Hugo uses a set of factors to identify a page's related content based on front matter parameters. This can be tuned to the desired set of indices and parameters or left to Hugo's default [Related Content configuration](#configure-related-content).
To list up to 5 related pages (which share the same _date_ or _keyword_ parameters) is as simple as including something similar to this partial in your single page template:
{{<codefile="layouts/partials/related.html">}}
{{ $related := .Site.RegularPages.Related . | first 5 }}
: Fragments holds a a list of special keywords that is used for indices configured as type "fragments". This will match the fragment identifiers of the documents.
A fictional example using all of the above options:
We improved and simplified this feature in Hugo 0.111.0. Before this we had 3 different methods: `Related`, `RelatedTo` and `RelatedIndicies`. Now we have only one method: `Related`. The old methods are still available but deprecated. Also see [this blog article](https://regisphilibert.com/blog/2018/04/hugo-optmized-relashionships-with-related-content/) for a great explanation of more advanced usage of this feature.
Hugo can index the headings in your content and use this to find related content. You can enable this by adding a index of type `fragments` to your `related` configuration:
* The `name` maps to a optional front matter slice attribute that can be used to link from the page level down to the fragment/heading level.
* If `applyFilter`is enabled, the `.HeadingsFiltered` on each page in the result will reflect the filtered headings. This is useful if you want to show the headings in the related content listing:
Hugo provides a sensible default configuration of Related Content, but you can fine-tune this in your configuration, on the global or language level if needed.
### Default configuration
Without any `related` configuration set on the project, Hugo's Related Content methods will use the following.
If you add a `related` configuration section, you need to add a complete configuration. It is not possible to just set, say, `includeNewer` and use the rest from the Hugo defaults.
: A value between 0-100. Lower value will give more, but maybe not so relevant, matches.
includeNewer
: Set to true to include **pages newer than the current page** in the related content listing. This will mean that the output for older posts may change as new related content gets added.
toLower
: Set to true to lower case keywords in both the indexes and the queries. This may give more accurate results at a slight performance penalty. Note that this can also be set per index.
: The index name. This value maps directly to a page parameter. Hugo supports string values (`author` in the example) and lists (`tags`, `keywords` etc.) and time and date objects.
: An integer weight that indicates _how important_ this parameter is relative to the other parameters. It can be 0, which has the effect of turning this index off, or even negative. Test with different values to see what fits your content best.
: {{<new-in"0.111.0">}}. A percentage (0-100) used to remove common keywords from the index. As an example, setting this to 50 will remove all keywords that are used in more than 50% of the documents in the index.
: This is currently only relevant for dates. When listing related content, we may want to list content that is also close in time. Setting "2006" (default value for date indexes) as the pattern for a date index will add weight to pages published in the same year. For busier blogs, "200601" (year and month) may be a better default.
Scott S. Lowe removed the "Related Content" section built using the `intersect` template function on tags, and the build time dropped from 30 seconds to less than 2 seconds on his 1700 content page sized blog.
He should now be able to add an improved version of that "Related Content" section without giving up the fast live-reloads. But it's worth noting that:
* If you don't use any of the `Related` methods, you will not use the Relate Content feature, and performance will be the same as before.
* Calling `.RegularPages.Related` etc. will create one inverted index, also sometimes named posting list, that will be reused for any lookups in that same page collection. Doing that in addition to, as an example, calling `.Pages.Related` will work as expected, but will create one additional inverted index. This should still be very fast, but worth having in mind, especially for bigger sites.
{{% note %}}
We currently do not index **Page content**. We thought we would release something that will make most people happy before we start solving [Sherlock's last case](https://github.com/joearms/sherlock).
