[Python] Add Support for Content-Disposition Header without filename

Created by: ckoegel

Generated python sdks previously threw an AttributeError when attempting to deserialize a file in an HTTP response body if there was no filename= attribute in the Content-Disposition header. model_utils.mustache has been updated to include support for responses with no filename in this header. The deserialize_file function now validates the type of the regex search before assigning the filename to the regex group. The regex search has been given a flag to allow it to search case-insensitively. If no filename is present, one is generated using the uuid library.

This can be validated by hitting the endpoint in the FastAPI app below. Removing ; filename="test.png" from the Content-Disposition header will cause the temporary file to be named default_<uuid>. With the filename populated, the filename will be test.png.

from fastapi import FastAPI, Response

app = FastAPI()


@app.get("/test-media")
async def media(response: Response):
    response.headers['Content-Disposition'] = 'attachment; filename="test.png"'
    response.headers['Content-Type'] = 'image/png'
    response.status_code = 200
    return response

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