com_api is a quick and easy way to add REST APIs to Joomla. Extendible via plugins, you an easily add support for more Joomla extensions. To get started, download the component and install the API plugins you need. Enable the plugins and you are ready to fetch your content via APIs
To add additional resources to the API, plugins need to be created. Each plugin can provide multiple API resources. Plugins are a convenient way to group several resources. Eg: A single plugin could be created for Quick2Cart with separate resources for products, cart, checkout, orders etc.
An app is essentially a Joomla plugin. However the plugin itself does nothing more than load the resources it contains. So the app is mainly used to package the API plugin and to enable adding any API specific parameters. Each app will have one or more resources.
Resources are thea actual files that have code that accept input and return the API output. You will usually have multiple resources in an app. A common use case is for an extension like Easysocial or Jomsocial you will have a single app, and the app contains resources for various objects like groups, events, photos, newsfeed etc.
The key is used to access authenticated resources. The admin section allows you to create keys. It's also possible to use the app=user&resource=login to login using username and password and get a key in response.
The URL to access any route is of the format -
/index.php?option=com_api&format=raw&app=<plugin name>&resource=<resource name>&key=<key>
Currently API token based authentication is supported. The token needs to be passed as a querystring variable with the name key. The next version will support sending this via an Authorization header. It is possible for an app to make an entire resource or a specific HTTP method in a resource public.
Each resorce can support the GET, POST, DELETE & PUT (needs some work) operations. These are exposed by creating methods of the same name, i.e. get() post() put() and delete() in each of the resources. This way, if a resouce URL is accessed via HTTP POST , the post() method is called, and similarly for the rest.
- language/en-GB - Resource folder having resource file, keep name same as plugin name.
- en-GB.plg_api_users.ini - add plugin language constant.
- en-GB.plg_api_users.sys.ini
- users - Resource folder having resource file, keep name same as plugin name.
- login.php - Resource file
- users.php - Resource file
- users.php - plugin file
- users.xml - xml file
You can add multiple resource in resource folder and use them for different purpose.
This is the entry file for the API plugin, the things that re deifned in the file are resource locations, and making certain resources public. Below is the code for the file -
jimport('joomla.plugin.plugin');
//class structure example
class plgAPIUsers extends ApiPlugin
{
public function __construct(&$subject, $config = array())
{
parent::__construct($subject, $config = array());
// Set resource path
ApiResource::addIncludePath(dirname(__FILE__).'/users');
// Load language files
$lang = JFactory::getLanguage();
$lang->load('plg_api_your_plugin_name', JPATH_ADMINISTRATOR,'',true);
// Set the login resource to be public
$this->setResourceAccess('your_plugin_name', 'public', 'post');
}
}Although you can place the resource files anywhere, the recommended approach is to place them within a folder inside your plugin. Below is example code for a resource file. Notice how the methods get() and post() are implemented. The methods will tpically return an array or an object which will be automatically converted to JSON, so the resource does not need to convert to JSON.
<?php
//class structure example
//ex - class UsersApiResourceLogin extends ApiResource
class UsersApiResourceLogin extends ApiResource
{
public function get()
{
// Add your code here
$this->plugin->setResponse( $result );
}
public function post()
{
// Add your code here
$this->plugin->setResponse( $result );
}
}The array or object from the plugin should be set via $this->plugin->setResponse().
It is possible to send HTTP errors with the right HTTP codes using the APIError::raiseError() method. Depending on the type of error you can raise different Exceptions that set the appropriate HTTP code.
<?php
public function post()
{
// Validation Error sets HTTP 400
ApiError::raiseError("VAL001", "Invalid Email", 'APIValidationException');
// Access Error sets HTTP 403
ApiError::raiseError("ACC001", "Not authorised", 'APIUnauthorisedException');
// Not Found Error sets HTTP 404
ApiError::raiseError("ERR005", "Record not found", 'APINotFoundException');
// General Error sets HTTP 400
ApiError::raiseError("ERR001", "Bad Request", 'APIException');
}You are free to specify your own error code and message. It is also possible to add more Exceptions in the site/libraries/exceptions folder. When using APIError::raiseError() there is no need to use $this->plugin->setResponse(). com_api will take care of sending the right HTTP code and error messages.
It is possible to make certain resource method public by using the setResourceAccess() access method as
$this->setResourceAccess('users', 'public', 'post') The first parameter is the resource name, second is status (should be public to make it public and last is method, which is you want to make public. Setting a resource public will mean that the URL will not need any authentication.
Finally create a manifest XML so that your plugin can be installed. Set group as 'api', add plugin name and other details.
<?xml version="1.0" encoding="utf-8"?>
<extension version="3.0.0" type="plugin" group="api" method="upgrade">
<name>YourPlugin</name>
<version>1.6</version>
<creationDate>10/11/2014</creationDate>
<author></author>
<description></description>
<files>
<filename plugin="your_plugin_name">your_plugin_name.php</filename>
<folder>your_plugin_name</folder>
</files>
<languages folder="language">
<language tag="en-GB">en-GB/en-GB.plg_api_plugin_name.ini</language>
<language tag="en-GB">en-GB/en-GB.plg_api_plugin_name.sys.ini</language>
</languages>
</extension>