topic Re: activiti-rest & -explorer sharing process engine? (v5.7) in Alfresco Archive

activiti-rest & -explorer sharing process engine? (v5.7)

f3lix — Mon, 12 Sep 2011 15:34:45 GMT

Hello,in the previous versions of Activiti (<= 5.6) my understanding was that there was one instance of a process engine that was shared using the REST interface; activiti-probe and activiti-explorer would use the REST interface to manipulate the state of the process engine.Now, in Activity 5.7 i

Re: activiti-rest & -explorer sharing process engine? (v5.7)

trademak — Mon, 12 Sep 2011 19:24:27 GMT

Hi,

Yes you're right, both web applications have a process engine instance.
In a production setup this is probably not the best setup. But it's really easy to combine the explorer and REST application into one web application using the same process instance.

Best regards,

Re: activiti-rest & -explorer sharing process engine? (v5.7)

f3lix — Wed, 14 Sep 2011 07:51:49 GMT

Ok, this information saved me some time. Now, I simply combined activiti-rest and -explorer as you proposed. Works fine as far as I can tell.

Cheers,
Felix

Re: activiti-rest & -explorer sharing process engine? (v5.7)

vnama — Wed, 18 Jan 2012 15:40:59 GMT

Can anyone explain how I can combine these two? I am new to web application deployment. I'd like to be able to upload a bpmn20.xml file through the explorer UI and be able to get those process definitions through the REST API. Is there a tutorial on how to combine the web apps so that they use a single process instance?

Re: activiti-rest & -explorer sharing process engine? (v5.7)

trademak — Thu, 19 Jan 2012 07:27:40 GMT

Hi,

I've described it in Activiti in Action with an example project.
But it's really easy, just combine the web.xml and the Spring configurations and combine the classes from both web apps.

Best regards,

Re: activiti-rest & -explorer sharing process engine? (v5.7)

vnama — Wed, 01 Feb 2012 21:52:12 GMT

Thank you for the insight. I was hoping the web apps did not each have a process engine, but you were right in that it was fairly easy to combine them. Thank you for the response.

Re: activiti-rest & -explorer sharing process engine? (v5.7)

damokles — Wed, 08 Feb 2012 12:33:01 GMT

Hi,

I've described it in Activiti in Action with an example project.
But it's really easy, just combine the web.xml and the Spring configurations and combine the classes from both web apps.

Best regards,

Hi Tijs,

I could not find the example in the svn repo, and in Section 8.1.2 of the book it is only mentioned that it is possible without explaining how. Did I miss something?

Re: activiti-rest & -explorer sharing process engine? (v5.7)

b_schnarr — Tue, 10 Dec 2013 10:21:30 GMT

Hi,

same here. I would like to combine the activiti explorer and the rest web application for activiti 5.14. I am very new to activiti. We need a shared state between explorer and rest web app. I bought and read Activiti in Action. There is described that it is possible to combine these two apps, but without further details. It would be a great help if there was a tutorial or an out-of-the-box appliance so that user without so much programming and activiti skill can easier start with activiti. I am of the opinion that this requirement (sharing one process instance for explorer and rest) is needed by nearly all users with a stand alone deployment.

Thanks and best regards
Ben

Re: activiti-rest & -explorer sharing process engine? (v5.7)

frederikherema1 — Tue, 10 Dec 2013 12:56:19 GMT

It's the same as you whould combine ANY 2 webapps. Steps involved (high-level):
1) Expand both war's (if not already exploded)
2) Merge all folders into one (ignoring web.xml), incuding libs, classes, …
3) Create a single web.xml file, containing both the servlets and filters from WEB-INF/web.xml-files from both war-files. normally, this is a straight forward copy-paste action of the relevant sections.
4) Enjoy!

Re: activiti-rest & -explorer sharing process engine? (v5.7)

ndup0nt — Fri, 27 Feb 2015 16:48:25 GMT

Also the dispatcher servlet for both webapps is mapped on /service/*

So you have to merge the Spring config as well. Also we can't assume there won't be any URL conflict, can we ?

Re: activiti-rest & -explorer sharing process engine? (v5.7)

jbarrez — Sat, 28 Feb 2015 10:07:54 GMT

Yes, there wont be a conflict.

Re: activiti-rest & -explorer sharing process engine? (v5.7)

ays — Wed, 18 Mar 2015 11:00:37 GMT

Hello,

Did anyone managed to produce combined webapp based on 5.17?
After adding of libs and classes from rest webapp into explorer and adding WebConfigurer filter into explorer web.xml I got NullPointerException (see below).
I don't have experience with the Spring, but I guess that it is related to Spring content initialization. Any hints? *help*
<code>
Mar 18, 2015 12:42:47 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class org.activiti.rest.servlet.WebConfigurer
java.lang.NullPointerException
        at org.activiti.rest.servlet.WebConfigurer.initSpring(WebConfigurer.java:71)
        at org.activiti.rest.servlet.WebConfigurer.contextInitialized(WebConfigurer.java:54)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1247)
        at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1898)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
</code>

Re: activiti-rest & -explorer sharing process engine? (v5.7)

jbarrez — Tue, 24 Mar 2015 12:45:07 GMT

I think the problem is that you now have multiple WebConfigurer classes in the web.xml, right? I dont believe that will work.

To make a combination, you would need to create a new webapp yourself, and combine the Webconfigurer for both endpoints. But i dont think that has been done before.

Re: activiti-rest & -explorer sharing process engine? (v5.7)

ays — Wed, 25 Mar 2015 20:56:20 GMT

Joram, thank you very much for this comment! It really helped to merge two apps
Will be playing with the result during the next few days. Hopefully the thing will not only start but also work as expected (quick tests shown no issues with explorer part).
Thank you so much for what you are doing!

Re: activiti-rest & -explorer sharing process engine? (v5.7)

ays — Fri, 27 Mar 2015 19:07:02 GMT

Just to confirm that the result acheived. For those who would attempt to merge explorer and rest 5.17:
* get sources for classes from WEB-INF/classes/org
* merge them one by one. I created a different package, then copied there explorer part and then added parts from rest which was missing.
* you can skip Demo related classes
* Change web.xml, make sure that it references new classes
* Merge WEB-INF/lib
* replace WEB-INF/classes with the newly created

This should do the job. Good luck to all of you!

Re: activiti-rest & -explorer sharing process engine? (v5.7)

jbarrez — Tue, 31 Mar 2015 08:50:17 GMT

Thanks for posting this back. i'm sure this will be helpful to a lot of people!

Re: activiti-rest & -explorer sharing process engine? (v5.7)

andrealuciano71 — Fri, 28 Aug 2015 14:33:59 GMT

Hi, I've just added activiti-rest API to activiti-explorer.

The merger is not so complex, but it heavily depends on the sources which have been changing throughout the different actitviti releases.
The question of merging rest and esplorer has been resumed different times in the forum, in my opinion it should be considered the opportunity of including the activiti-rest API in the next releases of activiti-explorer.

In a nutshell, what I did to add the API to release 5.17 was:

- copying the following jars from activiti-rest's WEB-INF/lib to activiti-explorer:

      activiti-rest-5.17.0.jar
      commons-fileupload-1.2.2.jar
      jsr250-api-1.0.jar

- downloading the source of activiti-webapp-explorer2 and activiti-webapp-rest2 from:

       http://repo1.maven.org/maven2/org/activiti/activiti-webapp-explorer2/
       http://repo1.maven.org/maven2/org/activiti/activiti-webapp-rest2/

- Copying from activiti-webapp-rest2 the files below and just changing the package to org.activiti.explorer.conf:

    RestConfiguration.java
    SecurityConfiguration .java

- Then the modification regarding Spring MVC dispatcher to apply to activiti-webapp-explorer2 to inject the rest api:

   One solution was to append "org.activiti.rest.exception" and "org.activiti.rest.service.api" to the ComponentScan annotation arguments in the class DispatcherServletConfiguration.java:
<code>
   @ComponentScan({"org.activiti.rest.editor", "org.activiti.rest.diagram", "org.activiti.rest.exception", "org.activiti.rest.service.api"})
</code>

   with the negative side effect that anyone could invoke the API without being authenticated, because /activiti-explorer/service is not protected.

   The second possibility was to create a subcontext of "/service", let's say "/service/api", protected by the basic authentication (actually if the authentication is enabled on /service the diagram-viewer ceases to work), and configure the rest API with this context:

   So I copied DispatcherServletConfiguration.java from activiti-webapp-rest2 to activiti-webapp-explorer2 as DispatcherServletAPIConfiguration.java and then I modified WebConfigurer.java:

<code>
public void contextInitialized(ServletContextEvent sce) {
    …
    initSpring(servletContext, rootContext);
    initSpringAPI(servletContext, rootContext);

    EnumSet<DispatcherType> disps = EnumSet.of(DispatcherType.REQUEST, DispatcherType.FORWARD, DispatcherType.ASYNC);
    initSpringSecurity(servletContext, disps);

    log.debug("Web application fully configured");
}
….
/**
* Initializes Spring and Spring MVC for /service/api context (activiti-rest services)
*/
private ServletRegistration.Dynamic initSpringAPI(ServletContext servletContext, AnnotationConfigWebApplicationContext rootContext) {
    /** ADD /api dispatcher */
    log.debug("Configuring Spring Web application context (activiti-rest API)");
    AnnotationConfigWebApplicationContext dispatcherServletAPIConfiguration = new AnnotationConfigWebApplicationContext();
    dispatcherServletAPIConfiguration.setParent(rootContext);
    dispatcherServletAPIConfiguration.register(DispatcherServletAPIConfiguration.class);

    log.debug("Registering Spring MVC Servlet (activiti-rest API)");
    ServletRegistration.Dynamic dispatcherAPIServlet = servletContext.addServlet("dispatcher-rest", new DispatcherServlet(dispatcherServletAPIConfiguration));
    dispatcherAPIServlet.addMapping("/service/api/*");
    dispatcherAPIServlet.setLoadOnStartup(1);
    dispatcherAPIServlet.setAsyncSupported(true);

    return dispatcherAPIServlet;
}

/**
   * Initializes Spring Security for /service/api context (activiti-rest services)
   */
private void initSpringSecurity(ServletContext servletContext, EnumSet<DispatcherType> disps) {
    log.debug("Registering Spring Security Filter");
    FilterRegistration.Dynamic springSecurityFilter = servletContext.addFilter("springSecurityFilterChain", new DelegatingFilterProxy());

    springSecurityFilter.addMappingForUrlPatterns(disps, false, "/service/api/*");
    springSecurityFilter.setAsyncSupported(true);
}
…
</code>

To finish, compile the modified activiti-webapp-explorer2 and copy the classes to activiti-explorer/WEB-INF/classes.

The API are accessible asking for authentication at "/activiti-explorer/service/api", such as in this example :

   http://localhost:8080/activiti-explorer/service/api/repository/process-definitions

It would be also possible to configure a prefix different from "/activti-explorer/service" but this means impacts on the activiti-explorer's org.activiti.explorer.filter.ExplorerFilter class which contains the context exceptions to the default activiti explorer authentication based on form (ignoreList variable).

   Bye.

   Andrea

Re: activiti-rest & -explorer sharing process engine? (v5.7)

vasile_dirla — Fri, 28 Aug 2015 19:39:31 GMT

Hi,
Thank you Andrea for your contribution to this forum.

Re: activiti-rest & -explorer sharing process engine? (v5.7)

srini_n — Tue, 22 Sep 2015 13:39:14 GMT

Hi,

I am new to Activiti and would like to understand this topic better to make an informed decision.

1. What are the benefits of merging Activiti-REST and Activiti-Explorer? Why do we need a single Activiti-Engine instance? If the 2 engine instances share state via DB what are the benefits of combining them? The flip side of merging them is that upgrades will get complicated and will require manual work that is error prone.
2. My understanding is that Activiti-Engine embedded within the application is preferable because of transaction management. Using REST will create a Transactions boundary where one may not be able to guarantee data integrity.

Appreciate any inputs on the above 2 points.

Thanks,
srini

Re: activiti-rest & -explorer sharing process engine? (v5.7)

ratik_singhal — Thu, 30 Mar 2017 13:54:44 GMT

Hello vnama,

Go to this url, I have written a tutorial that exactly match your requirement.

How to configure Activiti Explorer and REST to use the same database