Roadie

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Note: This README details the 3.x version of Roadie. You might be using 2.x, which is much older and only for Rails.

Making HTML emails comfortable for the Ruby rockstars

Roadie tries to make sending HTML emails a little less painful by inlining stylesheets and rewriting relative URLs for you inside your emails.

How does it work?

Email clients have bad support for stylesheets, and some of them blocks stylesheets from downloading. The easiest way to handle this is to work with all styles inline, but that is error prone and hard to work with as you cannot use classes and/or reuse styling.

This gem helps making this easier by automatically inlining stylesheet rules into the document before sending it. You just give it a list of stylesheets and it will go though all of the selectors assigning the styles to the maching elements. Careful attention has been put into rules being applied in the correct order, so it should behave just like in the browser¹.

Roadie also rewrites all relative URLs in the email to a absolute counterpart, making images you insert and those referenced in your stylesheets work. No more headaches about how to write the stylesheets while still having them work with emails from your acceptance environments.

¹: Of course, rules like :hover will not work by definition. Only static styles can be added.

Features

²: This might be removed in a future version, though. You really ought to create a good layout and not let Roadie guess how you want to have it structured.

Install & Usage

Add this gem to your Gemfile as recommended by Rubygems and run bundle install.

gem 'roadie', '~> x.y.0'

You may then create a new instance of a Roadie document:

document = Roadie::Document.new "<html><body></body></html>"
document.add_css "body { color: green; }"
document.transform
    # => "<html><body style=\"color:green;\"></body></html>"

Your document instance can be configured several options:

Making URLs absolute

In order to make URLs absolute you need to first configure the URL options of the document.

html = '... <a href="/about-us">Read more!</a> ...'
document = Roadie::Document.new html
document.url_options = {host: "myapp.com", protocol: "https"}
document.transform
  # => "... <a href=\"https://myapp.com/about-us\">Read more!</a> ..."

The following URLs will be rewritten for you: * a[href] (HTML) * img[src] (HTML) * url() (CSS)

Referenced stylesheets

By default, style and link elements in the email document's head are processed along with the stylesheets and removed from the head.

You can set a special data-roadie-ignore attribute on style and link tags that you want to ignore (the attribute will be removed, however). This is the place to put things like :hover selectors that you want to have for email clients allowing them.

Style and link elements with media="print" are also ignored.

<head>
  <link rel="stylesheet" type="text/css" href="/assets/emails/rock.css">         <!-- Will be inlined -->
  <link rel="stylesheet" type="text/css" href="http://www.metal.org/metal.css">  <!-- Will NOT be inlined; absolute URL -->
  <link rel="stylesheet" type="text/css" href="/assets/jazz.css" media="print">  <!-- Will NOT be inlined; print style -->
  <link rel="stylesheet" type="text/css" href="/ambient.css" data-roadie-ignore> <!-- Will NOT be inlined; ignored -->
  <style></style>                    <!-- Will be inlined -->
  <style data-roadie-ignore></style> <!-- Will NOT be inlined; ignored -->
</head>

Roadie will use the given asset providers to look for the actual CSS that is referenced. If you don't change the default, it will use the Roadie::FilesystemProvider which looks for stylesheets on the filesystem, relative to the current working directory.

Example:

# /home/user/foo/stylesheets/primary.css
body { color: blue; }

# /home/user/foo/script.rb
html = <<-HTML
<html>
  <head>
  <link rel="stylesheet" type="text/css" href="/stylesheets/primary.css">
  </head>
  <body>
  </body>
</html>
HTML

Dir.pwd # => "/home/user/foo"
document = Roadie::Document.new html
document.transform # =>
                   # <!DOCTYPE html>
                   # <html>
                   #   <head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head>
                   #   <body style="color:green;"></body>
                   # </html>

If a referenced stylesheet cannot be found, the #transform method will raise an Roadie::CssNotFound error. If you instead want to ignore missing stylesheets, you can use the NullProvider.

Configuring providers

You can write your own providers if you need very specific behavior for your app, or you can use the built-in providers.

Included providers: * FilesystemProvider - Looks for files on the filesystem, relative to the given directory unless otherwise specified. * ProviderList – Wraps a list of other providers and searches them in order. The asset_providers setting is an instance of this. It behaves a lot like an array, so you can push, pop, shift and unshift to it. * NullProvider - Does not actually provide anything, it always finds empty stylesheets. Use this in tests or if you want to ignore stylesheets that cannot be found by your other providers.

If you want to search several locations on the filesystem, just declare that:

document.asset_providers = [
  Roadie::FilesystemProvider.new(App.root.join("resources", "stylesheets")),
  Roadie::FilesystemProvider.new(App.root.join("system", "uploads", "stylesheets")),
]

If you want to ignore stylesheets that cannot be found instead of crashing, push the NullProvider to the end:

document.asset_providers << Roadie::NullProvider.new

Writing your own provider

Writing your own provider is also easy. You just need to provide: * #find_stylesheet(name), returning either a Roadie::Stylesheet or nil. * #find_stylesheet!(name), returning either a Roadie::Stylesheet or raising Roadie::CssNotFound.

class UserAssetsProvider
  def initialize(user_collection)
    @user_collection = user_collection
  end

  def find_stylesheet(name)
    if name =~ %r{^/users/(\d+)\.css$}
      user = @user_collection.find_user($1)
      Roadie::Stylesheet.new("user #{user.id} stylesheet", user.stylesheet)
    end
  end

  def find_stylesheet!(name)
    find_stylesheet(name) or raise Roadie::CssNotFound.new(name)
  end

  # Instead of implementing #find_stylesheet!, you could also:
  # include Roadie::AssetProvider
end

# Try to look for a user stylesheet first, then fall back to normal filesystem lookup.
document.asset_providers = [
  UserAssetsProvider.new(app),
  Roadie::FilesystemProvider.new('./stylesheets'),
]

You can test for compliance by using the built-in RSpec examples:

require 'spec_helper'
require 'roadie/rspec'

describe MyOwnProvider do
  # Will use the default `subject` (MyOwnProvider.new)
  it_behaves_like "roadie asset provider", valid_name: "found.css", invalid_name: "does_not_exist.css"

  # Extra setup just for these tests:
  it_behaves_like "roadie asset provider", valid_name: "found.css", invalid_name: "does_not_exist.css" do
    subject { MyOwnProvider.new(...) }
    before { Whatever.stub ... }
  end
end

Callbacks

Callbacks allow you to do custom work on documents before they are inlined. The Nokogiri document tree is passed to the callable:

class TrackNewsletterLinks
  def call(document)
    document.css("a").each { |link| fix_link(link) }
  end

  def fix_link(link)
    divider = (link['href'] =~ /?/ ? '&' : '?')
    link['href'] = link['href'] + divider + 'source=newsletter'
  end
end

document.before_transformation = { |document| logger.debug "Inlining document with title #{document.at_css('head > title').try(:text)}" }
document.after_transformation = TrackNewsletterLinks.new

Build Status

Tested with Travis CI using:

(Build status)

Let me know if you want any other VM supported officially.

Rubinius support is experimental since it it currently hindered by a Rubinius bug that will probably be fixed shortly.

Versioning

This project follows Semantic Versioning and has been since version 1.0.0.

FAQ

I'm getting segmentation faults (or other C-like problems)! What should I do?

Roadie uses Nokogiri to parse the HTML of your email, so any C-like problems like segfaults are likely in that end. The best way to fix this is to first upgrade libxml2 on your system and then reinstall Nokogiri. Instructions on how to do this on most platforms, see Nokogiri's official install guide.

My :hover selectors don't work. How can I fix them?

Put any styles using :hover in a separate stylesheet and make sure it is ignored. (See "Ignoring stylesheets" above)

My @media queries don't work. How can I fix them?

Put any styles using them in a separate stylesheet and make sure it is ignored. (See "Ignoring stylesheets" above)

My vendor-specific styles don't work. How can I fix them?

Put any styles using them in a separate stylesheet and make sure it is ignored. (See "Ignoring stylesheets" above)

Documentation

Running specs

bundle install
rake

History and contributors

This gem was previously tied to Rails. It is now framework-agnostic and supports any type of HTML documents. If you want to use it with Rails, check out roadie-rails.

Major contributors to Roadie:

You can see all contributors on GitHub.

License

(The MIT License)

Copyright (c) 2009-2014

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.