How to Gracefully Stop a Broadcast Upload Extension

Overview

This guide specifically focuses on how to properly terminate a Broadcast Upload Extension without generating errors, including Objective-C integration.

The Challenge

By default in Swift, you cannot stop a broadcast without specifying an error. The finishBroadcastWithError method requires an error parameter, making it impossible to stop the broadcast gracefully without generating an error message.

Solution: Objective-C Bridge

To suppress the implicit error creation, we can create an Objective-C helper class and use a bridging header in our Swift project. This approach allows us to bypass Swift’s strict error handling requirements.

Step 1: Create the Objective-C Helper Files

First, create a new header file (BroadcastHelper.h):

#import <ReplayKit/ReplayKit.h>

void finishBroadcastGracefully(RPBroadcastSampleHandler * _Nonnull broadcastSampleHandler);

Then, create the implementation file (BroadcastHelper.m):

#import "BroadcastHelper.h"

void finishBroadcastGracefully(RPBroadcastSampleHandler * _Nonnull broadcastSampleHandler) {
    #pragma clang diagnostic push
    #pragma clang diagnostic ignored "-Wnonnull"
    [broadcastSampleHandler finishBroadcastWithError:nil];
    #pragma clang diagnostic pop
}

Step 2: Set Up the Bridging Header

1. Create a bridging header file if you don’t already have one (e.g., YourProject-Bridging-Header.h)
2. Add the following import to your bridging header:

#import "BroadcastHelper.h"

Step 3: Use in Swift Code

Now you can call the Objective-C helper from your Swift broadcast extension:

class SampleHandler: RPBroadcastSampleHandler {
    func stopBroadcastGracefully() {
        finishBroadcastGracefully(self)
    }
}

Important Notes

• This approach uses Objective-C runtime features to bypass Swift’s strict type checking.
• The #pragma directives are used to suppress compiler warnings about passing nil to a non-null parameter.
• Make sure your bridging header is properly configured in your project settings.
• This method should be used carefully and only when you’re certain no error reporting is needed.

Conclusion

While Swift enforces strict error handling, there are cases where we need more flexibility in handling broadcast termination. This Objective-C bridge approach provides a clean way to stop broadcasts without generating errors, which can be particularly useful in scenarios where error reporting isn’t necessary or desired.

References

• Apple Documentation - ReplayKit Framework
• Swift and Objective-C Interoperability