Parsing Web Interface Description Language WSDL (2)

Web 2, WSDL object structure diagram

The WSDL object structure diagram shown in Figure 2 shows that a WSDL document can contain a types, multiple message, PortType, binding, and service.

Figure 2 WSDL Object structure diagram

Where types is a container of data type definitions, containing all the type definitions of XML elements that are required in the message definition.

The message specifically defines the data structure of the messages used in the communication, which contains a set of part elements, each of which is a component of the final message, each of which references a datatype to represent its structure. The part element does not support nesting (you can use datatype to do this), and it is all tied up.

PortType specifically defines a type of service access entry (the mode of the incoming/outgoing message and its format), a porttype can contain several operation, and one operation refers to a type of invocation supported by the Access portal. In the WSDL, four types of access calls are supported: 1 single request; 2) single response; 3) Request/response; 4) Response/request. In this case, the request refers to the client to the Web server, and the response is from the Web server to the client. The definition of porttype refers to one to two messages in the message definition section as a form of the request or response message.

Service describes the deployment details of all access portals provided by a specific deployed Web service, which often contains multiple service access portals, and each access portal is described with a port element.

Port describes the deployment details of a service access portal, including which web address (URL) to access, what message invocation mode should be used, and so on. Where the message invocation pattern is expressed by using the binding structure.

The binding structure defines a porttype that is bound to a specific network transport protocol or message Transfer Protocol, from which the description is related to the deployment of a specific service. For example, you can bind the porttype to the soap/http, or you can bind the porttype to the MIME/SMTP.