my recent reads..

Atomic Accidents: A History of Nuclear Meltdowns and Disasters; From the Ozark Mountains to Fukushima
Power Sources and Supplies: World Class Designs
Red Storm Rising
Locked On
Analog Circuits Cookbook
The Teeth Of The Tiger
Sharpe's Gold
Without Remorse
Practical Oscillator Handbook
Red Rabbit
Showing posts with label OC4J. Show all posts
Showing posts with label OC4J. Show all posts

Monday, June 02, 2008

Request header rewrites with Java servlet filters - now on sourceforge

Some time back I posted a sample and discussion of request header rewrites with Java servlet filters, and I now finally got around to setting it up with its own sourceforge project.

RewriteRequestHeaderFilter is a Java servlet filter for request header rewrites according to regex rules specified in the servlet init parameters. It is packaged as a sample application and also jar that can be inserted into any arbitrary site.

SourceForge.net Logo

Monday, January 07, 2008

Backup your WebCenter Wiki. Yikes!

Previously I wrote about installing Oracle WebCenter Wiki, and also had my 2c worth.

One of the surprises is that it uses file storage by default. Database storage seems to be a work-in-progress (Toplink, hibernate and HSQLDB are all involved somehow), but not a documented option at this point.

Now if you are going to run WebCenter Wiki for real, that means as a dilligent system admin you want to be pretty sure you really understand how the file storage is working so you can have good backup and recovery procedures in place.

The documentation on Backing Up and Restoring Wiki Content sounds straight-forward. Just make a backup of the OC4J_HOME/applications/application_name/owc_wiki/pages folder.

But BEWARE!

Gotcha #1: Don't Forget Your Toothbrush!
A little poking around, and it is clear that this is NOT all you need to backup. I've noted content modifications in at least the following locations also:
OC4J_HOME/applications/application_name/owc_wiki/attachments [any uploaded attachments]
OC4J_HOME/applications/application_name/owc_wiki/templates [added/changed page templates]
The jzwiki backup/restore instructions also tell you to backup WEB-INF/classes/yawikiDB.script (WebCenter wiki is based on jzwiki)

So to be sure you haven't left anything behind, I'd suggest you probably want to be backing up the entire OC4J_HOME/applications/application_name/owc_wiki directory structure no matter what the doc says, and practice some restores!

Gotcha #2: Beware of EAR Re-deployments!
If you've worked with OracleAS/OC4J deployment before, and also noticed that the wiki content is stored in the application directory structure, I hope it rang an alarm!

Yes, if you touch or replace the owc_wiki.ear, then say goodbye to your wiki content and pray your backup is good and not too old! OC4J will redeploy the application and give you a nice fresh install, deleting all your wiki content and customisations;-)

I have always had a sneaking suspicion that there can be other circumstances in which OracleAS/OC4J may choose to redeploy an EAR. I can't really substantiate this, but I have had situations in production where EARs are redeployed for no immediately apparent reason.

This is of course very hairy for any non-trivial production deployment. The obvious first step would be to configure wiki content storage to some other location. This isn't documented however, and I'm not sure if its even possible with the product as it is.

So for now, it seems just backup or rsync deep and often, and enjoy the view as you walk the edge of the abyss;-)

WebCenter Wiki Future?
So far, there's no real news on what is planned for WebCenter Wiki in 11g. If you've read my posts, it will come as no surprise that my view is the 10g wiki is far from production-ready.

Which makes the question of what is in store for 11g so interesting. Maybe a significant revamp of the 10g (jzwiki) wiki? Maybe an internally developed replacement based on Content DB or UCM?

Or maybe something completely different? A collegue pointed me to Jive Clearspace today .. "discussions, blogs, files, instant messaging, and wiki documents under one unified umbrella" .. and since Oracle already have Jive Forums integrated in WebCenter it raises interesting possibilities!

Monday, December 17, 2007

WebCenter - First Thoughts. WATCH/HOLD

I just posted about installing Oracle WebCenter Wiki. So what do I think?

The current release of Oracle WebCenter is 10.1.3, and presents the first attempt at providing a Web 2.0 platform incorporating a (development) framework, integrated Services, and mobility ("WebCenter Anywhere"). The roadmap for 11g emphasises features focused on improving a developer’s productivity.

Having spent a bit of time going beyond the powerpoints and whitepapers, I guess I would emphasise the "..first attempt.." in the statement above. There are concerns I have about the product mission, the egregious approach to Open Source project integration, and a work-in-progress information architecture. While I'll be closely following Oracle's progress with WebCenter, my personal view is that a cautious "watch/hold" position is prudent.

WebCenter as an out-of-the-box Web 2.0 Experience?


The first reactions to WebCenter typically concerned it's positioning with respect to Oracle Portal. After many repetitions, I think Oracle have managed to get the message through that there's a distinct value prop for Portal (classic, monolithic Enterprise Portal) and WebCenter (platform and services for a loosly-coupled "Web 2.0" user experience).

However when it comes to WebCenter itself, there's still tension in the 10.1.3 version between two very different audiences/usages it targets.

Firstly, there's the developer audience. There's great emphasis by Oracle on WebCenter as a development framework in the whitepapers and podcasts (e.g. a great interview between Justin and Vince Casarez on Oracle Fusion Middleware Radio).

Oracle WebCenter injects new capabilities into the standard JavaServer Faces development environment to allow developers to create context-rich applications that satisfy these needs.

The catch is that at present developers are well served with JDeveloper and associated developer downloads. WebCenter's attraction seems mainly as a licence bundle of pre-existing Oracle products like Secure Enterprise Search, Content Database and the Mobility Server. There's nothing very Web 2.0 about all that, except that taken altogether, developers certainly could build Web 2.0-style.

In a wild daydream, you may have hoped WebCenter would be to Java what Rails is to Ruby. An opinionated, highly productive, pre-integrated framework. For now I'm afraid you will be disappointed.

The second audience I refer to is the IT Operations/Business audience. These are the people who don't expect to be coding, but want a quick Web 2.0 jumpstart for their enterprise. They don't have the time or inclination to take on the job of investigating, integrating and maintaining a hodge-podge of all the possible open source options. Basically they just want to install it, and are happy to pay for the convenience.

In other words, hoping that WebCenter is to Web 2.0 out-of-the-box experience what Astaro is to security appliances. Again, I'm afraid you would be disappointed for now. The 11g roadmap does include an out-of-the-box application to enable self-service community creation and management.

I guess my problem at this point is that I'm not convinced that Oracle have really decided where to take this. The development focus is clear, but it is not clear at all how much will end up being "only available WebCenter" - one could easily imagine WebCenter ending up as just a licensing artifact, with all the framework technology also available separately. And on the other hand, I have real concerns over the commitment to WebCenter becoming a killer "Web 2.0 appliance".

Personally I think Oracle may have misjudged the market on this. Of the 20 or so people I have had casual WebCenter discussion with, all bar two were just after a blog/wiki/discussions platform to install. That's hardly representative, but I have a feeling Oracle would be more succesful in the market if they just focused on delivering the "appliance", with all the supporting framework rolled into the JDeveloper/OracleAS/ADF base.

As it seems to be going, I wouldn't mind betting the primary audience for WebCenter will turn out to be Oracle's own Fusion Applications development team, with most customers just adopting it as a result of their Applications investment.

Open Source Closure?


I am actually much more concerned about the approach Oracle have taken to integrate 3rd party open source components into the WebCenter Services layer.

Take the "standards-based, open-source wiki server that is included with Oracle WebCenter" for example (words from the 10.1.3.2 Technical whitepaper).

Oracle chose yawiki/jzwiki for their wiki component, and it certainly was (at least partially) an open source project. But in WebCenter, we seem to be dealing with a forked and closed source version. My concerns:
  • Oracle is not shipping source code for the Java classes in owc_wiki.ear

  • While some classes are available from the yawiki project, Oracle have made enhancements (I suspect the main cases being the controller to incorporate AdfAuthentiation; JSR-168 and WSRP portlet support). These are not provided as open source.

  • yawiki includes some packages (like jZonic-web.jar which contains the main controller framework) which are purportedly open source, but for which there seems to be no source code available on the Internet [Postscript: I take this back having since discovered that the source of jzonic-web.jar is from the femto module in the jZonic framework]

  • The version of the wiki in WebCenter has been forked from yawiki. There is no procedure provided to merge the yawiki main line. WebCenter wiki users seem to be completely dependent on Oracle to merge enhancements in yawiki into WebCenter updates. Or not.

  • There are already enhancements in yawiki that are not available in WebCenter (e.g. TagClouds, RSS feeds of page changes). And no procedure for adopting these enhancements.

  • The WebCenter wiki seems to only be supporting the file-based HSQLDB (see backup/restore procedures for example), despite the fact that yawiki has or promised relational database support - even Oracle!

  • Despite the customisation that Oracle have done to yawiki, there's currently no integration the content database component in WebCenter for content storage or tagging.

So I guess you could say I was underwhelmed. From a practical perspective of a wiki implementer, there seems to be little upside in chosing to go with WebCenter wiki over its true open source father, yawiki, or others such as xwiki. But some big downsides to consider.

I'd much prefer see Oracle take a very different tack with the integration of "open source" components into WebCenter.

  • Ship mainline version of the open source project (don't close the source)

  • Provide Oracle enhancements (for security integration etc) as patches to the open source project. Do not combine a version of the open source project with Oracle-written customisations, and ship as "closed source".

  • Where possible, contribute the "WebCenter" patch to the open source project so that it can be maintained in sync with that project.

  • Ideally, reach as many projects in the same category as possible (i.e. support a few different wikis in WebCenter). A great way to do this would be to encourage the community to do it themselves. Yawiki is OK, but there are certainly some great alternatives out there.

Wherefore art thou, my blog?


The WebCenter whitepapers repeatedly mention phrases like "key technologies such as wiki, RSS, and blogs". The Datasheet still specifically claims WebCenter has a "wiki/blog server for collaborative authoring of documents and sharing of ideas".

Wiki - got, despite concerns already discussed. RSS - some, but not in all places that it counts (like the wiki!). But blog? It's MIA!

I have a sneaking suspicion that this is because yawiki used to have a blog capability, but the project team wanted to rethink the approach and dropped it. It is now in the planned feature list;-)

OK, these things happen. But in the WebCenter 11g roadmap, Oracle seem to have defined blogs out of existence - at least in terms of their relevance for the "Enterprise"! Was this to gloss over the missing blog feature in yawiki? Or is there a real belief that blogging is not part of the Enterprise 2.0 model? I'm not sure which view concerns me most!

Blog? blog? Where's the blog support?

It is even more curious when you consider (as Bex Huff recently reminded us) Oracle Universal Content Management has Blogs, Wikis, and RSS Feeds. And the roadmap for WebCenter 11g has UCM replacing Content DB.

Conclusions?


I've presented some pretty frank views on WebCenter after my "first look". Take my comments with a grain of salt though. I have not investigated the framework developer experience in detail yet. But I would say that Oracle has a lot riding on the 11g release. I hope they make it a more "opinionated" and cohesive release and get to knock down some of my concerns.

Sunday, December 16, 2007

WebCenter Wiki - Up and Running with OC4J 10.1.3

I finally had a chance to sit down with Oracle WebCenter recently, primarily to give the wiki functionality a test drive. I wanted to test in a virgin OC4J 10.1.3.3 container (as opposed to the Preconfigured Standalone OC4J) just to make it interesting and see all the moving parts. As far as I could discover, there's not a great deal of information available on the topic. In this post I'm going to chronical the specific installation procedure I used to get WebCenter Wiki running under OCJ4 10.1.3.3.

This is the end result we're after..


Documentation and Downloads

The documentation for WebCenter Wiki is a little obscure when it comes to installing in a "plain" OC4J container. It turns out to be pretty straight-forward, but just as mc said in the forums recently: "Oracle documentation just make it look difficult"!

I refered to the following materials for the install:

It can all get a bit confusing, but the following diagram illustrates the installation dependencies

There are four downloads required, all readily available from OTN:

Installation Procedure


I'm going to document the install steps here in the order I actually executed them. Variations are possible. I'm installing this under Windows XP, but the same applies on other platforms (just switch \ to / and use the appropriate command shell syntax).

1. Get the OC4J container running
To be precise, I am using "Oracle Containers for J2EE (OC4J) 10g Release 3 (10.1.3.3)". I won't cover in detail here. Basically you need to unpack and startup. The only thing you may need to configure are the port settings to avoid conflicts with other services.

2. Install PDK-Java
Details for installing the Oracle Portlet Development Kit are in index.html from the Oracle Portlet Container and PDK-Java 10.1.3.2 download. Assuming we've exploded the download into "G:\pdksoftware", the following performs the installation into the 10.1.3.3 home:

set ORACLE_HOME=G:\MyCache\oc4j_extended_101330
set J2EE_HOME=%ORACLE_HOME%\j2ee\home
set JAVA_HOME=C:\bin\jdk1.6.0_03
set PDKPATH=G:\pdksoftware
%JAVA_HOME%\bin\java -jar -classpath %ORACLE_HOME%\lib\xmlparserv2.jar -jar %PDKPATH%\pdk\jpdk\v2\pdkinstaller.jar %J2EE_HOME%


3. Install the Portal Container
From the same kit, we install the Portlet container

set ORACLE_HOME=G:\MyCache\oc4j_extended_101330
set J2EE_HOME=%ORACLE_HOME%\j2ee\home
set JAVA_HOME=C:\bin\jdk1.6.0_03
set PDKPATH=G:\pdksoftware
%JAVA_HOME%\bin\java -jar %PDKPATH%\pdk\portlet-container\portlet-server-install.jar %J2EE_HOME%


4. Install and Test the Sample Portlets
Using Enterprise Manager (http://localhost:8888/em or similar), go to the "Applications" tab and deploy the %PDKPATH%\pdk\jpdk\v2\jpdk.ear.

Once done, you should be able to successfully access the sample providers at http://localhost:8888/jpdk/providers/sample and get a page like the one shown on the right.

5. Install ADF
Explode the Oracle ADF Installer, which uses a silent "runInstaller" to install.

First, you'll need to update the adfinstaller.properties file, paying particular attention to OracleHome, DesHome and type values. This is from my install:

# The absolute path to the directory containing the ADF jars to be installed.
# This is the location of the directory where you unzipped the adfinsatller.zip
OracleHome = G:\\Sources\\incoming\\www.oracle.com\\OracleAS\\ADF\\adfinstaller

# Home directory for the destination application server,
# where the ADF Jars need to be installed
DesHome = G:\\MyCache\\oc4j_extended_101330

# Specify the platform for the Application Server where the ADF libraries need
# to be installed. This has to be one of the following choices.
# OC4J/AS/TOMCAT/JBOSS/WEBLOGIC
type = OC4J

And then run:
java -jar runinstaller.jar adfinstaller.properties

Restart OC4J at this point.

BUT, if you were like me, my container failed to start at this point with Error initializing server: Shared library "adf.oracle.domain" could not be found..

Annoying, but no panic. Edit ORACLE_HOME/j2ee/home/config/server.xml, re-order the shared library entry for "adf.oracle.domain" (I moved it to just after the "oracle.persistence" shared library) and try to startup again.

NB: after getting to this point, I find my OC4J does not completely shutdown after issuing a shutdown request via RMI %ORACLE_HOME%\bin\oc4j -shutdown -port %RMIPORT% -password %adminpwd%. Leaving that problem for another day.. :sigh:

6. Install Oracle Wiki (finally)
Using Enterprise Manager (http://localhost:8888/em or similar), deploy the owc_wiki.ear from the Oracle WebCenter Additional Services CD

7. Configuring Security
If you try and hit the wiki now (http://localhost:8888/owc_wiki) you will probably get a 500 error because security is not started or configured.

For this test, I'm just going to use the out-of-the-box Java SSO File-Based Security Provider.

In EM, startup the Java SSO application (look under the application group "Middleware Services > Other Services"). If you try and access the wiki now, you should see a login form but get an error when you submit because we need to generate the Symmetric Key. Every time I go to do this, following the Java SSO documentation, I struggle to find the right link in EM.

To be clear, in 10.1.3 look for "SSO Configuration" on the Administration tab of the OC4J container (below). Go to the page, make sure "Generate new symmetric key" is checked, select your key type, and click "Apply". You will be prompted to restart OC4J.


Browse to the wiki again and we have .. Success!


8. Adding users
Remember we're using the JAZN XML security provider rather than OID or other directory. Andreas had a nice post recently on how to Add a user to the JavaSSO, and that's what I need to do to add a personal account for myself..

set ORACLE_HOME=G:\MyCache\oc4j_extended_101330
set J2EE_HOME=%ORACLE_HOME%\j2ee\home
set JAVA_HOME=C:\bin\jdk1.6.0_03

%JAVA_HOME%\bin\java -jar %J2EE_HOME%\jazn.jar -adduser jazn.com paul password1
%JAVA_HOME%\bin\java -jar %J2EE_HOME%\jazn.jar -grantrole users jazn.com paul

JAZN is a bit dumb compared to using a real directory, so you need to restart OC4J again to pick up the new credentials.


And there we go. Oracle Wiki up and running in OC4J. Just 8 "simple" steps;-)

Wednesday, March 28, 2007

Request header rewrites with Java servlet filters

A collegue and I have been looking at a setup with completely separate Oracle Portal (with SSO) and Oracle Collabsuite installations, and we wanted a simple way to have users automatically logged into Collabsuite after logging into Portal. If you are not familiar with Collabsuite, just think "J2EE" application.

Normally you would deploy a consolidated infrastructure, which makes this a no-brainer, but for various reasons we wanted to keep these two environments quite separate.

The details of how we did this are not really pertinent, but the bottom line is that we had everything sorted with one exception: the LDAP realm on Portal did not match Collabsuite. Everything was nicely working except the Collabsuite web applications keeled over, because the "osso-user-dn" request header set by the Portal SSO did not match Collabsuite.

If only we could hack/rewrite the osso-user-dn to fixup the realm part!

Now with Apache 2.0, this is probably quite easy by using the RequestHeaders directive in httpd.conf. That didn't exist in Apache 1.3, which unfortunately is what we are using.

This lead me to investigate what could be done at the J2EE level, and I discovered for the first time the servlet filter features in the Servlet API 2.3.

There are a few good tutorials floating around the web, such as Jason Hunter's JavaWorld article, but nothing I've found yet specifically demonstrates header rewrite.

Its pretty simple though. I've put together a demo RewriteRequestHeaderFilter with sources (download: RewriteRequestHeaderFilter-1.0-src.zip). It contains a complete demo site, but is also packaged and ready to insert into any arbitrary web application (just deploy the jar and fiddle the site's web.xml).

So, if you ever find yourself wanting to fiddle request headers in the J2EE environment and don't have "external" options, the RewriteRequestHeaderFilter could be just the ticket.

Postscript 2008-06-02: I've moved this to its own sourceforge project now.

Sunday, January 07, 2007

AXIS Revisited on OC4j - AXIS 2

Apache Axis2 is the core engine for Web services. It is a complete re-design and re-write of the widely used Apache Axis SOAP stack to build on the lessons learnt from Apache Axis. Version 1.1 was released in Nov'06. My first simple test was to update my deployment on Oracle OC4J.
Happily, it deployed just as easily as the original Axis, as I reported in a previous post.

Deployment of the Axis2 webapp is a little different, but just as straightforward. This is what I did:
  1. Download the Standard Binary Distribution and explode into a local folder
  2. In the $AXIS2_HOME/webapp directory, use ant to build the war file: ant create.war
  3. This creates the $AXIS2_HOME/dist/axis2.war file
  4. edit $ORACLE_HOME/j2ee/home/config/application.xml to add <web-module id="axis2" path="file:/d:/axis2/dist/axis2.war"/>
  5. edit $ORACLE_HOME/j2ee/home/config/http-web-site.xml to add <web-app application="default" name="axis2" root="/axis2"/>

And that's it. Axis2 up and running in my OC4J home at http://localhost/axis2/

Wednesday, December 14, 2005

Running Cocoon with Oracle OC4J

After testing AXIS , I quickly moved on to check the latest Cocoon 2.1.8 release. I'd tried getting earlier versions running with OC4J but given up due to the xerces, xalan and jdk certification mix - it was hell. Fortunately Cocoon 2.1.8 worked (almost) perfectly first time with Oracle Application Server Containers for J2EE 10g (10.1.2.0).

After building Cocoon, I simply used a manual installation with the standalone version, which simply required $ORACLE_HOME/j2ee/home/config/application.xml and $ORACLE_HOME/j2ee/home/config/http-web-site.xml to include the Cocoon webapp.

The only "fixup" required - and this is for a non-fatal SAX processing error - is to force Cocoon to use the XML parsers etc that are included in the Cocoon distribution instead of the default (Oracle) parsers included in the OC4J distribution. The fix is to force "search-local-classes-first. To do this edit $ORACLE_HOME/j2ee/home/application-deployments/<your Cocoon deployment path>/orion-web.xml. Uncomment the line:
<web-app-class-loader search-local-classes-first="true" include-war-manifest-class-path="true" />

Tuesday, December 13, 2005

Running AXIS with Oracle OC4J

AXIS 1.3 was released back in October, so I thought it was about time to test it out with Oracle Application Server Containers for J2EE 10g (10.1.2.0). Good news .. all went absolutely smoothly, no frigging about with jar files at all.
Since Axis is a simple web module, manually deploying to Standalone OC4J is straightforward. After putting the web application files in place, register the module in application.xml and the web app root in http-web-site.xml:

  1. copy the axis webapp directory into $ORACLE_HOME/j2ee/home/applications/axis
  2. edit $ORACLE_HOME/j2ee/config/application.xml to add <web-module id="axis" path="../applications/axis"/>
  3. edit $ORACLE_HOME/j2ee/config/http-web-site.xml
    to add <web-app application="default" name="axis" root="/axis"/>
At this point, I had the AXIS welcome page coming up nicely at http://localhost/axis/. For the next 5 minutes, I played around with some drop-in web services. Very cool and easy!