📡 Clean Core Real-Time UX Architecture

SAP Clean Core Real-Time WebSockets & Push Notifications Guide

How to transition from legacy polling loops to reactive sub-second push notifications using SAP BTP WebSocket gateways, Server-Sent Events (SSE), and SAP Event Mesh.

1. The Death of the Polling Anti-Pattern

In legacy enterprise web apps, frontend developers frequently implemented periodic polling: every 5 or 10 seconds, thousands of browser tabs fired HTTP GET requests to S/4HANA to check if a sales order status changed or if an approval arrived. In a 5,000-user enterprise, this generates over 30,000 requests per minute of completely wasted compute, overloading HANA database engines and saturating network gateways.

Dimension	Periodic Client Polling (Legacy)	Event-Driven Push Architecture (Clean Core)
Latency	High (Lag equal to polling interval, 5-30 seconds)	Sub-second (< 200ms instantaneous push)
Backend Load	Severe (Constant queries even when no data has changed)	Near zero idle load (Connection stays open in memory)
Clean Core Fit	Anti-pattern (Unnecessary load on Tier-1 core)	100% Compliant (Decoupled event-driven mesh)
Transport Protocol	Standard HTTP request/response loops	WebSocket (Full Duplex) or Server-Sent Events (SSE)

2. BTP Push Architecture Building Blocks

A production push notification solution involves three decoupled layers:

Event Producer (S/4HANA RAP): When a business object changes, the RAP behavior handler raises an official CloudEvent (e.g. SalesOrder.Created) via SAP Event Mesh.
Event Broker & Push Gateway (SAP BTP): A lightweight Node.js / CAP microservice subscribes to the queue, identifies connected users for that tenant, and streams the event over WebSocket or SSE.
Client Receiver (SAP Fiori / SAPUI5): The browser client maintains a persistent connection via SAP App Router ("ws": true) and updates the local JSON model reactively.

3. Configuring SAP BTP App Router for WebSockets

Because WebSockets upgrade normal HTTP connections, the SAP BTP App Router must be configured with "ws": true in xs-app.json:

{
  "source": "^/ws/notifications",
  "target": "/ws/notifications",
  "destination": "push-gateway-srv",
  "ws": true,
  "authenticationType": "xsuaa"
}

💡 Reconnection & Heartbeat Keep-Alive Mobile devices and enterprise proxies frequently terminate idle TCP connections after 60 seconds. Always configure client-side ping/pong heartbeats every 30 seconds and implement exponential backoff reconnection logic.

4. Interactive Tool Companion

Use our free web utility to generate BTP Push Gateways, SAPUI5 WebSocket controllers, and App Router configuration files:

→ Open SAP Real-Time WebSocket & Push Notification Architect (Tool #76)

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