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Procedure documentationProviding a Web Service Locate this document in the navigation structure

 

You can provide Web services in the following ways:

  • Based on existing functions (inside-out)

    The Web Service technology enables a company to act as a so-called "provider" and to provide services either within the company or externally. The problem posed by the use of different programming languages is overcome by encapsulating an existing function in a system using a Web service. The Web service definition contains the signature for the function and other information required to call it - such as the address of the server on which the function can be called. To provide this information to a consumer, you publish the Web service as a WSDL document. Using this XML standard, consumers of the services can generate a proxy in their application systems, with which they can then use the SOAP protocol to call the Web service.

    A programming-language-independent description of a function available in a system is provided to the outside for further use. In this case, we refer to "inside-out development".

    RFC-enabled function modules, function groups (that contain an RFC-enabled function module), and BAPIs can be made available as Web services without any additional programming. The service is in the system already and can be published externally (inside-out).

  • Using the Enterprise Services Repository (outside-in)

    This approach comprises basically two steps:

    • Development of the service starts in the Enterprise Services Builder (ES Builder). In contrast to inside-out development (whereby a WSDL document is generated on the basis of an existing function and then published), the ES Builder creates the service implicitly as a WSDL document in the Enterprise Service Repository (ES Repository).

    • To implement or call a service, developers generate proxies in the relevant application system for the service from the ES Repository. Developments therefore begins outside the application system and is then continued in the application system (hence the term outside-in).

    Since the ES Repository is a central storage for services from various applications and systems, modeling editors within the ES Builder can reference the relevant objects directly, without the need to log on to an application system first.

    For calling a service, development objects of a service that was described outside of the system are generated into the respective development system (outside-in) with the help of a WSDL document.

Note Note

Instead of "outside-in" and "inside-out", the SOA world commonly uses the following terms as well: „Contract-First“ and „Code-First“; „Top-Down“ and „Bottom-Up“.

End of the note.

Procedure

Developing a Web Service Using the Enterprise Services Repository (Outside-In)

Developing a Web Service Based on Existing Functions (Inside-Out)

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Developing Services for Enhanced A2A Processes