I need some clearification on the Workflow with OSGi Servlets and HTML Frontend. I am an old school HTML and Javascript programmer and new to all this OSGi, Ajax and JQuery stuff. I am working on an own OSGi server implementation. I created my OSGi Plugin with eclipse following this guide: https://docs.jboss.org/author/display/AS7/Creating+a+new+OSGi+Bundle+using+Eclipse
My Servlet is working perfectly fine so far. It is supposed to handle Database Requests. I coded a Website with HTML and Javascript(JQuery) from which I want to fire Ajax Requests to the Servlet.
My Problem is, that I have no idea how to integrate my HTML/Javascript/JQuery stuff into the OSGi Servlet. I tried to register it as resources within the Servlet Bundle, which worked fine but I'm not sure if this is a very elegant way... It needs to run on the same OSGi Server, but does it need to be in the same Bundle as the Servlet or in its own?
Which kind of project would I create in eclipse for the UI Bundle and how would I export it?
The only thing you need is to make your web resources (html, javascript and css files) available on a url. You could do this manually by hand with a Servlet. If you package the web resources in the bundle, you can get an InputStream to those resources from the BundleContext.getBundle().
An easier approach is to use the Amdatu ResourceHandler. This is a so called "extender" that has the sole purpose of making resources from bundles available on an url.
You need to do the following:
1) Make sure that your resources are packaged in the bundle
2) Add two extra headers to the manifest of the bundle that contains the resources
X-Web-Resource-Version: 1.0
X-Web-Resource: path/to/resources
3) Add the Apache Felix Whiteboard and Amdatu ResourceHandler bundles to your runtime.
Documentation can be found on the Amdatu website: http://amdatu.org/components/web.html (scroll to the bottom of the page).
The Pax Web project might be of interest for you, anyway there is a sample on how to publish resources available.
This sample should also work similar HTTP-Services like Apache Felix HTTP-Service, probably needs some minor tweaks :) .
Related
I'm building "read-only" webservice (Google Cloud Endpoints as backend for an Android App) so I created a project using maven:
mvn archetype:generate -Dappengine-version=1.9.10 -Dfilter=com.google.appengine.archetypes:
and selecting archetype hello-endpoints-archetype to have some sample code to work on.
This works well and my app is correctly calling the service as expected (and the service is correctly supplying the data in return).
Now I have to implement an "update" service to periodically (4 to 6 times a dya) update the data supplied to the app. So I added a servlet to my project to be called by cron. Trouble is: one of the library used during this update uses multi-threads which cause an AccessControlException to be thrown because apparently multi-thread is only allowed in backend modules...
But after having read dozens of pages on google app engine, I still don't know how to "break" my application into modules so that particular servlet would be run as a backend module while the already existing servlet keep working as they do. So far, all I got was that I should use an EAR application composed of several WAR modules, but I don't even know if my current application is an EAR or not...
I'm using Eclipse Luna, maven 3.2.1 (embeded with Eclipse), google app engine 1.9.10, writing in Java
Could anyone please help me by explaining the directory structure and/or configuration files I have to look at, modify and/or add?
Thanks for any help provided!
You can find an example of multi-modules project here.
However, note that even in backend modules the threading is limited to 50 threads, as stated here.
We run Restlet 2.1 in an OSGi environment (Equinox) as bundle (ie. not as library within a bundle). The problem is that the Restlet Engine does not detect helpers (like converters) that are provided by Restlet extensions. Specifically, the EngineClassLoader#getResources() call does not return any result. The extensions are also deployed as OSGi bundles in the target platform.
Is automatic converter registration actually supposed to work within OSGi environments?
In fact, Restlet supports such feature thanks to a dedicated activator (see the Activator class in the package org.restlet.engine.internal).
This activator introspects bundles to find out the following things:
servers corresponding to registered servers
servers corresponding to registered clients
authenticators corresponding to registered clients
converters
Be aware that to use this feature, we must use the OSGi edition of Restlet since it's the only that has the MANIFEST file of the org.restlet bundle with the activator class specified. Otherwise you don't have to care about the bundle loading order...
Hope it helps you.
Thierry
Unless the Restlet-bundle explicitly imports the packages that contain the extensions (and I doubt it does, and it shouldn't), it wouldn't be able to load them, because bundles have isolated class-spaces.
A possible solution would be to provide the extensions as fragments attached to the Restlet-bundle. Thus, if you make it use the bundle-classloader (the documentation says this can be done by setting the Engines classloader), it would be able to load classes from the fragments.
Indeed it doesn't quite work for OSGi, as it depends on the ability to see the entire class space.
The way to do this in OSGi would be to use the service registry for the extensions, but that only works for OSGi aware libraries.
There is some help on the way: In the recently released OSGi 5 (Service Loader Mediator) there will be support to 'bridge' META-INF/services (I don't know if Restlet uses those, though) onto OSGi services, so 'legacy' libraries should work well within OSGi.
There is an implementation in Apache Aries called Spi-Fly. I looked at it briefly a while back. It might do the trick for you, it might not.
I'm using a Content Repository (Adobe CQ5) that has Apache Sling underneath. I'd like to render web pages using FreeMarker instead of JSP.
For that to work should I upload the OSGi Freemarker extension to Sling, which is to be found in the contribution part of Sling source code, or should I upload an OSGi version of Freemarker instead? Both jars implement the interface javax.script.ScriptEngineFactory so I don't know which one to use, or to upload both.
I managed to get Freemarker working on CQ5.3 by doing the following:
get the source from svn checkout http://svn.apache.org/repos/asf/sling/trunk sling
go to the contrib/scripting/freemarker and remove all the logging and slf4j references from FreemarkerScriptEngine.java - it throws a 500 error due to NoClassDefFoundException - I think there is a conflict between CQ5 and a version of slf4j included in Freemarker (I didn't dig to find out what was wrong)
build it and install, it should appear in the Sling console under bundles and in the 'script engines' page, and let you use .ftl scripts now.
I did it slightly differently by creating the bundle inside CQ5, importing the code and adding a stock freemarker.jar into the bundle but this should work too as it's basically the same thing.
The problem I had was that the script engine does get listed but the logging prevents it from running, that's why you need to remove the log & slf4j from the engine.
I don't know about the OSGi version of Freemarker; we created our own bundling of Freemarker specially for Sling. If you have success using the OSGi version of Freemarker let us know ;-)
Testing is easy: Just install the bundle through the Web Console and check for the supported Script Engines in the Web Console Configuration Status. If you see the Freemarker Engine listed there, it should work.
pros! Looks like basic question, but I just can't find what I am looking for.
I have Equinox and want to run Spring in it (bootstraped in Servlet).
I can't use dm-server, nor can I use the http-bridge, just plain standalone Equinox.
On the other side, using plugin.xml http registry servlet extension is not good enough, since I need the fully-blown web.xml in order to bootstrap Spring.
Where should I dig?
Thanks!
Baruch.
To support "traditional" (aka legacy) web.xml file for webapp deployment you need an implementation of the OSGi Web Applications spec, part of the OSGi R4.2 Enterprise spec. This will allow you to deploy "Web Application Bundles" (WABs) or even plain old WAR files.
There are implementations of this container in both the Eclipse Gemini and Apache Aries projects. Note that the one found in Eclipse Gemini is also found in Eclipse Virgo (the new name for dm Server). You may find that using Virgo will give you a cleaner out-of-the-box experience rather than having to assemble components yourself. Then again I fully understand if it also provides an awful lot more than you really want!
An alternative to this is to move away from web.xml and to register servlets programmatically with the OSGi HttpService. This should be a lot more lightweight, but I don't know whether it will work for "bootstrapping Spring" — quite a vague requirement.
Or you can use the tomcat OSGi bundle that will make you to be able to load bundles as war files. The problem there is that your web bundle's name must end with ".war" and all that stands before that suffix is the application name. So if your bundle's name is myapp.war you connect to it with http://your.server.cc/myapp (and as far as i know there's no way to change that)
I would like to use an ajax toolkit/framework like ZK (www.zkoss.org) or GWT. But I don't know whether it's possible to bundle resources in a JAR? Do you know which one support such resource loading?
Not sure what your goal is, but if its to bundle a web application into one file, then you can do that with a WAR file - assuming your deploying onto a java webcontainer like tomcat or jboss.
My goal is to summarize the Java-classes and also their Templates-files for the view of various application modules, each in one Java-Jar-File. These modules I use in another application, which of course I summarize in a WAR-File for Deployment. I would like to know which ajax-Framework/Toolkit does support this.
Take a look at http://www.ztemplates.org which is simple and easy to learn. This one allows you to put all related templates, javascript and css into one jar and use it transparently. Means you even have not to care about declaring the needed javascript in your page when using a provided component, as the framework does it for you.