Fix File field when it receives an empty value

[uncle-lv]

When we don't select a file, swagger send an empty value like this:

POST http://localhost:5000/images HTTP/1.1
Content-Type: multipart/form-data; boundary=---------------------------70636434840698183742419445910

-----------------------------70636434840698183742419445910
Content-Disposition: form-data; name="image"


-----------------------------70636434840698183742419445910--

Then the value of File field(named image above) is an empty string, and a ValidationError("Not a valid file.") occurs.
But in fact it's missing.

[uncle-lv]

This bug is found here.

[sloria]

thanks for fixing these! I'll merge and release these File field fixes when i get some time today

[raulblanxart]

Hi, thanks for the fast fix of this issue.
I'm triying to check the fix, but now the error comes when add a file, i had the same 422 error

thanks.

[uncle-lv]

Hi, thanks for the fast fix of this issue. I'm triying to check the fix, but i can't use the new code, whuen I install apiflask i think that not dowload the new version.

When will be available the new version?

thanks.

A new version of apiflask hasn't been released. And I don't have permission to do it.
@greyli usually releases new versions on weekends.

For this bug, you can just upgrade your flask-marshmallow after it's new version is released.

[raulblanxart]

Yes sorry, was mi mistake, I didn't read the error, the plobelms comes for the file extension.

Yes now all it's working fine.

Thans!