Using Persistent Connections with SOAP::Lite HTTP clients

[tomhukins]

By default, SOAP::Lite creates new HTTP or HTTPS connections for every request. This makes long transactions run slowly, particularly over HTTPS where the SSL/TLS handshake takes place every time.

SOAP::Lite::Transport::HTTP::Client contains a hack to support the "Connection: Keep-Alive" header field in HTTP requests, but I've had no luck making it work.

LWP::UserAgent contains its own connection caching mechanism that allows it to use persistent connections. As SOAP::Lite::Transport::HTTP::Client subclasses LWP::UserAgent, we can initialise the connection cache on the SOAP transport object.

# $client should contain a SOAP::Lite client that uses HTTP/HTTPS

# Cache up to 10 connections
my $max_connections = 10;

# Retrieve the HTTP Transport object.
my $transport = $client->transport();
# Use LWP::UserAgent's conn_cache() method.
$transport->conn_cache({ total_capacity => $max_connections });