About Nickoli Roussakov

Nick is a SDL Tridion Consultant and takes part in solving a wide range of business challenges in content management primarily through the use of SDL Tridion, .NET and J2EE. Nick manages the North American side of Content Bloom, undertaking a variety of tasks including consultancy, development and developer mentoring.

Avoid Static Variables in Tridion Templates

I’ve recently helped a client resolve some interesting issues with their Tridion template building blocks. The issue was that when publishing the first time desired results were produced by the template. However, when publishing many pages, or republishing the same page/component presentation, subsequently produced strange output results.

The logic in our TBB parsed the Output item in the package and made various manipulations to it. I won’t get into the details of that. The issue was due to having static private variables declared within the TBB. These variables were various data structures and primitives manipulated by methods within our ITemplate-inherited class. The methods themselves had to also be declared as static.  Refactoring the code away from “static” resolved the issue.

Here is why you cannot use static variables in Tridion templates:  Primarily because they become global shared variables across all publish threads.  Here is what the Tridion TOM.NET Session and Engine class API states regarding this matter:

IMPORTANT NOTE: Session objects are not thread-safe; you must not share Session objects across threads. Furthermore, the thread that creates a Session object should be in a Single Threaded Apartment (STA), since the Session will internally create an Apartment Threaded COM object. See SetApartmentState(ApartmentState). 

The Tridion Session object, which the Engine uses (or, as the docs put it, “aggregates”) subscribes to the Single Threaded Apartment model (STA).

An STA is basically a model where the server controls the threads, and each individual thread must not spin off additional sub-threads that depend on the STA-controlled objects. So in our case: the Tridion CM is the server that spins off and controls threads (e.g. we can publish many items simultaneously), and each template is executed within it’s own thread. So if we develop a template that spins of other threads, the common memory across threads, i.e. static variables, isn’t managed.  So STA threads can overwrite each other.

Here is a snippet from an article explaining STAs in much more detail:

…all access to global variables and functions of the server will need to be serialized properly because more than one object may try to access these from different threads. This rule also applies to class static variables and functions. [http://www.codeproject.com/Articles/9190/Understanding-The-COM-Single-Threaded-Apartment-Pa]

So in a common scenario, when is it appropriate to use “static” within a TBB? Well, how about in procedural methods that take some inputs, create new objects, massage them and return them. In other words, if the method is self-contained. A Utility class is a common such scenario.

In conclusion, don’t use static variables inside your TBBs or Event System code.

SiteEdit 2012 Overview

I have been very fortunate this week to have had the opportunity to attend the Site Edit 2012 bootcamp at SDL’s offices in NYC. It was a hands-on 2 day workshop where each of us was given an Amazon instance with Tridion and SiteEdit installed. Our goal was to get our hands dirty and solve a wide variety of challenges (including going through the install). Thank you Nuno for making it a great success!

Site Edit 2012, now officially renamed to “SDL Tridion User Interface 2012″, is a very impressive tool. It seems to load into editing mode much faster than its predecessor (at least on the Amazon instance I was playing with), and usability and options available from the toolbar are incredible.  The user experience that can be achieved is mind-blasting!

Here are some rough notes that I took on the new features.  I realize you, the reader, may not have the full context around some of the notes – nevertheless, I think these should  generate some excitement:

  • SiteEdit is now called Tridion UI 2012
  • Not yet ready to go, but if a customer is ready to use it, then they need to talk to SDL on a case-by-case basis.
  • Controlled release. Only a few customers going to implement.
  • The pages are now previewed in an iFrame within the CM interface
  • “Update Preview” 
    • Doesn’t publish in session. Renders the result in the CM and pushes it via web service call.
    • Avoids the publishing queue bottlenecks.
    • i.e. Re-rendering is done “on the fly” rather than the queue
  • “Finish Editing” button commits and publishes
  • In SiteEdit there are no more page templates. They are now called Page Types, which are like a pre-configured page with a template and other defaults. – hole notha level!
  • Functionality is provided to allow previewing the Page Type (just a url to a simple preview page)
  • A page template, associated to a page type can have a custom icon in the ribbon toolbar. This is a great feature to give content editors a better experience
  • Content Types are component templates linked to a page template
  • In Publication settings where you define the Content Types you can specify which folder components get created in via SiteEdit.
    • Can also specify how content is named: user defined or auto-generated (based on a pattern).
  • One ribbon in the toolbar shows all the page templates. Functionality exists allowing to change icons for each template.
  • Ambient Data Framework allows to virtually specify a different environment, e.g. Show how something would display in IE, even though you’re using Chrome; or chane the OS type, etc.
  • Can set blueprint context for pages (e.g. New pages are created and edited in Pub A while content is created/edited in Pub B).

There is another interesting feature called Session Footprint that is designed to help with previewing and testing your page as if the session was created under different environments and conditions.  You can select to show the page as if it ran in a different browser and a different OS, change the session timeout values, pull up specific dynamic component presentations based on search criteria and more.  The Footprint is engineered based on SDL’s Ambient Data Framework, and the whole thing is quite remarkable.

Another cool concept that is provided is called Regions.

  • Allow specifying limits on what kind of component presentations can be dropped in.  For example: only allow dropping components based on a given schema or a component template, or limit the number of components that can be added to a region.
  • This is done by addingsyntax in the design template, just like the regions for SmartTarget.

Last but not least, I’d like to share a very high-level technical architecture of this tool.

Site Edit Architecture

To conclude I’d like to say that the R&D folks have done an outstanding job with this tool and I can’t wait to start developing with this new product!

Using XPath to find XML Elements with Inline/Default Namespace and Null Prefix

On the last SDL Tridion Community Webinar, Dominic Cronin suggested a great alternative to Regex for finding, adding, removing, or replacing certain elements or attributes, such as Component Links within Components (or Pages).  The more data-safe approach is to manipulate the Component source as an XML document [via XPath] rather than regex.  I gave it a shot, except that getting (what seems like) a simple XPath query to work took way more effort than I anticipated.  All of this due to a little unknown detail about XPath queries for items in the default namespace without a prefix.

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Generating Web.Sitemap from Tridion (SiteMapDataSource)

In spirit of Nuno’s post last week (http://nunolinhares.blogspot.com/2012/01/its-little-things-creating-page.html) regarding website navigation and more specifically, how to generate a Breadcrumb from Structure Groups in Tridion, I thought it was time to publish a related post (and a TBB) I’ve been baking for a while now.  Behold: hooking up Tridion to .NET’s standard Navigation Controls.  I’m talking about Menu, SiteMapPath, and TreeView.  Turns out they all feed off the same, rather basic, XML file called web.sitemap.  Here is the C# code for a generic TBB that creates such a file from your SDL Tridion Web Structure Group and Pages hierarchy.

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SDL Tridion Application Integration

When I first got the opportunity to work with Tridion, the biggest question I needed an answer to was how to integrate various applications with SDL Tridion.  At the time, I was running a project that required migrating about 20 J2EE applications tightly integrated with a legacy Plumtree Portal to a .NET platform driven by  SDL Tridion.  The organization was moving away from J2EE to become a .NET shop, so the apps needed to be rewritten in .NET – our #1 task.  All we had was a barebone Tridion installation and a bunch of manuals that did not mention anything about how to integrate apps into it.  SDL Tridion training also did not cover this topic – although we got some useful hints, we needed to see a proven design.  My intent with this article is to help any new Tridion teams to keep their project moving forward if faced with a similar situation.

The approaches discussed here are not limited to .NET.  They can be leveraged to integrate Tridion content into J2EE apps, mobile apps, or anything that you want, such as PHP, Perl, C++.  In other words, the sky is the limit.

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JavaScript Compression in SDL Tridion (minification and obfuscation. CSS too)

I’ve been building up my jot notes throughout the year and finally got the chance to make them into publishable form, which lead me to this sudden series of articles. Thanks, John, for letting me post on your site.

To achieve maximum compression on a JavaScript file, minification is not enough.  Obfuscation is where it’s at.  This means replacing variable names to the shortest amount of characters (or bytes) that the language syntax allows.  For example: var myReallyLongVariableName=”foobar” would become var a=”foobar”; but only within its scope, and so on.  You basically have to implement a decent chunk of code that usually comes as part of any language interpreter or compiler.  It’s quite a bit more involved than minification alone.  My point is, use a proven package that does this and just hook it up to the best CMS known to man.

My preferred way is actually to not store JavaScript or CSS in Tridion.  Put it with the rest of your website’s code into the repository like TFS or Subversion.  Basically, bundle it into your build process which should go through Change Management with the likes of JAR/DLL files and DB packages.  JS is code after all.  This way you can just add a step to your build process.  Ask the build master to crunch the JS/CSS through a compressor (possibly as a manual step) before or automate within an ANT, NANT or MSBuild script.  If, however, you are a content author or Support person that hates dealing with your org’s Change Management process or have some other reason to store js and/or CSS code as easily publishable as content, then this is for you.

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More fun with Dreamweaver Templates – TemplateRepeatCount

Quite a while back (in ’09’ I think) I replied to a thread on the sdltridionworld forum regaring how to get the total count of your elements when doing a TemplateBeginRepeat inside a DWT.

For example when you have a special css class that needs to be applied to the last item in the list.

<li><a href="/contact/">Contact Us</a></li>
<li><a href="/sitemap/">Site Map</a></li>
<li class="last"><a href="/terms-of-use/"></a></li>

An intuitive approach is to have a function or a variable that provides the count so that you can use syntax like this:

<!– TemplateBeginRepeat name="Component.LinkList" –>
<li><a href="@@MyUrlField@@">@@MyUrlText@@</a></li>

<!– TemplateBeginIf cond="TemplateRepeatIndex == TemplateRepeatCount()-1 –>
<li class="last"><a href="@@MyUrlField@@">@@MyUrlText@@</a></li>

<!– TemplateEndIf –>
<!– TemplateEndRepeat –>

Here is the code for it:

public string TemplateRepeatCount(string componentTcmId, string fieldName)
    Logger.Info("Start of Count");

    IdentifiableObject item = _engine.GetObject(componentTcmId);
    int count = 0;
    if (item.GetType().Name == "Component")
        Component c = item as Component;
        //find the field collection and get the count
        ItemFields fields = new ItemFields(c.Content, c.Schema);

        Logger.Debug("Got component itemfields");
        if (fields.Contains(fieldName))
            Logger.Debug("Found item field: " + fieldName);

            ItemField field = fields[fieldName];
            Logger.Debug("Field type: " + field.GetType().Name);

            switch (field.GetType().Name)
                case "ComponentLinkField":
                    Logger.Debug("Field is ComponentLinkField");
                    ComponentLinkField typedField = field as ComponentLinkField;
                    count = typedField.Values!=null?typedField.Values.Count:0;

                case "EmbeddedSchemaField":
                    Logger.Debug("Field is EmbeddedSchemaField");
                    EmbeddedSchemaField typedField = field as EmbeddedSchemaField;
                    count = typedField.Values != null ? typedField.Values.Count : 0;

                case "SingleLineTextField":
                case "ExternalLinkField":
                case "XhtmlField":
                case "MultiLineTextField":
                    Logger.Debug("Field is TextField");
                    TextField typedField = field as TextField;
                    count = typedField.Values != null ? typedField.Values.Count : 0;

                case "DateField":
                    Logger.Debug("Field is DateField");
                    DateField typedField = field as DateField;
                    count = typedField.Values != null ? typedField.Values.Count : 0;

                case "NumberField":
                    Logger.Debug("Field is NumberField");
                    NumberField typedField = field as NumberField;
                    count = typedField.Values != null ? typedField.Values.Count : 0;

                case "KeywordField":
                    Logger.Debug("Field is KeywordField");
                    KeywordField typedField = field as KeywordField;
                    count = typedField.Values != null ? typedField.Values.Count : 0;

    return count.ToString();

Though, here is another approach which I used one late night in the office wanting to finish a template.  It was past my sys admin’s office time, so I couldn’t ask him to deploy a new Custom Functions DLL to the CM server’s GAC/bin, but I just had to get the template done by end of day – I was in the zone.  Besides, I couldn’t let it linger the next day.  

So here is a quick C# fragment that should be used in sequence after Will Price’s “Get Linked Components” extension (just Google it if you don’t know.  It’s the best thing since the combustion engine/sliced bread/eh…SDL Tridion CMS).

Anyway, just drop this C# Fragment in after “Get Linked Components”:

<%@ Import Namespace="Tridion.ContentManager.ContentManagement.Fields"%>
<%@ Import Namespace="System.Collections.Generic"%>

/// This TBB loops through all the items in the package and for any items which are Component Arrays
/// adds a new package item with the array entry count.  This is useful when a Dreamweaver TBB needs to know
/// the total count of components or when needing to know if you're on the last component.

List<KeyValuePair<string, Item>> extractedComponentLists = new List<KeyValuePair<string, Item>>();
foreach (KeyValuePair<string, Item> kvp in package.GetEntries())
    if (kvp.Value.ContentType == ContentType.ComponentArray)
        //get count

// This code has to be kept in a separate loop since you can't modify the package.GetEntries collection while looping through it.
foreach (KeyValuePair<string, Item> kvp in extractedComponentLists)
    IComponentPresentationList linkCollectionCPList = ComponentPresentationList.FromXml(kvp.Value.GetAsString());
    int componentCount = linkCollectionCPList.Count;
    package.PushItem(kvp.Key + "Count", package.CreateStringItem(ContentType.Number, componentCount.ToString()));

After this TBB runs, you’ll get a new entry on the package with the count for each “Tridion/Component[]” item type that “Get Linked Components” fetches.  So if we had a multi-value component link field in the component called “LinkList”, then “Get Linked Components” should fetch a component array and call it after your field name – something like “LinkList”.  Then after this DWT a new entry will appear called “LinkListCount”.

Use it like this in your DWT:

<!-- TemplateBeginRepeat name="Component.LinkList" -->
<li><a href="@@MyUrlField@@">@@MyUrlText@@</a>
<li><!-- TemplateBeginIf cond="TemplateRepeatIndex == LinkListCount-1 --> 
<li><a href="@@MyUrlField@@">@@MyUrlText@@</a>
<li><!-- TemplateEndIf -->
<!-- TemplateEndRepeat -->

Get and Set Variables in DWTs

Here is a creative and useful set of Dreamweaver Custom Functions that allow instantiating your own variables in a Dreamweaver Tridion template.  Credit goes out to my fellow team members Trevor Bartlett and Riyaz Hameed.

You can do stuff like this:

<!-- TemplateBeginRepeat name="Field.columnSection" --> <div class="wpsPortlet"> <div class="wpsPortletTitle"> <br />@@Field.title@@</div> @@SetVariable(“columnSectionIndex”, "${TemplateRepeatIndex}")@@ <!-- TemplateBeginRepeat name="Field.subColumnSection" --> @@GetVariable("columnSectionIndex")@@ <!-- TemplateBeginRepeat name="Field.subTitle" --> … <!-- TemplateEndRepeat --> </div> <!-- TemplateEndRepeat -->

Here is the code:

/// <summary>
/// Sets a varialbe in the package to the name and value specifed. Also removes any other variable that was set with the same name before.
/// </summary>
/// <param name="variableName">Name of the varialbet</param>
/// <param name="value">Value of the variable</param>
public string SetVariable(string variableName, object value)
    //Remove the old variable and set the new variable
    _engine.PublishingContext.RenderContext.ContextVariables.Add(variableName, value);
    return "";
/// <summary>
/// Gets a varialbe from the publishing context.
/// </summary>
/// <param name="variableName">Name of the variable</param>
public object GetVariable(string variableName)
    //Get the varialbe
    return _engine.PublishingContext.RenderContext.ContextVariables[variableName];