.. _rest_services_implementing_mapper:

Implementing a REST PathMapper
==============================

In this section is described how to implement a new *RESTUploadPathMapper* sub-class. 
A *RESTUploadPathMapper* object is used for mapping the path of the uploaded files following new remapping policy. An example could be a Regular Expression remapping
based on the input file name.

This is the *RESTUploadPathMapper* interface::

	/**
	 * Plugin interface used to transform the position of files during rest uploads
	 */
	public interface RESTUploadPathMapper{
		/**
		 * Remaps the position of a store path. The implementor is free to append, modify 
		 * or replace the store root directory, REST upload will append workspace/store to 
		 * it
		 * 
		 * @throws IOException
		 */
		public void mapStorePath(StringBuilder rootDir, String workspace, String store,
			Map<String, String> storeParams) throws IOException;

		/**
		 * Remaps the position of a file inside a store (e.g., a image being harvested into 
		 * a mosaic. The implementor is free to alter the item path.
		 * 
		 * @throws IOException
		 */
		public void mapItemPath(String workspace, String store,
			Map<String, String> storeParams, StringBuilder itemPath, String itemName) throws IOException;
	}

Implementation
-------------- 

Each implementation must follows these rules:

* Remapping of the Root Directory requires to create a final root of the following structure::
	
	${rootDirectory}/workspace/store
	
* Developers can choose both the relative path of the file (if it is inside a zip directory structure) and the filename itself.
* File remapping cannot return directories.
* If additional parameters are required, they can be stored inside the Metadata Map of the Global, WorkSpace or Store settings.

The steps for creating a new **RESTUploadPathMapper** implementation are:

#. Extend the base implementation *RESTUploadPathMapperImpl* and create the desired PathMapper.
#. Configure it as a Spring Bean inside the *applicationContext*. For example::

    <bean id="ECQLRUPathMapper" class="org.geoserver.rest.ecql.RESTUploadECQLPathMapper">
      <constructor-arg ref="catalog"/>
    </bean>
	
If any optional parameter requires to be configured, then a GUI panel must be created using Wicket. The panel will be added to the Global and WorkSpace Settings configuration page. 

The steps for creating the GUI panel are:

#. Creation of a new extension of the *SettingsPluginPanel* class.

	.. note:: Note that this panel must extract the parameters from the Metadata Map of the *settings* object.

#. Definition of a Spring Bean which will be an instance of the *SettingsPluginPanelInfo* class and will have the class defined above as component class (*priority* property can be avoided). For example::

	<bean id="restECQLSettingsPanel" class="org.geoserver.web.data.settings.SettingsPluginPanelInfo">
	  <description>This bean adds the necessary form fields to REST Settings</description>
	  <property name="id" value="restECQLSettingsPanel"/>
	  <property name="titleKey" value="restECQLsettings"/>
	  <property name="componentClass" value="org.geoserver.rest.web.RESTECQLSettingsPanel"/>
	  <property name="priority" value="1"/>
	</bean>
	
#. Then the result will be added at the bottom of the GeoServer *Global Settings* and *Edit WorkSpace* Pages:
	
	
	.. figure:: settings.png