WSDL, or Web Services Description Language, is an XML-based interface description language used to describe the functionality offered by web services. It serves as a formal contract between a web service provider and a consumer, detailing how the service can be called, what parameters it expects, and what data structures it returns.
Key Features of WSDL:
XML-Based: WSDL is written in XML, making it both machine-readable and platform-independent[2][6].
Service Description: It describes the public interface to the web service, including the operations available, the format and structure of messages, and the protocols used for communication[2][6].
Abstract and Concrete Descriptions: WSDL separates the abstract definitions of ports and messages from their concrete use or instance, allowing for reuse of these definitions. Abstract definitions include the operations and messages, while concrete definitions include the binding to specific network protocols and message formats[2][6].
Components: A typical WSDL document includes several key elements:
: The root element that defines the name of the web service and its target namespace[14].
: Defines the data types used by the web service, typically using XML Schema[1][7].
: Defines the data elements for each operation, specifying the input and output messages[1][3].
: Describes the operations that can be performed and the messages involved[3][11].
: Specifies the protocol and data format for each port type[3][11].
: Provides information about where the web service is located[3][14].
Usage:
SOAP Integration: WSDL is often used in combination with SOAP (Simple Object Access Protocol) and XML Schema to provide web services over the Internet. A client program can read the WSDL file to determine what operations are available on the server and use SOAP to call these operatio...
