Web service standards

Web service protocols

The AR System serveruses standard web service protocols, including:

• HyperText Transfer Protocol (HTTP)—The standard communication protocol for exchanging information on the web.
• Extensible Markup Language (XML)—A markup language defined in the XML 1.0 Specification, used to encode documents and represent data structures by describing data types. XML facilitates sharing of data across different hardware and software platforms.
• Simple Object Access Protocol (SOAP)—The standard messaging protocol for exchanging information with web services. It is based on HTTP and XML and provides the envelope format for transferring information and a set of rules for translating applications and platform-specific data types into XML.
• Web Services Description Language (WSDL)—An XML-based language used to define a web service, its operations, and how to access it. For an example of a WSDL file, see WSDL file displayed in WSDL panel of web services editor.
  The AR System web services implementation is based on SOAP 1.1 and WSDL 1.1 specifications from the World Wide Web Consortium (W3C). SOAP 1.2 is supported for consuming web services only.

• Universal Description Discovery and Integration (UDDI)—A specification used to provide directories of information about available web services. The BMC Atrium Web Services Registry uses this standard, and if it is installed, AR System developers can use it to register and locate web services. For more information, see Registering-a-web-service.
  For more information about web service standards and protocols, see the W3C website at http://www.w3.org.

Operation types

Each web service has a list of operations. AR System server supports these operation types: Get, Create, Set, and Service. You can rename, delete, and even create operations, but they must be of one of these supported operation types. You can have multiple operations of the same type or have no operations of a particular type.

By default, when you create a web service, it automatically has these operations:

• Get
• Create
• GetList (of the type Get)
• Set
• Service

For the procedures to add and remove operations, see Publishing-a-web-service and Consuming-a-web-service. For details about using each operation type, see Web-service-operation-types.

Each web service is associated with an XML Schema Definition (XSD file). The XML schema defines the global elements and complex types that are used in the field mappings associated with operations. For a basic web service using the default operation types, AR System server populates the XML Schema automatically. You can also define your own XML schema or use an existing one.  For more information about working with the XML schema, see XML editing introduction. For a list of supported and unsupported XML constructs, see Supported-schema-constructs-and-web-service-limitations.

WSDL types

In general, web services use the following messaging styles:

• Remote Procedure Call (RPC-style)—One application makes a function call to another application, passing arguments and receiving return values.
• Document-style—Applications exchange XML documents whose syntax is defined by an XML schema, for example, a Purchase Order document.

These styles can be divided into literal substyles (messages are encoded according to the XML schema) or encoded substyles (messages are constructed according to SOAP encoding rules). This results in four WSDL styles:

• RPC-literal
• RPC-encoded
• Document-literal
• Document-encoded

For publishing, AR System supports only document-literal web services. For consumption, AR System supports document-literal and RPC-encoded web services.