Question

I am currently dabbling around with perl and SOAP, using SOAP::Lite.

I have a simple SOAP server that appears to run fine:

#!perl -w

  use SOAP::Transport::HTTP;

  use Demo;

  # don't want to die on 'Broken pipe' or Ctrl-C
  $SIG{PIPE} = $SIG{INT} = 'IGNORE';

  my $daemon = SOAP::Transport::HTTP::Daemon
    -> new (LocalPort => 801)
    -> dispatch_to('/home/soaplite/modules')
  ;

  print "Contact to SOAP server at ", $daemon->url, "\n";
  $daemon->handle;

It includes a small class called Demo, which simply retrieves the systems total memory:

Demo.py

#!/usr/bin/perl
use Sys::MemInfo qw(totalmem freemem totalswap);

print "total memory: ".(&totalmem / 1024)."\n";

I have an example of a SOAP client below written in PERL, although I am unsure how to communicate with the server (since the tutorial I am following here goes of on a tangent e.g. retrieve the result of the Demo.py class from the client:

  #!perl -w

  use SOAP::Lite;

  # Frontier http://www.userland.com/

  $s = SOAP::Lite 
    -> uri('/examples')
    -> on_action(sub { sprintf '"%s"', shift })
    -> proxy('http://superhonker.userland.com/')
  ;

  print $s->getStateName(SOAP::Data->name(statenum => 25))->result; 

Any help would be greatly appreciated 🙂

Answer 1

For the server script, the dispatch_to method takes the path to the package to load, and the name of the package itself. If you pass a third parameter, it will limit the names of the methods made visible by the server. (e.g. 2 methods named memory and time, passing Demo::time as the 3rd param will make memory invisible to the client service.)

File server.pl

my $daemon = SOAP::Transport::HTTP::Daemon
    -> new (LocalPort => 801)
    -> dispatch_to('/home/soaplite/modules', 'Demo')
;

Your Demo package should be a package with methods that return the values. I couldn’t get Sys::MemInfo compiled on my system, so I just used localtime instead. I’m not sure why you named your package Demo.py, but Perl packages must have the extension pm, otherwise they won’t be properly loaded.

File Demo.pm

#!/usr/bin/perl

package Demo;

#use Sys::MemInfo qw(totalmem freemem totalswap);

sub memory {
    #print "total memory: ".(&totalmem / 1024)."\n";
    return "Can't load Sys::MemInfo, sorry";
}

sub time {
    my $time = localtime;
    return $time;
}

1;

For the client code, there’s 2 important pieces that must be properly specified to work, the proxy and the uri. The proxy is the url path to the soap web service. Since you are running the server script as a daemon process, your path is just the web site’s url. My computer doesn’t have a url, so I used http://localhost:801/. The 801 is the port you specified above. If you were running as a cgi script inside of a different web server (such as Apache), then you would need to specify the cgi script to call (e.g. http://localhost/cgi-bin/server.pl, changing the package in server.pl to SOAP::Transport::HTTP::CGI.

uri is probably the most confusing, but it’s the namespace of the xml files returned by the web service. Turn on +trace => 'debug' to see the xml file returned by the web service. The uri should just be the name of the server. Even if you switch ports or to a cgi dispatch method, this uri stays the same.

File test.pl

#!perl -w

use SOAP::Lite +trace => 'debug';

# Frontier http://www.userland.com/

$s = SOAP::Lite->new(proxy => 'http://superhonker.userland.com:801/',
        uri => 'http://superhonker.userland.com/');
               #might be http://www.userland.com/
               #but I could not test sub-domains

print $s->time()->result;