Use curl to upload a file in a multipart/form-data request, with custom content-type for the file (not the request)

upload.sh

filename='yourfilename'
filetype='text/csv'
token='my oauth token'
url='http://localhost/upload'

curl "$url" \
  --form "data=@$filename;type=$filetype" \
  --form "name=somename" \
  -H "Authorization: Bearer $token"
  

This generates the below HTTP request:

POST /upload HTTP/1.1

Host: localhost
User-Agent: curl/7.73.0
Accept: */*
Authorization: Bearer my oauth token
Content-Length: 13087
Content-Type: multipart/form-data; boundary=------------------------9aa33de891382f2a

--------------------------9aa33de891382f2a
Content-Disposition: form-data; name="name"

somename
--------------------------9aa33de891382f2a
Content-Disposition: form-data; name="data"; filename="yourfilename"
Content-Type: text/csv

...your file content...

Note that there's another Content-Type in the multipart request's body. It's different from the multipart request itself. This Content-Type is specified using the type= part in the --form header. If you didn't specify this, a default content type would be application/octet-stream (i.e. a binary file).

The curl command generated from Postman is almost always wrong, as Postman relies on Chromium to do the multipart handling.

Thank you so much for this! Scoured the entire internet until I found a simple explanation as to why all my requests were denied.

You sir, are a gentleman and a scholar, thanks!

thanks, that saved me quite the headache!