Docs: Add example for parsing files

Hey guys,

I’ve been consulting the documentation and the web for a proper solution to parse file arguments from a post request using webargs, but still couldn’t find an answer to my question.

The docs says you can use the files location during parsing but mentions no straightforward solution on which field to use for files?

Can you include an example in the docs for this one, if it’s possible to do at all?

[sloria]

If you use fields.Field, marshmallow won’t do any processing on the value, so you’ll get a framework-specific file wrapper object. For example, you’ll get a FileStorage object in Flask.

[johnny-cy]

It seems not working for me, postman upload through body->form-data->choose a zip file and put ‘file’ in its key, it still gave me 422 when I set required=True, don’t know why, here is what I tried @use_kwargs({"file": fields.Field(validate=lambda file: "zip" == file.filename.split(".")[-1].lower(), location="files", required=True)}) and couldn’t find fields.Field validate on doc or anywhere, am I doing it correct ?

I found the problem I put location in wrong place, it should be put as second arg of use_kwargs: @use_kwargs({"file": fields.Field(validate=lambda file: "zip" == file.filename.split(".")[-1].lower(), required=True)}, location="files")