Introduction
Binding servlets by paths has several disadvantages when compared to binding by resource types, namely:
- Path-bound servlets cannot be access controlled using the default JCR repository ACLs
- Path-bound servlets can only be registered to a path and not a resource type (i.e. no suffix handling)
- If a path-bound servlet is not active, e.g. if the bundle is missing or not started, a POST might result in unexpected results. usually creating a node at
/bin/xyzwhich subsequently overlays the servlets path binding
the mapping is not transparent to a developer looking just at the repository
Given these drawbacks it is strongly recommended to bind servlets to resource types rather than paths
Create Servlet
Launch your aem-banking project in IntelliJ. Create a servlet called GetFieldChoices under the servlets folder as shown in the screen-shot below.
Sample Servlet
The following servlet is bound to the Sling resource type: azure/fetchchoices
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.apache.sling.servlets.annotations.SlingServletResourceTypes;
import org.osgi.framework.Constants;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.jcr.Session;
import javax.servlet.Servlet;
import java.io.IOException;
import java.io.Serializable;
@Component(
service={Servlet.class }
)
@SlingServletResourceTypes(
resourceTypes="azure/fetchchoices",
methods= "GET",
extensions="json"
)
public class GetFieldChoices extends SlingAllMethodsServlet implements Serializable {
private static final long serialVersionUID = 1L;
private final transient Logger log = LoggerFactory.getLogger(this.getClass());
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) {
log.debug("The form path I got was "+request.getParameter("formPath"));
}
}
Create Resources in CRX
- Login to your local AEM SDK.
- Create a resource named
fetchchoices(you can name this node anyway you want it) of typecq:Pageunder content node. - Save your changes
- Create a node called
jcr:contentof typecq:PageContentand save the changes - Add the following properties to the
jcr:contentnode
azure/fetchchoicesThe sling:resourceType value has to match resourceTypes="azure/fetchchoices specified in the servlet.
You can now invoke your servlet by requesting the resource with sling:resourceType = azure/fetchchoices at its full path, with any selectors or extensions registered in the Sling servlet.
http://localhost:4502/content/fetchchoices/jcr:content.json?formPath=/content/forms/af/forrahul/jcr:content/guideContainer
The path /content/fetchchoices/jcr:content is the path of the resource and extension .json is what is specified in the servlet
Sync your AEM Project
- Open the AEM project in your favorite editor. I have used intelliJ for this.
- Create a folder called
fetchchoicesunder\aem-banking-application\ui.content\src\main\content\jcr_root\content - Right click
fetchchoicesfolder and selectrepo | Get Command(This menu item is setup in a previous chapter of this tutorial).
This should sync this node from AEM to your local AEM project.
Your AEM project structure should look like this
Update the filter.xml in the aem-banking-application\ui.content\src\main\content\META-INF\vault folder with the following entry
<filter root="/content/fetchchoices" mode="merge"/>
You can now push your changes to an AEM as a Cloud Service environment using Cloud Manager.