Using the Watson Explorer Engine API

This section introduces SOAP and REST, and provides an overview of how to use Watson Explorer Engine with web-based services and standard interfaces such as SOAP and REST. For general information about selecting the right mechanism for integrating Watson Explorer Engine into web-based applications or frameworks, see Using Watson Explorer Engine Output.

Web services today are commonly implemented using two basic architectural models:

SOAP (Simple Object Access Protocol) is a lightweight XML-based communications protocol that is designed for exchanging information in heterogenous, distributed computing environment. SOAP services are defined using a WSDL (Web Services Definition Language) specification for the Watson Explorer Engine API are accessed via a URL that is known as a SOAP endpoint.
REST (Representational State Transfer) is a set of architectural principles for exchanging information between networked resources, using standard protocols such as HTTP and without the need for additional messaging layers such as those used by SOAP.

Watson Explorer Engine API functions can be called using either SOAP or REST. Complete user and reference documentation for the Watson Explorer Engine API is available both online and in printable (PDF) form.

Watson Explorer Engine's SOAP/REST API provides a stable and consistent interface to Watson Explorer Engine internals. Historically, Watson Explorer Engine has also provided custom APIs for most of the programming languages and Web-based interaction mechanisms that have been popular on various platforms. These interfaces have been deprecated in favor of the more modern, web-oriented, and powerful SOAP/REST API.

Tip: Watson Explorer Engine provides a built-in XML query mechanism that enables you to integrate Watson Explorer Engine output with other applications and frameworks by calling Watson Explorer Engine with customized URLs and a special display function. This mechanism is provided for developers who need to interact with Watson Explorer Engine but do not need the low-level capabilities provided by the SOAP/REST API. Using this built-in integration mechanism was explained earlier in this chapter in Overview.

If you are planning to use Watson Explorer Engine's SOAP and REST APIs to integrate Watson Explorer Engine into a web service or framework, you should be familiar with the general Watson Explorer Engine installation process before proceeding.