ret_dict['message'] = "The image exceeds our maximum allowed size" \
" of %s bytes." % UPLOAD_MAX_SIZE
return ret_dict
try:
# To test it's actually an image we can use, we translate
# to an in memory IOString and try an open with PIL.
buffer = cStringIO.StringIO(req.content)
buffered_image = Image.open(buffer)
except IOError:
ret_dict['message'] = "We are unable to open the image, is it corrupt?"
return ret_dict
else:
ret_dict.update({'image': ContentFile(req.content),
'filetype': ALLOWED_MIMETYPES[mimetype],
'mimetype': mimetype,
'message': 'Success'})
return ret_dict
