Octopress Filters

A set of handy liquid filters used by Octopress.

full_urls - Replace relative URLs with absolute URLs (searches for href and src properties).
full_url - Replace a relative URL with an absolute URL.
canonical_url - Convert a URL to the proper canonical version.
titlecase - Properly capitalize titles with John Gruber’s Title Case.
smartquotes - Smartly curl your quotation marks with John Gruber’s Smarty Pants.
unorphan - Insert a non-breaking space between the last two words in a title.
sluggify - Replaces all non-word characters in a string with dashes.
classify - An alias for sluggify (seems appropriate when working with CSS class names).
compact_newlines - Compact groups of empty lines into one, because Liquid templates have lots of whitespace.
join_lines - Remove all new lines, joining each line with a separator. (defaults to a space).
strip_url_protocol - Remove the protocol before a URL, e.g. http:// or https://.

Also, not a filter, but this adds excerpted (true/false) to post's data. Meaning you can use {% if post.excerpted %} in a post loop.

Installation

If you're using bundler add this gem to your site's Gemfile in the :jekyll_plugins group:

group :jekyll_plugins do
  gem 'octopress-filters'
end

Then install the gem with Bundler

$ bundle

To install manually without bundler:

$ gem install octopress-filters

Then add the gem to your Jekyll configuration.

gems:
  -octopress-filters

Examples

Full URLs

Any relative links in your site will be expanded with the url configuration in Jekyll's _config.yml. This filter only affects URLs beginning with / inside of href or src attributes.

{{ post.content | full_urls }}

You might use this if you're working on an RSS feed, you'll need to be sure all relative URLs in your content are expanded to full URLs.

Full URL

This filter prepends input with the url configuration in Jekyll's _config.yml.

{{ post.url | full_url }}

Canonical URL

This filter expands the URL to be a full URL, then removes "index.html" if it is present. Here are some examples.

{{ "about/index.html" | canonical_url }}  //=> http://example.com/about/
{{ "about.html" | canonical_url }}        //=> http://example.com/about.html
{{ "/" | canonical_url }}                 //=> http://example.com/

Titlecase

{{ post.title | titlecase }}  //=> This Is a Properly Capitalized Title

Smartquote

{{ post.content | smartquotes }}

Unorphan

{{ post.title | unorphan }}  //=> This Is a Properly Capitalized&nbsp;Title

Sluggify/Classify

<article class="{{ post.class | classify }}">

Compact newlines

{{ content | compact_newlines }}

Join lines

{% capture page_title %}
{{ page.title }}
{{ site.header.title }}
{% endcapture %}

<head>
  <title>{{ page_title | join_lines: " - " }}</title>
  …

Strip URL protocol

{{ site.url }}                        # https://some-site.com/
{{ site.url | strip_url_protocol }}   # some-site.com/

Excerpted posts

In your templates, you may want to show different content if a post is excerpted. This plugin automatically searches each post for the excerpt separator and adds the excerpted state to the post data. So you can do something like this.

{% if post.excerpted %}
  {{ post.excerpt }}
  <a href="{{ post.url }}"Continue reading →</a>
{% else %}
  {{ post.content }}
{% endif %}

Jekyll has an excerpt_separator configuration which lets you define how Jekyll selects your post excerpts. By default this config is set to "\n\n", but redefining the config to something like excerpt_separator:  makes it easy to decide which content is excerpted, or even whether posts have excerpts at all.

Contributing

Fork it ( https://github.com/octopress/filters/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request