Umbraco, like a lot of CMS systems, decided against creating a custom search functionality from scratch, instead, they implement one of the most widely used search providers available, Lucene. Lucene is a really powerful search library that is also super quick. In today's guide, I'm going to cover the basics to get you up and running with your own custom indexes with Umbraco.
Where Are My Indexes?
If you are new to Umbraco, in your website's webroot, in 'App_Data' -> 'TEMP' -> 'ExamineIndexes' you will find all your websites Lucene files. Out of the box, you should see some folder called 'Internal' and 'External'. The first tip I'm going to go over is how to force Umbraco to re-index your website. Open your Umbraco backend up in a browser:
Click on the 'Developer' section and then the 'Examine Management' tab. Under the Indexes section, you should see a list of Indexes that have been set-up in your site. If you click on any of the indexes, you should see a 'Rebuild index' button. Clicking on this should generate your indexes for you.
How Are Umbraco Indexes Defined?
If you are wondering how these indexes magically appear on your website, then you can take a look in your 'Config' folder:
In here you will see two files called, 'ExamineIndex.config' and 'ExamineSettings.config'. If you look at both files, you should be able to see where the indexes are defined.
Custom Umbraco Indexes
You might be wondering why you would need to create a custom Umbraco index, a few examples include:
- Locking down your search for security by only exposing certain Umbraco items
- Creating a specialist search that only contains results for a given language
To get started with a custom index, first, you need to define a custom indexset. An indexset is a configuration element you will need to add within the 'ExamineIndex.config' file. An index defines all the doctypes and fields the index will use. An example of a custom Index I've created, include:
The element might look scary at first, but it's quite easy when you break it down:
- SetName This is the name of the index (or alias in Umbraco talk). This is the name you will use in your code to reference the index
- IndexPath Where the index will live on disk
- IndexAttributeFields Defines the in-built Umbraco fields to include in the index
- IndexUserFields The custom fields in your doctypes to include
- IncludeNodeTypesThe doctypes you want to include
- ExcludeNodeTypesThe doctypes you want to exclude
After defining what you want to include in your custom index, you need to register it with Umbraco. This is done in 'examine settings.config'. Registering an index is done in a two-step process, first, by registering an indexer and then a provider. The code to register an ExamineIndexProviders looks like this and needs to live within the ExamineIndexProviders -> Providers section.
Next, you will need to register the ExamineSearchProviders, in the ExamineSearchProviders -> providers section.
The most import part of this section is that the IndexSet' property matches your index name that was defined in the ExamineIndexProviders.
Searching The Index
So, now you've defined an index if you follow the steps above you should see the files populate on disk. The next step is to use it in code:
In the code above we use the ExamineManager, passing in the index name to select which provider to query. We set a searchCriteria and passed in a search term. You can be very detailed in how you want to query the index, but, in this example, I'm just doing a basic search. Lastly, we query the index and order the results based on the 'score' property. When Lucene searches and indexes, it will also rate how close a match it is, so filtering with most relevant results first is a pretty standard factor.
If you followed everything correctly, you should now have a custom index defined, you should be able to see the physical files being generated and you should be able to use Umbraco ExamineManager to search that index in your code. If you have a simple need for an index, then I'm hoping this guide covers everything you need to get up and running. If you have more complex needs, then Lucene can be a complicated beast and you can get your hands a lot dirtier.