cURL POST --data-binary vs --form

Question

I have a simple question regarding to the usage of cURL. Didn't find much during my Google search or Man page to get a clear answer.

In here talks about using either --data vs --form on sending file/attachment. I'm curious to know what are the main difference and under what scenarios you would pick --data-binary VS --form ?

The POST "body" can be sent via either --data (for application/x-www-form-urlencoded) or --form (for multipart/form-data):

-F "foo=bar"                  # 'foo' value is 'bar' -F "foo=<foovalue.txt"        # the specified file is sent as plain text input -F "[email protected]"        # the specified file is sent as an attachment  -d "foo=bar" -d "foo=<foovalue.txt" -d "[email protected]" -d "@entirebody.txt"          # the specified file is used as the POST body  --data-binary "@binarybody.jpg" 

Answer 1

The difference is explained in the HTML 4.01 Specification section on Forms:

application/x-www-form-urlencoded is the default content type.

The content type "application/x-www-form-urlencoded" is inefficient for sending large quantities of binary data or text containing non-ASCII characters. The content type "multipart/form-data" should be used for submitting forms that contain files, non-ASCII data, and binary data.