hugo/docs/content/en/hugo-pipes/introduction.md

title	description	date	publishdate	lastmod	categories	keywords	menu	weight	sections_weight	draft	aliases
Hugo Pipes Introduction	Hugo Pipes is Hugo's asset processing set of functions.	2018-07-14	2018-07-14	2018-07-14	asset management		docs parent weight pipes 20	01	01	false	/assets/

Asset directory

Asset files must be stored in the asset directory. This is /assets by default, but can be configured via the configuration file's assetDir key.

From file or URL to resource

In order to process an asset with Hugo Pipes, it must be retrieved as a resource using resources.Get. The first argument can be the filepath of the file relative to the asset directory or the URL of the file.

{{ $style := resources.Get "sass/main.scss" }}
{{ $remoteStyle := resources.Get "https://www.example.com/styles.scss" }}

Request options

When using an URL, the resources.Get function takes an optional options map as the last argument, e.g.:

{{ $resource := resources.Get "https://example.org/api" (dict "headers" (dict "Authorization" "Bearer abcd"))  }}

If you need multiple values for the same header key, use a slice:

{{ $resource := resources.Get "https://example.org/api"  (dict "headers" (dict "X-List" (slice "a" "b" "c")))  }}

You can also change the request method and set the request body:

{{ $postResponse := resources.Get "https://example.org/api"  (dict 
    "method" "post"
    "body" `{"complete": true}` 
    "headers" (dict 
        "Content-Type" "application/json"
    )
)}}

Asset publishing

Assets will only be published (to /public) if .Permalink or .RelPermalink is used.

Go Pipes

For improved readability, the Hugo Pipes examples of this documentation will be written using Go Pipes:

{{ $style := resources.Get "sass/main.scss" | resources.ToCSS | resources.Minify | resources.Fingerprint }}
<link rel="stylesheet" href="{{ $style.Permalink }}">

Method aliases

Each Hugo Pipes resources transformation method uses a camelCased alias (toCSS for resources.ToCSS). Non-transformation methods deprived of such aliases are resources.Get, resources.FromString, resources.ExecuteAsTemplate and resources.Concat.

The example above can therefore also be written as follows:

{{ $style := resources.Get "sass/main.scss" | toCSS | minify | fingerprint }}
<link rel="stylesheet" href="{{ $style.Permalink }}">

Caching

Hugo Pipes invocations are cached based on the entire pipe chain.

An example of a pipe chain is:

{{ $mainJs := resources.Get "js/main.js" | js.Build "main.js" | minify | fingerprint }}

The pipe chain is only invoked the first time it is encountered in a site build, and results are otherwise loaded from cache. As such, Hugo Pipes can be used in templates which are executed thousands or millions of times without negatively impacting the build performance.