in R, how can I call a web service if I have WSDL description of it? (consume web service)

Question

I am not an expert of SOAP and WSDL but I have Perl code which I would like to port to R.

The Perl code looks like this (from https://www.pharmgkb.org/resources/downloads_and_web_services.jsp):

use SOAP::Lite;
import SOAP::Data 'type';

sub main {
  my $argcount = scalar (@ARGV);
  if ($argcount != 1) {
    print "usage: diseases.pl <PharmGKB accession id>\n";
    exit -1;
  }

  # make a web services call to server
  my $call = SOAP::Lite
    -> readable (1)
    -> uri('PharmGKBItem')
    -> proxy('http://www.pharmgkb.org/services/PharmGKBItem')
    -> searchDisease($ARGV[0]);

  if ($call->fault) {
    print $call->faultcode . ": " . $call->faultstring . "\n";
  } else {
    my $result = $call->result;

The read things about rsoap and SSOAP packages but did not get any nice info. What I need is full support, such as call the service and provide libraries to parse the output. I prefer some libraries rather then raw coding. I am good with XML package and not very good with RCurl. I am correct in thinking that there is no good and current (actively maintained) support in R for this?

Answer 1

Checkout the SSOAP package on OmegaHat. It's compatible with both S and R. It even has an genSOAPClientInterface function for generating the available Operations in the WSDL as R functions and generating the associated S4 classes for all of your data types described in the WSDL. It leverages XML and RCurl (both of which were created by the same author). He provides a directory full of examples and pretty useful PDF documentation.

I had a few problems with it when using my WSDL (and am still using modified code to get it to work), but the author of the package is extremely helpful and responsive to bug reports, if you run into issues.