The "test-httpmsg" command:

Usage: fossil test-httpmsg URL ?PAYLOAD? ?OPTIONS?

Send an HTTP message to URL and get the reply. PAYLOAD is a file containing the payload, or "-" to read payload from standard input. a POST message is sent if PAYLOAD is specified and is non-empty. If PAYLOAD is omitted or is an empty file, then a GET message is sent.

Options:

--compress
Use ZLIB compression on the payload
--mimetype TYPE
Mimetype of the payload
--out FILE
Store the reply in FILE
-v
Verbose output