Integrate applet on workflow Alfresco

Question

Question: I have an applet that makes "changes" on PDFs, and after this I have to save the changes to the respective file on the respository. How can I integrate this applet on a workflow? Any hint or document to read?

I thought in a task form (in a task-edit page), with a new component with a button to call the applet, but this is a good idea? And works? Because I wanted when the person press the accept button, the applet is called, and only then when the change was made, the task would be completed. But how?

Answer 1

I do not have the details of your applet and so I cannot be sure that it is possible, but you can try to simply use some javascript to access public methods of your applet.

The form-engine in Alfresco is easily customisable writing your custom controls. The custom control will generate the html and the javascript necessary to embed your applet in the form and call it when a button is pressed.

It would be useful to know if you can intercept on Alfresco the update executed by the applet. For example, you can have a listener (behaviour) in Alfresco that will be called when the document is updated. If, based on your business logic, the listener can understand that the applet has completed the operation, it can automatically fire the transition of the workflow. This solution is robust because the update executed by the applet and the update of the task will be transactional: they both succeed or the update is rolled back.

If possible, do not call the applet and the transition of the workflow separately : the two operations won't be atomic and you can end up with an inconsistent repository.

Update To avoid any customisation of Alfresco functionality, do not modify the acitiviti transitions. Given that you only need to add a button to call your applet, use a custom ftl and specify it in the configuration of your form.

The following article is a good guide to learn how to do it (I strongly suggest to read it and follow the exercise):

Jeff Potts' article on Advanced Workflows

As you can see at paragraph Edit share-config-custom.xml , you can specify the free marker template for rendering each field in your form. You can specify, if you prefer, a different template to use for your transition button. This template will render the applet and the html and javascript to call it.

The following class is an example (it is a snippet copied from real code, I have not tested it, it is meant only to show the main part of a behaviour) of a behaviour that listens for the creation of a node or the update of its properties. You have to choose what it is better for you. What exactly does the applet? Does it create a new node? Or update its properties ? Or update the content of the node?

The following link gives you an example of code that triggers the transition: Trigger Activiti workflow for task sitting in ReceiveTask looping

package com.someco.alfresco.behaviours;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import org.alfresco.repo.node.NodeServicePolicies.OnCreateNodePolicy;
import org.alfresco.repo.node.NodeServicePolicies.OnUpdatePropertiesPolicy;
import org.alfresco.repo.policy.Behaviour;
import org.alfresco.repo.policy.JavaBehaviour;
import org.alfresco.service.cmr.repository.ChildAssociationRef;
import org.alfresco.service.cmr.repository.NodeRef;
import org.alfresco.service.cmr.site.SiteInfo;
import org.alfresco.service.namespace.NamespaceService;
import org.alfresco.service.namespace.QName;
import org.apache.log4j.Logger;


public class SomeObjectCreatePolicy implements OnCreateNodePolicy, OnUpdatePropertiesPolicy {
    private final Logger logger = Logger.getLogger(SomeObjectCreatePolicy.class);

    @Override
    public void init() {
        this.policyComponent.bindClassBehaviour(
                QName.createQName(NamespaceService.ALFRESCO_URI, "onCreateNode"),
                Model.TYPE_ENTITY_OBJECT,
                new JavaBehaviour(this, "onCreateNode", 
                        Behaviour.NotificationFrequency.TRANSACTION_COMMIT));

        this.policyComponent.bindClassBehaviour(
                QName.createQName(NamespaceService.ALFRESCO_URI, "onUpdateProperties"),
                Model.TYPE_ENTITY_OBJECT,
                new JavaBehaviour(this, "onUpdateProperties", 
                        Behaviour.NotificationFrequency.EVERY_EVENT));
    }

    @Override
    public void onCreateNode(ChildAssociationRef childAssocRef) {
        /* Your logic to fire the transition */
    }

    @Override
    public void onUpdateProperties(NodeRef nodeRef,
            Map<QName, Serializable> before, Map<QName, Serializable> after) {
        /* Your logic to fire the transition */
    }
}

Of course, you can instantiate the object using Spring:

<bean id="org.alfresco.behaviours.someObjectCreatePolicy" class="com.someco.alfresco.policy.SomeObjectCreatePolicy"
        init-method="init">
</bean>

Answer 2

We did a similar integration by opening the 3th party app (applet) in an iframe. The entry point was a custom document library action with custom client side java script to open the iframe and pass parameters to it, but I suppose if you want it to popup from a form button, you could provide a custom control for it.

The 3th pary app then communicates with alfresco using custom alfresco webscripts we wrote (for saving your pdf).

=>Alternatively If you have the applets java code, you might be able to move it to an alfresco java web script. That would simplify architecture significantly.

Answer 3

As I mentioned in my comment , it's doable, BUT I DO NOT APPROVE THE WAY YOU ARE DOING THIS

My understanding (from previous questions here on SO) is that you which to integrate document signing feature within your alfresco instance. And you have developed a doclib action that navigates to a special page with an applet to verify the user identity, sign the document and then upload a new (signed) version of it. Now, you need to integrate that same applet in a workflow in order to give users the possibility of asking other users to digitally sign documents (or something like that ..).

Again, I would suggest you migrate your code from the applet to a service task (server side) as it would have more compatibility and more security (FYI: not all browsers still support NPAPI, afaik at least Chrome doesn't any more, and so they need configuration in order to be able to run your applet !)

That being said, I guess the way for you to do this is :

1. Get some inspiration from /org/alfresco/components/form/controls/workflow/activiti-transitions.ftl and create your own sign-transition.ftl FTL in which you add html and js code for your applet just the same way you did in that page of yours.
2. Remember to fetch document noderef from the workflow package items (Remember, last time you got that information from a get param on your page url)
3. Once you had successfully uploaded the document on your repo (after signing it with your applet), your JS callback should invoke the same logic as when you press the transition button (make an Xhr to the form processor webscript with task as itemKind and <taskId> as itemId ....)