AEM Global Objects for Backend and Front-end Sightly (HTL) Development

While working on an AEM project, we can speed up the process of development by utilizing the global objects offered by AEM Framework.

1. AEM Backend, an example of using global objects

• The global objects are accessible by OSGI’s dependency injection annotation; @inject.
• GET, SET, and other methods can be invoked by the POJO class.

import com.day.cq.wcm.api.Page;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.models.annotations.Model;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import java.util.logging.Logger;

@Model(adaptables = {SlingHttpServletRequest.class, Resource.class},
resourceType = ExampleComponent.RESOURCE_TYPE)
public class ExampleComponent {

static final String RESOURCE_TYPE = "sourcedc/components/structure/examplecomponent";

@ScriptVariable
private Logger log;

@ScriptVariable
private SlingHttpServletResponse response;

@SlingObject
private SlingHttpServletRequest request;

@ScriptVariable
private Page currentPage;

@ScriptVariable
private Resource resource;

@PostConstruct
private void init() {
String componentsProp = resource.getValueMap().get("subtitleText", String.class);
String currentPagePath = currentPage.getPath();
String userID = request.getParameter("userid");
String localeCountry = response.getLocale().getCountry();

// setting json response
response.setContentType("application/json");
String contentType = response.getContentType();
log.info("Example component initiated.");
}

}

2. AEM Front-End, an example of using global objects, stored in reserved variables:

• The global objects are accessible by using unique variables (defined below).
• Only GET methods can be invoked by Sightly/HTL.
• While previewing the java documentation, only the get methods can be used. While using the global object, exclude the “get” prefix.

Current Page Path : ${currentPage.path} <!-- javadocs : getPath(); -->

Current Page Name : ${currentPage.name} <!-- javadocs : getName(); -->

response country : ${response.locale.country} <!-- javadocs : getLocale().getCountry(); -->

response type : ${response.contentType} <!-- javadocs : geetContentType(); -->

component's property subTitleText : ${properties.subTitleText}

<!-- loop through all children page's of current page -->
<div data-sly-list="">
<p>${child.name}</p>
</div>

// this article does not cover the usage of the Sightly(HTL) syntax. For a quick reference, check out this document:
https://github.com/adobe/htl-spec/blob/master/SPECIFICATION.md

3. Mapping of Sightly/HTL Variables and AEM Backend Objects:

Sightly/HTL Variables	AEM Backend Objects	Documentation
component	com.day.cq.wcm.api.components.Component	documentation
componentContext	com.day.cq.wcm.api.components.ComponentContext	documentation
currentDesign	com.day.cq.wcm.api.designer.Design	documentation
currentNode	javax.jcr.Node	documentation
currentPage	com.day.cq.wcm.api.Page	documentation
currentSession	javax.servlet.http.HttpSession	documentation
currentStyle	com.day.cq.wcm.api.designer.Style	documentation
designer	com.day.cq.wcm.api.designer.Designer	documentation
editContext	com.day.cq.wcm.api.components.EditContext	documentation
log	org.slf4j.Logger	documentation
out	java.io.PrintWriter	documentation
pageManager	com.day.cq.wcm.api.PageManager	documentation
reader	java.io.BufferedReader	documentation
request	org.apache.sling.api.SlingHttpServletRequest	documentation
resolver	org.apache.sling.api.resource.ResourceResolver	documentation
resource	org.apache.sling.api.resource.Resource	documentation
resourceDesign	com.day.cq.wcm.api.designer.Design	documentation
resourcePage	com.day.cq.wcm.api.Page	documentation
response	org.apache.sling.api.SlingHttpServletResponse	documentation
sling	org.apache.sling.api.scripting.SlingScriptHelper	documentation
slyWcmHelper	com.adobe.cq.sightly.WCMScriptHelper	documentation
wcmmode	com.adobe.cq.sightly.SightlyWCMMode	documentation
xssAPI	com.adobe.granite.xss.XSSAPI	documentation