How can I write an IRIS interoperability adapter for high-throughput WebSocket connections?

To create a custom High Throughput WebSocket inbound adapter for InterSystems IRIS-based productions, follow these considerations and steps:

1. Choose Asynchronous Operation for WebSocket Processing:
   Use asynchronous operations for your WebSocket server to handle many concurrent socket connections efficiently. This setup shares a pool of gateway connections between multiple clients, avoiding the overhead of dedicated connections [1][2].

2. Extend %CSP.WebSocket for a Server-Side Implementation:
   Create a server class that extends %CSP.WebSocket. Implement required server methods such as Server(), OnPreServer(), and OnPostServer() for managing WebSocket lifecycle events and processing messages [3][2].

3. Configure Shared Connections:
   In the OnPreServer() method, set the SharedConnection property to 1 to enable pooling of Web Gateway connections. This approach helps in efficiently managing resource allocation for many WebSocket clients [3][2].

4. Implement Message Processing Workflow:

   • Use the Read() and Write() methods to manage incoming and outgoing messages.
   • Implement a robust queuing mechanism to handle messages from multiple clients efficiently.
   • Use IRIS globals or %DynamicObject for storing and manipulating incoming JSON data [2].

5. Design for Scalability:

   • Consider distributing the load across multiple application servers in a load-balanced environment.
   • Use a shared notification table available to all server instances [2].

6. Integration with IRIS Interoperability Productions:

   • Treat each WebSocket inbound message as an interoperability message.
   • Map messages received via the WebSocket server to business processes or operations within your IRIS production.

7. Test Across Load Scenarios:

   • Simulate high WebSocket traffic in your testing environment.
   • Profile the system performance using tools or scripts that connect multiple clients to your WebSocket adapter and generate traffic.

8. Asynchronous Callback Management (Optional):
   Implement asynchronous callbacks to gracefully handle scenarios where you need to defer WebSocket responses to a later server operation [3].

By following these steps, you can create a high-throughput WebSocket inbound adapter that works effectively within your InterSystems IRIS platform.

Further reference:
- [3][2]: Guide to implementing WebSocket-based servers and managing a pool of Web Gateway connections.

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