com.dotcms.hooks.pubsub

com.dotcms.hooks.pubsub

Purpose

This plugin demonstrates publishing cluster-aware Pub/Sub events from a content publish hook.

What This Plugin Does

• Registers a post-content hook that runs when content is published.
• Publishes a custom topic event containing published content identifiers.
• Subscribes to publish-related local system events and logs event details.

When a Customer Might Use This

• You need node-to-node notifications after publish activity.
• You want to trigger custom downstream processing based on publish events.
• You need a reference for combining hooks and Pub/Sub in dynamic plugins.

How to build this example

To build the JAR, run the following Maven command:

mvn clean install

This will generate the plugin JAR in the target directory.

How to install this bundle

• To install this bundle:

  Copy the bundle JAR file inside the Felix OSGI container (dotCMS/felix/load).

  OR

  Upload the bundle JAR file using the dotCMS UI (CMS Admin -> Plugins -> Upload Plugin).

• To uninstall this bundle:

  Remove the bundle JAR file from the Felix OSGI container (dotCMS/felix/load).

  OR

  Undeploy the bundle JAR using the dotCMS UI (CMS Admin -> Plugins -> Undeploy).

How to create a bundle plugin for dotCMS hook classes

In order to create this OSGI plugin, Maven is configured to generate the META-INF/MANIFEST.MF file automatically. If needed, you can customize the configuration in the pom.xml.

Below is a description of the required fields in the MANIFEST.MF and how they are configured in a pom.xml:

Bundle-Name: The name of your bundle
Bundle-SymbolicName: A short and unique name for the bundle
Bundle-Vendor: The vendor of the bundle (example: dotCMS)
Bundle-Description: A brief description of the bundle
Bundle-DocURL: URL for the bundle documentation
Bundle-Activator: Package and name of your Activator class (example: com.dotmarketing.osgi.actionlet.Activator)
Export-Package: Declares the packages that are visible outside the plugin. Any package not declared here has visibility only within the bundle.
Import-Package: This is a comma-separated list of the names of packages to import. This list must include the packages that you are using inside your OSGI bundle plugin and are exported and exposed by the dotCMS runtime.

These fields are configured in the pom.xml as follows:

<plugin>
    <groupId>org.apache.felix</groupId>
    <artifactId>maven-bundle-plugin</artifactId>
    <version>5.1.9</version>
    <extensions>true</extensions>
    <configuration>
        <instructions>
            <Bundle-Name>Your Bundle Name</Bundle-Name>
            <Bundle-SymbolicName>com.example.yourbundle</Bundle-SymbolicName>
            <Bundle-Vendor>dotCMS</Bundle-Vendor>
            <Bundle-Description>dotCMS - OSGI Actionlet example</Bundle-Description>
            <Bundle-DocURL>https://dotcms.com/</Bundle-DocURL>
            <Bundle-Activator>com.dotmarketing.osgi.actionlet.Activator</Bundle-Activator>
            <Export-Package>com.example.yourbundle.package</Export-Package>
            <Import-Package>*</Import-Package>
        </instructions>
    </configuration>
</plugin>

Beware (!)

In order to work inside the Apache Felix OSGI runtime, the import and export directives must be bidirectional:

• Exported Packages

  The dotCMS must declare the set of packages that will be available to the OSGI plugins by updating the file: dotCMS/WEB-INF/felix/osgi-extra.conf. This can also be configured using the dotCMS UI (CMS Admin -> Plugins -> Exported Packages).

  Only after the exported packages are defined in this list, can a plugin import the packages to use them inside the OSGI bundle.

• Fragment (Deprecated)

  Previously, a bundle fragment was used to make its contents available to other bundles by exporting 3rd party libraries from dotCMS. Fragments do not participate in the lifecycle of the bundle and therefore cannot have a Bundle-Activator. As this is no longer required, this section is deprecated.

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Components

com.dotmarketing.osgi.hooks.PublishContentPostContentHook AND com.dotmarketing.osgi.hooks.SamplePreContentHook

Hooks classes that will override the contentletCount method to see how they work.

Activator

This bundle activator extends from com.dotmarketing.osgi.GenericBundleActivator and implements BundleActivator.start(). Calls ContentletAPI.contentletCount() who will fire ours hooks methods.