Xamarin.Mac URL Scheme

Question

How do you setup and debug URL schemes with Xamarin.Mac?

I added the following to my Info.plist:

I then built an installer package and installed the app. But if I open mytest:// in a browser or run open mytest:// command line, neither launches my app.

Additionally, is there a way to attach the debugger in Xamarin Studio after running mytest://? On Windows I'd use Debugger.Break and Debugger.Attach but those methods don't seem to be implemented in Mono.

Answer 1

It doesn't directly address your issue, but does the answer to this question help you at all?

Specifically, it addresses using the custom execution command option on your project. You can define a custom command to execute your application in the debugger:

Open 'Project Options', got to the 'Run>Custom Commands' section, add a custom command for 'Execute'

It also mentions the Debugger.Break behaviour:

If your app is running inside the Mono Soft Debugger with Mono 2.11 or later [...], it will set a soft breakpoint for the soft debugger and work as expected

---

EDIT:

You can call a URL on an already running Mac app... Can you set up a handler to trap the event, set a breakpoint inside and check that your URL is calling the already-running app properly? It might give you a clue to the behaviour or a way to further debug. Something like this:

    public override void FinishedLaunching(NSObject notification)
    {
        NSAppleEventManager appleEventManager = NSAppleEventManager.SharedAppleEventManager;

        appleEventManager.SetEventHandler(this, new Selector("handleGetURLEvent:withReplyEvent:"), AEEventClass.Internet, AEEventID.GetUrl);
    }

    [Export("handleGetURLEvent:withReplyEvent:")]
    private void HandleGetURLEvent(NSAppleEventDescriptor descriptor, NSAppleEventDescriptor replyEvent)
    {
        // Breakpoint here, debug normally and *then* call your URL
    }

Answer 2

As posted by @TheNextman the solution does work but this is a more complete solution. I got the following information from this Xamarin forums thread. As user (and Xamarin employee) Sebastien Pouliot (@poupou) states,

I never used that specific API but the four characters in enums values are common in Apple API.

The four characters (4 bytes) are compiled into an integer. If there's no C# enum already available then you can convert the strings to an integer which this code:

public static int FourCC (string s) {
    return (((int)s [0]) << 24 |
        ((int)s [1]) << 16 |
        ((int)s [2]) << 8 |
        ((int)s [3]));
}

So the complete sample would be as follows,

public override void FinishedLaunching(NSObject notification)
{
    NSAppleEventManager.SharedAppleEventManager.SetEventHandler(this, new Selector("handleGetURLEvent:withReplyEvent:"), AEEventClass.Internet, AEEventID.GetUrl);
}

[Export("handleGetURLEvent:withReplyEvent:")]
private void HandleGetURLEvent(NSAppleEventDescriptor descriptor, NSAppleEventDescriptor replyEvent)
{
    string keyDirectObject = "----";
    uint keyword = (((uint)keyDirectObject[0]) << 24 |
                   ((uint)keyDirectObject[1]) << 16 |
                   ((uint)keyDirectObject[2]) << 8 |
                   ((uint)keyDirectObject[3]));
    string urlString = descriptor.ParamDescriptorForKeyword(keyword).StringValue;
}