Add support for CAS LogoutRequests

Fixes #2346
This changes the serviceURL sent by SOGo to the CAS server:
  /SOGo/so/ -> /SOGo/so/index

SoObjects/SOGo/SOGoCASSession.m

@@ -20,6 +20,7 @@
  * Boston, MA 02111-1307, USA.
  */
 
+#import <Foundation/NSBundle.h>
 #import <Foundation/NSDictionary.h>
 #import <Foundation/NSURL.h>
 
@@ -35,6 +36,11 @@
 #import <NGObjWeb/WOResponse.h>
 #import <NGExtensions/NSObject+Logs.h>
 
+#import <SaxObjC/SaxObjC.h>
+#import <SaxObjC/SaxMethodCallHandler.h>
+#import <SaxObjC/SaxObjectDecoder.h>
+#import <SaxObjC/SaxXMLReaderFactory.h>
+
 #import "NSDictionary+Utilities.h"
 #import "NSString+Utilities.h"
 #import "SOGoCache.h"
@@ -106,6 +112,43 @@
   return session;
 }
 
++ (void) handleLogoutRequest: (NSString *) logoutRequest
+{
+  CASLogoutRequest *rq;
+  SOGoCache *cache;
+  NSBundle *bundle;
+  NSDictionary *root;
+  NSString *mapFile, *sessionIndex;
+
+  bundle = [NSBundle bundleForClass: [self class]];
+  mapFile = [bundle pathForResource: @"CASLogoutRequestMap" ofType: @"plist"];
+  if (![mapFile length])
+    {
+      [self errorWithFormat: @"mapFile not found (CASLogoutRequest.plist)"];
+      return;
+    }
+
+  id<NSObject,SaxXMLReader> parser = nil;
+  SaxObjectDecoder *sax = nil;
+  parser = [[SaxXMLReaderFactory standardXMLReaderFactory]
+             createXMLReaderForMimeType:@"text/xml"];
+
+  sax = [[SaxObjectDecoder alloc] initWithMappingAtPath: mapFile];
+  [sax autorelease];
+  [parser setContentHandler:sax];
+  [parser setErrorHandler:sax];
+  [parser parseFromSource: logoutRequest];
+
+  rq = [sax rootObject];
+  sessionIndex = [rq sessionIndex];
+
+  if ([sessionIndex length])
+    {
+      cache = [SOGoCache sharedCache];
+      [cache removeCASSessionWithTicket: sessionIndex];
+    }
+}
+
 - (id) init
 {
   if ((self = [super init]))
@@ -381,7 +424,12 @@
   NSString *serviceURL;
 
   soURL = [[WOApplication application] soURL];
-  serviceURL = [soURL absoluteString];
+
+  /* appending 'index' to /SOGo/so/ so that callbacks made by the CAS server
+   * are not greeted with a 302 generated by sope. The CAS server doesn't
+   * follow redirects, and we'd end up losing the LogoutRequests
+   */
+  serviceURL = [NSString stringWithFormat: @"%@index", [soURL absoluteString]];
 
   params = [NSDictionary dictionaryWithObjectsAndKeys:
                            ticket, @"ticket", serviceURL, @"service",
@@ -466,3 +514,28 @@
 }
 
 @end
+
+@implementation CASLogoutRequest
+
+- (id) init
+{
+  if ((self = [super init]))
+    {
+      sessionIndex = nil;
+    }
+
+  return self;
+}
+
+- (void) dealloc
+{
+  [sessionIndex release];
+  [super dealloc];
+}
+
+- (NSString *) sessionIndex
+{
+  return sessionIndex;
+}
+
+@end