Web service standards
BMC Remedy AR System web services use most standard web service messaging and transport protocols, XML schema constructs, message types, and operation types.
Web service protocols
The AR System server uses standard web service protocols, including:
- HyperText Transfer Protocol (HTTP) — The standard communication protocol for exchanging information 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 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 BMC Remedy 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, BMC Remedy AR System developers can use it to register and locate web services. See Registering a web service.
For more information about web service standards and protocols, see the W3C website at http://www.w3.org.
The web services namespace format structure was changed between the BMC Remedy AR System server version 220.127.116.11 release and the BMC Remedy AR System server version 18.104.22.168 release. In the earlier release, the tags were prepended with ns1, and with the newer release they are prepended with ns0. Because of that change, some customer implemented web services that were created on a version before the change might not work after upgrading to a version after that change was implemented. For any web services that stop running after upgrading, the SOAP Input document needs to be regenerated using the ns1 tag.
Each web service has a list of operations. BMC Remedy AR System server supports four operation types: Get, Create, Set, and Service. You can rename, delete, and even create operations, but they must be one of these supported operation types. You can have multiple operations of the same type, or you can have no operations of a particular type.
By default, when you create a web service, it automatically has these five operations:
- GetList (of the type Get)
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, BMC Remedy 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.
In general, web services use these 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 are 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:
For publishing, BMC Remedy AR System supports only document-literal web services. For consumption, BMC Remedy AR System supports document-literal and RPC-encoded web services.