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shortcode-templates.md (17519B)

    1 ---
    2 title: Create Your Own Shortcodes
    3 linktitle: Shortcode Templates
    4 description: You can extend Hugo's built-in shortcodes by creating your own using the same templating syntax as that for single and list pages.
    5 date: 2017-02-01
    6 publishdate: 2017-02-01
    7 lastmod: 2017-02-01
    8 categories: [templates]
    9 keywords: [shortcodes,templates]
   10 menu:
   11   docs:
   12     parent: "templates"
   13     weight: 100
   14 weight: 100
   15 sections_weight: 100
   16 draft: false
   17 aliases: []
   18 toc: true
   19 ---
   20 
   21 Shortcodes are a means to consolidate templating into small, reusable snippets that you can embed directly inside of your content. In this sense, you can think of shortcodes as the intermediary between [page and list templates][templates] and [basic content files][].
   22 
   23 {{% note %}}
   24 Hugo also ships with built-in shortcodes for common use cases. (See [Content Management: Shortcodes](/content-management/shortcodes/).)
   25 {{% /note %}}
   26 
   27 ## Create Custom Shortcodes
   28 
   29 Hugo's built-in shortcodes cover many common, but not all, use cases. Luckily, Hugo provides the ability to easily create custom shortcodes to meet your website's needs.
   30 
   31 {{< youtube Eu4zSaKOY4A >}}
   32 
   33 ### File Location
   34 
   35 To create a shortcode, place an HTML template in the `layouts/shortcodes` directory of your [source organization][]. Consider the file name carefully since the shortcode name will mirror that of the file but without the `.html` extension. For example, `layouts/shortcodes/myshortcode.html` will be called with either `{{</* myshortcode /*/>}}` or `{{%/* myshortcode /*/%}}` depending on the type of parameters you choose.
   36 
   37 You can organize your shortcodes in subfolders, e.g. in `layouts/shortcodes/boxes`. These shortcodes would then be accessible with their relative path, e.g:
   38 
   39 ```
   40 {{</* boxes/square */>}}
   41 ```
   42 
   43 Note the forward slash.
   44 
   45 ### Shortcode Template Lookup Order
   46 
   47 Shortcode templates have a simple [lookup order][]:
   48 
   49 1. `/layouts/shortcodes/<SHORTCODE>.html`
   50 2. `/themes/<THEME>/layouts/shortcodes/<SHORTCODE>.html`
   51 
   52 ### Positional vs Named Parameters
   53 
   54 You can create shortcodes using the following types of parameters:
   55 
   56 * Positional parameters
   57 * Named parameters
   58 * Positional *or* named parameters (i.e, "flexible")
   59 
   60 In shortcodes with positional parameters, the order of the parameters is important. If a shortcode has a single required value (e.g., the `youtube` shortcode below), positional parameters work very well and require less typing from content authors.
   61 
   62 For more complex layouts with multiple or optional parameters, named parameters work best. While less terse, named parameters require less memorization from a content author and can be added in a shortcode declaration in any order.
   63 
   64 Allowing both types of parameters (i.e., a "flexible" shortcode) is useful for complex layouts where you want to set default values that can be easily overridden by users.
   65 
   66 ### Access Parameters
   67 
   68 All shortcode parameters can be accessed via the `.Get` method. Whether you pass a key (i.e., string) or a number to the `.Get` method depends on whether you are accessing a named or positional parameter, respectively.
   69 
   70 To access a parameter by name, use the `.Get` method followed by the named parameter as a quoted string:
   71 
   72 ```
   73 {{ .Get "class" }}
   74 ```
   75 
   76 To access a parameter by position, use the `.Get` followed by a numeric position, keeping in mind that positional parameters are zero-indexed:
   77 
   78 ```
   79 {{ .Get 0 }}
   80 ```
   81 
   82 For the second position, you would just use: 
   83 
   84 ```
   85 {{ .Get 1 }}
   86 ```
   87 
   88 `with` is great when the output depends on a parameter being set:
   89 
   90 ```
   91 {{ with .Get "class" }} class="{{ . }}"{{ end }}
   92 ```
   93 
   94 `.Get` can also be used to check if a parameter has been provided. This is
   95 most helpful when the condition depends on either of the values, or both:
   96 
   97 ```
   98 {{ if or (.Get "title") (.Get "alt") }} alt="{{ with .Get "alt" }}{{ . }}{{ else }}{{ .Get "title" }}{{ end }}"{{ end }}
   99 ```
  100 
  101 #### `.Inner`
  102 
  103 If a closing shortcode is used, the `.Inner` variable 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` as an indicator of its existence.
  104 
  105 A shortcode with content declared via the `.Inner` variable can also be declared without the 
  106 content and without the closing 
  107 by using the self-closing syntax:
  108 
  109 ```
  110 {{</* innershortcode /*/>}}
  111 ```
  112 
  113 #### `.Params`
  114 
  115 The `.Params` variable in shortcodes contains the list parameters passed to shortcode for more complicated use cases. You can also access higher-scoped parameters with the following logic:
  116 
  117 `$.Params`
  118 : these are the parameters passed directly into the shortcode declaration (e.g., a YouTube video ID)
  119 
  120 `$.Page.Params`
  121 : refers to the page's params; the "page" in this case refers to the content file in which the shortcode is declared (e.g., a `shortcode_color` field in a content's front matter could be accessed via `$.Page.Params.shortcode_color`).
  122 
  123 `$.Page.Site.Params`
  124 : refers to global variables as defined in your [site's configuration file][config].
  125 
  126 #### `.IsNamedParams`
  127 
  128 The `.IsNamedParams` variable checks whether the shortcode declaration uses named parameters and returns a boolean value.
  129 
  130 For example, you could create an `image` shortcode that can take either a `src` named parameter or the first positional parameter, depending on the preference of the content's author. Let's assume the `image` shortcode is called as follows:
  131 
  132 ```
  133 {{</* image src="images/my-image.jpg" */>}}
  134 ```
  135 
  136 You could then include the following as part of your shortcode templating:
  137 
  138 ```
  139 {{ if .IsNamedParams }}
  140 <img src="{{ .Get "src" }}" alt="">
  141 {{ else }}
  142 <img src="{{ .Get 0 }}" alt="">
  143 {{ end }}
  144 ```
  145 
  146 See the [example Vimeo shortcode][vimeoexample] below for `.IsNamedParams` in action.
  147 
  148 {{% warning %}}
  149 While you can create shortcode templates that accept both positional and named parameters, you *cannot* declare shortcodes in content with a mix of parameter types. Therefore, a shortcode declared like `{{</* image src="images/my-image.jpg" "This is my alt text" */>}}` will return an error.
  150 {{% /warning %}}
  151 
  152 You can also use the variable `.Page` to access all the normal [page variables][pagevars].
  153 
  154 A shortcodes can also be nested. In a nested shortcode, you can access the parent shortcode context with [`.Parent` variable][shortcodesvars]. This can be very useful for inheritance of common shortcode parameters from the root.
  155 
  156 ### Checking for Existence
  157 
  158 You can check if a specific shortcode is used on a page by calling `.HasShortcode` in that page template, providing the name of the shortcode. This is sometimes useful when you want to include specific scripts or styles in the header that are only used by that shortcode.
  159 
  160 ## Custom Shortcode Examples
  161 
  162 The following are examples of the different types of shortcodes you can create via shortcode template files in `/layouts/shortcodes`.
  163 
  164 ### Single-word Example: `year`
  165 
  166 Let's assume you would like to keep mentions of your copyright year current in your content files without having to continually review your markdown. Your goal is to be able to call the shortcode as follows:
  167 
  168 ```
  169 {{</* year */>}}
  170 ```
  171 
  172 {{< code file="/layouts/shortcodes/year.html" >}}
  173 {{ now.Format "2006" }}
  174 {{< /code >}}
  175 
  176 ### Single Positional Example: `youtube`
  177 
  178 Embedded videos are a common addition to markdown content that can quickly become unsightly. The following is the code used by [Hugo's built-in YouTube shortcode][youtubeshortcode]:
  179 
  180 ```
  181 {{</* youtube 09jf3ow9jfw */>}}
  182 ```
  183 
  184 Would load the template at `/layouts/shortcodes/youtube.html`:
  185 
  186 {{< code file="/layouts/shortcodes/youtube.html" >}}
  187 <div class="embed video-player">
  188 <iframe class="youtube-player" type="text/html" width="640" height="385" src="https://www.youtube.com/embed/{{ index .Params 0 }}" allowfullscreen frameborder="0">
  189 </iframe>
  190 </div>
  191 {{< /code >}}
  192 
  193 {{< code file="youtube-embed.html" copy="false" >}}
  194 <div class="embed video-player">
  195     <iframe class="youtube-player" type="text/html"
  196         width="640" height="385"
  197         src="https://www.youtube.com/embed/09jf3ow9jfw"
  198         allowfullscreen frameborder="0">
  199     </iframe>
  200 </div>
  201 {{< /code >}}
  202 
  203 ### Single Named Example: `image`
  204 
  205 Let's say you want to create your own `img` shortcode rather than use Hugo's built-in [`figure` shortcode][figure]. Your goal is to be able to call the shortcode as follows in your content files:
  206 
  207 {{< code file="content-image.md" >}}
  208 {{</* img src="/media/spf13.jpg" title="Steve Francia" */>}}
  209 {{< /code >}}
  210 
  211 You have created the shortcode at `/layouts/shortcodes/img.html`, which loads the following shortcode template:
  212 
  213 {{< code file="/layouts/shortcodes/img.html" >}}
  214 <!-- image -->
  215 <figure {{ with .Get "class" }}class="{{.}}"{{ end }}>
  216     {{ with .Get "link" }}<a href="{{ . }}">{{ end }}
  217         <img src="{{ .Get "src" }}" {{ if or (.Get "alt") (.Get "caption") }}alt="{{ with .Get "alt" }}{{ . }}{{ else }}{{ .Get "caption" }}{{ end }}"{{ end }} />
  218     {{ if .Get "link" }}</a>{{ end }}
  219     {{ if or (or (.Get "title") (.Get "caption")) (.Get "attr") }}
  220     <figcaption>{{ if isset .Params "title" }}
  221         <h4>{{ .Get "title" }}</h4>{{ end }}
  222         {{ if or (.Get "caption") (.Get "attr") }}<p>
  223         {{ .Get "caption" }}
  224         {{ with .Get "attrlink" }}<a href="{{ . }}"> {{ end }}
  225             {{ .Get "attr" }}
  226         {{ if .Get "attrlink" }}</a> {{ end }}
  227         </p> {{ end }}
  228     </figcaption>
  229     {{ end }}
  230 </figure>
  231 <!-- image -->
  232 {{< /code >}}
  233 
  234 Would be rendered as:
  235 
  236 {{< code file="img-output.html" copy="false" >}}
  237 <figure>
  238     <img src="/media/spf13.jpg"  />
  239     <figcaption>
  240         <h4>Steve Francia</h4>
  241     </figcaption>
  242 </figure>
  243 {{< /code >}}
  244 
  245 ### Single Flexible Example: `vimeo`
  246 
  247 ```
  248 {{</* vimeo 49718712 */>}}
  249 {{</* vimeo id="49718712" class="flex-video" */>}}
  250 ```
  251 
  252 Would load the template found at `/layouts/shortcodes/vimeo.html`:
  253 
  254 {{< code file="/layouts/shortcodes/vimeo.html" >}}
  255 {{ if .IsNamedParams }}
  256   <div class="{{ if .Get "class" }}{{ .Get "class" }}{{ else }}vimeo-container{{ end }}">
  257     <iframe src="https://player.vimeo.com/video/{{ .Get "id" }}" allowfullscreen></iframe>
  258   </div>
  259 {{ else }}
  260   <div class="{{ if len .Params | eq 2 }}{{ .Get 1 }}{{ else }}vimeo-container{{ end }}">
  261     <iframe src="https://player.vimeo.com/video/{{ .Get 0 }}" allowfullscreen></iframe>
  262   </div>
  263 {{ end }}
  264 {{< /code >}}
  265 
  266 Would be rendered as:
  267 
  268 {{< code file="vimeo-iframes.html" copy="false" >}}
  269 <div class="vimeo-container">
  270   <iframe src="https://player.vimeo.com/video/49718712" allowfullscreen></iframe>
  271 </div>
  272 <div class="flex-video">
  273   <iframe src="https://player.vimeo.com/video/49718712" allowfullscreen></iframe>
  274 </div>
  275 {{< /code >}}
  276 
  277 ### Paired Example: `highlight`
  278 
  279 The following is taken from `highlight`, which is a [built-in shortcode][] that ships with Hugo.
  280 
  281 {{< code file="highlight-example.md" >}}
  282 {{</* highlight html */>}}
  283   <html>
  284     <body> This HTML </body>
  285   </html>
  286 {{</* /highlight */>}}
  287 {{< /code >}}
  288 
  289 The template for the `highlight` shortcode uses the following code, which is already included in Hugo:
  290 
  291 ```
  292 {{ .Get 0 | highlight .Inner }}
  293 ```
  294 
  295 The rendered output of the HTML example code block will be as follows:
  296 
  297 {{< code file="syntax-highlighted.html" copy="false" >}}
  298 <div class="highlight" style="background: #272822"><pre style="line-height: 125%"><span style="color: #f92672">&lt;html&gt;</span>
  299     <span style="color: #f92672">&lt;body&gt;</span> This HTML <span style="color: #f92672">&lt;/body&gt;</span>
  300 <span style="color: #f92672">&lt;/html&gt;</span>
  301 </pre></div>
  302 {{< /code >}}
  303 
  304 ### Nested Shortcode: Image Gallery
  305 
  306 Hugo's [`.Parent` shortcode variable][parent] returns a boolean value depending on whether the shortcode in question is called within the context of a *parent* shortcode. This provides an inheritance model for common shortcode parameters.
  307 
  308 The following example is contrived but demonstrates the concept. Assume you have a `gallery` shortcode that expects one named `class` parameter:
  309 
  310 {{< code file="layouts/shortcodes/gallery.html" >}}
  311 <div class="{{ .Get "class" }}">
  312   {{ .Inner }}
  313 </div>
  314 {{< /code >}}
  315 
  316 You also have an `img` shortcode with a single named `src` parameter that you want to call inside of `gallery` and other shortcodes, so that the parent defines the context of each `img`:
  317 
  318 {{< code file="layouts/shortcodes/img.html" >}}
  319 {{- $src := .Get "src" -}}
  320 {{- with .Parent -}}
  321   <img src="{{$src}}" class="{{ .Get "class" }}-image">
  322 {{- else -}}
  323   <img src="{{$src}}">
  324 {{- end -}}
  325 {{< /code >}}
  326 
  327 You can then call your shortcode in your content as follows:
  328 
  329 ```
  330 {{</* gallery class="content-gallery" */>}}
  331   {{</* img src="/images/one.jpg" */>}}
  332   {{</* img src="/images/two.jpg" */>}}
  333 {{</* /gallery */>}}
  334 {{</* img src="/images/three.jpg" */>}}
  335 ```
  336 
  337 This will output the following HTML. Note how the first two `img` shortcodes inherit the `class` value of `content-gallery` set with the call to the parent `gallery`, whereas the third `img` only uses `src`:
  338 
  339 ```
  340 <div class="content-gallery">
  341     <img src="/images/one.jpg" class="content-gallery-image">
  342     <img src="/images/two.jpg" class="content-gallery-image">
  343 </div>
  344 <img src="/images/three.jpg">
  345 ```
  346 
  347 
  348 ## Error Handling in Shortcodes
  349 
  350 Use the [errorf](/functions/errorf) template func and [.Position](/variables/shortcodes/) variable to get useful error messages in shortcodes:
  351 
  352 ```bash
  353 {{ with .Get "name" }}
  354 {{ else }}
  355 {{ errorf "missing value for param 'name': %s" .Position }}
  356 {{ end }}
  357 ```
  358 
  359 When the above fails, you will see an `ERROR` log similar to the below:
  360 
  361 ```bash
  362 ERROR 2018/11/07 10:05:55 missing value for param name: "/Users/bep/dev/go/gohugoio/hugo/docs/content/en/variables/shortcodes.md:32:1"
  363 ```
  364 
  365 ## More Shortcode Examples
  366 
  367 More shortcode examples can be found in the [shortcodes directory for spf13.com][spfscs] and the [shortcodes directory for the Hugo docs][docsshortcodes].
  368 
  369 
  370 ## Inline Shortcodes
  371 
  372 {{< new-in "0.52" >}}
  373 
  374 Since Hugo 0.52, you can implement your shortcodes inline -- e.g. where you use them in the content file. This can be useful for scripting that you only need in one place.
  375 
  376 This feature is disabled by default, but can be enabled in your site config:
  377 
  378 {{< code-toggle file="config">}}
  379 enableInlineShortcodes = true
  380 {{< /code-toggle >}}
  381 
  382 It is disabled by default for security reasons. The security model used by Hugo's template handling assumes that template authors are trusted, but that the content files are not, so the templates are injection-safe from malformed input data. But in most situations you have full control over the content, too, and then `enableInlineShortcodes = true` would be considered safe. But it's something to be aware of: It allows ad-hoc [Go Text templates](https://golang.org/pkg/text/template/) to be executed from the content files.
  383 
  384 And once enabled, you can do this in your content files:
  385 
  386  ```go-text-template
  387  {{</* time.inline */>}}{{ now }}{{</* /time.inline */>}}
  388  ```
  389 
  390 The above will print the current date and time.
  391 
  392  Note that an inline shortcode's inner content is parsed and executed as a Go text template with the same context as a regular shortcode template.
  393 
  394 This means that the current page can be accessed via `.Page.Title` etc. This also means that there are no concept of "nested inline shortcodes".
  395 
  396 The same inline shortcode can be reused later in the same content file, with different params if needed, using the self-closing syntax:
  397 
  398  ```go-text-template
  399 {{</* time.inline /*/>}}
  400 ```
  401 	
  402 
  403 [basic content files]: /content-management/formats/ "See how Hugo leverages markdown--and other supported formats--to create content for your website."
  404 [built-in shortcode]: /content-management/shortcodes/
  405 [config]: /getting-started/configuration/ "Learn more about Hugo's built-in configuration variables as well as how to us your site's configuration file to include global key-values that can be used throughout your rendered website."
  406 [Content Management: Shortcodes]: /content-management/shortcodes/#using-hugo-s-built-in-shortcodes "Check this section if you are not familiar with the definition of what a shortcode is or if you are unfamiliar with how to use Hugo's built-in shortcodes in your content files."
  407 [source organization]: /getting-started/directory-structure/#directory-structure-explained "Learn how Hugo scaffolds new sites and what it expects to find in each of your directories."
  408 [docsshortcodes]: https://github.com/gohugoio/hugo/tree/master/docs/layouts/shortcodes "See the shortcode source directory for the documentation site you're currently reading."
  409 [figure]: /content-management/shortcodes/#figure
  410 [hugosc]: /content-management/shortcodes/#using-hugo-s-built-in-shortcodes
  411 [lookup order]: /templates/lookup-order/ "See the order in which Hugo traverses your template files to decide where and how to render your content at build time"
  412 [pagevars]: /variables/page/ "See which variables you can leverage in your templating for page vs list templates."
  413 [parent]: /variables/shortcodes/
  414 [shortcodesvars]: /variables/shortcodes/ "Certain variables are specific to shortcodes, although most .Page variables can be accessed within your shortcode template."
  415 [spfscs]: https://github.com/spf13/spf13.com/tree/master/layouts/shortcodes "See more examples of shortcodes by visiting the shortcode directory of the source for spf13.com, the blog of Hugo's creator, Steve Francia."
  416 [templates]: /templates/ "The templates section of the Hugo docs."
  417 [vimeoexample]: #single-flexible-example-vimeo
  418 [youtubeshortcode]: /content-management/shortcodes/#youtube "See how to use Hugo's built-in YouTube shortcode."