How to Set Your Cocoa Application as the Default Web Browser in macOS

Creating a web browser might sound daunting, but what if you want your Cocoa application to take on that role? Setting your application as the default web browser in macOS is not only feasible but also allows you to enhance user experience by providing seamless interactions with HTTP and HTTPS links. In this blog post, we’ll walk through the essential steps to accomplish this.

The Problem

When users click on a web link in applications like Mail or iChat, their default web browser launches. If you’re developing a Cocoa application and want it to be the one that opens these links, you need to configure your app to handle HTTP and HTTPS links and set it as the default browser.

The Solution

To make your Cocoa application the default web browser, you can follow these four steps:

1. Add URL Schemes to Your Application’s Info.plist

Your first task is to inform macOS that your application can handle HTTP and HTTPS requests. This is done by modifying your application’s Info.plist file. Here’s how to do it:

1. Open your application’s Info.plist file.
2. Add the following XML snippet:

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleURLName</key>
        <string>http URL</string>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>http</string>
        </array>
    </dict>
    <dict>
        <key>CFBundleURLName</key>
        <string>Secure http URL</string>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>https</string>
        </array>
    </dict>
</array>

With this addition, you’re declaring that your app can handle both types of URL schemes.

2. Write a URL Handler Method

Next, you need to create a method that will be triggered when your application is asked to open a URL. Here’s a simple example:

- (void)getUrl:(NSAppleEventDescriptor *)event 
    withReplyEvent:(NSAppleEventDescriptor *)replyEvent 
{
    NSString *urlStr = [[event paramDescriptorForKeyword:keyDirectObject] 
        stringValue];

    // TODO: Your custom URL handling code here
}

In this method, you’ll eventually implement the logic to handle the URL after it’s fetched.

3. Register the URL Handler Method

Now that you have your URL handler method, you need to register it with the macOS Event Manager. You can do this by adding the following code to your application’s initialization section:

NSAppleEventManager *em = [NSAppleEventManager sharedAppleEventManager];
[em setEventHandler:self 
  andSelector:@selector(getUrl:withReplyEvent:) 
  forEventClass:kInternetEventClass 
  andEventID:kAEGetURL];

Additionally, to support older applications, register for the WWW!/OURL Apple Event:

[em setEventHandler:self 
  andSelector:@selector(getUrl:withReplyEvent:) 
  forEventClass:'WWW!' 
  andEventID:'OURL'];

4. Set Your App as the Default Browser

Finally, you need to set your app as the default handler for HTTP and HTTPS schemes using the Launch Services API. Add the following code:

CFStringRef bundleID = (CFStringRef)[[NSBundle mainBundle] bundleIdentifier];
OSStatus httpResult = LSSetDefaultHandlerForURLScheme(CFSTR("http"), bundleID);
OSStatus httpsResult = LSSetDefaultHandlerForURLScheme(CFSTR("https"), bundleID);
// TODO: Check httpResult and httpsResult for errors

Tip: It’s a good practice to ask the user for permission before changing their default browser settings.

Custom URL Schemes

In addition to standard URL schemes, you can also implement your own custom schemes. To avoid conflicts with other applications, it is wise to base your custom scheme on your app’s bundle identifier. For example, if your bundle ID is com.example.MyApp, consider implementing configurations like x-com-example-myapp://.

Conclusion

By following this straightforward guide, you can turn your Cocoa application into the default web browser for users on macOS. This not only enhances application utility but also provides a better, integrated web experience for users. Remember to always prioritize user consent when altering default settings for a smoother transition.

Feel free to ask further questions or leave comments if you encounter any issues during implementation!