14 KiB
| aliases | lastmod | date | menu | next | prev | title | toc | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
2016-02-03 | 2013-07-01 |
|
/extras/highlighting | /extras/scratch | Shortcodes | true |
Hugo uses Markdown for its simple content format. However, there are a lot of things that Markdown doesn’t support well.
We are unwilling to accept being constrained by our simple format. Also unacceptable is writing raw HTML in our Markdown every time we want to include unsupported content such as a video. To do so is in complete opposition to the intent of using a bare-bones format for our content and utilizing templates to apply styling for display.
To avoid both of these limitations, Hugo created shortcodes.
A shortcode is a simple snippet inside a content file that Hugo will render using a predefined template. Note that shortcodes will not work in template files---if you need a functionality like that in a template, you most likely want a partial template instead.
Another benefit is, you can update your shortcode with any related new classes or techniques, and upon generation, Hugo will easily merge in your changes. You avoid a possibly complicated search and replace operation.
Using a shortcode
In your content files, a shortcode can be called by using the {{%/* name parameters */%}} form. Shortcode parameters are space delimited. Parameters with spaces
can be quoted.
The first word is always the name of the shortcode. Parameters follow the name.
Depending upon how the shortcode is defined, the parameters may be named,
positional or both (although you can't mix parameter types in a single call).
The format for named parameters models that of HTML with the format
name="value".
Some shortcodes use or require closing shortcodes. Like HTML, the opening and closing shortcodes match (name only), the closing being prepended with a slash.
Example of a paired shortcode:
{{</* highlight go */>}} A bunch of code here {{</* /highlight */>}}
The examples above use two different delimiters, the difference being the % and the < character:
Shortcodes with Markdown
The % characters indicates that the shortcode's inner content needs further processing by the page's rendering processor (i.e. Markdown), needed to get the bold text in the example below:
{{%/* myshortcode */%}}Hello **World!**{{%/* /myshortcode */%}}
Shortcodes without Markdown
The < character indicates that the shortcode's inner content doesn't need any further rendering, this will typically be pure HTML:
{{</* myshortcode */>}}<p>Hello <strong>World!</strong></p>{{</* /myshortcode */>}}
Built-in Shortcodes
Hugo ships with a set of predefined shortcodes.
highlight
This shortcode will convert the source code provided into syntax highlighted HTML. Read more on highlighting.
Usage
highlight takes exactly one required parameter of language and requires a
closing shortcode.
Example
{{</* highlight html */>}}
<section id="main">
<div>
<h1 id="title">{{ .Title }}</h1>
{{ range .Data.Pages }}
{{ .Render "summary"}}
{{ end }}
</div>
</section>
{{</* /highlight */>}}
Example Output
<span style="color: #f92672"><section</span> <span style="color: #a6e22e">id=</span><span style="color: #e6db74">"main"</span><span style="color: #f92672">></span>
<span style="color: #f92672"><div></span>
<span style="color: #f92672"><h1</span> <span style="color: #a6e22e">id=</span><span style="color: #e6db74">"title"</span><span style="color: #f92672">></span>{{ .Title }}<span style="color: #f92672"></h1></span>
{{ range .Data.Pages }}
{{ .Render "summary"}}
{{ end }}
<span style="color: #f92672"></div></span>
<span style="color: #f92672"></section></span>
figure
figure is simply an extension of the image capabilities present with Markdown.
figure provides the ability to add captions, CSS classes, alt text, links etc.
Usage
figure can use the following named parameters:
- src
- link
- title
- caption
- class
- attr (attribution)
- attrlink
- alt
Example
{{</* figure src="/media/spf13.jpg" title="Steve Francia" */>}}
Example output
<figure>
<img src="/media/spf13.jpg" />
<figcaption>
<h4>Steve Francia</h4>
</figcaption>
</figure>
ref, relref
These shortcodes will look up the pages by their relative path (e.g.,
blog/post.md) or their logical name (post.md) and return the permalink
(ref) or relative permalink (relref) for the found page.
ref and relref also make it possible to make fragmentary links that work
for the header links generated by Hugo.
Read more on [cross-references]({{% ref "extras/crossreferences.md" %}}).
Usage
ref and relref take exactly one required parameter of reference.
Example
[Neat]({{</* ref "blog/neat.md" */>}})
[Who]({{</* relref "about.md#who" */>}})
If the page exists in multiple [output formats]({{< relref "extras/output-formats.md" >}}), ref or relref can be used with a output format name:
[Neat]({{</* ref "blog/neat.md" "amp" */>}})
Example Output
Assuming that standard Hugo pretty URLs are turned on.
<a href="/blog/neat">Neat</a>
<a href="/about/#who:c28654c202e73453784cfd2c5ab356c0">Who</a>
You want to include a single tweet into your blog post? Everything you need is the URL of the tweet, e.g.:
Pass the tweet's ID from the URL as parameter to the shortcode as shown below:
{{</* tweet 666616452582129664 */>}}
YouTube
This shortcode embeds a responsive video player for YouTube videos. Only the ID of the video is required, e.g.:
Copy the ID from behind v= and pass it to the shortcode:
{{</* youtube w7Ft2ymGmfc */>}}
Furthermore, you can autostart the embedded video by setting the autostart parameter to true. Remember that you can't mix named an unamed parameters. Assign the yet unamed video id to the parameter id like below too.
{{</* youtube id="w7Ft2ymGmfc" autoplay="true" */>}}
Vimeo
Adding a video from Vimeo is equivalent to the YouTube shortcode above. Extract the ID from the URL, e.g.:
and pass it to the shortcode:
{{</* vimeo 146022717 */>}}
GitHub gists
Including code snippets with GitHub gists while writing a tutorial is common situation bloggers face. With a given URL of the gist, e.g.:
pass the owner and the ID of the gist to the shortcode:
{{</* gist spf13 7896402 */>}}
If the gist contains several files and you want to quote just one of them, you can pass the filename (quoted) as an optional third argument:
{{</* gist spf13 7896402 "img.html" */>}}
Speaker Deck
To embed slides from Speaker Deck, click on "< /> Embed" (under Share right next to the template on Speaker Deck) and copy the URL, e.g.:
<script async class="speakerdeck-embed" data-id="4e8126e72d853c0060001f97" data-ratio="1.33333333333333" src="//speakerdeck.com/assets/embed.js"></script>
Extract the value from the field data-id and pass it to the shortcode:
{{</* speakerdeck 4e8126e72d853c0060001f97 */>}}
If you'd like to embed photo from Instagram, all you need is photo ID from the URL, e. g.:
Pass it to the shortcode:
{{</* instagram BMokmydjG-M */>}}
Optionally, hide caption:
{{</* instagram BMokmydjG-M hidecaption */>}}
Creating your own shortcodes
To create a shortcode, place a template in the layouts/shortcodes directory. The template name will be the name of the shortcode.
In creating a shortcode, you can choose if the shortcode will use positional
parameters, or named parameters, or both. A good rule of thumb is that if a
shortcode has a single required value in the case of the youtube example below,
then positional works very well. For more complex layouts with optional
parameters, named parameters work best. Allowing both types of parameters is
useful for complex layouts where you want to set default values that can be
overridden.
Inside the template
To access a parameter by position, the .Get method can be used:
{{ .Get 0 }}
To access a parameter by name, the .Get method should be utilized:
{{ .Get "class" }}
with is great when the output depends on a parameter being set:
{{ with .Get "class"}} class="{{.}}"{{ end }}
.Get can also be used to check if a parameter has been provided. This is
most helpful when the condition depends on either one value or another...
or both:
{{ or .Get "title" | .Get "alt" | if }} alt="{{ with .Get "alt"}}{{.}}{{else}}{{.Get "title"}}{{end}}"{{ end }}
If a closing shortcode is used, the variable .Inner will be populated with all
of the content between the opening and closing shortcodes. If a closing
shortcode is required, you can check the length of .Inner and provide a warning
to the user.
A shortcode with .Inner content can be used without the inline content, and without the closing shortcode, by using the self-closing syntax:
{{</* innershortcode /*/>}}
The variable .Params contains the list of parameters in case you need to do
more complicated things than .Get. It is sometimes useful to provide a
flexible shortcode that can take named or positional parameters. To meet this
need, Hugo shortcodes have a .IsNamedParams boolean available that can be used
such as {{ if .IsNamedParams }}...{{ else }}...{{ end }}. See the
Single Flexible Example below for an example.
You can also use the variable .Page to access all the normal Page Variables.
A shortcodes can be nested. In a nested shortcode you can access the parent shortcode context with .Parent. This can be very useful for inheritance of common shortcode parameters from the root.
Single Positional Example: youtube
{{</* youtube 09jf3ow9jfw */>}}
Would load the template /layouts/shortcodes/youtube.html
<div class="embed video-player">
<iframe class="youtube-player" type="text/html" width="640" height="385" src="http://www.youtube.com/embed/{{ index .Params 0 }}" allowfullscreen frameborder="0">
</iframe>
</div>
This would be rendered as:
<div class="embed video-player">
<iframe class="youtube-player" type="text/html"
width="640" height="385"
src="http://www.youtube.com/embed/09jf3ow9jfw"
allowfullscreen frameborder="0">
</iframe>
</div>
Single Named Example: image with caption
{{</* img src="/media/spf13.jpg" title="Steve Francia" */>}}
Would load the template /layouts/shortcodes/img.html
<!-- image -->
<figure {{ with .Get "class" }}class="{{.}}"{{ end }}>
{{ with .Get "link"}}<a href="{{.}}">{{ end }}
<img src="{{ .Get "src" }}" {{ if or (.Get "alt") (.Get "caption") }}alt="{{ with .Get "alt"}}{{.}}{{else}}{{ .Get "caption" }}{{ end }}"{{ end }} />
{{ if .Get "link"}}</a>{{ end }}
{{ if or (or (.Get "title") (.Get "caption")) (.Get "attr")}}
<figcaption>{{ if isset .Params "title" }}
<h4>{{ .Get "title" }}</h4>{{ end }}
{{ if or (.Get "caption") (.Get "attr")}}<p>
{{ .Get "caption" }}
{{ with .Get "attrlink"}}<a href="{{.}}"> {{ end }}
{{ .Get "attr" }}
{{ if .Get "attrlink"}}</a> {{ end }}
</p> {{ end }}
</figcaption>
{{ end }}
</figure>
<!-- image -->
Would be rendered as:
<figure >
<img src="/media/spf13.jpg" />
<figcaption>
<h4>Steve Francia</h4>
</figcaption>
</figure>
Single Flexible Example: vimeo with defaults
{{</* vimeo 49718712 */>}}
{{</* vimeo id="49718712" class="flex-video" */>}}
Would load the template /layouts/shortcodes/vimeo.html
{{ if .IsNamedParams }}
<div class="{{ if .Get "class" }}{{ .Get "class" }}{{ else }}vimeo-container{{ end }}">
<iframe src="//player.vimeo.com/video/{{ .Get "id" }}" allowfullscreen></iframe>
</div>
{{ else }}
<div class="{{ if len .Params | eq 2 }}{{ .Get 1 }}{{ else }}vimeo-container{{ end }}">
<iframe src="//player.vimeo.com/video/{{ .Get 0 }}" allowfullscreen></iframe>
</div>
{{ end }}
Would be rendered as:
<div class="vimeo-container">
<iframe src="//player.vimeo.com/video/49718712" allowfullscreen></iframe>
</div>
<div class="flex-video">
<iframe src="//player.vimeo.com/video/49718712" allowfullscreen></iframe>
</div>
Paired Example: Highlight
Hugo already ships with the highlight shortcode
{{</* highlight html */>}}
<html>
<body> This HTML </body>
</html>
{{</* /highlight */>}}
The template for this utilizes the following code (already included in Hugo)
{{ .Get 0 | highlight .Inner }}
And will be rendered as:
<div class="highlight" style="background: #272822"><pre style="line-height: 125%"><span style="color: #f92672"><html></span>
<span style="color: #f92672"><body></span> This HTML <span style="color: #f92672"></body></span>
<span style="color: #f92672"></html></span>
</pre></div>
Please notice that this template makes use of a Hugo-specific template function
called highlight which uses Pygments to add the highlighting code.
Simple Single-word Example: Year
Let's assume you would like to have a shortcode to be replaced by the current year in your Markdown content files, for a license or copyright statement. Calling a shortcode like this:
{{</* year */>}}
... would load your one-line template /layouts/shortcodes/year.html, which contains:
{{ .Page.Now.Year }}
More shortcode examples can be found at spf13.com.