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Hussein Mahdi
Hussein Mahdi

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🔄 Simplified Approach: Asynchronous Request-Reply

In modern app development, when clients need to interact with remote APIs for business logic or services, the Asynchronous Request-Reply pattern shines. Here's how it works :

  • Client Makes Request: The client (like a web browser) sends a request to the backend API over HTTP(S).

  • Backend Acknowledges: Upon receiving the request, the backend immediately acknowledges it, letting the client know it's been received.

  • Backend Processes Asynchronously: Instead of making the client wait, the backend processes the request asynchronously. This means it can handle multiple tasks simultaneously without blocking.

  • Immediate Response: While the backend works, the client gets an immediate response, indicating the request has been accepted.

  • Notification of Completion: Once processing is complete, the backend notifies the client, providing the result or status update.
    Benefits:

  • Improved Responsiveness: Clients get immediate feedback, making interactions smoother.

  • Efficient Resource Utilization: Asynchronous processing allows the backend to handle tasks concurrently, optimizing resource usage.

  • Scalability: The system can handle more requests without sacrificing performance.

This approach simplifies communication between clients and servers, making applications more responsive and scalable.

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✅ When to Use This Pattern:

  • Client-Side Code: Ideal for client-side applications like browsers where setting up callback endpoints or long-running connections is complex.

  • Service Calls Over HTTP: Useful when only HTTP protocol is available and firewall restrictions prevent callback firing on the client-side.

  • Integration with Legacy Architectures: When integrating with older systems that lack support for modern callback technologies such as WebSockets or webhooks.

❌ When Not to Use This Pattern:

  • Alternative Services Available: If there's a service designed for asynchronous notifications like Azure Event Grid, it may be a better fit.

  • Real-Time Streaming Required: Not suitable when real-time streaming responses are needed.

  • Many Results with Low Latency: For scenarios where the client needs to collect numerous results with low latency, consider a service bus pattern instead.

  • Persistent Network Connections Supported: If server-side persistent network connections like WebSockets or SignalR are feasible, they can be used for real-time result notifications.

  • Network Design Constraints: If network design allows for opening ports to receive asynchronous callbacks or webhooks, consider those options.

  • Using the Asynchronous Request-Reply pattern can simplify communication in certain scenarios, but it's essential to consider alternative solutions when they better align with specific requirements or constraints.


More Details :

1- https://learn.microsoft.com/en-us/azure/architecture/patterns/async-request-reply?WT.mc_id=DX-MVP-5004571

2- https://youtu.be/LCbR58sCmvQ?si=qrSA_2zlzG0cV9_i

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