Problem Statement

Demonstrate how to connect to a web server over HTTPS where that server requires that the client present a certificate to prove who (s)he is. Unlike with the HTTPS request with authentication task, it is not acceptable to perform the authentication by a username/password or a set cookie. This task is in general useful for use with webservice clients as it offers a high level of assurance that the client is an acceptable counterparty for the server. For example, Amazon Web Services uses this style of authentication.

Let's start with the solution:

package require http
package require tls

set cert myCert.p12
http::register https 443 [list \
    ::tls::socket -certfile $cert -password getPass]
proc getPass {} {
    return "myPassword";  # Just a noddy example...
} 

# Make a secure authenticated connection
set token [http::geturl https://verysecure.example.com/]
 
# Now as for conventional use of the “http” package
set data [http::data $token]
http::cleanup $token