The SAP NetWeaver Application Server for ABAP can be used both as a provider and as a consumer of web services. You can create, configure, publish, and consume web services. A web service can be called in various system landscapes and is not restricted to a specific host system. While web services represent a technical concept, the Service-Oriented Architecture (SOA) allows you to design the complete solution for a business application.
The Web Services Framework includes:
- The SAP NetWeaver Application Server for ABAP development environment.
- The Enterprise Services Repository tools to support UDDI registration with the Services Registry.
- An interoperable SOAP runtime environment.
SOAP requests are processed using the Internet Communication Framework. The HTTP protocol of the Internet Communication Framework is used for communication between consumer and provider.
Supported Specifications
Web service technology must be based on generally accepted standards. When you build your environment using web services, you link up application modules developed in different programming languages on different hardware and in different systems with the business process. When you do this, you are faced with the important questions of interoperability and adherence to prescribed standards.
Conventional internet standards are used for communication. The interface of a web service is specified using WSDL, remote procedure calls are transmitted using SOAP, and web services are determined using UDDI.
Although standards such as SOAP, WSDL, and UDDI became the general norm, there is still much to be accomplished by standardization committees. The committees develop some new standards and update other standards. SAP continuously updates and integrates the enhanced standards - such as security standards or additional protocols - into the Web Service Framework.
General Web Service Specifications
- SOAP (1.1 and 1.2)
- WSDL (1.1)
- UDDI 3.02
- WS-I Basic Profile (1.1)
- XML (1.0)
- HTTP (1.1)
- WS-Policy (1.2)
- WS-Policy Attachments (2004/09)
- Web Service Inspection Language (WSIL) 1.0
- WS-MetadataExchange
- WS-Addressing (1.0)
- WS-ReliableMessaging (1.1)
- MTOM
- WS-Security (1.0 and 1.1)
- WS-Security
- WS-Security Policy (1.2)
- WS-SecureConversation (1.3)
- SAML 2.0
- WS-Trust (1.3)
This chapter lists the specifications related to web services which are supported in this release.
- SOAP (1.1 and 1.2)
Simple Object Access Protocol (SOAP), provides the definition of the lightweight protocol for XML-based information exchanged between parties in a distributed environment. SOAP version 1.2 supports major features required for communication with other web service vendors.
- WSDL (1.1)
Web Service Description Language (WSDL), describes web services as abstract endpoints operating on messages. The definition of operations and messages is abstract while the binding to a specific network protocol is concrete.
- UDDI 3.02
Universal Description, Discovery, and Integration (UDDI), defines a uniform way of publishing and discovering web services.
- WS-I Basic Profile (1.1)
Provides interoperability guidance for core web services specifications, such as SOAP, WSDL, and UDDI.
- XML (1.0)
Extensible Markup Language (XML), a self-descriptive language designed for exchanging structured data over the internet. It is the foundation of web services.
- HTTP (1.1)
Hyper Text Transfer Protocol (HTTP), a lightweight document transfer protocol that provides an effective universal data transfer.
Description and Discovery Specifications
- WS-Policy (1.2)
Defines the model and syntax to describe and communicate the policies of a web service. A policy is a collection of policy assertions, which describe one or more characteristics that a web service provider requires from a web service consumer to follow.
- WS-Policy Attachments (2004/09)
Defines how to attach WS-Policy assertions to WSDL documents and UDDI descriptions.
Note
Only attachments to WSDL 1.1 is supported.
- WSIL (1.0)
Web Service Inspection Language (WSIL), defines how to locate web service descriptions on a provider system.
For ABAP-based SAP systems, call an URL in this format: http://<host>:<port>/sap/bc/srt/wsil?sapclient=<client>.
For Java-based SAP systems, call an URL in this format: http://<host>:<port>/inspection.wsil.
- WS-Metadata Exchange
Defines how endpoints can request the various types of metadata they may need to effectively communicate with the web service.
Messaging Specifications
- WS-Addressing (1.0)
Defines a standard mechanism for identifying and exchanging web services messages between multiple endpoints.
- WS-Reliable Messaging (1.1)
Describes a protocol that allows messages to be delivered reliably between distributed applications in the case of software component, system, or network failures.
The following scenario is supported: anonymous client and one-way operations.
The following scenarios are not supported:
Anonymous client and request-response operations.
Addressable client and one-way operations.
Addressable client and request-response operations.
- MTOM
The SOAP Message Transmission Optimization Mechanism (MTOM) allows more efficient sending of binary data in a SOAP request or response.
Security Specifications
- WS-Security (1.0 and 1.1)
Describes extensions to SOAP that allow for quality of protection of SOAP messages including binary tokens for message authentication, digital signatures for message integrity, and content encryption for message confidentiality.
- WS-Security
SAML Token Profile 1.1
- WS-Security Policy (1.2)
Defines security assertions detailing a web service's requirements that the web service consumer can meet.
Note
WS-Security Policy is available in PI 7.1 only for SAP to SAP scenarios.
- WS-Secure Conversation (1.3)
Defines how to establish and maintain a persistent context for a secure session over which multiple web service invocations might be sent without requiring authentication each time.
Note
WS-Secure Conversation is available only for Secure Context Token (SCT) over SSL bootstrap.
- SAML 2.0
Security Assertion Markup Language (SAML) is an XML based standard for exchanging security information between systems.
- WS-Trust (1.3)
WS-Security defines the basic mechanisms for providing secure messaging. WS-Trust uses these base mechanisms and defines additional primitives and extensions for security token exchange to enable the issuance and dissemination of credentials within different trust domains.