Catching AEM Content installation event - aem

Question

The use case here is to get the information of content with type cq:Page and dam:Asset that is being installed/updated in the JCR using package manager in AEM.
I would like to know if there are any event listener or API's that can be used for this purpose.
Is there a way to know if the content was installed/updated using the package manager?
AEM 6.2 is being used here.
Thanks!!

Answer 1

To detect Resource changes, you need to create a ResourceChangeListener
Here is an example based on ACS commons SampleResourceChangeListener but restricted to ADDED and CHANGED events.
import org.apache.felix.scr.annotations.*;
import org.apache.sling.api.resource.observation.ExternalResourceChangeListener;
import org.apache.sling.api.resource.observation.ResourceChange;
import org.apache.sling.api.resource.observation.ResourceChangeListener;
import org.apache.sling.event.jobs.JobManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nonnull;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* The Sling Resource Change Listener is the preferred method for listening for Resource Change events in AEM.
* This is preferred over the Sling Resource Event Listener, or the JCR Event Handler approaches.
*
* ResourceChangeListener Javadoc:
* - https://docs.adobe.com/docs/en/aem/6-2/develop/ref/javadoc/org/apache/sling/api/resource/observation/ResourceChangeListener.html
*
* Note: To listen for External events, implements the ExternalResourceChangeListener. If ONLY local events are in scope, implement only the ResourceChangeListener.
*/
#Component(
label = "Sample - Resource Change Listener",
description = "A sample implementation of the Sling Resource Change Listener",
metatype = true
)
#Properties({
// Scope the paths as tightly as possible based on your use-case.
#Property(
label = "Paths",
description = "[ Required ] A list of resource paths this listener will listen for change events.",
name = ResourceChangeListener.PATHS,
value = {"/content"}
),
// Scope the types as tightly as possible based on your use-case.
// If This property is not provided, ALL ChangeTypes will be accepted.
// Available values are defined on: ResourceChange.ChangeType
#Property(
label = "Change Types",
description = "[ Optional ] The change event types this listener will listener for. ",
name = ResourceChangeListener.CHANGES,
value = {"ADDED", "CHANGED"}
)
})
#Service
public class SampleResourceChangeListener implements ResourceChangeListener, ExternalResourceChangeListener {
private static final Logger log = LoggerFactory.getLogger(SampleResourceChangeListener.class);
#Reference
private JobManager jobManager;
public void onChange(#Nonnull List<ResourceChange> changes) {
// Iterate over the ResourceChanges and process them
for (final ResourceChange change : changes) {
// Process each change quickly; Do not do long-running work in the Resource Change Listener.
// If expensive/long-running work is required to handle the event, create a Sling Job to perform that work.
if (change.isExternal()) {
// Since this implements BOTH the ResourceChangeListener AND ExternalResourceChangeListener
// we can conditionally handle local vs external events.
}
switch (change.getType()) {
case ADDED:
log.debug("Change Type ADDED: {}", change);
if (change.getAddedPropertyNames().contains("someProperty")) {
// Do some work
// In this case we will pass some some data from the Event to a custom job via a custom Job topic.
final Map<String, Object> props = new HashMap<String, Object>();
props.put("path", change.getPath());
props.put("userId", change.getUserId());
jobManager.addJob("com/adobe/acs/commons/samples/somePropertyAdded", props);
}
break;
case CHANGED:
log.debug("Change Type CHANGED: {}", change);
if (change.getChangedPropertyNames().contains("someOtherProperty")) {
// Do some other work
}
break;
default:
// Do nothing
}
}
}
}
Alternatively, you can use a JcrEventListener, again ACS has a good example here: SampleJcrEventListener.java
I don't know of a way to detect if the cause of the add/update is package manager. However, if you want to execute some code before a package is installed, you can use InstallHook. I have not tried this before.