Multipart requests

Hello!

I did not found standard way to describe a multipart request. Is it supported?

Currently i had to write something like this to let uploaded files work:

request_body_description = {
    "content": {
        "multipart/form-data": {
            "schema": {
                "type": "object",
                "properties": {"logo": {"type": "string", "format": "binary"}},
            }
        }
    }
}


@bp.route("/update-logo")
class UpdateLogo(MethodView):
    @bp.response(code=204)
    @bp.doc(requestBody=request_body_description)
    def post(self):
        file = flask.request.files["logo"]
        filename = secure_filename(file.filename)
        binary = file.read()
        
        ... do something with file ...

This code allows swagger to render input type=“file” with name “logo” and send multipart request when executing request from web interface.

Am i missing something?

Thanks!

[lafrech]

I’ve been banging my head against this a little more. Unfortunately, auto-documenting mixed multipart request bodies is a bit complicated.

There are issues because for instance arguments allows to pass description, but this is a requestBody level attribute, not a part (as in multi-part) level attribute, therefore, what we expect from the following would be undetermined:

        @blp.arguments(FilesSchema, location='files', description='Some description')
        @blp.arguments(FormSchema, location='form', description='Some other description')

---

This implementation issues make me think that the sanest way to do that would be to require more explicitness from the user.

We could add a multipart_arguments decorator so that we don’t have to detect multipart cases and we can ask for all needed parameters.

Things would go relatively smooth if we could pass apispec a schema that would be the aggregation of the different schemas involved ( a single schema inheriting from all). This could avoid duplicating apispec code, or having to pull functions from there to do the job here.

To be able to do so, we’d need to add a restriction to multipart_argument: only pass schema classes (or perhaps field dicts), not schema instances. Otherwise, modifiers would be lost in the process. I think we can live with this limitation.

---

I don’t think I’ll do that for the next release.

Once https://github.com/marshmallow-code/flask-smorest/tree/document_multipart_files is merged (almost done, just waiting for apispec 3.0), we’ll be able to send files (using multipart), and to properly set a content type. This is already an improvement.

We shall add a note in the docs saying mixed multipart is not supported.

[aprilahijriyan]

Any progress here? i am currently looking for a way how to work with this.