Multitasking aware applications in iOS 4 and Custom URL Schemes

I'm trying to implement OAuth securely as detailed here: http://fireeagle.yahoo.net/developer/documentation/oauth_best_practice#custom-url-osx. I seem to have hit a stumbling block, as I am unable to figure out how to handle a url which launches my application when in the background.

I have registered my application to handle oauthtest. I have confirmed that oauthtest:// and oauthtest://callbacktest both launch my application and operate as intended when my application is not running in the background.

I am implementing

application:(UIApplication *) didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

which is successfully called when my application starts up cold. I can easily get the url passed to my application.

However, if my application开发者_开发百科 is already running in the background, neither

application:(UIApplication *) didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 

nor

application:(UIApplication *) handleOpenURL:(NSURL *)url 

is called and I have no way of getting the parameters passed to my application as part of the URL.

Does anyone know how to get the parameters passed to a backgrounded application by a custom url scheme?

I am aware that I could work around this issue by disabling multitasking, but I would rather not do that for obvious reasons. Thanks in advance.

Here's some sample code that seemed to work for me, tested in iOS4:

- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url {
     NSLog(@"handleOpenURL - %@", [url absoluteURL]);
     return YES;    
}

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    NSLog(@"applicationDidFinishLaunching");
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    NSLog(@"didFinishLaunchingWithOptions - %@", [launchOptions objectForKey:@"UIApplicationLaunchOptionsURLKey"]);
    return NO;
}

If I launch the application for the first time, didFinishLaunching: handles the URL. If I then put the app in the background, go back to Safari, and tap a link that brings the app back into the foreground, then handleOpenURL: takes care of the URL. Good luck!