Shortcodes are a means to consolidate templating into small, reusable snippets that you can embed directly inside your content. In this sense, you can think of shortcodes as the intermediary between [page and list templates][templates] and [basic content files].
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.
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 /*/%}}`.
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:
You can create shortcodes using the following types of parameters:
* Positional parameters
* Named parameters
* Positional *or* named parameters (i.e, "flexible")
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.
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.
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.
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.
To access a parameter by name, use the `.Get` method followed by the named parameter as a quoted string:
If a closing shortcode is used, the `.Inner` variable will be populated with 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.
A shortcode with content declared via the `.Inner` variable can also be declared without the content and without the closing tag by using the self-closing syntax:
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:
`$.Params`
: these are the parameters passed directly into the shortcode declaration (e.g., a YouTube video ID)
: refers to the page's parameters; the "page" in this case refers to the content file in which the shortcode is declared (e.g., a `shortcode_color` field in a content's front matter could be accessed via `$.Page.Params.shortcode_color`).
: refers to global variables as defined in your [site's configuration file][config].
#### `.IsNamedParams`
The `.IsNamedParams` variable checks whether the shortcode declaration uses named parameters and returns a boolean value.
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:
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.
You can also use the variable `.Page` to access all the normal [page variables][pagevars].
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.
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.
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:
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]:
Would load the template at `/layouts/shortcodes/youtube.html`:
{{<codefile="/layouts/shortcodes/youtube.html">}}
<divclass="embed video-player">
<iframeclass="youtube-player"type="text/html"width="640"height="385"src="https://www.youtube.com/embed/{{ index .Params 0 }}"allowfullscreenframeborder="0">
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:
Hugo's [`.Parent` shortcode variable][parent] provides access to the parent shortcode context when the shortcode in question is called within the context of a *parent* shortcode. This provides an inheritance model for common shortcode parameters.
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`:
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`:
More shortcode examples can be found in the [shortcodes directory for spf13.com][spfscs] and the [shortcodes directory for the Hugo docs][docsshortcodes].
You can also 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.
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.
And once enabled, you can do this in your content files:
```go-text-template
{{</* time.inline */>}}{{ now }}{{</* /time.inline */>}}
```
The above will print the current date and time.
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.
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".
