Custom Development of Enterprise Services

CustomCustom DevelopmentDevelopment of Enterprise Services of Enterprise Services --

WhatWhat doesdoes an Software an Software ArchitectArchitect needneed to to knowknow??

Tobias Trapp

© Tobias Trapp 2010 2

Table of Table of ContentContent

Implementation Details

Standardization of Web Services

Summary

Component Architecture


WhichWhich SAP technology SAP technology isis thethe mostmost appropriateappropriate forfor specificspecific purposespurposes??

� lightweight interfaces: REST are very useful for integration of output and

document management systems

� application integration: A2A services outside-in using PI

� commerce transactions between businesses : B2B services generated

outside-in, propably using PI

� integration using arbitrary clients: A2X services generated outside in

� exposing BOL classes on the fly: CRM Web Service framework

� mobile apps: Sybase CRM Mobile Sales and Mobility for SAP

� coming soon: project Gateway

� exposing function modules on thy fly: inside out generation

WelcomeWelcome to ABAP Web Service to ABAP Web Service JungleJungle!!


„„InsideInside OutOut““ isis a a DeadDead End StreetEnd Street

„Inside Out“ means poor man‘s SOA

� no standardized data types

� we can‘t control mandatory and

non-mandatory elements

� no standardized naming conventions

� no standardized communication patterns

� no patterns for asynchronous scenarios

� no standardized change strategies: first one wins vs. last one wins

� complicated & database–like because of TABLES parameters

� important frameworks are missing

- idempotency

- forward error handling

- no enhancement concept for customers


Enterprise ServicesEnterprise Services

Build your SOA on standards and best practices

� use global data types according UN/CEFACT standards

� develop enterprise „outside in“: generate ABAP proxies from a WSDL (file, URL,

ESR) using transaction SPROXY / SE80

� follow ESR modelling guidelines and create ESR certified content

� from SAP Guidelines for Best-Built Applications that Integrate with

SAP Business Suite:


NearlyNearly everythingeverything youyou needneed to to knowknow isis writtenwritten downdown

There are lots of resources on SCN and SAP Press

� many tutorials about ESR on SDN

� SOA 300 training

� everything about modelling & implementation is written down

in SAP Press Book „Developing Enterprise Services for SAP“

� „How To… Develop, Monitor and Debug WS Consumer

and Provider“

� Enterprise SOA Development Handbook 1.1

� chapter about SOA & loose coupling of

applications in SAP Guidelines for

Best-Built Applications that Integrate

with SAP Business Suite


Enterprise Services Enterprise Services havehave wellwell--defineddefined SemanticsSemantics

Use naming conventions and communication patterns

� naming convention is: <business object view> <action> <message type>

Sales Order Create Request

� actions are Create, Read, Update (first one wins), Change (last one wins),

Cancel and Check: Purchase Order Cancel Check Query Request

� there are well-defined semantics described below:





Summary



SOA SOA byby „„ControlledControlled EvolutionEvolution““

SOA by Design vs. SOA by Evolution

� SAP‘s SOMAID methodology is heavy weight – you need a list of all processes

whether they are IT-based or not

� whenever you can use Enterprise Services of SAP Business Suite - you‘ll find them

on ES work place http://www.sdn.sap.com/irj/bpx/esworkplace

� if necessary enhance SAP standard services as described in

Enterprise Service Enhancement Guide

� create custom Enterprise Services using SAP‘s

modelling approach - construct them from business

objects of your ABAP app.


ABAP ABAP AppsApps, ESR , ESR SWCVsSWCVs and XML and XML NamespacesNamespaces

How to structure ESR development

� SWVCs in ESR correspond to ABAP SCs

� an ABAP application corresponds to an repository namespace

� define data types for reuse in separate namespaces

� create repository namespace for each application containing business objects

� this leads to a hierarchy of repository namespaces

http://tempuri.org/xi/flightmanagement/CRM

http://tempuri.org/xi/flightmanagement/CRM/Global

http://tempuri.org/xi/flightmanagement/BP

http://tempuri.org/xi/flightmanagement/BP/Global

http://tempuri.org/xi/flightmanagement/Global

� hint: avoid special characters in XML names because package names of generatedclasses consumers tend to get complicated – this is a problem of many non-SAPframeworks


ABAP ABAP ComponentComponent StructureStructure

How to structure server proxies according to your ABAP component hierarchy?

� in NW 7.01 there can be only one proxy element per system (and ABAP

namespace).

� ESR dependencies lead to dependencies in ABAP: proxy elements will be reused -

so be careful if the proxies are in different ABAP components:

http://tempuri.org/xi/flightmanagement/CRM

http://tempuri.org/xi/flightmanagement/CRM/Global

http://tempuri.org/xi/flightmanagement/BP

http://tempuri.org/xi/flightmanagement/BP/Global

http://tempuri.org/xi/flightmanagement/Global

� create packages that contain only ABAP proxies

}}

CUSTBP

CUSTCRM

SCs in an

ABAP system





Summary



Best Best PracticesPractices forfor Creating Enterprise ServicesCreating Enterprise Services

Common mistakes and how to avoid them

� specify error handling: system errors, wrong input parameters, missingauthorities…

� consider compensation scenarios: what happens if a web service call fails?

� use forward error handling in asynchronous scenarios

� consider reviews for ESR development – developers tend to break every rulebecause they can do anything in XML

� keep code in generated classes small – delegate to classescontaining business logic for each method

� use naming conventions for data types, parameters, message types and message data types in generated classes

� develop in a test driven way: check ABAP classes using unit tests,test Enterprise Services using ABAP test tool resp. eCATT

� study best practices in SAP guidelines esp. the SAP Press book

� don‘t follow guidelines for SAP Business Suite blindly: asually an ES doesn‘tneed to be XI 3.0 conform and contain more than 1 operation.


AbsolutelyAbsolutely necessarynecessary to to knowknow: : ExtendedExtended XML HandlingXML Handling

Empty values vs. Null values

� NULL values have different semantics compared to initial values:

- NULL values in an update service mean that they should not be changed

- NULL values in a query mean that a data element is not relevant in a search

� Initial values can be coded as empty XML elements

� NULL values can be coded using xsi:nil and missing elements

� In the constructor of a server proxy switch extended XML handling on:

set_extended_xml_handling( i_switch_on = abap_true ).

� Then you get the information about every data element (omitted, xsi:nil, initial) in

an structure PRXCTRLTAB


A A hiddenhidden gemgem: : GenericGeneric Code List Provider FrameworkCode List Provider Framework

Codes can be defined an ABAP backend system

� define code lists as XML schema enumeration types

only if the values are well-defined & do not change

� In most cases code lists are defined in ABAP backend in

customizing tables

� you can bind domain values, (text) tables to server

proxy data elements and read them using the

generic Enterprise Service QueryCodeList

� the framework is extensible – think of time depended

customizing, subsets of customizing sets…





Summary



ExplainExplain to to developersdevelopers thethe conceptconcept of Enterprise Servicesof Enterprise Services

As software architect now you are well prepared for a SOA project, but don‘t

forget:

� keep yourself informed - ABAP frameworks are rapidly evolved by SAP

� learn about eventing, service groups, forward error handling…

What do developers of Enterprise Services need to know?

� a prototype implementation will help developers to understand the concepts

� teach developers the transactional behaviour esp. in update/change services: SET

UPDATE TASK LOCAL, cl_soap_commit_rollback and that enterprise

services are stateless – no DB cursor!

� don‘t forget to test the enterprise services with user with different authorization

profiles in the ABAP backend.

Date post:	23-Jan-2015
Category:	Technology
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Custom Development of Enterprise Services

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