XML Interface for Network Services

The specification-oriented approach is at the heart of XINS: • first specifications need to be written; • then documentation and code is generated from these specifications; • then both testing and implementation can start. From specifications, XINS is able to generate: • HTML documentation • test forms • SOAP-compliant WSDL • a basic Java web application • unit test code (in Java) • stubs (in Java) • client-side code (in Java) ==Components of the XINS technology==

Technically, XINS is composed of the following: • An XML-based specification format for projects, APIs, functions, types and error codes • A POX-style RPC protocol (called the XINS Standard Calling Convention), compatible with web browsers (HTTP parameters in, XML out). • A tool for generating human-readable documentation, from the specifications. • A tool for generating WSDL, from the specifications. • A Log4J-based technology for logging (called Logdoc), offering a specification format, internationalization of log messages, generation of HTML documentation and generation of code. • A Java library for calling XINS functions, the XINS/Java Client Framework; in xins-client.jar. • A server-side container for Java-based XINS API implementations, the XINS/Java Server Framework; in xins-server.jar. This is like a servlet container for XINS APIs. • A Java library with some common functionality, used by both the XINS/Java Client Framework and the XINS/Java Server Framework: the XINS/Java Common Library, in xins-common.jar. An introductory tutorial called the XINS Primer takes the reader by the hand with easy-to-follow steps to perform, with screenshots. Since version 1.3.0, the XINS/Java Server Framework supports not only POX-style calls, but also SOAP and XML-RPC. And it supports conversion using XSLT. As of version 2.0, it also supports JSON and JSON-RPC. XINS is open-source and is distributed under the liberal BSD license. ==Specifications==

All XINS specification files are Plain Old XML. Compared to SOAP/WSDL/UDDI/etc. the format is extremely simple. There are specifications for projects, environment lists, APIs, functions, types and error codes. Below is an example of a XINS project definition. Here is an example of a specification of an environment list: An example of an API specification file: My first XINS API An example of a function definition: Greets the indicated person. The name of the person to be greeted. The constructed greeting. ==RPC protocol==

The XINS Standard Calling Convention is a simple HTTP-based RPC protocol. Input consists of HTTP parameters, while output is an XML document. This approach makes it compatible with plain Web browsers. Example of a request: http://somehost/someapi/?_convention=_xins-std&_function=SayHello&firstName=John&lastName=Doe Example of a successful response: Hello John Doe! ==Competition==

There are no known products that provide an integrated approach to specification-oriented development, similar to XINS. However, there are several frameworks and libraries that provide functionality similar to individual parts of XINS, including: • JWSDP: Collection of various XML and SOAP technologies for the Java programming language. • Apache Axis: Java-based framework for SOAP implementations. • Codehaus XFire: Idem. • Hessian Web Service Protocol: Binary alternative to the XINS Standard Calling Convention. == References ==