Magnolia 4.5 reached end of life on June 30, 2016. This branch is no longer supported, see End-of-life policy.
The Observation module allows you to listen to events in the repository and trigger a reaction. Use observation to automate tasks such as publishing newly added assets or sending an email notification when a comment is added. Custom event listeners can react to almost any event. The Observation module is based on the JCR observation feature.
Download the Observation module from Magnolia Store or Nexus repository.
Observation is a Community Edition module.
The Observation module is not installed by default. To check whether it is installed, go to Magnolia Store > Installed modules in AdminCentral. If you don't find a version node in
/modules/observation
then the module is not installed. You can find listeners installed by other modules under the config
node even if the Observation module is not installed.
To install the module, please see the general module installation instructions.
See the general module uninstalling instructions and advice.
An event listener registers an interest in a particular type of event. The job of the listener is to detect the event and possibly react to it.
Example: You want to send an email notification when a new page is added. Configure an event listener that listens to the NODE_ADDED event. This event occurs when a new node is added. Limit the listener to the mgnl:page
node type so you only get notified about pages, not other types of nodes. Finally, define the mail command as the desired reaction.
Magnolia provides two types of event listeners: listeners that react to the event on their own and listeners that delegate the reaction to a command. Both listeners are configured the same way but command event listeners have some extra properties.
Here is a basic pageAddedAlert
listener. It listens to the NODE_ADDED event and reacts by writing a message to the console when new content is added. This is an example of a self-contained listener that reacts to the event on its own. The reaction is hard-coded in the
PageListener
class.
Here's what the output written to the console looks like:
EventListener Test: Text Message EventListener Test: Text Message2
Listener properties:
listener name
> listener
: Identifies the configuration as an event listener. class
: Fully-qualified listener class name.nodeType
: Optional. Restricts observation to events that occur in the specified node type, for example mgnl:page
for pages. Use together with a listener class that observes node type. By default all node types are monitored.active
: Enables and disables the listener. Default is false
.delay
: Optional. Delay in milliseconds before the reaction is triggered.description
: Optional. Listener description.eventTypes
: Optional. The type of JCR event monitored. Possible types are NODE_ADDED
, NODE_MOVED
, NODE_REMOVED
, PROPERTY_ADDED
, PROPERTY_CHANGED
, PROPERTY_REMOVED
and PERSIST
. Separate multiple types with a comma. All types are monitored by default.includeSubNodes
: Optional. Observes also events in subnodes. Default is false
. For example, by default only changes to the page itself would be observed. If you also want to observe changes to components under the page node, set includeSubNodes
to true
.maxDelay
: Optional. Maximum delay milliseconds before the reaction is triggered.path
: Mandatory. Path to the node that is observed. repository
: Mandatory. Workspace in which the observed node resides.
A single listener can monitor a single nodeType
or all types. To monitor two types to the exclusion of other types, two listener configurations are required. Folders and contacts, for example, require one listener to monitor folders (nodeType=mgnl:folder
) and another to monitor files (nodeType=mgnl:contact
). You can verify the nodeType
by exporting the node to be monitored to XML and searching for the value of jcr:primaryType property
in the file.
Magnolia provides the following listener classes:
Class | Description |
---|---|
info.magnolia.module.observation.sample.PageListener | Writes a message to the console when a page is added. |
info.magnolia.module.observation.commands.CommandEventListener | Executes a command when an event occurs. |
info.magnolia.module.observation.commands.RestrictToNodeTypeEventListener | Executes a command when an event occurs in the specified node type. |
info.magnolia.module.observation.commands.RegexEventListener | Executes a command when an event occurs in the specified node type and matches a regular expression pattern. |
info.magnolia.module.observation.commands.SpecifiedNodeTypeOnlyEventListener | Executes a command when an event occurs in a node that is in the "included" list of node types and not on the "excluded" list. |
A command event listener delegates the reaction to a command. You can reuse any of Magnolia's existing commands or write your own.
Here's an example sendMailOnPageChanges
listener. It observes changes to pages and delegates the reaction to MailCommand
which sends a notification. This example assumes the
pageChangeNotification
mail template has been configured in the Mail module.
Properties specific to command listeners:
<listener name>
command
: class
: Fully-qualified name of the command class the reaction is delegated to.params
: Optional. Parameters passed to the command. For example the mailTemplate
used to compose the mail body, required by the MailCommand
.repository
: Workspace passed to the command. Some commands require this so you need to define it in two places: here as a parameter and under the listener configuration.
<other>
: Any other configuration supported by the command. For example nodeType
in the case of RestrictToNodeTypeEventListener
.
includes
: Optional. Included list of node types that the SpecifiedNodeTypeOnlyEventListener
observes.<node type name 1>
: Node type to observe.<node type name 2>
: Node type to observe.<node type name 3>
: Node type to observe.excludes
: Optional. Excluded list of node types that the SpecifiedNodeTypeOnlyEventListener
ignores.<node type name 1>
: Node type to ignore.<node type name 2>
: Node type to ignore.<node type name 3>
: Node type to ignore.
class
: Fully-qualified name of the command listener class.
Listeners may rely on the Mail module to send emails. Configure SMTP setting to ensure that they work.
Magnolia provides the following example listeners:
sendMailOnPageChanges
: Sends an email message when a page is created, updated or deleted. sendMailOnPageComments
: Installed by the Mail module to send an email when a user comments on a page.activateAddedPages
: Automatically activates new pagesversionResourcesOnChange
: Automatically versions STK resources.versionTemplatesOnChange
: Installed by the In-place Templating module to automatically version STK templates.generateCategories
: Installed by Categorization module to automatically generate categories.The example below automatically activates any new asset added in the DMS. The listener observes the NODE_ADDED
event in the dms
workspace. To test the listener, upload a new asset.