Custom Sitecore DocumentOptions with Solr

Almost 2 years ago I wrote a post about using custom indexes in a Helix environment. That post is still accurate, but the code was based on Lucene. As we are now all moving towards using Solr with our (non-PAAS) Sitecore setups, I though it might be a good idea to bring this topic back on the table with a Solr example this time.

(custom) indexes

I am assuming that you know about Helix, and about custom indexes. If you ever created a custom index you probably have used the documentOptions configuration section - maybe without noticing. It is used to include and/or exclude fields and templates and define computed fields. So you probably used it :)

And it wouldn't be Sitecore if we couldn't customize this...

Our own documentOptions

Why? Because we can. No..  we might have a good reason, like making our custom index definitions (more) Helix compliant. Normally your feature will not have a clue about "page" templates. But what if you want to define the include templates in your index? Those could be page templates.. or at least templates that inherit from your feature template. That is why I build my own documentOptions - to include a way to include templates derived from template-X.

Configuration

So the idea now is to create a custom document options class by inheriting from the SolrDocumentBuilderOptions. We add a new method to allow adding templates in a new section with included base templates. This will not break any other existing configuration sections.

An example config looks like:

<documentOptions type="YourNamespace.TestOptions, YourAssembly">
    <indexAllFields>true</indexAllFields>
    <include hint="list:AddIncludedBaseTemplate">
        <BaseTemplate1>{B6FADEA4-61EE-435F-A9EF-B6C9C3B9CB2E}</BaseTemplate1>
    </include>
</documentOptions>

This looks very familiar - as intended. We create a new include section with the hint "list:AddIncludedBaseTemplate". The name 'AddIncludedBaseTemplate' will come back later in our code.

Code

AddIncludedBaseTemplate

public virtual void AddIncludedBaseTemplate(string templateId)
{
  Assert.ArgumentNotNull(templateId, "templateId");
  ID id;
  Assert.IsTrue(ID.TryParse(templateId, out id), "Configuration: AddIncludedBaseTemplate entry is not a valid GUID. Template ID Value: " + templateId);
  foreach (var linkedId in GetLinkedTemplates(id))
  {
    AddTemplateFilter(linkedId, true);
  }
}

To see the rest of the code, I refer to the original post as nothing has to be changed to that in order to make it work on Solr (instead of Lucene).

Conclusion

To change the code from the Lucene example to a Solr one, we just had to change the base class to SolrDocumentBuilderOptions. 
We are now again able to configure our index to only use templates that inherit from our base templates. Still cool. And remember you can easily re-use this logic to create other document options to tweak your index behavior.