Wiki source code of Web Services-Web Service Provider

Last modified by Pascal Robert on 2007/09/03 19:49

version	line-number	content
4.1	1	WebObjects supports Web Services both as a producer and a consumer, and it actually works quite well once you figure out how to get things properly configured. Hopefully this walkthrough can jumpstart that process for you.
1.1	2
3.1	3	= Setting up a WO Web Services Project =
1.1	4
	5	Here are the basic steps for setting up a Web Services producer with WebObjects and Eclipse/WOLips:
	6
	7	1. Create a new WOApplication project
	8	1. Edit the project's Build Path, and go to the Libraries tab
	9	11. Add the following external jars from /Library/WebObjects/Extensions.
	10	11*. axis.jar
	11	11*. commons-logging.jar
	12	11*. commons-discovery.jar
	13	11*. wsdl4j.jar
	14	11*. saaj.jar
	15	11*. jaxrpc.jar
	16	11. Edit the WO Frameworks collection and add the JavaWebServicesSupport framework from the System frameworks
4.1	17	1. Create a class to hold your web service methods. The methods do not need to be static and can both take complex types as parameters and return complex types as return values. For now, just return primitive types and/or String.
1.1	18	1. Edit your Application class and add WOWebServiceRegistrar.registerWebService("PublishedNameOfYourWebService", NameOfTheClassYouJustMade.class, true);
	19
4.1	20	That's it. Now when you start your app, you can request [[http:~~/~~/yourserver.com/cgi-bin/WebObjects/YourApp.woa/ws/PublishedNameOfYourWebService?wsdl>>url:http://yourserver.com/cgi-bin/WebObjects/YourApp.woa/ws/PublishedNameOfYourWebService?wsdl\|\|shape="rect"]] and it will return the autogenerated WSDL document that you can use with any number of web service clients to interact with your server.
1.1	21
3.1	22	= Complex Types with WO Web Services =
1.1	23
4.1	24	So now the issue of complex types. Returning complex types is fine, but you have to register the serializer and deserializer classes for each complex type you reference. If you do not, the server will attempt to serialize your object using the ArraySerializer (you'll see this exception on the server), and the client will complain about a nonsensical error with SYSTEMID (gotta love terrible error handling!). The fix for this is for each of your complex types, call the following method in your Application constructor:
1.1	25
	26	{{panel}}
4.1	27	WOWebServiceRegistrar.registerFactoriesForClassWithQName(new BeanSerializerFactory(_class, _qName), new BeanDeserializerFactory(_class, _qName), _class, _qName);
1.1	28	{{/panel}}
	29
4.1	30	where _class is the Class object that represents your complex type, and _qName is the QName (fully qualified name) of the class as it appears in your WSDL document. For instance, if you created a complex return type named Person and it is in the com.yourserver.service package, _class would be com.yourserver.service.Person.class and _qName would be new QName("http:~/~/service.yourserver.com", "Person"). Notice that the namespace is the inverse of your package name. You will need to call this method for each of the parameters and return types your reference.
1.1	31
4.1	32	For the record, I have no idea why you have to do this step manually - The WSDL was autogenerated, and thus it KNOWS the classes and their QName WSDL mappings, but I was not able to get things to work properly without this step. If anyone knows why this is, or a way around it, please update this article.
1.1	33
	34	With these registrations, you should now be able to communicate with WO using any standard Web Service client (Axis, .NET, etc).
	35
3.1	36	= Sessions and WO Web Services =
1.1	37
4.1	38	You may have noticed in your Web Service methods that you have no WOContext, WORequest, WOSession, and friends passed in. Do not fret. The WebServiceRequestHandler takes care to hook you up in this department using Axis's MessageContext class. You can use the following code to get to your WOSession:
1.1	39
	40	{{panel}}
3.1	41	WOContext context = (WOContext)MessageContext.getCurrentContext().getProperty("com.webobjects.appserver.WOContext");
4.1	42	WOSession session = context.session();
1.1	43	{{/panel}}
	44
	45	or the shortcut
	46
	47	{{panel}}
3.1	48	WOSession session = WOWebServiceUtilities.currentWOContext().session();
1.1	49	{{/panel}}
	50
	51	The following additional keys are accessible through the MessageContext:
	52
	53	* "com.webobjects.appserver.WOContext" = the WOContext for this request
	54	* "transport.url" = I /believe/ this contains the full request URL up to the query string
4.1	55	* org.apache.axis.transport.http.HTTPConstants.MC_HTTP_SERVLETPATHINFO = contains the request's request handler path
1.1	56	* "Authorization" = contains the Authorization header, in the event that you need to process things like Kerberos/SPNEGO, etc.
	57	* "remoteaddr" = contains the request's remote address
	58
3.1	59	= Consuming with Axis in Java =
1.1	60
4.1	61	If you are using Axis to consume a WO Web Service, be advised that there is an outstanding bug (open since circa 2003, no less) that axis by default does not support passing more than one cookie to the server. WO sends both woinst AND wosid, so you lose your session ID from the client on the return trip to the server. This can be fixed by applying the patch from [[http:~~/~~/issues.apache.org/jira/browse/AXIS-1059>>url:http://issues.apache.org/jira/browse/AXIS-1059\|\|shape="rect"]] to your client's axis.jar. Axis 1.1 has been archived at Apache, but you can download the source from [[http:~~/~~/archive.apache.org/dist/ws/axis/1_1/>>url:http://archive.apache.org/dist/ws/axis/1_1/\|\|shape="rect"]] . The patch does not perfectly apply. There are two rejected hunks, but it should be very obvious how to fix the rejects (the patch has two System.out.printlns that it claims were in the original source that were not). After fixing that, you can setStoreSessionIdInCookies(true) on your server's WOSession and setMaintainSessions(true) on your client's ServiceLocator and you'll be good to go.
1.1	62
	63	This Axis bug appears to be fixed in recent versions of Axis, including version 1.4. Trying to upgrade the version of Axis in your WO Web Services server is not likely to be a happy experience (and likely neither will be upgrading Axis in a Direct To Web Services client - though I haven't tried this). However, it does seem to be possible to use a later version of the Axis jars on the classpath of a WebObjects application that intends to use classes generated by WSDL2Java to connect to a remote Web Services server - assuming that there are no WebObjects classes included in the WSDL. It is important in this case that you use matching version of WSDL2Java.
	64
3.1	65	= Consuming with WebServicesCore.framework =
1.1	66
4.1	67	There are several complications when it comes to using WebServicesCore with WebObjects, all of which stem from the WSMakeStubs generated code. Upon using the code generated by WSMakeStubs, you will run into the following issues that need to be fixed in its code:
1.1	68
3.1	69	= WSMakeStubs =
1.1	70
4.1	71	Apple provides a program called WSMakeStubs that is similar to WSDL2Java in Axis, except that it sucks. It will, however, at least give you a starting point for building your web service client code, and with the changes outlined below, you can end up with decent client APIs.
1.1	72
	73	Running WSMakeStubs is very simple:
	74
4.1	75	/Developer/Tools/WSMakeStubs -x ObjC -name NameOfServiceClass -url [[http:~~/~~/yourserver.com/cgi-bin/WebObjects/YourWOA.woa/ws/YourService?wsdl>>url:http://yourserver.com/cgi-bin/WebObjects/YourWOA.woa/ws/YourService?wsdl\|\|shape="rect"]]
1.1	76
4.1	77	This will produce Objective-C code that you can use to call your web service. As opposed to Axis, WSMakeStubs produces stateless code for your service (i.e. no session tracking or cookie support - only static methods for each method of your web service). All of the methods appear at the end of NameOfServiceClass.m that you will need to call. WSMakeStubs also produces WSGeneratedObj.m, which contains the lower level web service core calls.
1.1	78
3.1	79	= Service Methods Without Return Values =
1.1	80
4.1	81	Another bug in WSMakeStubs is related to methods that don't have return values. For void methods, the methods are never actually CALLED by WSMakeStubs. If you look at the code for the returnValue method, you will see that it never calls [[doc:WO.super getResultDictionary]]. The problem with this is that [[doc:WO.super getResultDictionary]] is the code that actually executes the web service method. Simply change the definition for your void method to be:
1.1	82
3.1	83	{{code}}
1.1	84
3.1	85	- (id) resultValue {
	86	return [self getResultDictionary];
	87	}
1.1	88
	89
3.1	90	{{/code}}
	91
1.1	92	And everything will work as planned.
	93
3.1	94	= Bugs and Changes to WSGeneratedObj =
1.1	95
4.1	96	WSGeneratedObj is MOSTLY bug free. However, there there are a couple changes required to fix a memory leak it generates (from cocoadev.com):
1.1	97
	98	At the end of getResultDictionary, add:
	99
3.1	100	{{code}}
1.1	101
3.1	102	if (fRef) { // new code
	103	WSMethodInvocationSetCallBack(fRef, NULL, NULL); // new code
	104	} // new code
	105	return fResult; // original code
1.1	106
3.1	107	{{/code}}
1.1	108
	109	which now reveals that the NSURL that is used is double-freed, fixable by removing one line from createInvocationRef:
	110
3.1	111	{{code}}
1.1	112
3.1	113	NSURL* url = [NSURL URLWithString: endpoint];
	114	if (url == NULL) {
	115	[self handleError: @"NSURL URLWithString failed in createInvocationRef" errorString:NULL errorDomain:kCFStreamErrorDomainMacOSStatus errorNumber:paramErr];
	116	} else {
	117	ref = WSMethodInvocationCreate((CFURLRef) url, (CFStringRef)methodName, (CFStringRef) protocol);
	118	// [url release]; remove this line
	119	....
1.1	120
3.1	121	{{/code}}
1.1	122
4.1	123	Another change I like to make in the generated is to remove the hard-coded service URLs and pass them in from the code that calls the service (much like Axis does). This should be a fairly straightforward change, but I wanted to make a note about doing it. It will be fairly common that you want to talk to a development server and a production server using the same code, and as a result, you will want that variable to be parameterized.
1.1	124
3.1	125	= Passing a Complex Type to WO =
1.1	126
3.1	127	WSMakeStubs provides no direct support for passing complex types around - All you get is an NSDictionary, and all you can send back is an NSDictionary, with no instructions as to what exactly is IN these dictionaries.
1.1	128
	129	To send a complex type back to WO, you have to set the following keys in your dictionary:
	130
3.1	131	{{code}}
1.1	132
3.1	133	[dictionary setObject:@"http://extranet.mdtask.mdimension.com" forKey:(NSString *)kWSRecordNamespaceURI];
	134	[dictionary setObject:@"WSCompany" forKey:(NSString *)kWSRecordType];
1.1	135
3.1	136	{{/code}}
1.1	137
4.1	138	Where kWSRecordNamespaceURI's value is the XML namespace of the type of the complex object you are passing, and kWSRecordType's value is the name of the type. On the WO side, the namespace will be the reverse of the type's class name, and the record type will be the name of the class. For instance, in the example above, the actual class on the server was named com.mdimension.mdtask.extranet.WSCompany .
1.1	139
4.1	140	The rest of the dictionary contains attribute=>value mappings. For instance, WSCompany in the example above has a "name" attribute, so the dictionary would also contains a "name" key that maps to the corresponding value.
1.1	141
4.1	142	When sending NSDictionary instances from Cocoa, the WO will fire the WOGlobalIDDeserializer and it will not properly parse the nsdictionary or nsarray, it appears that there is no default deserializer on the WO side for those classes.
1.1	143
4.1	144	One solution is to add
1.1	145
3.1	146	{{code}}
1.1	147
3.1	148	@implementation NSObject (NSObject_WOXML)
1.1	149
3.1	150	- (NSString*)xmlPlist {
	151	NSString* error;
	152	NSData* data = [NSPropertyListSerialization dataFromPropertyList:self
	153	format:NSPropertyListXMLFormat_v1_0
	154	errorDescription:&error];
	155	return [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];
	156	}
1.1	157
3.1	158	@end
1.1	159
3.1	160	{{/code}}
1.1	161
3.1	162	on the cocoa side, than call it when compiling the arguments for the WSMethodInvocationRef
4.1	163	Than on the WO side use NSPropertyListSerialization.propertyListFromString(xmlPlist) to recreate the object.
1.1	164
3.1	165	= Return Values from WO =
1.1	166
4.1	167	One of the other problems WSMakeStubs has is that it doesn't produce a valid identifier for retrieving a WO web service return value. In the generated code, you will see something like
1.1	168
3.1	169	{{code}}
1.1	170
3.1	171	- (id) resultValue {
	172	return [[super getResultDictionary] objectForKey: @"getBillableCompaniesReturn"];
	173	}
1.1	174
	175
3.1	176	{{/code}}
1.1	177
4.1	178	however, the actual return value name requires its namspace to be included. The fixed version of the routine looks like:
1.1	179
3.1	180	{{code}}
1.1	181
3.1	182	- (id) resultValue {
	183	return [[super getResultDictionary] objectForKey: @"ns1:getBillableCompaniesReturn"];
	184	}
1.1	185
3.1	186	{{/code}}
1.1	187
4.1	188	Notice the key starts with "ns1:". This value should match the value that appears in your WSDL.
1.1	189
3.1	190	= Example Type Wrappers =
1.1	191
4.1	192	Here's an example type wrapper I use based on the WSCompany example above. In the static methods that WSMakeStubs creates that wrap my web service methods, I simply initWithDictionary this type with the result dictionary from the web service and return an instance of WSCompany rather than the dictionary. When I send one of these objects back, I simply send [[doc:WO.wsCompany dictionary]] in the wrapper method.
1.1	193
3.1	194	{{code}}
	195	@interface WSCompany : NSObject {
	196	NSMutableDictionary *myDictionary;
	197	}
1.1	198
3.1	199	-(id)initWithDictionary:(NSDictionary *)_dictionary;
	200	-(NSDictionary *)dictionary;
	201	-(NSString *)name;
	202	-(NSString *)companyID;
	203	@end
4.1	204	{{/code}}
1.1	205
3.1	206	{{code}}
1.1	207
3.1	208	@implementation WSCompany
1.1	209
3.1	210	-(id)initWithDictionary:(NSDictionary *)_dictionary {
	211	self = [super init];
	212	myDictionary = [[_dictionary mutableCopy] retain];
	213	[myDictionary setObject:@"http://extranet.mdtask.mdimension.com" forKey:(NSString *)kWSRecordNamespaceURI];
	214	[myDictionary setObject:@"WSCompany" forKey:(NSString *)kWSRecordType];
	215	return self;
	216	}
1.1	217
3.1	218	-(void)dealloc {
	219	[myDictionary release];
	220	[super dealloc];
	221	}
1.1	222
3.1	223	-(NSDictionary *)dictionary {
	224	return myDictionary;
	225	}
1.1	226
3.1	227	-(NSString *)name {
	228	return [myDictionary objectForKey:@"name"];
	229	}
1.1	230
3.1	231	-(NSString *)companyID {
	232	return [myDictionary objectForKey:@"companyID"];
	233	}
	234	@end
1.1	235
3.1	236	{{/code}}
1.1	237
3.1	238	= Fault Handling =
1.1	239
4.1	240	WSMakeStubs doesn't handle the fault properly but it's in the dictionary. In +resultForInvocation: I added a few lines to check for and return the fault
1.1	241
3.1	242	{{code}}
1.1	243
3.1	244	+ (id) resultForInvocation:(WSGeneratedObj*)invocation; {
	245	result = [[invocation resultValue] retain];
	246	// Added check if a fault occured and return the fault string if so
	247	if([invocation isComplete]) {
	248	if([invocation isFault]) {
	249	result = [[invocation getResultDictionary] valueForKey:@"/FaultString"];
	250	}
	251	}
	252	//
	253	[invocation release];
	254	return result;
	255	}
1.1	256
	257
3.1	258	{{/code}}
1.1	259
3.1	260	= Stateful Services =
1.1	261
	262	Below is the necessary code to enable cookie support and stateful session with the files generated by WSMakeStubs. This code also includes changes so the base web services URL is supplied in the init method and allows specifying a timeout value (which I defaulted to 30 seconds). To WSGeneratedObj.h, add three new member variables:
	263
3.1	264	{{code}}
1.1	265
3.1	266	@interface WSGeneratedObj : NSObject {
	267	WSMethodInvocationRef fRef;
	268	NSDictionary* fResult;
	269	NSDictionary* fCookies;
	270	NSString fURLString;
	271	int fTimeout;
1.1	272
3.1	273	id fAsyncTarget;
	274	SEL fAsyncSelector;
	275	};
1.1	276
3.1	277	{{/code}}
	278
1.1	279	Here are the new methods to add to WSGeneratedObject.m:
	280
3.1	281	{{code}}
	282	-- (id) initWithWebServicesURLString:(NSString*)urlString
	283	{
	284	if (self = [super init]) {
	285	fURLString = [urlString copy];
	286	}
	287	return self;
	288	}
1.1	289
3.1	290	- (NSString*) getWebServicesURLString { return fURLString; }
1.1	291
3.1	292	- (NSURL*) getWebServicesURL { return [NSURL URLWithString: [self getWebServicesURLString]]; }
1.1	293
3.1	294	- (NSArray*) getReturnedCookies
	295	{
	296	NSDictionary *results = [self getResultDictionary];
	297	if (nil == results)
	298	return nil;
	299	CFHTTPMessageRef msgRef = (CFHTTPMessageRef)[results objectForKey: (id)kWSHTTPResponseMessage];
	300	NSDictionary headers = (NSDictionary)CFHTTPMessageCopyAllHeaderFields(msgRef);
	301	[headers autorelease];
	302	//parse the cookies
	303	NSArray *cookies = [NSHTTPCookie cookiesWithResponseHeaderFields: headers forURL: [self getWebServicesURL]];
	304	return cookies;
	305	}
1.1	306
3.1	307	- (void) setCookies:(NSArray*)cookies
	308	{
	309	[fCookies release];
	310	fCookies = [[NSHTTPCookie requestHeaderFieldsWithCookies: cookies] retain];
	311	WSMethodInvocationSetProperty([self getRef], kWSHTTPExtraHeaders, fCookies);
	312	}
4.1	313	{{/code}}
1.1	314
3.1	315	{{code}}
1.1	316
3.1	317	- (int)timeoutValue { return fTimeout; }
	318	- (void)setTimeout:(int)t
	319	{
	320	if (t >= 0 && t < 600)
	321	fTimeout = 30;
	322	}
1.1	323
	324
3.1	325	{{/code}}
1.1	326
4.1	327	You will need to modify -dealloc to release fCookies and fURLString. Below is my modified version getCreateInvocationRef. It is modified to get the URL using the new accessor methods above, to get the method name from the class name (which makes a lot more sense than hard-coding it to the class name in every subclass), and to set the timeout. After that is a generic resultValues method so that your generated subclasses can have their -resultValues and -getCreateInvocationRef methods removed~-~--the only methods they require are for setting parameters. There is also a commented out line that you can uncomment to have debug information included in the results dictionary. This is very helpful when trying to debug the transfer of complex objects.
3.1	328
	329	{{code}}
	330
	331	- (WSMethodInvocationRef) genCreateInvocationRef
	332	{
	333	WSMethodInvocationRef invRef = [self createInvocationRef
	334	/endpoint/: [self getWebServicesURLString]
	335	methodName: NSStringFromClass([self class])
	336	protocol: (NSString*) kWSSOAP2001Protocol
	337	style: (NSString*) kWSSOAPStyleRPC
	338	soapAction: @""
	339	methodNamespace: @"http://DefaultNamespace"];
	340	//set a time-out value
	341	if (fTimeout > 0) {
	342	WSMethodInvocationSetProperty(invRef, kWSMethodInvocationTimeoutValue, (CFTypeRef)[NSNumber numberWithInt: fTimeout]);
	343	// WSMethodInvocationSetProperty(invRef, kWSDebugIncomingBody, (CFTypeRef)kCFBooleanTrue);
	344	}
	345	return invRef;
	346	}
	347
	348	- (id) resultValue
	349	{
	350	NSString *key = [NSString stringWithFormat: @"ns1:%@Return", NSStringFromClass([self class])];
	351	return [[self getResultDictionary] objectForKey: key];
	352	}
	353
	354
	355	{{/code}}
	356
1.1	357	To use stateful services, call getReturnedCookies after the first request and store the cookie dictionary. Then call setCookies: with that dictionary on all of your subsequent web services calls. Depending on the cookies you use, you might want to save a new copy of the cookies dictionary after each request.

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