Incorrect s3 upload path separator on windows

[AbsoluteDestiny]

When django is being hosted on a windows machine (such as a local dev environment) the file is uploaded using backslashes as the path separator. So, instead of uploading to the /tmp/s3file folder the file get a single long filename with backslashes in it.

This then causes a File Does Not Exist IOError in boto3 when it tries to pull the file back.

[codingjoe]

Hi @AbsoluteDestiny that's interesting. To be honest, I haven't tried the package on Windows yet. Do you happen to have a stacktrace for me or some sample code to reproduce this?

[codingjoe]

@AbsoluteDestiny I think I found the bug and wrote a patch, can you test it please?
#94

[AbsoluteDestiny]

@codingjoe I'm getting the following error:

'PurePosixPath' object has no attribute 'endswith'

in botocore\signers.py in generate_presigned_post

the boto code wants to do this:

    # Append that the bucket name to the list of conditions.
    conditions.append({'bucket': bucket})
    # If the key ends with filename, the only constraint that can be
    # imposed is if it starts with the specified prefix.
    if key.endswith('${filename}'): ...
        conditions.append(["starts-with", '$key', key[:-len('${filename}')]])
    else:
        conditions.append({'key': key})
    # Add the key to the fields.
    fields['key'] = key

on line 32 of your forms.py:

        response = self.client.generate_presigned_post(
            self.bucket_name, pathlib.PurePosixPath(self.upload_folder, '${filename}'),
            Conditions=self.get_conditions(accept),
            ExpiresIn=self.expires, ...
        )

looks like pathlib.PurePosixPath(self.upload_folder, '${filename}').as_posix() would give you the str boto expects.

[codingjoe]

thx @AbsoluteDestiny I just updated the PR, it should work now