File name not submitted with multipart/form-data

[Dronakurl]

Did you search for existing issues already?
yes

Describe the bug

I want to use slumber to upload a file to an endpoint with multipart/form-data.
Here are the parts of my config.

  test_h265_video:
    source: !file
      path: /home/ddt/regioncounter/faceswapper/test_h265.mp4
....
      upload_test_h265: !request
        name: Upload H.265 Test Video
        method: POST
        url: "{{server}}/api/videos/upload"
        headers:
          Accept: application/json
        authentication: !bearer "{{chains.auth_token}}"
        body: !form_multipart
          video: "{{chains.test_h265_video}};type:video/mp4"

In the upload, the "filename" is missing. I checked with curl:

curl -v -X POST "http://localhost/faceapi/api/videos/upload" \
        -H "Authorization: Bearer $(slumber request -p production login | jq -r .token)" \
        -H "Accept: application/json" \
        -F "video=@test_h265.mp4"

This is accepted by my endpoint.
The endpoint is an axum endpoint which expects Multipart and within the "video" field a filename in the "Content-Disposition" header.
I tried to pass this header, but there was still no filename found. Also, curl's verbose output does not show anything like this header, so I don't know where to explicitely include the filename in the slumber config.

To Reproduce
Please tell me, if I've got something wrong. If you are interested, I can provide a minimal reproducible example

Expected behavior
I would expected that slumber sends the form data exactly like curl does

Version (please complete the following information):

• OS: Ubuntu 24.04
• Terminal: alacritty
• Slumber Version: 3.4.0

[LucasPickering]

Yes, this is a current limitation of the multipart form support. The file name is not forwarded to the HTTP body builder. The type:video/mp4 magic string is also not passed along. This relates to #256 because both involve adding special logic for file+multipart bodies.

Unfortunately I don't have a workaround for this. I'll plan to work on this next. For now you'll have to keep using curl.

[LucasPickering]

I have the first batch work needed for this done. The feature is incomplete but the rest of it should go pretty quickly. It'll be released in 4.1.0. You'll need to upgrade to the new template format from 4.0 in order to use this. Here's what your recipe body would look like:

body: 
  type: form_multipart
  data:
    video: "{{ file('/home/ddt/regioncounter/faceswapper/test_h265.mp4') }}"

Slumber will automatically identify that the video field should be streamed from the file because the template is just a file() call. Reqwest (the HTTP library that Slumber uses) should automatically include the Content-Type based on the file's extension, as well as the filename field in the Content-Disposition header.

[LucasPickering]

This fix was released yesterday in 4.1.0