I wrote about Charles at length on TechPortal recently, so if you’re new to Charles that would be a good place to learn more. I set up Charles to proxy requests on port 8888, and I was running the PHP scripts on the same machine. To set the proxy, I simply added some entries to the $options array that gets passed to the SoapClient constructor:

$options = array(
    "cache_wsdl" => WSDL_CACHE_NONE,
    "soap_version" => SOAP_1_1,
    "trace" => 1,
    "proxy_host" => "localhost",
    "proxy_port" => 8888,
);

$client = new SoapClient($wsdl, $options);

The specific bits that are relevant to proxying through Charles here are the proxy_host and proxy_port settings, this sends these SOAP requests through port 8888 on my local machine, which is where Charles is listening for proxy activity. This means that I can easily keep one eye on the detail of the request without having large headers or SOAP responses all over my output or in the logs. As I mentioned earlier, there was also a moment where we thought that PHP was sending some incorrect headers (it wasn’t) and I was able to use Charles to rewrite just those headers, which helped us to see that this wasn’t the problem. You can also set a stream_context option to set any specific HTTP-related settings you need to, but some headers such as Content-Type will be ignored as the SOAP extension has clear ideas on which to send.

I hope that helps someone working with a remote SOAP service, they aren’t always easy to debug but this is one of many tools in my box so I thought I’d share.