An Application Programming Interface (API) is a protocol that, when invoked, performs an action or set of actions. You can invoke an API from your own code directly through a Java invocation, or through web services. This chapter provides an overview of several essential Liferay APIs available to you for use in developing your Liferay Portal.
Liferay comes with a host of APIs that provide powerful portal and portlet services. The following table shows you the entities for which services are available:
|Portal Services||Portlet Services|
|User||Documents and Media Library|
The ability to call Liferay APIs with a Java method or web service invocation gives you the flexibility to implement client code in Java or any language (even a scripting language such as PHP) that supports web service invocations. The APIs can be called from within portlet or non-portlet code. You can make calls to the APIs locally from within the portal or remotely outside of the portal’s Java virtual machine (JVM).
This chapter covers the following topics:
- Finding Services
- Invoking the API Locally
- Invoking the API Remotely
- Service Security Layers
- SOAP Web Services
- JSON Web Services
- Service Context
- Using Message Bus
- Device Detection
- Liferay’s Deprecation Policy
You can find Liferay’s services by searching for them in the Javadocs: http://docs.liferay.com/portal/6.1/javadocs/. Below we’ll show you how to search for portal services and portlet services.
Let’s start by finding a portal service.