hugo/content/content-management/cross-references.md
Bjørn Erik Pedersen ecf5e081b5 Squashed 'docs/' changes from 000ab7c42..4628b9ec2
4628b9ec2 commands: Regen CLI doc
2525f2ed0 data: Regenerate docs helper
6f5a0eb19 Add Hugo 0.30 poster image
72c3fac9e Merge branch 'chroma-next2' into next
364973d3f Fix typo in syntax highlighting.
ce10cc02e Update Chroma highlighting docs
9dcc4d4dd Update robots.md
1e64cb483 Rename title of cross references' page
d6dfbbc51 Add warning about MMark and TOCs
e8d259d32 Fix link to subsection in page
6adead19d Merge commit '040d8d2833c26c53cf9f0e035910821ed50e3863'
040d8d283 Squashed 'themes/gohugoioTheme/' changes from cdaa89c8..6b632895
bde95d890 Add Atlas starter kit
fc40d078d Remove page arg from examples of relref shortcode
c578620b5 Remove page arg from examples of ref shortcode
ee81931a4 Remove delimiters in YAML and TOML config examples
62d7b269f Clarify that .Lastmod automatically uses .GitInfo.AuthorDate (#226)

git-subtree-dir: docs
git-subtree-split: 4628b9ec2c52df4de673a4d6b9621a65d8e8f5a4
2017-10-15 10:20:55 +02:00

123 lines
5 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
title: Links and Cross References
description: Hugo makes it easy to link documents together.
date: 2017-02-01
publishdate: 2017-02-01
lastmod: 2017-03-31
categories: [content management]
keywords: ["cross references","references", "anchors", "urls"]
menu:
docs:
parent: "content-management"
weight: 100
weight: 100 #rem
aliases: [/extras/crossreferences/]
toc: true
---
The `ref` and `relref` shortcodes link documents together, both of which are [built-in Hugo shortcodes][]. These shortcodes are also used to provide links to headings inside of your content, whether across documents or within a document. The only difference between `ref` and `relref` is whether the resulting URL is absolute (`http://1.com/about/`) or relative (`/about/`), respectively.
## Use `ref` and `relref`
```
{{</* ref "document.md" */>}}
{{</* ref "#anchor" */>}}
{{</* ref "document.md#anchor" */>}}
{{</* relref "document.md" */>}}
{{</* relref "#anchor" */>}}
{{</* relref "document.md#anchor" */>}}
```
The single parameter to `ref` is a string with a content `documentname` (e.g., `about.md`) with or without an appended in-document `anchor` (`#who`) without spaces.
### Document Names
The `documentname` is the name of a document, including the format extension; this may be just the filename, or the relative path from the `content/` directory. With a document `content/blog/post.md`, either format will produce the same result:
```
{{</* relref "blog/post.md" */>}} => `/blog/post/`
{{</* relref "post.md" */>}} => `/blog/post/`
```
If you have the same filename used across multiple sections, you should only use the relative path format; otherwise, the behavior will be `undefined`. This is best illustrated with an example `content` directory:
```
.
└── content
├── events
│   └── my-birthday.md
├── galleries
│   └── my-birthday.md
├── meta
│   └── my-article.md
└── posts
└── my-birthday.md
```
To be sure to get the correct reference in this case, use the full path:
{{< code file="content/meta/my-article.md" copy="false" >}}
{{</* relref "events/my-birthday.md" */>}} => /events/my-birthday/
{{< /code >}}
{{< todo >}}Remove this warning when https://github.com/gohugoio/hugo/issues/3703 is released.{{< /todo >}}
A relative document name must *not* begin with a slash (`/`).
```
{{</* relref "/events/my-birthday.md" */>}} => ""
```
### With Multiple Output Formats
If the page exists in multiple [output formats][], `ref` or `relref` can be used with a output format name:
```
[Neat]({{</* ref "blog/neat.md" "amp" */>}})
```
### Anchors
When an `anchor` is provided by itself, the current pages unique identifier will be appended; when an `anchor` is provided appended to `documentname`, the found page's unique identifier will be appended:
```
{{</* relref "#anchors" */>}} => #anchors:9decaf7
{{</* relref "about-hugo/hugo-features.md#content" */>}} => /blog/post/#who:badcafe
```
The above examples render as follows for this very page as well as a reference to the "Content" heading in the Hugo docs features pageyoursite
```
{{</* relref "#who" */>}} => #who:9decaf7
{{</* relref "blog/post.md#who" */>}} => /blog/post/#who:badcafe
```
More information about document unique identifiers and headings can be found [below]({{< ref "#hugo-heading-anchors" >}}).
### Examples
* `{{</* ref "blog/post.md" */>}}` => `https://example.com/blog/post/`
* `{{</* ref "post.md#tldr" */>}}` => `https://example.com/blog/post/#tldr:caffebad`
* `{{</* relref "post.md" */>}}` => `/blog/post/`
* `{{</* relref "blog/post.md#tldr" */>}}` => `/blog/post/#tldr:caffebad`
* `{{</* ref "#tldr" */>}}` => `#tldr:badcaffe`
* `{{</* relref "#tldr" */>}}` => `#tldr:badcaffe`
## Hugo Heading Anchors
When using Markdown document types, Hugo generates heading anchors automatically. The generated anchor for this section is `hugo-heading-anchors`. Because the heading anchors are generated automatically, Hugo takes some effort to ensure that heading anchors are unique both inside a document and across the entire site.
Ensuring heading uniqueness across the site is accomplished with a unique identifier for each document based on its path. Unless a document is renamed or moved between sections *in the filesystem*, the unique identifier for the document will not change: `blog/post.md` will always have a unique identifier of `81df004c333b392d34a49fd3a91ba720`.
`ref` and `relref` were added so you can make these reference links without having to know the documents unique identifier. (The links in document tables of contents are automatically up-to-date with this value.)
```
{{</* relref "content-management/cross-references.md#hugo-heading-anchors" */>}}
/content-management/cross-references/#hugo-heading-anchors:77cd9ea530577debf4ce0f28c8dca242
```
[built-in Hugo shortcodes]: /content-management/shortcodes/#using-the-built-in-shortcodes
[lists]: /templates/lists/
[output formats]: /templates/output-formats/
[shortcode]: /content-management/shortcodes/