Developing a Custom Transport Handler

In this blog post I wanted to show a more advanced feature available in SDL Tridion, this feature gives developers a more deeper control on the Transport Package. Unfortunately this nice feature is neither documented nor supported but I think it is good enough to show how to use it in a Blog Post.

Developing a Transport Handler is very similar to developing other Tridion extension points like Resolvers or Event Systems. So, let’s provide a list of steps in order to develop one. In this sample I am writing a Transport Handler that overrides the existing TaxonomyTransportHandler in order to add the user that published the Category in the Instructions document.

1.       Implement a class that inherits ITransportHandler interface. This interface is not available in the DLLs available in /bin/client, you have to reference Tridion.ContentManager.Publishing.Transporting.dll that is in the GAC

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Xml;

using Tridion.ContentManager.Publishing.Rendering;

using Tridion.ContentManager.Publishing.Resolving;

using Tridion.ContentManager.Publishing.Transporting;

namespace TransportHandlers {

    public class CustomTaxonomyTransportHandler : ITransportPackageHandler {

        private TaxonomyTransportPackageHandler _defaultTaxonomyHandler;

        private XmlDocument _defaultInstructionsDocument;

        private string _user;

        public CustomTaxonomyTransportHandler(TransportPackage package) {

            _defaultTaxonomyHandler = new TaxonomyTransportPackageHandler(package);

            _defaultInstructionsDocument = package.InstructionsDocument;

            _user = package.PublishTransaction.Creator.Title;

        }

        public void HandleItemForPublishing(object item, XmlElement parentElement) {

            _defaultTaxonomyHandler.HandleItemForPublishing(item, parentElement);

        }

        public XmlElement HandleRenderedItemForPublishing(RenderedItem renderedItem, XmlElement parentElement) {

            XmlElement customCategoryElement = _defaultInstructionsDocument.CreateElement("CustomCategoryInfo");

            customCategoryElement.InnerXml = string.Format("<Category>{0}</Category><User>{1}</User>", renderedItem.ResolvedItem.Item.Id, _user);

            _defaultInstructionsDocument.DocumentElement.AppendChild(customCategoryElement);

            return _defaultTaxonomyHandler.HandleRenderedItemForPublishing(renderedItem, parentElement);

        }

        public void HandleResolvedItemForUnPublishing(ResolvedItem resolvedItem) {

            _defaultTaxonomyHandler.HandleResolvedItemForUnPublishing(resolvedItem);

        }

    }

}

2.       The class above should be compiled in an Strong Name Assembly and registered in the GAC

3.       Register it in the Tridion.ContentManager.config configuration file

<transporting rootStorageFolder="c:\Temp">

  <mappings>

    .

    .

    .

    <add itemType="Tridion.ContentManager.ContentManagement.Category">

      <handler type="TransportHandlers.CustomTaxonomyTransportHandler" assembly="TransportHandlers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=3b4b2f6e0f11afc8" />

    </add>

    .

    .

    .

  </mappings>

</transporting>

4.       Restart the TcmPublisher Windows Service

5.       Publish any Publishable Category, as a Result you will see a custom Xml Element appended in the Transport Package Instructions document

<ProcessorInstructions version="7.1.0.1290">

  <Publication Id="tcm:0-3-1" Title="400 Example Site" Key="400 Example Site" PublicationPath="\" PublicationUrl="/" MultimediaPath="\media" MultimediaUrl="/media/" />

  <Action>Deploy</Action>

  <Target Type="6" />

  <CustomCategoryInfo>

    <Category>tcm:3-29-512</Category>

    <User>T2013SP1\Administrator</User>

  </CustomCategoryInfo>

  <Section Type="Taxonomies" Name="Taxonomies">

    <Taxonomy Id="tcm:3-29-512" Name="tcm_3-29-512.xml" UseForIdentification="False" />

  </Section>

</ProcessorInstructions>