Magnolia uses commands to publish and unpublish content, send email, flush cache, take backups, import and export data and for many other tasks. Commands can perform duties within the system or connect to external resources. Commands are typically executed by actions or scheduled for execution by the Scheduler module.
Characteristics of commands:
- Independent of the UI
- Back-end executable
- Executed by UI (for example by an action), Web services or other modules such as the Workflow and Scheduler
You can write your ownand execute them on-demand or scheduled.
A command definition makes the command available to the system.
Here are the command definitions for the basic commands that are used throughout Magnolia, configured in Configuration >
Commands are organized into catalogs. A catalog is an intermediate folder in the configuration hierarchy. It resides under the
commands folder and contains commands. Catalogs are used to distinguish multiple commands with the same name. For example, the
activation module has two command catalogs:
versioned. This configuration is in the Configuration app >
The advantage of using a catalog is that you can have identically named commands. You might want two
activate commands – one for pages and another for assets. To call a command that resides in a catalog, use the catalog name followed by a hyphen, then the command name. For example, you would distinguish the two activate commands by calling one with
workflow-activate and the other with
Catalog names have to be unique across the system. Magnolia will not merge commands with same name from various catalogs. It will load commands only from one of them. Since the
ui-admininterface module has a
default catalog, the name is already taken. If you created a
default catalog the names would conflict and the system would not load your command. Choose a catalog name that characterizes its commands, such as "
messaging" for commands that send emails and notifications. See Querying for catalogs and commands how to check for currently used names.
Commands can be grouped and executed as a chain. When you call the parent node its child commands are executed one-by-one in the node order from top down.
activate command in the
versioned catalog is an example of this.This configuration is in the Configuration app >
It is a group of two commands that are executed one after the other
versioncreates a new version of the node.
activatedelegates to the
activatecommand configured in the
defaultcatalog. Note the use of the
commandNameproperty in the
Executing commands with actions
In the UI commands are executed by actions. Here's an example action definition for the
activate action in the Pages app. You can find it in Configuration >
/modules/pages/apps/pages/subApps/browser/actions/activate. See Dialog action definition for the properties and their values.
You can use the Scheduler module to execute commands at a given time. You could for example activate a press release on a certain day, take a weekly backup of content, or synchronize a taxonomy of terms with an external source. There is an example configuration in the Configuration app >
/modules/scheduler/config/jobs/demo that you can adapt to suit your needs
params: Parameters passed to the command. Depends on the command. For example, the
activatecommand expects to receive a
repositoryname and a content
catalog: Name of the catalog where your command resides.
command: Name of the command.
description: Describes the job, for example "Send an email message on the hour"
cron: Schedule that indicates the execution time, written as a CRON expression. For example
0 0 1 5 11 ? 2010means "run on November 5 at 01:00 am". Cronmaker is a useful tool for building expressions.
active: Set value to
trueto activate the job.
|0 0 * * * *|
|activate each hour the page news.html|
You can use the Observation module to listen to events in the repository and execute a command in reaction.
Use observation to automate tasks such as publishing newly added assets or sending an email notification when a comment is added.
See Observation module for usage examples.
Querying for existing catalogs and commands
To query for existing commands:
- Go to Tools > JCR Queries.
- In the Query area, select
sqlquery language and
nt:baseresult item type.
- Paste the following query into the box: "
select * from nt:base where jcr:path like '%/commands/%'".
- Click Execute.
The result looks like this. Path notation:
Executing a command in the Groovy console
Use the Groovy console to execute command business logic manually, in ad hoc fashion. This is a quick way to test a custom command before you compile it as a Java class.
- Go to Dev > Groovy.
- Issue the following commands in the console:
This example activates the page
/travel/about/careers. You can test it by making a small change on the careers page, executing the Groovy commands, and viewing the modified history page on the public instance.
execute() method is passed a Magnolia context instance
ctx which is an implicit object the console always puts at your disposal.
Executing a command as a Groovy script
You can also save a command as a Groovy script. This is more comfortable than writing and executing one line at a time in the console. Groovy scripts can be run from the dialog used to edit them.
- Go to Dev > Groovy.
- Click New Script.
- Double-click the script name to change it.
- Double-click the script icon to edit it.
- Paste the example activation commands from above into the Source box.
- Check the Is a script? box.
- Check the Enabled box.
- Click Run.
Creating a custom command
You can write your own custom commands and execute them either on demand or scheduled. For example, you could execute the standard Magnolia
sendMail command when a page is activated. This way you can send an email notification to a user who needs to review the page.
To create a command definition:
commandsfolder in the configuration hierarchy of your module.
catalogsubfolder under the
commandsfolder. Choose a catalog name that characterizes its commands, such as
messagingfor commands that send emails and notifications.
- Create a content node under the catalog. This is the name of your command in Magnolia. If you did not create a catalog make sure that your command name is unique across Magnolia.
- Create a
classproperty. Set its value to the fully-qualified name of the Java class that contains the command logic such as
info.magnolia.module.mail.commands.MailCommand. The Java class should reside inside the module JAR.
You don't necessarily need to create a new module if you just want to add a command. You can put the command definition into any existing module and copy the class file to
WEB-INF/classes under the Magnolia webapp. However, it is easier to maintain your own classes, templates and configuration when you organize them in a module rather than leaving them scattered around.
A command is typically implemented as a Java class. You probably want to extend BaseRepositoryCommand which provides useful methods for working with the repository.
See the commands in the
info.magnolia.commands.impl package for examples.