Content adapters

Overview

A content adapter is a template that dynamically creates pages when building a site. For example, use a content adapter to create pages from a remote data source such as JSON, TOML, YAML, or XML.

Unlike templates that reside in the layouts directory, content adapters reside in the content directory, no more than one per directory per language. When a content adapter creates a page, the page's logical path will be relative to the content adapter.

content/
├── articles/
│   ├── _index.md
│   ├── article-1.md
│   └── article-2.md
├── books/
│   ├── _content.gotmpl  <-- content adapter
│   └── _index.md
└── films/
    ├── _content.gotmpl  <-- content adapter
    └── _index.md

Each content adapter is named _content.gotmpl and uses the same syntax as templates in the layouts directory. You can use any of the template functions within a content adapter, as well as the methods described below.

Methods

Use these methods within a content adapter.

AddPage

Adds a page to the site.

{{ $content := dict
  "mediaType" "text/markdown"
  "value" "The _Hunchback of Notre Dame_ was written by Victor Hugo."
}}
{{ $page := dict
  "content" $content
  "kind" "page"
  "path" "the-hunchback-of-notre-dame"
  "title" "The Hunchback of Notre Dame"
}}
{{ .AddPage $page }}

AddResource

Adds a page resource to the site.

{{ with resources.Get "images/a.jpg" }}
  {{ $content := dict
    "mediaType" .MediaType.Type
    "value" .
  }}
  {{ $resource := dict
    "content" $content
    "path" "the-hunchback-of-notre-dame/cover.jpg"
  }}
  {{ $.AddResource $resource }}
{{ end }}

Then retrieve the new page resource with something like:

{{ with .Resources.Get "cover.jpg" }}
  
{{ end }}

Site

Returns the Site to which the pages will be added.

{{ .Site.Title }}

[!note] Note that the Site returned isn't fully built when invoked from the content adapters; if you try to call methods that depends on pages, e.g. .Site.Pages, you will get an error saying "this method cannot be called before the site is fully initialized".

Store

Returns a persistent "scratch pad" to store and manipulate data. The main use case for this is to transfer values between executions when EnableAllLanguages is set. See examples.

{{ .Store.Set "key" "value" }}
{{ .Store.Get "key" }}

EnableAllLanguages

By default, Hugo executes the content adapter only once for the first matching site in the sites matrix. Use this method to expand execution to all languages while maintaining the current role and version.

For more fine-grained control, define a sites.matrix in front matter or in a content mount.

{{ .EnableAllLanguages }}
{{ $content := dict
  "mediaType" "text/markdown"
  "value" "The _Hunchback of Notre Dame_ was written by Victor Hugo."
}}
{{ $page := dict
  "content" $content
  "kind" "page"
  "path" "the-hunchback-of-notre-dame"
  "title" "The Hunchback of Notre Dame"
}}
{{ .AddPage $page }}

EnableAllDimensions

By default, Hugo executes the content adapter only once for the first matching site in the sites matrix. Use this method to expand execution to every possible combination of language, version, and role.

For more fine-grained control, define a sites.matrix in front matter or in a content mount.

{{< new-in v0.153.0 />}}

Page map

Set any front matter field in the map passed to the AddPage method, excluding markup. Instead of setting the markup field, specify the content.mediaType as described below.

This table describes the fields most commonly passed to the AddPage method.

[!note] While path is the only required field, we recommend setting title as well.

When setting the path, Hugo transforms the given string to a logical path. For example, setting path to A B C produces a logical path of /section/a-b-c.

Resource map

Construct the map passed to the AddResource method using the fields below.

[!note] When content.value is a string, Hugo generates a new resource with a publication path relative to the page. However, if content.value is already a resource, Hugo directly uses its value and publishes it relative to the site root. This latter method is more efficient.

When setting the path, Hugo transforms the given string to a logical path. For example, setting path to A B C/cover.jpg produces a logical path of /section/a-b-c/cover.jpg.

Example

Create pages from remote data, where each page represents a book review.

Step 1 : Create the content structure.

content/
└── books/
    ├── _content.gotmpl  <-- content adapter
    └── _index.md

Step 2 : Inspect the remote data to determine how to map key-value pairs to front matter fields.
https://gohugo.io/shared/examples/data/books.json

Step 3 : Create the content adapter.

{}
{{ $data := dict }}
{{ $url := "https://gohugo.io/shared/examples/data/books.json" }}
{{ with try (resources.GetRemote $url) }}
  {{ with .Err }}
    {{ errorf "Unable to get remote resource %s: %s" $url . }}
  {{ else with .Value }}
    {{ $data = . | transform.Unmarshal }}
  {{ else }}
    {{ errorf "Unable to get remote resource %s" $url }}
  {{ end }}
{{ end }}

{}
{{ range $data }}

  {}
  {{ $content := dict "mediaType" "text/markdown" "value" .summary }}
  {{ $dates := dict "date" (time.AsTime .date) }}
  {{ $params := dict "author" .author "isbn" .isbn "rating" .rating "tags" .tags }}
  {{ $page := dict
    "content" $content
    "dates" $dates
    "kind" "page"
    "params" $params
    "path" .title
    "title" .title
  }}
  {{ $.AddPage $page }}

  {}
  {{ $item := . }}
  {{ with $url := $item.cover }}
    {{ with try (resources.GetRemote $url) }}
      {{ with .Err }}
        {{ errorf "Unable to get remote resource %s: %s" $url . }}
      {{ else with .Value }}
        {{ $content := dict "mediaType" .MediaType.Type "value" .Content }}
        {{ $params := dict "alt" $item.title }}
        {{ $resource := dict
          "content" $content
          "params" $params
          "path" (printf "%s/cover.%s" $item.title .MediaType.SubType)
        }}
        {{ $.AddResource $resource }}
      {{ else }}
        {{ errorf "Unable to get remote resource %s" $url }}
      {{ end }}
    {{ end }}
  {{ end }}

{{ end }}

Step 4 : Create a page template to render each book review.

{{ define "main" }}
  <h1>{{ .Title }}</h1>

  {{ with .Resources.GetMatch "cover.*" }}
    
  {{ end }}

  <p>Author: {{ .Params.author }}</p>

  <p>
    ISBN: {{ .Params.isbn }}

    Rating: {{ .Params.rating }}

    Review date: {{ .Date | time.Format ":date_long" }}
  </p>

  {{ with .GetTerms "tags" }}
    <p>Tags:</p>
    <ul>
      {{ range . }}
        <li><a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a></li>
      {{ end }}
    </ul>
  {{ end }}

  {{ .Content }}
{{ end }}

Multilingual projects

With multilingual projects you can:

1. Create one content adapter for all languages using the EnableAllLanguages method as described above.
2. Create content adapters unique to each language. See the examples below.

Translations by file name

With this project configuration:

{{< code-toggle file=hugo >}} [languages.en] weight = 1

[languages.de] weight = 2 {{< /code-toggle >}}

Include a language designator in the content adapter's file name.

content/
└── books/
    ├── _content.de.gotmpl
    ├── _content.en.gotmpl
    ├── _index.de.md
    └── _index.en.md

Translations by content directory

With this project configuration:

{{< code-toggle file=hugo >}} [languages.en] contentDir = 'content/en' weight = 1

[languages.de] contentDir = 'content/de' weight = 2 {{< /code-toggle >}}

Create a single content adapter in each directory:

content/
├── de/
│   └── books/
│       ├── _content.gotmpl
│       └── _index.md
└── en/
    └── books/
        ├── _content.gotmpl
        └── _index.md

Page collisions

Two or more pages collide when they have the same publication path. Due to concurrency, the content of the published page is indeterminate. Consider this example:

content/
└── books/
    ├── _content.gotmpl  <-- content adapter
    ├── _index.md
    └── the-hunchback-of-notre-dame.md

If the content adapter also creates books/the-hunchback-of-notre-dame, the content of the published page is indeterminate. You can not define the processing order.

To detect page collisions, use the --printPathWarnings flag when building your project.