CPI Proxy Part 1: ABAP Proxies with the XI Adapter

📌 KEY POINTS
✅ ABAP proxies are generated from service interfaces and exchange messages in the XI 3.0 protocol.
✅ Cloud Integration's XI adapter can act as sender and receiver for proxy messages.
✅ The ABAP integration engine is configured to route messages to Cloud Integration via an HTTP destination.
✅ Quality of service (exactly once, exactly once in order) must be preserved end to end.
⚠️ Changing proxy implementations when only the middleware changes is unnecessary work.

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▶ WHERE WE ARE
This series covers web-service-style integration. Part 1 covers ABAP proxies.

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▶ 1. WHAT PROXIES ARE
ABAP proxies are ABAP classes generated from service interface definitions. Applications call outbound proxies to send messages and implement inbound proxies to receive them. Messages are exchanged with the XI 3.0 protocol, historically through PI/PO.

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▶ 2. OUTBOUND TO CLOUD INTEGRATION
In the S/4HANA system, the local integration engine is configured (for example in SXMB_ADM) to send messages to an HTTP destination pointing to the XI sender adapter endpoint of an iFlow. The proxy code doesn't change.

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▶ 3. INBOUND FROM CLOUD INTEGRATION
For messages to S/4HANA, the iFlow uses the XI receiver adapter to call the S/4HANA integration engine endpoint through Cloud Connector, delivering the message to the inbound proxy. Authorizations and service activation in S/4HANA must allow it.

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▶ 4. QUALITY OF SERVICE
Proxies support exactly once (EO) and exactly once in order (EOIO). The XI adapter supports these with persistence such as JMS or data stores in the iFlow, so messages are not lost or duplicated, and order is kept where required.

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▶ 5. MONITORING
On the S/4HANA side, SXMB_MONI or the corresponding monitors show proxy message status; in Cloud Integration, the message processing log. Correlate by message ID, which is preserved through the XI protocol.

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▶ STEP BY STEP

1. Configure an XI sender adapter iFlow and deploy it.
2. Point the S/4HANA integration engine to its endpoint.
3. Send a proxy message and trace it on both sides.
4. Configure an XI receiver adapter to an inbound proxy.

✅ CHECKPOINT: proxy messages flow both ways via Cloud Integration with the required quality of service.

An EOIO proxy interface for stock movements started arriving out of order after migration because the iFlow used parallel processing without persistence. Configuring the XI adapter with ordered processing and JMS persistence restored the sequence.

• Rewriting proxies for middleware changes.
• Losing EOIO order in the iFlow.
• Not correlating message IDs.
• Missing service activation for inbound proxies.

• XI adapter for proxy scenarios.
• Persistence for EO/EOIO.
• Correlate with message IDs.
• Monitor both systems.

Interviewers ask how ABAP proxies work with Cloud Integration, the role of the XI adapter and how EO and EOIO are preserved.