MultipartFormDataContent does not conform to RFC7578 4.2 #121484
Description
Description
According to RFC7578 section 4.2 the filename= and filename*= fields for the Content-Disposition: form-data header field must not be combined.
NOTE: The encoding method described in [[RFC5987](https://www.rfc-editor.org/rfc/rfc5987)], which would add a
"filename*" parameter to the Content-Disposition header field, MUST
NOT be used.
Reproduction Steps
[Fact]
public async Task Test()
{
MultipartFormDataContent c = new MultipartFormDataContent();
c.Add(new StringContent("MyFileContent"), "name", "special€filename");
var str = await c.ReadAsStringAsync();
Assert.Contains("filename*=utf-8''special%E2%82%ACfilename", str);
Assert.DoesNotContain("filename=", str);
}
Expected behavior
Either filename or filename* should be present
Actual behavior
The provided test method produces an output like this:
--4a424cac-7519-4ce0-b0b8-cb117505a4c3
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=name; filename="=?utf-8?B?c3BlY2lhbOKCrGZpbGVuYW1l?="; filename*=utf-8''special%E2%82%ACfilename
MyFileContent
--4a424cac-7519-4ce0-b0b8-cb117505a4c3--
Regression?
No response
Known Workarounds
No response
Configuration
No response
Other information
No response