Skip to main content

Passing PageUri to a DCP for Dynamic Linking

Image
By

We should all know by now that passing an empty (aka Null TcmUri) as PageUri when resolving a Component Link is very bad practice. The reason -- this kind of link resolving is not cached. So, in case you are using a Content Delivery DB, you will make a trip to the DB for every single Component Link resolving.

I have written an older article available here on SDLTridionWorld, about solving these issues, but that's about old school templating. This post presents the mechanism to use when writing Compound Templates.

So, I have a DWT TBB that generates some output for an RTF field. Something like @@Component.Fields.Paragraph@@. I have some ComponentLinks in the RTF field.

The templates runs on a DCP and it generates a TCDL link like this:
<tcdl:Link type="Component" origin="tcm:0-0-0" destination="tcm:37-968" templateURI="tcm:0-0-0" linkAttributes="" textOnFail="true" addAnchor="false" variantId="">Read more</tcdl:Link>.

The problem is the origin is tcm:0-0-0. I want to have my own value/variable here. In JSP, I can use a JSTL variable like this:
<tridion:ComponentLink pageURI="${PageUri}" componentURI="tcm:37-969" templateURI="tcm:0-0-0" addAnchor="false" linkText="Read more" linkAttributes="" textOnFail="true"/>

Where ${PageUri} is some JSTL variable set with the following code in the ‘calling’ JSP:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<c:set var="PageUri" value="tcm:37-986-64" scope="request"/>

But anyway, the problem for me is how to get that PageURI attribute (or origin) assigned to my actual value?

The solution I used in this case is the following:
  • C# TBB that parses the <tcdl:Link origin="tcm:0-0-0"… and replaces the NullUri with ${PageUri}
    • Only does that for ‘Publish’, not for preview;
  • Add this TBB at the bottom of the Dynamic CT (after DefaultFinishActions, or after LinkResolver);
Code sample:

private static Regex ComponentLinkRegex = new Regex(@"<tcdl:Link type=""Component"" origin=""tcm:0-0-0""");

public void Transform(Engine engine, Package package)
{
    if (!engine.RenderMode.Equals(RenderMode.Publish))
    {
        Logger.Debug("Render mode not Publish. Do not perform any replacements");
        return;
    }

    Item OutputItem = package.GetByName(Package.OutputName);
    String OutputText = OutputItem.GetAsString();

    // Component Links with null origin
    Match match = ComponentLinkRegex.Match(OutputText);
    while (match.Success)
    {
        String ReplaceLink = match.Value.Replace("tcm:0-0-0", inputParam);
        // inputParam is the value to replace with. e.g. "${PageUri}"
        OutputText = OutputText.Replace(match.Value, ReplaceLink);
        match = match.NextMatch();
    }

    OutputItem.SetAsString(OutputText);
}



Labels:

Comments

Nuno said…
Awesome, I needed this code just now. :)
22 May, 2012 03:36
Post a Comment

Popular posts from this blog

Scaling Policies

By
This post is part of a bigger topic Autoscaling Publishers in AWS . In a previous post we talked about the Auto Scaling Groups , but we didn't go into details on the Scaling Policies. This is the purpose of this blog post. As defined earlier, the Scaling Policies define the rules according to which the group size is increased or decreased. These rules are based on instance metrics (e.g. CPU), CloudWatch custom metrics, or even CloudWatch alarms and their states and values. We defined a Scaling Policy with Steps, called 'increase_group_size', which is triggered first by the CloudWatch Alarm 'Publish_Alarm' defined earlier. Also depending on the size of the monitored CloudWatch custom metric 'Waiting for Publish', the Scaling Policy with Steps can add a difference number of instances to the group. The scaling policy sets the number of instances in group to 1 if there are between 1000 and 2000 items Waiting for Publish in the queue. It also sets the
Post a Comment
Read more

Toolkit - Dynamic Content Queries

By
This post if part of a series about the  File System Toolkit  - a custom content delivery API for SDL Tridion. This post presents the Dynamic Content Query capability. The requirements for the Toolkit API are that it should be able to provide CustomMeta queries, pagination, and sorting -- all on the file system, without the use third party tools (database, search engines, indexers, etc). Therefore I had to implement a simple database engine and indexer -- which is described in more detail in post Writing My Own Database Engine . The querying logic does not make use of cache. This means the query logic is executed every time. When models are requested, the models are however retrieved using the ModelFactory and those are cached. Query Class This is the main class for dynamic content queries. It is the entry point into the execution logic of a query. The class takes as parameter a Criterion (presented below) which triggers the execution of query in all sub-criteria of a Criterio
Post a Comment
Read more

Running sp_updatestats on AWS RDS database

By
Part of the maintenance tasks that I perform on a MSSQL Content Manager database is to run stored procedure sp_updatestats . exec sp_updatestats However, that is not supported on an AWS RDS instance. The error message below indicates that only the sa  account can perform this: Msg 15247 , Level 16 , State 1 , Procedure sp_updatestats, Line 15 [Batch Start Line 0 ] User does not have permission to perform this action. Instead there are several posts that suggest using UPDATE STATISTICS instead: https://dba.stackexchange.com/questions/145982/sp-updatestats-vs-update-statistics I stumbled upon the following post from 2008 (!!!), https://social.msdn.microsoft.com/Forums/sqlserver/en-US/186e3db0-fe37-4c31-b017-8e7c24d19697/spupdatestats-fails-to-run-with-permission-error-under-dbopriveleged-user , which describes a way to wrap the call to sp_updatestats and execute it under a different user: create procedure dbo.sp_updstats with execute as 'dbo' as
1 comment
Read more