hugo/docs/content/en/content-management/front-matter.md
2024-08-09 15:17:43 +02:00

430 lines
15 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: Front matter
description: Use front matter to add metadata to your content.
categories: [content management]
keywords: [front matter,yaml,toml,json,metadata,archetypes]
menu:
docs:
parent: content-management
weight: 60
weight: 60
toc: true
aliases: [/content/front-matter/]
---
## Overview
The front matter at the top of each content file is metadata that:
- Describes the content
- Augments the content
- Establishes relationships with other content
- Controls the published structure of your site
- Determines template selection
Provide front matter using a serialization format, one of [JSON], [TOML], or [YAML]. Hugo determines the front matter format by examining the delimiters that separate the front matter from the page content.
[json]: https://www.json.org/
[toml]: https://toml.io/
[yaml]: https://yaml.org/
See examples of front matter delimiters by toggling between the serialization formats below.
{{< code-toggle file=content/example.md fm=true >}}
title = 'Example'
date = 2024-02-02T04:14:54-08:00
draft = false
weight = 10
[params]
author = 'John Smith'
{{< /code-toggle >}}
Front matter fields may be [scalar], [arrays], or [maps] containing [boolean], [integer], [float], or [string] values. Note that the TOML format also supports date/time values using unquoted strings.
[scalar]: /getting-started/glossary/#scalar
[arrays]: /getting-started/glossary/#array
[maps]: /getting-started/glossary/#map
[boolean]: /getting-started/glossary/#boolean
[integer]: /getting-started/glossary/#integer
[float]: /getting-started/glossary/#float
[string]: /getting-started/glossary/#string
## Fields
The most common front matter fields are `date`, `draft`, `title`, and `weight`, but you can specify metadata using any of fields below.
{{% note %}}
The field names below are reserved. For example, you cannot create a custom field named `type`. Create custom fields under the `params` key. See the [parameters] section for details.
[parameters]: #parameters
{{% /note %}}
###### aliases
(`string array`) An array of one or more aliases, where each alias is a relative URL that will redirect the browser to the current location. Access these values from a template using the [`Aliases`] method on a `Page` object. See the [aliases] section for details.
[`aliases`]: /methods/page/aliases/
[aliases]: /content-management/urls/#aliases
###### build
(`map`) A map of [build options].
[build options]: /content-management/build-options/
###### cascade {#cascade-field}
(`map`) A map of front matter keys whose values are passed down to the pages descendants unless overwritten by self or a closer ancestors cascade. See the [cascade] section for details.
[cascade]: #cascade
###### date
(`string`) The date associated with the page, typically the creation date. Note that the TOML format also supports date/time values using unquoted strings. Access this value from a template using the [`Date`] method on a `Page` object.
[`date`]: /methods/page/date/
###### description
(`string`) Conceptually different than the page `summary`, the description is typically rendered within a `meta` element within the `head` element of the published HTML file. Access this value from a template using the [`Description`] method on a `Page` object.
[`description`]: /methods/page/description/
###### draft
(`bool`)
If `true`, the page will not be rendered unless you pass the `--buildDrafts` flag to the `hugo` command. Access this value from a template using the [`Draft`] method on a `Page` object.
[`draft`]: /methods/page/draft/
###### expiryDate
(`string`) The page expiration date. On or after the expiration date, the page will not be rendered unless you pass the `--buildExpired` flag to the `hugo` command. Note that the TOML format also supports date/time values using unquoted strings. Access this value from a template using the [`ExpiryDate`] method on a `Page` object.
[`expirydate`]: /methods/page/expirydate/
###### headless
(`bool`) Applicable to [leaf bundles], if `true` this value sets the `render` and `list` [build options] to `never`, creating a headless bundle of [page resources].
[leaf bundles]: /content-management/page-bundles/#leaf-bundles
[page resources]: /content-management/page-resources/
###### isCJKLanguage
(`bool`) Set to `true` if the content language is in the [CJK] family. This value determines how Hugo calculates word count, and affects the values returned by the [`WordCount`], [`FuzzyWordCount`], [`ReadingTime`], and [`Summary`] methods on a `Page` object.
[`fuzzywordcount`]: /methods/page/wordcount/
[`readingtime`]: /methods/page/readingtime/
[`summary`]: /methods/page/summary/
[`wordcount`]: /methods/page/wordcount/
[cjk]: /getting-started/glossary/#cjk
###### keywords
(`string array`) An array of keywords, typically rendered within a `meta` element within the `head` element of the published HTML file, or used as a [taxonomy] to classify content. Access these values from a template using the [`Keywords`] method on a `Page` object.
[`keywords`]: /methods/page/keywords/
[taxonomy]: /getting-started/glossary/#taxonomy
<!-- Added in v0.123.0 but purposefully omitted from documentation. -->
<!--
kind
: The kind of page, e.g. "page", "section", "home" etc. This is usually derived from the content path.
-->
<!-- Added in v0.123.0 but purposefully omitted from documentation. -->
<!--
lang
: The language code for this page. This is usually derived from the module mount or filename.
-->
###### lastmod
(`string`) The date that the page was last modified. Note that the TOML format also supports date/time values using unquoted strings. Access this value from a template using the [`Lastmod`] method on a `Page` object.
[`lastmod`]: /methods/page/date/
###### layout
(`string`) Provide a template name to [target a specific template], overriding the default [template lookup order]. Set the value to the base file name of the template, excluding its extension. Access this value from a template using the [`Layout`] method on a `Page` object.
[`layout`]: /methods/page/layout/
[template lookup order]: /templates/lookup-order/
[target a specific template]: templates/lookup-order/#target-a-template
###### linkTitle
(`string`) Typically a shorter version of the `title`. Access this value from a template using the [`LinkTitle`] method on a `Page` object.
[`linktitle`]: /methods/page/linktitle/
###### markup
(`string`) An identifier corresponding to one of the supported [content formats]. If not provided, Hugo determines the content renderer based on the file extension.
[content formats]: /content-management/formats/#classification
###### menus
(`string`,`string array`, or `map`) If set, Hugo adds the page to the given menu or menus. See the [menus] page for details.
[menus]: /content-management/menus/#define-in-front-matter
###### outputs
(`string array`) The [output formats] to render.
[output formats]: /templates/output-formats/
<!-- Added in v0.123.0 but purposefully omitted from documentation. -->
<!--
path
: The canonical page path.
-->
###### params
{{< new-in 0.123.0 >}}
(`map`) A map of custom [page parameters].
[page parameters]: #parameters
###### publishDate
(`string`) The page publication date. Before the publication date, the page will not be rendered unless you pass the `--buildFuture` flag to the `hugo` command. Note that the TOML format also supports date/time values using unquoted strings. Access this value from a template using the [`PublishDate`] method on a `Page` object.
[`publishdate`]: /methods/page/publishdate/
###### resources
(`map array`) An array of maps to provide metadata for [page resources].
[page-resources]: /content-management/page-resources/#page-resources-metadata
###### sitemap
(`map`) A map of sitemap options. See the [sitemap templates] page for details. Access these values from a template using the [`Sitemap`] method on a `Page` object.
[sitemap templates]: /templates/sitemap/
[`sitemap`]: /methods/page/sitemap/
###### slug
(`string`) Overrides the last segment of the URL path. Not applicable to section pages. See the [URL management] page for details. Access this value from a template using the [`Slug`] method on a `Page` object.
[`slug`]: /methods/page/slug/
[URL management]: /content-management/urls/#slug
###### summary
(`string`) Conceptually different than the page `description`, the summary either summarizes the content or serves as a teaser to encourage readers to visit the page. Access this value from a template using the [`Summary`] method on a `Page` object.
[`Summary`]: /methods/page/summary/
###### title
(`string`) The page title. Access this value from a template using the [`Title`] method on a `Page` object.
[`title`]: /methods/page/title/
###### translationKey
(`string`) An arbitrary value used to relate two or more translations of the same page, useful when the translated pages do not share a common path. Access this value from a template using the [`TranslationKey`] method on a `Page` object.
[`translationkey`]: /methods/page/translationkey/
###### type
(`string`) The [content type], overriding the value derived from the top level section in which the page resides. Access this value from a template using the [`Type`] method on a `Page` object.
[content type]: /getting-started/glossary/#content-type
[`type`]: /methods/page/type/
###### url
(`string`) Overrides the entire URL path. Applicable to regular pages and section pages. See the [URL management] page for details.
###### weight
(`int`) The page [weight], used to order the page within a [page collection]. Access this value from a template using the [`Weight`] method on a `Page` object.
[page collection]: /getting-started/glossary/#page-collection
[weight]: /getting-started/glossary/#weight
[`weight`]: /methods/page/weight/
## Parameters
{{< new-in 0.123.0 >}}
Specify custom page parameters under the `params` key in front matter:
{{< code-toggle file=content/example.md fm=true >}}
title = 'Example'
date = 2024-02-02T04:14:54-08:00
draft = false
weight = 10
[params]
author = 'John Smith'
{{< /code-toggle >}}
Access these values from a template using the [`Params`] or [`Param`] method on a `Page` object.
[`param`]: /methods/page/param/
[`params`]: /methods/page/params/
Hugo provides [embedded templates] to optionally insert meta data within the `head` element of your rendered pages. These embedded templates expect the following front matter parameters:
Parameter|Data type|Used by these embedded templates
:--|:--|:--
`audio`|`[]string`|[`opengraph.html`]
`images`|`[]string`|[`opengraph.html`], [`schema.html`], [`twitter_cards.html`]
`videos`|`[]string`|[`opengraph.html`]
The embedded templates will skip a parameter if not provided in front matter, but will throw an error if the data type is unexpected.
[`opengraph.html`]: {{% eturl opengraph %}}
[`schema.html`]: {{% eturl schema %}}
[`twitter_cards.html`]: {{% eturl twitter_cards %}}
[embedded templates]: /templates/embedded/
## Taxonomies
Classify content by adding taxonomy terms to front matter. For example, with this site configuration:
{{< code-toggle file=hugo >}}
[taxonomies]
tag = 'tags'
genre = 'genres'
{{< /code-toggle >}}
Add taxonomy terms as shown below:
{{< code-toggle file=content/example.md fm=true >}}
title = 'Example'
date = 2024-02-02T04:14:54-08:00
draft = false
weight = 10
tags = ['red','blue']
genres = ['mystery','romance']
[params]
author = 'John Smith'
{{< /code-toggle >}}
You can add taxonomy terms to the front matter of any these [page kinds]:
- `home`
- `page`
- `section`
- `taxonomy`
- `term`
[page kinds]: /getting-started/glossary/#page-kind
Access taxonomy terms from a template using the [`Params`] or [`GetTerms`] method on a `Page` object. For example:
{{< code file=layouts/_default/single.html >}}
{{ with .GetTerms "tags" }}
<p>Tags</p>
<ul>
{{ range . }}
<li><a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a></li>
{{ end }}
</ul>
{{ end }}
{{< /code >}}
[`Params`]: /methods/page/params/
[`GetTerms`]: /methods/page/getterms/
## Cascade
Any [node] can pass down to its descendants a set of front matter values.
[node]: /getting-started/glossary/#node
### Target specific pages
The `cascade` block can be an array with an optional `_target` keyword, allowing you to target different page sets while cascading values.
{{< code-toggle file=content/_index.md fm=true >}}
title ="Home"
[[cascade]]
[cascade.params]
background = "yosemite.jpg"
[cascade._target]
path="/articles/**"
lang="en"
kind="page"
[[cascade]]
[cascade.params]
background = "goldenbridge.jpg"
[cascade._target]
kind="section"
{{</ code-toggle >}}
Use any combination of these keywords to target a set of pages:
###### path {#cascade-path}
(`string`) A [Glob](https://github.com/gobwas/glob) pattern matching the content path below /content. Expects Unix-styled slashes. Note that this is the virtual path, so it starts at the mount root. The matching supports double-asterisks so you can match for patterns like `/blog/*/**` to match anything from the third level and down.
###### kind {#cascade-kind}
(`string`) A Glob pattern matching the Page's Kind(s), e.g. "{home,section}".
###### lang {#cascade-lang}
(`string`) A Glob pattern matching the Page's language, e.g. "{en,sv}".
###### environment {#cascade-environment}
(`string`) A Glob pattern matching the build environment, e.g. "{production,development}"
Any of the above can be omitted.
{{% note %}}
With a multilingual site it may be more efficient to define the `cascade` values in your site configuration to avoid duplicating the `cascade` values on the section, taxonomy, or term page for each language.
With a multilingual site, if you choose to define the `cascade` values in front matter, you must create a section, taxonomy, or term page for each language; the `lang` keyword is ignored.
{{% /note %}}
### Example
{{< code-toggle file=content/posts/_index.md fm=true >}}
date = 2024-02-01T21:25:36-08:00
title = 'Posts'
[cascade]
[cascade.params]
banner = 'images/typewriter.jpg'
{{</ code-toggle >}}
With the above example the posts section page and its descendants will return `images/typewriter.jpg` when `.Params.banner` is invoked unless:
- Said descendant has its own `banner` value set
- Or a closer ancestor node has its own `cascade.banner` value set.
## Emacs Org Mode
If your [content format] is [Emacs Org Mode], you may provide front matter using Org Mode keywords. For example:
{{< code file=content/example.org lang=text >}}
#+TITLE: Example
#+DATE: 2024-02-02T04:14:54-08:00
#+DRAFT: false
#+AUTHOR: John Smith
#+GENRES: mystery
#+GENRES: romance
#+TAGS: red
#+TAGS: blue
#+WEIGHT: 10
{{< /code >}}
Note that you can also specify array elements on a single line:
{{< code file=content/example.org lang=text >}}
#+TAGS[]: red blue
{{< /code >}}
[content format]: /content-management/formats/
[emacs org mode]: https://orgmode.org/