This post captures FAQs, and other tips for AEM that AEM Developers will find useful. We will update this list on an on-going basis.
I am new to AEM, where can i start?
See:
https://forums.adobe.com/thread/2452057
Can I use the Sling API to adapt a SlingHttpServletRequest?
Yes, you can use the Sling API to adapt from a SlingHttpServletRequest by using a method such as modelFactory.getModelFromWrappedRequest(). To see a code example of this - see:
If you are new to AEM and OSGi - read this article --
https://helpx.adobe.com/experience-manager/using/osgi_getting_started.html
How to integrate AEM with Adobe Target Via Adobe Launch
How can I integrate AEM with Adobe Analytics?
Can I see a list of events in AEM
See - http://localhost:4502/system/console/events
I want to read the Binary property of a node?
You can use the JCR API to read the binary property of a node and retrieve a Java InputStream. For details, see this article:
Can I use the AssetManager API to dynamically delete Assets?
Yes you can, In fact, you can define conditions for application logic to read values and then depending upon the value, you can use the Asset Manager's removeAsset() to delete the asset from the AEM DAM.
I want to update my AEM project to latest version. Is there any recommendations?
How can i add my own template type to Experience Fragments?
It it is the cq:allowedTemplates property on /content/experience-fragments node that drives the availability of XF variations:
How can I use OSGi R6 Annotations to read OSGi configuration values.
We cover this use case in these two HELPX articles:
When i search using QueryBuilder, only 10 items are displayed.
BY default, QueryBuilder only returns 10 results
So add this parameter p.limit=-1 to fix that. For example--
//set QueryBuilder search criteria
map.put("type", "cq:Page");
map.put("path", "/content/we-retail");
map.put("p.limit", "-1");
I want to understand Dispatcher better
How can I view all the Node Types in AEM?
See: http://localhost:4502/crx/explorer/nodetypes/index.jsp
Whats the Difference between an Experience Fragment and a Content Fragment?
Does AEM Support SPA?
See these resources:
Some of the documentation we have for that:
Can I use the Asset Manager API to get asset renditions?
Yes - you can use the Asset Manager API to read asset renditions. See this code example:
public String getAsset(){
ResourceResolver resolver = null;
Map<String, Object> param = new HashMap<String, Object>();
param.put(ResourceResolverFactory.SUBSERVICE, "datawrite");
try {
//Invoke the adaptTo method to create a Session used to create a QueryManager
resolver = resolverFactory.getServiceResourceResolver(param);
log.info("Cretae the Asset");
//Use AssetManager to place the file into the AEM DAM
AssetManager assetMgr = resolver.adaptTo(AssetManager.class);
Asset myAsset = assetMgr.getAsset("/content/dam/we-retail/en/people/womens/women_6.jpg");
Rendition myRen = myAsset.getRendition("/content/dam/we-retail/en/people/womens/women_6.jpg/jcr:content/renditions/cq5dam.thumbnail.140.100.png");
InputStream is = myRen.getStream();
//Cretae a new Asste with the Rendition
//Use AssetManager to place the file into the AEM DAM
com.day.cq.dam.api.AssetManager assetMgr2 = resolver.adaptTo(com.day.cq.dam.api.AssetManager.class);
String newFile = "/content/dam/travel/test.png" ;
assetMgr2.createAsset(newFile, is,"image/jpeg", true);
return ("New Asset Created");
}
catch(Exception e)
{
e.printStackTrace();
}
return "ERROR";
}
How can I develop a custom RTE plug-in
How to generate a PDF from AEM content
How to Recompile JSP files in AEM
How can I use the Document Services API
-
The RTE Editor plug-in are not visible until I click within the RTE. How can i fix?
How can i use HTL syntax to include a clientlib
use this syntax -- <sly data-sly-use.clientLib="/libs/granite/sightly/templates/clientlib.html" data-sly-call="${clientLib.js @ categories='cq.jquerycar'}" data-sly-unwrap/>
What are Design Dialogs used for?
How How to access to an URL selector at a component level?
How can I define a new path for a Sling Servlet
How can I read page properties from multiple pages and construct JSON
To perform this use case, you need to query pages using QueryBuilder or JCR SQL2. Read the node properties that you want and then place them into a list. Use that list to construct the JSON using a Java lib such as GSON. See this example...
WRITE CODE TO GET JCR API SESSION....
//Obtain the query manager for the session ...
javax.jcr.query.QueryManager queryManager = session.getWorkspace().getQueryManager();
String sqlStatement = "select * from [cq:Page] where isdescendantnode('/content/we-retail/us/en/experience') " ;
javax.jcr.query.Query query = queryManager.createQuery(sqlStatement,"JCR-SQL2");
//Execute the query and get the results ...
javax.jcr.query.QueryResult result = query.execute();
//Iterate over the nodes in the results ...
javax.jcr.NodeIterator nodeIter = result.getNodes();
long size = nodeIter.getSize();
Bean myBean = null;
ArrayList<Bean> list = new ArrayList() ;
while ( nodeIter.hasNext() ) {
//For each node-- get the path of the node
javax.jcr.Node node = nodeIter.nextNode();
myBean = new Bean();
javax.jcr.Node context = node.getNode("jcr:content");
//Set Bean and push to List
myBean.setTitle(context.getProperty("jcr:title").getString());
myBean.setTemplate(context.getProperty("cq:template").getString());
list.add(myBean);
}
System.out.println("the list is this big "+list.size() ) ;
doGSON(list) ;
}
catch(Exception e){
e.printStackTrace();
}
return null;
}
public String doGSON(ArrayList theList)
{
// create the albums object
JsonObject albums = new JsonObject();
// add a property calle title to the albums object
albums.addProperty("name", "page");
// create an array called datasets
JsonArray datasets = new JsonArray();
// create a dataset
JsonObject dataset = null ;
int size = theList.size();
for (int index =0; index<size; index++)
{
dataset = new JsonObject();
Bean singleBean = (Bean) theList.get(index);
String title = singleBean.getTitle();
String template = singleBean.getTemplate();
dataset.addProperty("title", title);
// add the property album_year to the dataset
dataset.addProperty("template", template);
datasets.add(dataset);
albums.add("dataset", datasets);
}
Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE).create();
System.out.println(gson.toJson(albums));
return "";
}
Can I use a Radio data type in a Multi-field?
See this video --
https://www.youtube.com/watch?v=Fu4mV4Xridg&t=6s
I want to know about how Sling locates resources
I want to know more about DS Annotations
I want to use sling models to retrieve Multi-field values using sling models
How to print the jcr:lastModified using HTL without writing a java class
You can use the following syntax:
${properties['jcr:lastModified'] @format='dd/MM/yyyy'}
Can I use OAuth in AEM?
Can I programmatically remove a user from groups?
Authorizable groupAuthorizable = userManager.getAuthorizable(group);
if (groupAuthorizable != null && groupAuthorizable instanceof Group) {
((Group) groupAuthorizable).removeMember(user);
}
Can I use an API to update OSGi configuration values
How can I add a FAVICON to an AEM Site
How can I create a Nested Touch UI Multifield?
How can I extend Core Components?
How can I create an OAK Index
Unlike Jackrabbit 2, Oak does not index content by default. Custom indexes need to be created when necessary, much like with traditional relational databases. If there is no index for a specific query, possibly many nodes will be traversed. The query may still work but probably be very slow.
To avoid performance issues, you need to create an OAK index. See these resources for more information:
2. GEMS Session on OAK Index
I want to see a basic Architecture diagram for AEM
I want to start migrating data from a non-AEM site to AEM
How come I cannot use Design Mode for We Retail?
If you attempt to use Design Mode for We Retail in order to add new components, you will notice that Design mode is not there.
The reason is pages based on Editable Templates do not have Design Mode. To add a component group, you need to add the component group by using the editable templates Policy.
I am trying to render a RTE value in HTL, but is displayed as HTML Tags - not HTML content?
If you want to read the value of a RTE and display in a HTL component - along with the tags such as a hyperlink, you need to use this HTL syntax:
${head.text @ context='html'}
where head.text is the RTE value.
What are Projects in AEM?
How can I test my AEM Code?
For example, assume you create a project named AEM633. Once you build this project, you will have a class named TestHelloWorldModel located in this package:
com.foo.core.models (under src\test\java)
All of the POM dependencies are set up for you. Create a simple interface in the Core package named Foo.
package com.foo.core;
public interface Foo {
public String getName();
}
Then create an implementation class that uses a @Component annotation in the same package.
package com.foo.core;
import org.osgi.service.component.annotations.Component;
@Component
public class FooImpl implements Foo{
public String getName()
{
return "Scott" ;
}
}
This is about the most basic AEM class that you can build. It has one method that returns a static value for the getName method. Now the question is how can we test this method?
The answer is to use the TestHelloWorldModel class that already exists. You can create a Foo object and then test the getName method. See the bold code below.
package com.foo.core.models;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
import java.util.UUID;
import junitx.util.PrivateAccessor;
import org.apache.sling.settings.SlingSettingsService;
import org.junit.Before;
import org.junit.Test;
import com.foo.core.Foo;
import com.foo.core.FooImpl;
/**
* Simple JUnit test verifying the HelloWorldModel
*/
public class TestHelloWorldModel {
//@Inject
private HelloWorldModel hello;
private Foo myFoo;
private String slingId;
@Before
public void setup() throws Exception {
SlingSettingsService settings = mock(SlingSettingsService.class);
slingId = UUID.randomUUID().toString();
when(settings.getSlingId()).thenReturn(slingId);
hello = new HelloWorldModel();
PrivateAccessor.setField(hello, "settings", settings);
hello.init();
myFoo = new FooImpl();
}
@Test
public void testGetMessage() throws Exception {
// some very basic junit tests
String msg = hello.getMessage();
assertNotNull(msg);
assertTrue(msg.length() > 0);
}
@Test
public void testFooMessage() throws Exception {
//custom service
String msgFoo = myFoo.getName() ;
assertNotNull(msgFoo);
assertTrue(msgFoo.length() > 0);
}
}
When you build the Maven project (for example, mvn clean install), you can see the Test results that are written to this file:
C:\AdobeCQ\AEM633\core\target\surefire-reports\com.foo.core.models.TestHelloWorldModel.txt
For AEM and MOCK examples - see: https://github.com/adaptto/2018-junit5-and-sling-aem-mocks
How can I disable the options in the Assets Toolbar?
I have a requirement to remove options on the Assets toolbar.
If you simply want to disable those, you can overlay:
/libs/dam/gui/content/assetdetails/jcr:content/actions
and add disabled (boolean) = true for these actions
How can I apply color to a Table in the RTE?
This works as shown here:
I need to create a QUIZ in AEM. Can I use AEM Forms?
You cannot use AEM Forms to create a quiz component. It's best to use a JQuery plugin and develop a custom component as discussed here:
How can I configure AEM Link Checker to ignore certain URL patterns
How do you display a DATE value in HTL?
Assume you have a node named startDate, which is based on a Date data type. To display this value in HTL, you can use the following HTL syntax.
${'yyyy-MM-dd HH:mm:ss.SSSXXX' @ format=head.startDate, timezone='UTC'}
How can I used GSON within AEM
To use the GSON XML library in AEM, you need to use the following dependency.
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.0</version>
</dependency>
How can I track Requests in AEM?
You can use the "Recent requests" view in the web console ( /system/console/requests) to actually check what the request is internally doing. Every include and every forward is listed there and this should give you insight what's going on.
How can i align fields in a Touch UI Dialog?
How can I use Sling Queries?
Core Project has dependency on javax.inject [0,1) Bundles and imports not getting deployed
You can add
<!-- Import any version of javax.inject, to allow running on multiple versions of AEM -->
<Import-Package>javax.inject;version=0.0.0,*</Import-Package>
to your bundles pom.xml. This should solve your issue. This says take any version from the felix console for this bundle. Add it under maven-scr-plugin
How can I use an AEM API to find all Assets in a page?
How come when a Workflow is assigned to 1 user, sometimes another user can see it
Assume you have two users:
Next, assume that you have a Workflow model that uses an OR Split and where the 1st step is assigned to User A. See this model.
Sometimes even if User A is assigned the a Workflow task- it may show up in User B inbox. This may happen if you have not specified User A as the 1st step. Also - it may happen if they Users are part of the workflow admin group. In order for User B not to see a task assigned to another member, ensure that they both belong to the workflow-users group.
Notice that User A is assigned a task when the workflow is started. Even if User B invokes the Workflow, a message is sent to User A - as shown here:
Although User B invoked the Workflow, they do not get a message in their corresponding inbox.
How can I get a reference to an AEM Service from a Sling Model
You cannot use
@Reference to inject a service into a Sling Model. When attempting to get a service into an AEM Sling Model class - you can use @inject. See this thread:
https://forums.adobe.com/message/9864292#9864292
How can I limit the fields located in Multifield?
How can i change the Theme of a Touch UI Dialog?
How can i modify the default text of a Parsys component?
Where can I find good reference docs for Coral APIs
How do i use HTL syntax to include a Core Component in my static template?
You can use HTL syntax to include AEM Core components into a static template. For example, to include the List component into a template - specify this syntax:
<div data-sly-resource="${'content' @ resourceType='core/wcm/components/list/v1/list'}">
Whats the difference between a static template and an editable template
In AEM 6.3 - I am getting osgi bundle whitelist error-osgi-service is NOT whitelisted to use SlingRepository.loginAdministrative
You can either use a System user and the sling mapping service:
http://scottsdigitalcommunity.blogspot.ca/2014/12/querying-adobe-experience-manager-6.html.
Or configure AEM -
https://forums.adobe.com/thread/2355506
How can i integrate AEM with Hybris?
In HTL, how can i add the parsys component?
Add this code:
<sly data-sly-resource="${'content-par' @ resourceType='wcm/foundation/components/parsys'}"/>
I can use both JCR API and SLing API to work with the AEM JCR. Which one is better?
I want to send a message to a users AEM inbox?
Easiest way is to create a task assigned to the user you want to notify.
When working with Sling Models, can I reference grandchildren nodes and work with Collections?
Yes, when you work with Sling Models, you can work with Grandchildren nodes from the node that you adapt. For example, consider the following JCR structure.
Assume you adapt NodeCollections in your Sling Model:
Resource resource = resourceResolver.getResource("/content/NodeCollections");
You can get the grandchildren nodes using this syntax and return them to a Java LIST object.
@Model(adaptables = Resource.class)
public class UserInfo {
@Inject
private List<Resource> Dad;
public List getGrandChildren()
{
return Dad ;
}
}
In this example, the List Object would contain six items. See more here:
https://sling.apache.org/documentation/bundles/models.html
I want to know the difference between Sling Models and WCMUsePojo
Can Forms interact with Workflows?
I want to know more information about OSGi Declarative Services Annotations in AEM
Whats the difference between Foundation components and Core components?
See this community article for an answer:
http://adobeaemclub.com/aem63-core-components/
To learn to work with Core Components - see:
https://helpx.adobe.com/experience-manager/using/aem63_components.html
A user does not have permission to modify Assets, can they execute a Workflow that modifies them?
Any member of the workflow-users group can list and start workflows, irrespective of their permissions on the payload the selected to run the workflow.
Does AEM by default use J2EE Sessions and Cookies?
Nothing in AEM uses JavaEE Sessions.
Components cannot be moved. Why?
If you want to move components upwards or downwards, you need to use copymove in cq:actions property.
Here it is!!
<jcr:root xmlns:cq="http://www.day.com/jcr/cq/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0"
cq:actions="[text:My Component,-,edit,delete,insert,copymove]"
cq:dialogMode="floating"
cq:layout="editbar"
jcr:primaryType="cq:EditConfig">
</jcr:root>
I am using AEM Forms, not AEM Sites
See these docs: https://helpx.adobe.com/aem-forms/6-1/help-tutorials.html
Can I use @Reference in an HTL Class that extends WCMUsePojo
You cannot use the @Reference annotation from a HTL class that extends WCMUsePojo. This can be used from a Java class that uses @Service to reference another service known as dependency injection. To learn about Dependency Injection in AEM, see this article:
Now to learn how to get a referenece to another AEM service from a class that extends WCMUsePojo, see this article:
Can I use @Reference from within a Sling Servlet
You can use Dependency Injection from within a Sling Servlet. See this community article/video.
Can I manipulate the Touch UI Rich Text Editor using code
See this community article - http://experience-aem.blogspot.ca/2015/01/aem-6-sp1-touch-ui-rich-text-editor-plugin-to-upper-case.html
How can I programmatically retrieve HTML from an AEM page
See this great community article by Nolle Yolles: http://www.nateyolles.com/blog/2015/10/get-rendered-html-for-an-aem-resource-or-component
What is cq.editconfig and when should i use it
Where do Lucene, Solr, ElasticSearch fit in the AEM Platform?
Can i view an asset's metadata in CRXDE lite?
Assume you have added metadata to a digital asset, as shown in this illustration.
You can view the assets metadata by viewing a node named metadata under the asset in the AEM dam (/content/dam). For example, the above image is located here:
/content/dam/geometrixx-instore/cover-images/seasonal.jpg
The metadata is stored as node properties as shown in this illustration.
Can I programmatically work with Coral UI object such as checkboxes?
Yes you can. It involves creating a JS script in an AEM Clientlib and then coding. See the reference documentation here:
Given this setup in CRXDE Lite:
Code:
(function ($, $document) {
"use strict";
$document.on("dialog-ready", function() {
$('#kitten').attr('checked', true);
});
})(jQuery, jQuery(document));
The result is the checkbox is checked via code:
Note - we are planning on conducting a full session of AEM Ask the Community Experts on AEM Developing with the Coral API.
Need to search for special characters when searching JCR via JCR SQL2
Read this topic -- https://wiki.apache.org/jackrabbit/EncodingAndEscaping. YOU need to escape illegal JCR characters.
How can i work with custom JARs that are not in the Maven repository
You can place the JAR in your local Maven Repository and then reference it in your POM file. For example, to resolve myCustomJAR_1.0.0.jar within an AEM service, the myCustomJAR_1.0.0.jar file must be located in the Maven repository. You can upload the myCustomJAR_1.0.0.jar to Maven by using this Maven command:
mvn install:install-file -Dfile=C:/plugins/myCustomJAR_1.0.0.jar -DgroupId=com.foo.reports -DartifactId=jrurbersrt1.0 -Dversion=1.0 -Dpackaging=jar -DgeneratePom=true
Notice that you must specify the location of the myCustomJAR file in the -Dfile argument. Also notice that you specify the Dgroup and DartifactID values. Once you upload the JAR to Maven using this command, you can reference this JAR file using this Dependency.
<groupId>com.foo.reports</groupId>
<artifactId>jrurbersrt1.0</artifactId>
<version>1.0</version>
<scope>system</scope>
<systemPath>C:\Users\scottm\.m2\repository\com\foo\reports\jrurbersrt1.0\1.0\myCustomJAR_1.0.0.jar</systemPath>
</dependency>
Notice that scope element is system and systemPath references the location of the JAR file in the repository. (This dependency is used later in this article to build the AEM service)
How can i work with 3rd party JARs when i create an OSGi bundle
When working with OSGi bundles that use 3rd party JARs (that are located in the Maven Repository), you can embed the 3rd party JAR (for example, Simple JSON JAR) into a separate bundle and deploy to AEM. See this community article/video for details.
http://scottsdigitalcommunity.blogspot.ca/2013/06/posting-form-data-to-adobe-cq-using.html
Enable CORS Access-Control-Allow-Origin in AEM
If you use the default AEM JQuery, it has a token that lets you perform AJAX operations to AEM.
AEM is experiencing slow page loading
How does Dispatcher Caching work
The dispatcher caches only files which have an extension; and the extensions which should be considered for caching can be configured in the dispatcher config as part of the caching rules.
So you need to add an extension to your service request (e.g. ".json"), and configure the dispatcher accordingly, then the caching will work.
Capturing comments in a default email template used by an AEM 6.2 workflow
You can write a custom workflow step and inject values you want to populate into a email template with Java logic. For example:
//Populate the MAP with the values
myMap.put("topic.subject",TopicSubject);
myMap.put("time",timeStamp);
myMap.put("host.prefix",hostPrefix);
myMap.put("forum.url",forumUrl);
//Declare a MessageGateway service
MessageGateway<HtmlEmail> messageGateway;
//Specify the EMail template
String template ="/etc/notification/email/html/com.day.cq.collab.forum/en.txt";
Resource templateRsrc = request.getResourceResolver().getResource(template);
MailTemplate mailTemplate = MailTemplate.create(templateRsrc.getPath(), templateRsrc.getResourceResolver().adaptTo(Session.class));
HtmlEmail email = mailTemplate.getEmail(StrLookup.mapLookup(myMap), HtmlEmail.class);
A solution without coding is to use the variable
${item.data.comment} in the default en.txt. To see other variables that can be used, see
https://docs.adobe.com/docs/en/aem/6-2/administer/operations/notification.html#Configuring the Workflow Email Notification Service.
com.adobe.granite.crxde-lite reinstall in publisher
Recently we observed com.adobe.granite.crxde-lite bundle is not present/got deleted in publisher node. Due to this reason we are not able to login to http://localhost:4503/crx/de
To solve this - Try the following actions:
1. On author log into OSGi /system/console/bundles.
2. Type CRX in the search field and click Apply filter
3. Most likely Adobe Granite CRXDE Lite com.adobe.granite.crxde-lite bundle is missing, however, you can do the same search on Publish and compare the result to indetify the difference.
4. Note Adobe Granite CRXDE bundle ID, in my sample, it is 222.
5. On your AEM author navigate to /crx-quickstart/launchpad/felix/bundle222 /AEM64/author/crx-quickstart/launchpad/felix/bundle222/version0.0
6. Deploy bundle.jar to AEM publish via /system/console/bundles -> Install/Update...
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I (Scott Macdonald) am a Senior Experience League Community Manager at Adobe Systems with 20 years in the high tech industry. I am also a programmer with knowledge in Java, JavaScript, C#,C++, HTML, XML and ActionScript. If you would like to see more AEM or other end to end articles like this, then leave a comment and let me know what content you would like to see.
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