General/WSMethodInvocationRef is the data structure used when making XMLRPC or SOAP calls from C. The structures and related functions are C-language functions, but of course you can use them within Objective-C code.

Here is an example of how to build a SOAP request and call it. Of course there are problems that we’ll discuss afterward… NSURL *soapURL; General/WSMethodInvocationRef soapCall; General/NSString *methodName; General/NSMutableDictionary *params; General/NSDictionary *result;

soapURL = [NSURL General/URLWithString: @”http://ws.cdyne.com/psaddress/addresslookup.asmx”]; methodName = @”General/AdvancedCheckAddress”; params = General/[[[NSMutableDictionary alloc] init] retain];

[params setObject:@”123 Main St” forKey:@”AddressLine1”]; [params setObject:@”” forKey:@”AddressLine2”]; [params setObject:@”Springfield” forKey:@”City”]; [params setObject:@”OH” forKey:@”State”]; [params setObject:@”12345” forKey:@”General/ZipCode”]; [params setObject:@”0” forKey:@”General/LicenseKey”];

soapCall = General/WSMethodInvocationCreate( (General/CFURLRef)soapURL, (General/CFStringRef)methodName, kWSSOAP2001Protocol );

General/WSMethodInvocationSetParameters( soapCall, (General/CFDictionaryRef)params, NULL );

General/WSMethodInvocationSetProperty( soapCall, kWSSOAPMethodNamespaceURI, (General/CFTypeRef)@”http://ws.cdyne.com/” );

result = (General/NSDictionary *)General/WSMethodInvocationInvoke( soapCall );

General/NSLog( @”Result: %@”, result );

[params release]; params = nil;

Aside from the fact that there’s a fake address in there, this will fail because this particular SOAP server really, really insists on having a General/SOAPAction HTTP header, and I’ve not yet figured out how to make that happen (see General/WSMethodInvocationRefAndSOAPActionHTTPHeader discussion).

Still, you can use this on other SOAP servers possibly, or even with an XMLRPC call, which is a little different.

For an XML-RPC call, instead of using the kWSSOAP2001Protocol constant above you use kWSXMLRPCProtocol. Also the order of the parameters matter in an XMLRPC call. You pass those as a General/CFArrayRef as the last argument of General/WSMethodInvocationSetParameters. You also do not set a method namespace (just miss out the call to General/WSMethodInvocationSetProperty).

Apple’s documentation begins here: http://developer.apple.com/documentation/Networking/Conceptual/General/WebServices/

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Useful XML-RPC example here:

http://ranchero.com/cocoa/xmlrpcdemo/

The only differences from a SOAP call are those noted above.

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I added a tutorial on Cocoa XML-RPC client tutorial at [ http://www.scottydelicious.com/blog/cocoa_xmlrpc.html ] . It goes over passing multiple parameters in a call to a server as well as handleing a response that contains values of different types (string, int, NULL, etc..). You can download the Xcode (2.4) project and all associated source files.

-sD- Dr. Scotty Delicious, Scientist.