About Web services
Web services allow you to use preexisting components (available
on the Internet or on a local network) instead of writing new business
logic to perform common tasks invoked by the applications that you
develop. Web services originated when the Simple Object Access Protocol
(SOAP) was introduced. SOAP leverages Extensible Markup Language
(XML) and usually employs Hypertext Transfer Protocol (HTTP) as
the transport. Invoking Web services through SOAP requires serialization
and deserialization of datatypes, and the building and parsing of
SOAP messages.
Part of the value of Web services comes from the Web Services
Description Language (WSDL), which enables a service to be self-describing.
WSDL defines an XML grammar for describing Web services as collections
of communication endpoints capable of exchanging messages. WSDL
service definitions provide documentation for distributed systems
and serve as a recipe for automating the details involved in applications
communication.
With Sybase EAServer and
the Web Services Toolkit, these descriptions can be used by applications
and registered on a Web site that uses Universal Description, Discovery,
and Integration (UDDI). You can search UDDI registry sites with
your browser of choice and find the services you need for your application.
With SOAP, WSDL, and UDDI, using third-party components is
easier because interfaces between applications become standardized
across disparate platforms.
PowerBuilder supports the following Web services standards:
- SOAP 1.1
- WSDL 1.1
- HTTP or HTTPS
You can access Web services from a PowerScript target or a
JSP target. For information on accessing Web services in JSP applications
that you create with PowerBuilder, see the chapter on JSP targets
in the Working with Web and JSP Targets
book
or the JSP page authoring topic in the online Help.
About building a Web services client
A PowerBuilder application can act as a client consuming a
Web service that is accessed through the Internet. Using SOAP and
WSDL, a collection of functions published remotely as a single entity
can become part of your PowerBuilder application. A Web service
accepts and responds to requests sent by applications or other Web
services.
PBSoapClient100.pbd and pbsoapclient100.pbx
Invoking Web services through SOAP requires serialization
and deserialization of data types, and the building and parsing
of XML-based SOAP messages. Using the PBSoapClient100.pbd and
the pbsoapclient100.pbx, the Web services client
proxy performs these tasks for you, thereby eliminating the need
to have extensive knowledge of the SOAP specification and schema,
the XML Schema specification, or the WSDL specification and schema.