https://github.com/tkareine/jekyll-minibundle

A minimalistic asset bundling plugin for Jekyll
https://github.com/tkareine/jekyll-minibundle

asset-bundling assets bundler fingerprinting jekyll jekyll-plugin minification minimalist ruby ruby-gem

Last synced: 10 days ago
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A minimalistic asset bundling plugin for Jekyll

• Host: GitHub
• URL: https://github.com/tkareine/jekyll-minibundle
• Owner: tkareine
• License: mit
• Created: 2012-12-06T05:52:03.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2024-01-08T19:01:33.000Z (10 months ago)
• Last Synced: 2024-04-24T20:03:07.751Z (7 months ago)
• Topics: asset-bundling, assets, bundler, fingerprinting, jekyll, jekyll-plugin, minification, minimalist, ruby, ruby-gem
• Language: Ruby
• Homepage:
• Size: 527 KB
• Stars: 67
• Watchers: 6
• Forks: 9
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE.txt

Awesome Lists containing this project

• awesome-jekyll-plugins - **Mini Bundle** - minibundle](https://rubygems.org/gems/jekyll-minibundle)) -- asset bundling and cache busting using external minification tool of your choice. No gem dependencies. (Assets & Converters & Minifiers)

README

        
# Jekyll Minibundle plugin

[![Gem version](https://badge.fury.io/rb/jekyll-minibundle.svg)][MinibundleGem]

[![CI](https://github.com/tkareine/jekyll-minibundle/workflows/CI/badge.svg)][MinibundleCI]

A straightforward asset bundling plugin for [Jekyll], utilizing external

minification tool of your choice. It provides asset concatenation for

bundling and asset fingerprinting with MD5 digest for cache busting.

There are no runtime dependencies, except for the minification tool used

for bundling (fingerprinting has no dependencies).

The plugin requires Jekyll version 3 or 4. It is tested with Ruby MRI

2.7 and later.

The plugin works with Jekyll's watch mode (auto-regeneration, Jekyll

option `--watch`), but not with incremental feature enabled (Jekyll

option `--incremental`).

## Features

There are two features: fingerprinting with [MD5 digest][MD5] over the

contents of the asset file (any type of file will do), and asset

bundling combined with the first feature.

Asset bundling consists of concatenation and minification. The plugin

implements concatenation and leaves choosing the minification tool up to

you. [UglifyJS][UglifyJS2] is a good and fast minifier, for example. The

plugin connects to the minifier with standard unix pipe, feeding asset

file contents to it in desired order via standard input, and reads the

result from standard output.

Why is this good? A fingerprint in asset's path is the [recommended

way][GoogleWebDevHttpCache] to handle caching of static resources,

because you can allow browsers and intermediate proxies to cache the

asset for a very long time. Calculating MD5 digest over the contents of

the file is fast and the resulting digest is reasonably unique to be

generated automatically.

Asset bundling is good for reducing the number of requests to the

backend upon page load. The minification of stylesheets and JavaScript

sources makes asset sizes smaller and thus faster to load over network.

## Usage

The plugin ships as a [RubyGem][MinibundleGem]. To install:

1. Add the following line to the [Gemfile] of your site:

   ``` ruby

   gem 'jekyll-minibundle'

   ```

2. Run `bundle install`.

3. Instruct Jekyll to load the gem by adding this line to the

[configuration file][JekyllConf] of your site (`_config.yml`):

   ``` yaml

   plugins:

     - jekyll/minibundle

   ```

   (Use the `gems` key instead of `plugins` for Jekyll older than v3.5.0.)

An alternative to using the `plugins` configuration option is to add the

`_plugins/minibundle.rb` file to your site project with this line:

``` ruby

require 'jekyll/minibundle'

```

You must allow Jekyll to use custom plugins. That is, do not enable

Jekyll's `safe` configuration option.

### Asset fingerprinting

If you just want to have an MD5 fingerprint in your asset's path, use

the `ministamp` [Liquid] tag in a Liquid template file. For example,

fingerprinting CSS styles:

``` liquid

```

When it's time to render the `ministamp` tag, the plugin copies the

source file (`_assets/site.css`, the first tag argument) to the

specified destination path (`assets/site.css`, the second tag argument)

in Jekyll's site destination directory. The filename will contain a

fingerprint.

The tag outputs the asset destination path, encoded for HTML, into

Liquid's template rendering outcome. For example, when `site.baseurl` is

empty:

``` html

```

Another example, this time fingerprinting an image and using the

[absolute_url][JekyllLiquidFilters] Liquid filter of Jekyll to render

the absolute URL of the image in the `src` attribute:

``` liquid



```

This feature can be combined with asset generation tools external to

Jekyll. For example, you can configure [Sass] to take input files from

`_assets/styles/*.scss` and to produce output to `_tmp/site.css`. Then,

you use the `ministamp` tag to copy the file with a fingerprint to

Jekyll's site destination directory:

``` liquid

```

#### `ministamp` call syntax

The argument for the `ministamp` tag must be in [YAML] syntax, and

parsing the argument as YAML must result either in a String or a

Hash. What you saw previously was the argument being parsed as a String;

it's effectively a shorthand version of passing the argument as a Hash

with certain keys. That is, in the following call:

``` liquid

{% ministamp _tmp/site.css assets/site.css %}

```

the argument is a String: `"_tmp/site.css assets/site.css"`. The call is

equivalent to the following call with a Hash argument:

``` liquid

{% ministamp { source_path: _tmp/site.css, destination_path: assets/site.css } %}

```

The Hash argument allows expressing more options and quoting

`source_path` and `destination_path` values, if needed.

The supported keys for the Hash argument are:

| Key | Required? | Value type | Value example | Default value | Description |

| --- | --- | --- | --- | --- | --- |

| `source_path` | yes | string | `'_tmp/site.css'` | - | The source path of the asset file, relative to the site directory. |

| `destination_path` | yes | string | `'assets/site.css'` | - | The destination path of the asset file, relative to Jekyll's site destination directory. If the value begins with `/` and `render_basename_only` is `false`, `ministamp`'s output will begin with `/`. |

| `render_basename_only` | no | boolean | `true` | `false` | If `true`, `ministamp`'s rendered URL will be the basename of the asset destination path. See [Separating asset destination path from generated URL](#separating-asset-destination-path-from-generated-url) for more. |

With a Hash argument, the plugin processes `source_path` and

`destination_path` values through a tiny template engine. This allows

you to use Liquid's variables as input to `ministamp` tag. An example

with Liquid's [`assign`][LiquidAssignTag] tag:

``` liquid

{% assign asset_dir = 'assets' %}

```

The above would use `assets/site.css` as the destination path.

Note that you must quote `destination_path`'s value, otherwise YAML does

not recognize it as a proper string.

To refer to Jekyll's configuration options ([`_config.yml`][JekyllConf])

in the template, prefix the variable name with `site.`. For example, to

refer to `baseurl` option, use syntax `{{ site.baseurl }}` in the

template.

See [Variable templating](#variable-templating) for details about the

template syntax.

### Asset bundling

This is a straightforward way to bundle assets with any minification

tool that supports reading input from stdin and writing the output to

stdout. You write the configuration for input sources directly into the

content file where you want the markup tag for the bundle file to

appear. The markup tag contains the path to the bundle file, and the

Jekyll's site destination directory will have the bundle file at that

path. The path will contain an MD5 fingerprint.

Place the `minibundle` [Liquid] block into the Liquid template file

where you want the block's generated markup to appear. Write bundling

configuration inside the block in [YAML] syntax. For example, to bundle

a set of JavaScript sources:

``` text

{% minibundle js %}

source_dir: _assets/scripts

destination_path: assets/site

baseurl: '{{ site.baseurl }}/'

assets:

  - dependency

  - app

attributes:

  id: my-scripts

  async:

{% endminibundle %}

```

Then, specify the command for launching your favorite minifier in

`_config.yml`:

``` yaml

baseurl: ''

minibundle:

  minifier_commands:

    js: node_modules/.bin/uglifyjs

```

When it's time to render the `minibundle` block, the plugin launches the

minifier and connects to it with a Unix pipe. The plugin feeds the

contents of the asset files in `source_dir` directory as input to the

minifier (stdin). The feeding order is the order of the files in the

`assets` key in the block configuration. The plugin expects the minifier

to produce output (stdout) and writes it to the file at

`destination_path` in Jekyll's site destination directory. The filename

will contain a fingerprint.

The block outputs `` (for `css` type) or `` (for `js`

type) HTML element into Liquid's template rendering outcome. Continuing

the example above, the block's output will be:

``` html

<script src="/assets/site-8e764372a0dbd296033cb2a416f064b5.js" type="text/javascript" id="my-scripts" async>

```

You can pass custom attributes, like `id="my-scripts"` and `async`

above, to the generated markup with `attributes` map inside the

`minibundle` block.

As shown above for the `baseurl` key, you can use Liquid template syntax

inside the contents of the block. Liquid renders block contents before

the `minibundle` block gets the turn to render itself. Just ensure that

block contents will result in valid YAML.

For bundling CSS assets, use `css` as the argument to the `minibundle`

block:

``` text

{% minibundle css %}

source_dir: _assets/styles

destination_path: assets/site

baseurl: '{{ site.baseurl }}/'

assets:

  - reset

  - common

attributes:

  media: screen

{% endminibundle %}

```

And then specify the minifier command in `_config.yml`:

``` yaml

minibundle:

  minifier_commands:

    css: _bin/remove_whitespace

    js: node_modules/.bin/uglifyjs

```

#### `minibundle` call syntax

Use `css` or `js` as the argument to the opening tag, for example `{% minibundle css %}`.

The block contents must be in [YAML] syntax. The supported keys are:

| Key | Value type | Value example | Default value | Description |

| --- | --- | --- | --- | --- |

| `source_dir` | string | - | `'_assets'` | The source directory of `assets`, relative to the site directory. You can use period (`.`) to select the site directory itself. |

| `assets` | array of strings | `['deps/one', 'deps/two', 'app']` | `[]` | Array of assets relative to `source_dir` directory, without type extension. These are the asset files to be bundled, in order, into one bundle destination file. |

| `destination_path` | string | - | `'assets/site'` | The destination path of the bundle file, without type extension, relative to Jekyll's site destination directory. If the value begins with `/` and `baseurl` is empty, `baseurl` will be set to `'/'` implicitly. |

| `baseurl` | string | `'{{ site.baseurl }}/'` | `''` | If nonempty, the bundle destination URL inside `minibundle`'s rendered HTML element will be this value prepended to the destination path of the bundle file. Ignored if `destination_baseurl` is nonempty. |

| `destination_baseurl` | string | `'{{ site.cdn_baseurl }}/'` | `''` | If nonempty, the bundle destination URL inside `minibundle`'s rendered HTML element will be this value prepended to the basename of the bundle destination path. See [Separating asset destination path from generated URL](#separating-asset-destination-path-from-generated-url) for more. |

| `attributes` | map of keys to string values | `{id: my-link, media: screen}` | `{}` | Custom HTML element attributes to be added to `minibundle`'s rendered HTML element. |

| `minifier_cmd` | string | `'node_modules/.bin/uglifyjs'` | - | Minifier command specific to this bundle. See [Minifier command specification](#minifier-command-specification) for more. |

### Minifier command specification

You can specify minifier commands in three places:

1. In `_config.yml` (as shown earlier):

   ``` yaml

   minibundle:

     minifier_commands:

       css: _bin/remove_whitespace

       js: node_modules/.bin/uglifyjs

   ```

2. As environment variables:

   ``` bash

   export JEKYLL_MINIBUNDLE_CMD_CSS=_bin/remove_whitespace

   export JEKYLL_MINIBUNDLE_CMD_JS="node_modules/.bin/uglifyjs"

   ```

3. Inside the `minibundle` block with `minifier_cmd` option, allowing

   blocks to have different commands from each other:

   ``` text

   {% minibundle js %}

   source_dir: _assets/scripts

   destination_path: assets/site

   minifier_cmd: node_modules/.bin/uglifyjs

   assets:

     - dependency

     - app

   attributes:

     id: my-scripts

   {% endminibundle %}

   ```

These ways of specification are listed in increasing order of

specificity. Should multiple commands apply to a block, the most

specific one wins. For example, the `minifier_cmd` option inside the `{%

minibundle js }%` block overrides the setting in the

`$JEKYLL_MINIBUNDLE_CMD_JS` environment variable.

### Recommended directory layout

It's recommended that you exclude the files you use as asset sources

from Jekyll itself. Otherwise, you end up with duplicate files in the

site destination directory.

For example, in the following snippet we're using `assets/src.css` as

asset source to `ministamp` tag:

``` liquid

```

By default, Jekyll includes this file to the site destination

directory. As a result, there will be both `src.css` and

`dest-.css` files in `_site/assets/` directory, which you probably

do not want.

In order to avoid this, exclude the asset source file from Jekyll.

Because Jekyll's site generation excludes underscore directories (that

is, directories whose name begins with underscore character), consider

using the following directory layout:

* `_assets/` for JavaScript and CSS assets handled by the plugin that

  are in version control

* `_tmp/` for temporary JavaScript and CSS assets handled by the plugin

  that are not in version control (for example, Sass output files)

* `assets/` for images and other assets handled by Jekyll directly

However, Jekyll's watch mode (auto-regeneration) does monitor files

inside underscore directories. If such a file is modified, the watch

mode triggers site generation. For Minibundle's functionality, this is

beneficial: it allows the plugin to check if assets need to be updated

to the site destination directory.

The `exclude` [Jekyll configuration][JekyllConf] option affects Jekyll's

watch mode. Given the recommended directory layout above, if you set the

following in `_config.yml`:

``` yaml

exclude:

  - _assets

  - _tmp

```

Then Jekyll won't see if files inside those directories have changed and

the plugin won't get the chance to update assets to the site destination

directory. So, don't explicitly exclude the `_assets` and `_tmp`

directories.

See [Jekyll configuration][JekyllConf] for more about excluding files

and directories.

### Development mode

If you set the `$JEKYLL_MINIBUNDLE_MODE` environment variable to

`development`, then the plugin will copy asset files as is to Jekyll's

site destination directory and omit fingerprinting.

The development mode changes `minibundle` block's `destination_path`

option to be the base directory for files mentioned in the `assets`

option. This is useful in development workflow, where you need the

filenames and line numbers of the original asset sources.

``` bash

$ JEKYLL_MINIBUNDLE_MODE=development jekyll serve --watch

```

Alternatively, you can enable development mode from `_config.yml`:

``` yaml

minibundle:

  mode: development

```

Should both be defined, the setting from the environment variable wins.

### Variable templating

The template engine used by `ministamp` tag's Hash argument has syntax

resembling the ones of [Liquid] and [Mustache], with `{{` and `}}` tags

surrounding the variable to be substituted into the output string. For

example, given Liquid variable `var = 'foo'`, the template `begin{{ var

}}end` results in `beginfooend`.

The engine supports variable substitution only. It does not support

other expressions. If you need to, you can write complex expressions in

Liquid, store the result to a variable, and use the variable in the

template.

If you need literal `{` or `}` characters in the template, you can

escape them with backslash. For example, `\{` results in `{` in the

output. To output backslash character itself, write it twice: `\\`

results in `\` in the output.

Inside variable subsitution (between `{{` and `}}`), anything before the

closing `}}` tag is interpreted as part of the variable name, except

that the engine removes any leading and trailing whitespace from the

name. For example, in the template `{{ var } }}`, `var }` is treated as

the name of the variable.

A reference to undefined variable results in empty string. For example,

`begin{{ nosuch }}end` will output `beginend` if there's no variable

named `nosuch`.

### Separating asset destination path from generated URL

Use the `render_basename_only: true` option of the `ministamp` tag and

the `destination_baseurl` option of the `minibundle` block to separate

the destination path of the asset file from the generated URL of the

asset. This allows you to serve the asset from a separate domain, for

example.

Example usage, with the following content in `_config.yml`:

``` yaml

cdn_baseurl: 'https://cdn.example.com'

```

For the `ministamp` tag:

``` liquid

```

The asset file will be in Jekyll's site destination directory with path

`assets/site-ff9c63f843b11f9c3666fe46caaddea8.css`, and Liquid's

rendering will result in:

``` html

```

For the `minibundle` block:

``` liquid

{% minibundle js %}

source_dir: _assets/scripts

destination_path: assets/site

destination_baseurl: '{{ site.cdn_baseurl }}/js/'

assets:

  - dependency

  - app

{% endminibundle %}

```

The bundle file will be in Jekyll's site destination directory with path

`assets/site-4782a1f67803038d4f8351051e67deb8.js`, and Liquid's

rendering will result in:

``` html

```

### Capturing Liquid output

Use Liquid's [`capture`][LiquidCaptureBlock] block to store output

rendered inside the block to a variable, as a string. Then you can

process the string as you like.

For example:

``` liquid

{% capture site_css %}{% ministamp _assets/site.css assets/site.css %}{% endcapture %}

```

Liquid's rendering outcome:

``` html

```

## Example site

See the sources of [an example site][JekyllMinibundleExampleSite].

## Known caveats

The plugin does not work with Jekyll's incremental rebuild feature

(Jekyll option `--incremental`).

## License

MIT. See [LICENSE.txt].

[Gemfile]: https://bundler.io/gemfile.html

[GoogleWebDevHttpCache]: https://web.dev/http-cache/

[JekyllConf]: https://jekyllrb.com/docs/configuration/

[JekyllLiquidFilters]: https://jekyllrb.com/docs/liquid/filters/

[JekyllMinibundleExampleSite]: https://github.com/tkareine/jekyll-minibundle-example

[Jekyll]: https://jekyllrb.com/

[LICENSE.txt]: https://raw.githubusercontent.com/tkareine/jekyll-minibundle/master/LICENSE.txt

[LiquidAssignTag]: https://shopify.github.io/liquid/tags/variable/#assign

[LiquidCaptureBlock]: https://shopify.github.io/liquid/tags/variable/#capture

[Liquid]: https://shopify.github.io/liquid/

[MD5]: https://en.wikipedia.org/wiki/MD5

[MinibundleCI]: https://github.com/tkareine/jekyll-minibundle/actions?workflow=CI

[MinibundleGem]: https://rubygems.org/gems/jekyll-minibundle

[Mustache]: https://mustache.github.io/

[Sass]: https://sass-lang.com/

[UglifyJS2]: https://github.com/mishoo/UglifyJS2

[YAML]: https://yaml.org/