Create NSDictionary based on a URL structure with keys and values

AppDelegate.m

/*
 * Example implementation
 */

- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
  NSLog(@"Launched with URL: %@", url.absoluteString);

  NSDictionary *userDict = [self urlPathToDictionary:url.absoluteString];
  
  //Do something with the information in userDict  

  return YES;
}

NSDictionaryFromURL.m

/*
 -(NSDictionary *)urlPathToDictionary:(NSString *)path
 Takes a url in the form of: your_prefix://this_item/value1/that_item/value2/some_other_item/value3
 And turns it into a dictionary in the form of:
 {
   this_item: @"value1",
   that_item: @"value2",
   some_other_item: @"value3"
 }
 
 Handles everything properly if there is a trailing slash or not.
 Returns `nil` if there aren't the proper combinations of keys and pairs (must be an even number)

 NOTE: This example assumes you're using ARC. If not, you'll need to add your own autorelease statements.
 */

-(NSDictionary *)urlPathToDictionary:(NSString *)path
{
  //Get the string everything after the :// of the URL.
  NSString *stringNoPrefix = [[path componentsSeparatedByString:@"://"] lastObject];
  //Get all the parts of the url
  NSMutableArray *parts = [[stringNoPrefix componentsSeparatedByString:@"/"] mutableCopy];
  //Make sure the last object isn't empty
  if([[parts lastObject] isEqualToString:@""])[parts removeLastObject];
  
  if([parts count] % 2 != 0)//Make sure that the array has an even number
    return nil;
  
  //We already know how many values there are, so don't make a mutable dictionary larger than it needs to be.
  NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithCapacity:([parts count] / 2)];
  
  //Add all our parts to the dictionary
  for (int i=0; i<[parts count]; i+=2) {
    [dict setObject:[parts objectAtIndex:i+1] forKey:[parts objectAtIndex:i]];
  }

  //Return an NSDictionary, not an NSMutableDictionary
  return [NSDictionary dictionaryWithDictionary:dict];
}