ABAP Proxy Communication Scenario (Client Proxy)

By Neeraja Surapaneni, YASH PI Competency Core Team, YASH Technologies

This document is focused to give a better understanding on ABAP client proxies. 

From WAS 6.20 onwards, proxy generation feature enables application systems to communicate with XI using proxies.

Proxy objects implement message interfaces from Integration Repository. Proxy generation converts non-language-specific interface descriptions in WSDL into executable interfaces in the application system. Proxies separate Business Application logic from the integration logic of the Exchange infrastructure. 

There are 2 types of proxies available.

1. Java Proxies
2. ABAP Proxies.

1. Java Proxies: - Java proxies are used when JAVA applications needs to send or receive messages with other applications. JAVA proxies are generated from the WSDL description of the interface in the Integration Repository, and the result is a .jar file containing generated java classes corresponding to the integration objects. 

2. ABAP Proxies: - ABAP proxies are used when ABAP applications needs to send or receive messages. ABAP proxies are generated on the Application server with transaction SPROXY, based on the WSDL representation of the message interface.

The type of the message interface determines what type of proxy is generated. The counterparts to outbound message interface in application systems are client proxies, these are called to send a message to inbound interface. And the counterparts of inbound message interface in application systems are server proxies. 

Advantages of ABAP Proxies.

1. Proxy communication always by passes the Adapter Engine and will directly interact with the application system and Integration engine. So it will give us better performance.
2. Proxies communicate with the XI server by means of native SOAP calls over HTTP.
3. Easy to handle messages with ABAP programming.
4. Proxy is good for large volumes of data. we can catch and persist the errors ( both system & application fault ) which was generated by Proxy setting  

The rest of the document gives you pre-requisites and steps that are necessary for generating and executing ABAP client proxies.  

Also Read ABAP Proxy Communication (Server Proxy)

Pre-requisites  

1. The business systems should be based on SAP Web AS 6.20 and SAP Web AS 6.20 kernel patch level above 1253
2. You have installed the XI Add-On in each of these business systems as described in the Installation Guide SAP Exchange Infrastructure 3.0
3. The business systems and your central Integration Server are maintained in the System Landscape Directory (SLD).

Steps required for developing ABAP Proxies

• Establish the connection between WAS and Integration Builder, this allows the application system to retrieve WSDL description of the interface as the basis of proxy generation.
• Create a source data type and a target data type.
• Create Message types for the source and target data types.
• Create Message Interfaces includes Inbound Message interface and Outbound Message interface.
• Create message mapping between the source and target message types.
• Create Interface mapping.
• Create ABAP proxies using the transaction SPROXY in the application system.
• Create Collaboration agreements and Collaboration profiles in Integration directory.
• Write a program in the application system for creating the client proxy request.

Scenario demonstrating ABAP Client Proxies.

Take a business scenario where in business (Source System) sends an Employee details to their Payroll system for calculating the monthly salaries of their employees. But here the source business is running on SAP R/3 and corresponding Payroll system is not on SAP, hence the interpretation of data/communication is different. Because source system sends employee information through proxy communication and the target Payroll system is not aware of these proxy call, so in order to provide a communication between these two we need some interface mechanism which accepts proxy request and converts it into the format understandable by the target payroll system and vice versa.  

Objects needed to be developed in IR 

For this scenario we need to create the corresponding Data types, Message types and Message interfaces for source and target messages. Once the source Message interface is created we can generate the interface in source R/3 system using SPROXY transaction. 

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