Another protocol that is a standard for invoking methods remotely over the web is SOAP. The standard itself is modular, which means that both way in which machines communicate and how content is sent can be implemented in any way. However, most implementations use XML for sending content and the HTTP / HTTPS protocol for sending information.
One of the major features of this protocol is that it is self-descriptive, which means that all that a client needs is WSDL. It specifies the available data types, methods, what arguments they accept, what is the result type. It also specifies address of host that we should use.
Usually applications first download the WSDL file from a remote server, which looks as follows:
WSDL can also ...