Pushing files to WebLayout from an UCM Component

Two days ago I got a question from a friend that wanted to know how to push files to the weblayout from withing a UCM (WebCenter Content) component. We knew it was no longer supported to do things the way we used to in 10g, but how it should be done was not immediately obvious. So I set out on a quest to find out. The two resources I found most helpful were Kyle's blog (that touches this subject briefly) and most importantly the 11g UCM default components (those in the middleware home), especially the YahooUserInterfaceLibrary and the ContentFolios component.

Note: Although most weblayout publishing features are already available in UCM 10g, not all features in UCM 11g are supported in UCM 10g. This article will focus on how to properly setup resource publishing for 11g and may therefore not work as expected on UCM 10g.

When to use WebLayout Publishing

A lot of times when you develop some functionality in an UCM component you will end up making UI templates which use external resources like images, cascading stylesheets and Javascript files. These external resources are the primary candidates for weblayout publishing. Of course you could put the CSS and Javascript inline in your templates, but having them as external resources gives us caching possibilities.

Different types of WebLayout Publishing

There are basically two ways of publishing resources to the weblayout, either copy files from the component to the weblayout (static files) or generate the weblayout files based on an iDoc template (dynamic files).

In UCM there are three mechanisms to do weblayout publishing, which will be discussed one at a time.

• Publishing Static Files
• Publishing Dynamic Files
• Bundling Published Files

But first we need to touch the concept of 'class' which is used by all three mechanisms. A class can be thought of as a package, a namespace or a tree structure (like DOM), each part separated by a ':' (colon). An example will make it all clear (at least I hope so).

image:companyX:functionalityZ

The class name in the above example I could use for all images at company X for functionality Z. It is primarily a grouping mechanism (at least as far as I understand). It will be more obvious once we start using it, I promise.

Publishing Static Files

Static resources will just be copied as-is to the desired weblayout location (this is most like the old way of doing this by adding a weblayout entry in the build settings). These resources will only be rarely published automatically (think disabling/enabling component).

You can publish static files by creating a static table in the Component Wizard that merges with 'PublishedStaticFiles' (you can pick it from dropdown list). The tables has the following columns:

• srcPath: the source path to the file or directory contained in the component, relative to the component directory (field is idoc evaluated)
• path: the target path to a file or directory in the weblayout directory, relative to the weblayout directory (field is idoc evaluated)
• class: the class of this resource, as discussed above
• loadOrder: the load order of this resource, the higher the load order, the later it will be published, allowing you to override already published resources
• doPublishScript: a piece of idoc script that should set the idoc variable 'doPublish' (it defaults to 0 (false) which means the resource will not be published) (obviously this field is idoc evaluated)
• canDeleteDir: whether or not the directories in the 'path' can be deleted when the component is disabled/uninstalled (note: it should only delete a directory when there is no longer a published resource using that directory)

Time for an example:

<@table MyPublishTestComponent_PublishedStaticFiles@>


 
srcPath
 
path
 
class
 
loadOrder
 
doPublishScript
 
canDeleteDir



 
publish/img/icons/
 
images/publishtest/
 
image:publishtest:icons
 
10
 
<$doPublish = 1$>
 
1


 
publish/img/other/someOtherImage.png
 
images/publishtest/someOtherImage.png
 
image:publishtest:other
 
10
 
<$if isTrue(someConfigVar)$><$doPublish = 1$><$endif$>
 
1


 
publish/js/utils.js
 
resources/publishtest/js/utils.js
 
javascript:publishtest:utils
 
10
 
<$doPublish = 1$>
 
1


<@end@>

The above example does the following:

• always publishing all the files from a directory in my component ($MYCOMPONENT/publish/img/icons/) to a weblayout directory ($WEBLAYOUT/images/publishtest/).
• only when someConfigVar is set to true publishing a specific image ($MYCOMPONENT/publish/img/other/someOtherImage.png) to the weblayout ($WEBLAYOUT/images/publishtest/someOtherImage.png)
• always publishing a javascript utility ($MYCOMPONENT/publish/js/utils.js) to the weblayout ($WEBLAYOUT/resources/publishtest/js/utils.js)

Publishing Dynamic Files

Dynamic resources are idoc templates that are evaluated and the result is copied to the desired weblayout location. These resources will be published regularly (at startup).

You can publish weblayout files by creating a static table in the Component Wizard that merges with 'PublishedWeblayoutFiles' table (again, you can pick it from the dropdown list). The tables has the following columns:

• template: the name of the template (defined in a component)
• srcPath: the source path to the file contained in the component, relative to the component directory. This field is only used when the template column is empty (this field is idoc evaluated)
• path: the target path to a resulting file in the weblayout directory (idoc evaluated), relative to the weblayout directory
• class: the class of this resource, as discussed above
• loadOrder: the load order of this resource, the higher the load order, the later it will be published, allowing you to override already published resources
• doPublishScript: a piece of idoc script that should set the idoc variable 'doPublish' (it defaults to 0 (false) which means the resource will not be published) (obviously this field is idoc evaluated)

Time for an example:

<@table MyPublishTestComponent_PublishedWeblayoutFiles@>


 
template
 
srcPath
 
path
 
class
 
loadOrder
 
doPublishScript



 
MY_PUBLISH_TEST_CSS
 

 
resources/publishtest/css/base.css
 
css:publishtest:base
 
10
 
<$doPublish = 1$>


 
MY_PUBLISH_TEST_VALIDATIONS
 

 
resources/publishtest/js/validations.js
 
javascript:publishtest:validations
 
10
 
<$doPublish = 1$>


 

 
templates/constants.idoc
 
resources/publishtest/js/constants.js
 
javascript:publishtest:constants
 
10
 
<$doPublish = 1$>


<@end@>

The above example does the following:

• always publish the result of the MY_PUBLISH_TEST_CSS to a weblayout file ($WEBLAYOUT/resources/publishtest/css/base.css).
• always publish the result of the MY_PUBLISH_TEST_VALIDATIONS to the weblayout file ($WEBLAYOUT/resources/publishtest/js/validations.js)
• always publish the result of the specified template file ($MYCOMPONENT/templates/constants.idoc) to the weblayout file ($WEBLAYOUT/resources/publishtest/js/constants.js)

Publishing Bundles

Now this is where the fun really starts and where the use of classes finally make sense. Bundle publishing packs together multiple published resources into a single file (a bundle). As far as I know this works only for Javascript and CSS resources (starting with class 'javascript' or 'css').

To use this functionality by creating a static table in the Component Wizard that merges with 'PublishedWeblayoutBundles' table (again, you can pick it from the dropdown list). The tables has the following columns:

• bundlePath: the target path to a resulting file in the weblayout directory, relative to the weblayout directory
• includeClass: include certain classes from the bundle
• excludeClass: exclude certain classes from the bundle
• loadOrder: the load order of this resource, the higher the load order, the later it will be published, allowing you to override already published resources

Time for an example:

<@table MyPublishTestComponent_PublishedWeblayoutBundles@>


 
bundlePath
 
includeClass
 
excludeClass
 
loadOrder



 
resources/publishtest/js/bundle.js
 
javascript:publishtest:
 

 
10


<@end@>

The above example does the following:

publish all resources with the class 'javascript:publishtest:', in this article it'll combine the statically published utils.js file ($WEBLAYOUT/resources/publishtest/js/utils.js), the dynamically generated validation.js file ($WEBLAYOUT/resources/publishtest/js/validations.js) and the dynamically generated constants.js ($WEBLAYOUT/resources/publishtest/js/constants.js) into a single javascript file, bundle.js ($WEBLAYOUT/resources/publishtest/js/bundle.js).

Thanks for reading through all my rambling, I hope you've found something useful.

Gain access to UCM log messages

The Problem
If you have implemented the LogWriter interface in UCM 10g (or before) you may have noticed it does not quite work in UCM 11g as expected (most error log messages never seem to come through the LogWriter implementation, though some low level stuff does). An example of the LogWriter use can be found in the RssFeeds component that is freely available on OTN (for 7.5 and 10g). This post will discuss the UCM 11g (and probably also UCM 10g) approach for gaining access to the messages that are written to your logs.

UCM 10g - LogWriter interface
The LogWriter interface is a very simple interface with just one method. The code below shows a very typical LogWriter implementation. The RssFeeds component contains a more detailed implementation of how you could use this interface.

public class SampleLogWriter implements LogWriter {
 
 public SampleLogWriter () {
  // do your initialization here
 }

 @Override
 public void doMessageAppend (
  final int logLevel,
  final String message,
  final LogDirInfo context,
  final Throwable exception
 ) {
  try {
   // do something with your logging here 
   // note: don't log anything from here on! (trace is safe)
  } catch ( final Throwable someException ) {
   someException.printStackTrace();
  }
 }

}

And yes, you want to catch ALL possible RunTimeExceptions/Errors, otherwise you are very likely to end up in an infinite loop if your code for some reason throws something (like a NullPointerException or an AssertionError). Obviously, don't log an error in your log message handling code either.

To configure its use you had to create an entry in your content server configuration (config.cfg) as described below and it would work.

ExtraLogWriter=my.SampleLogWriter

UCM 11g - ReportHandler interface
As described in the introduction, the LogWriter no longer functions propertly in UCM 11g. Luckily there is a good alternative that gives you access to all messages written to the logs... and even more! Lets show you a very typical implementation of the ReportHandler interface.

public class SampleReportHandler implements ReportHandler {

 public SampleReportHandler() {
  // you may do some initiation of your report handler here
 }

 @Override
 public void init ( final Map settings ) {
  // you can use some settings here to initialize (further)
  // (called prior to the first call to the message() method) 
 }

 @Override
 public boolean isActiveSection ( final String traceSection ) {
  // whether or not the given tracing section is active in this
  // report handler
  return true;
 }

 @Override
 public void message (
  final String application,
  final String section,
  final int logLevel,
  final IdcMessage message,
  final byte[] bytes,
  final int offset,
  final int length,
  final Throwable throwable,
  final Date date
 ) {
  try {
   // do something with your logging here
   // note: don't log OR trace anything here!
   if ( logLevel >= Report.LEVEL_TRACE ) {
    return;
   }
   // after the above if statement tracing in your custom code is safe
  } catch ( final Throwable someException ) {
   someException.printStackTrace();
  }
 }
}

Again, catch all to avoid infinite loops. And again, don't log any error in your code. But this time... also don't trace (even verbose) because the ReportHandler handles all messages.

Configuring the content server to pick up your ReportHandler implementation and use that, there is - unfortunately - no simple config parameter. The good thing is that you can set this up in your component by editing your component hda and adding the following result set at the end of your <component_name>.hda file.

@ResultSet StateCfgExportedVars
2
name
value
JAVA_OPTIONS_sample_reporthandler
${DEFINE_PREFIX}idc.report.sample.implementor=my.SampleReportHandler
JAVA_CLASSPATH_sample
$COMPONENT_DIR/classes/
@end

The first entry in the result set adds a java option setting up your report handler class as a report implementation. The second entry makes sure the classes directory in your component is part of the java classpath. This last entry is needed because this will be setup before all components are loaded (thus try not to have any dependencies on libraries or code outside of the classes folder and the default loaded libraries such as IdcServer.jar).

Important Differences

• The log levels use different backing integers, don't mix them up; LogWriter uses the constants setup in intradoc.common.Log (ie. Log.m_warningType = 3) whereas ReportHandler uses the constants setup in intradoc.common.Report (ie. Report.LEVEL_WARNING = 4000).
• The ReportHandler method message contains more parameters than the doMessageAppend method in the LogWriter interface (luckily all parameters from the LogWriter have an (almost) equivalent parameter in the ReportHandler).
• As said before, the ReportHandler has access to much more than the logging messages, this includes but is not limited to trace messages.
• And the most important difference is ofcourse that LogWriter does not function properly in UCM 11g, whilst the ReportHandler does work in UCM 11g and also seems available in UCM 10g (although I have not tested if this works correctly).

Homework
Rewrite the RssFeeds component to work in 11g with the ReportHandler interface.

Calling stored procedures from within UCM

The Problem
When creating customizations for UCM (Oracle Universal Content Management), there have been a couple of times that I've wanted to call a procedure or function from within a service or filter (ie. to make use autonomous transactions for logging stuff). This post will show you how this can be done (without having to resort to using workarounds like making the procedure into a function and select it from dual).

The procedure
So lets create an interesting - yet compact - procedure that contains in, in-out and out parameters (as this is where the workaround can't be applied anymore). So here it is; my very own example_procedure:

create or replace procedure example_procedure (
   param1 in number,
   param2 in out varchar2,
   param3 out number
) as
begin
   param2 := param2 || param1;
   param3 := param1 + 2;
end example_procedure;

The query (definition)
Now we will define the query we want to call using the Component Wizard (note that you need to use Launch Editor and manually edit the entry because these options can't be selected from a dropdown menu). I am going to call my query exampleQuery and have defined it as:

<tr>
    <td>(ORACLE.CALLABLE)exampleQuery</td>
    <td>{call example_procedure( ?, ?, ? )}</td>
    <td>param1 int
        param2 inout:varchar
        param3 out:int</td>
</tr>

There are several interesting things about this definition that you need to remember:

• There is an (ORACLE.CALLABLE) tag in front of the query name; I believe this prepares the query parser for a procedure/function call.
• The statement itself is between brackets and is preceded by the word call; the syntax to call a procedure or function
• Two parameters have a prefix (inout: and out:); they are pretty self explanatory

The custom Java code 
Finally there is the Java code necessary to call our fancy procedure.

private void testProcedureCall (
   final Workspace workspace,
   final DataBinder binder
) throws DataException {

   // prepare the "in" parameters
   binder.putLocal( "param1", Integer.toString( 33 ) );
   binder.putLocal( "param2", "some test string" );

   // the magical moment; calling the procedure
   final CallableResults myResults = workspace.executeCallable( "exampleQuery", binder );

   // retrieve the "out" parameters
   final String myInOutParameter = myResults.getString( "param2" );
   final int myOutParameter = myResults.getInteger( "param3" );

   // now you can use the output parameters however you like!

}

The above is not that special, except for the executeCallable call. It's use (and arguments) are exactly equal to a createResultSet or execute call on the workspace, except that you get a CallableResults from which you can retrieve the parameters.

And... that should do the trick!