AutoHtml is a collection of filters that transforms plain text into HTML code. See live demo.
Add this line to your application's Gemfile:
gem 'auto_html'And then execute:
$ bundleOr install it yourself as:
$ gem install auto_htmlAutoHtml uses concepts found in "Pipes and Filters" processing design pattern:
Filter- transforms an input. In AutoHtml context, this is any object that does the transformation through#call(String)method. Filter options should be passed in initializer. AutoHtml provides some filters already, ie Link, Image, Markdown, etc.Pipeline- a composition of filters that transforms input by passing the output of one filter as input for the next filter in line. In AutoHtml context, this is theAutoHtml::Pipelineclass. Since the same interface (method#call) is used to pass input, we can say that Pipeline is just another Filter, which means it can be used as a building block for other Pipelines, in a mix with other filters.
link_filter = AutoHtml::Link.new(target: '_blank')
link_filter.call('Checkout out auto_html: https://github.com/dejan/auto_html')
# => 'Checkout out my blog: <a target="blank" href="https://github.com/dejan/auto_html">https://github.com/dejan/auto_html</a>'
emoji_filter = AutoHtml::Emoji.new
emoji_filter.call(':point_left: yo!')
# => '<img src="/https/github.com/images/emoji/unicode/1f448.png" class="emoji" title=":point_left:" alt=":point_left:" height="20" witdh="20" align="absmiddle" /> yo!'
# Use Pipeline to combine filters
base_format = AutoHtml::Pipeline.new(link_filter, emoji_filter)
base_format.call('Checkout out auto_html: https://github.com/dejan/auto_html :point_left: yo!')
# => 'Checkout out my blog: <a href="https://github.com/dejan/auto_html">https://github.com/dejan/auto_html</a> <img src="/https/github.com/images/emoji/unicode/1f448.png" class="emoji" title=":point_left:" alt=":point_left:" height="20" witdh="20" align="absmiddle" /> yo!'
# A pipeline can be reused in another pipeline. Note that the order of filters is important - ie you want
# `Image` before `Link` filter so that URL of the image gets transformed to `img` tag and not `a` tag.
comment_format = AutoHtml::Pipeline.new(AutoHtml::Markdown.new, AutoHtml::Image.new, base_format)
comment_format.call("Hello!\n\n Checkout out auto_html: https://github.com/dejan/auto_html :point_left: yo! \n\n http://gifs.joelglovier.com/boom/booyah.gif")
# => "<p>Hello!</p>\n\n<p>Checkout out my blog: <a href="<img src="https://github.com/dejan/auto_html" target="_blank">https://github.com/dejan/auto_html</a> <img src="/https/github.com/images/emoji/unicode/1f448.png" />" class="emoji" title=":point_left:" alt=":point_left:" height="20" witdh="20" align="absmiddle" /> yo! </p>\n\n<p><a href="<img src="http://gifs.joelglovier.com/boom/booyah.gif" />" target="_blank"><img src="http://gifs.joelglovier.com/boom/booyah.gif" /></a></p>\n"Bellow is the list of bundled filters along with their optional arguments on initialization and their default values.
AutoHtml::EmojiAutoHtml::HtmlEscapeAutoHtml::Image, proxy: nil, alt: nilAutoHtml::Link, target: nil, rel: nilAutoHtml::MarkdownAutoHtml::SimpleFormat
For performance reasons it's a good idea to store the formated output in the database, in a separate column, to avoid generating the same content on each access. This can be acomplished simply by overriding the attribute writter:
class Comment < ActiveRecord::Base
FORMAT = AutoHtml::Pipeline.new(
AutoHtml::HtmlEscape.new,
AutoHtml::Markdown.new
)
def text=(t)
super(t)
self[:text_html] = FORMAT.call(t)
end
endNow, every time text attribute is set, text_html will be set as well:
comment = Comment.new(text: 'Hey!')
comment.text_html # => '<p>Hey!</p>'bundle installrake rubocoprake specAutoHtml is released under the MIT License.