Roadie

Making HTML emails comfortable for the Rails rockstars

Roadie tries to make sending HTML emails a little less painful in Rails 3 by inlining stylesheets and rewrite relative URLs for you.

If you want to have this in Rails 2, please see MailStyle.

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.

Build Status

Tested with Travis CI using the all combinations of:

• Ruby:
  • 1.8.7
  • 1.9.2
  • 1.9.3
• Rails
  • 3.0
  • 3.1
  • 3.2

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

Versioning

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

Features

• Supports Rails' Asset Pipeline and simple filesystem access out of the box
• You can add support for CSS from any place inside your apps
• Writes CSS styles inline
  • Respects !important styles
  • Does not overwrite styles already present in the style attribute of tags
  • Supports the same CSS selectors as Nokogiri (use CSS3 selectors in your emails!)
• Makes image urls absolute
  • Hostname and port configurable on a per-environment basis
• Makes link hrefs absolute
• Automatically adds proper html skeleton when missing (you don't have to create a layout for emails)²

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

Add the gem to Rails' Gemfile

gem 'roadie'

Configuring

Roadie listens to the following options (set in Application.rb or in your environment's configuration files:

• config.action_mailer.default_url_options - Used for making URLs absolute
• config.assets.enabled - If the asset pipeline is turned off, Roadie will default to searching for assets in public/stylesheets
• config.roadie.provider - Set the provider manually, ignoring all other options. Use for advanced cases, or when you have non-default paths or other options.

Usage

Just add a <link rel="stylesheet" /> or <style type="text/css"></style> element inside your email layout and it will be inlined automatically.

Note: Do not use stylesheet_link_tag in your mail views. Just use a regular tag pointing to the logical asset name instead; e.g. emails.css instead of emails-<SHA>.css. This should hopefully be fixed in a later version. You are recommended to use the :css option to the mailer (detailed below) instead if you want to avoid problems with this.

You can also specify the :css option to mailer to have it inlined automatically without you having to make a layout:

class Notifier < ActionMailer::Base
  default :css => :email, :from => 'support@mycompany.com'

  def registration_mail
    mail(:subject => 'Welcome Aboard', :to => 'someone@example.com')
  end

  def newsletter
    mail(:subject => 'Newsletter', :to => 'someone@example.com', :css => [:email, :newsletter])
  end
end

This will look for a css file called email.css in your assets. The css method can take either a string, a symbol or an array of both. The ".css" extension will be added automatically.

Image URL rewriting

If you have default_url_options[:host] set in your mailer, then Roadie will do it's best to make the URLs of images and in stylesheets absolute.

In application.rb:

class Application
  config.action_mailer.default_url_options = {:host => 'example.com'}
end

If you want to to be different depending on your environment, just set it in your environment's configuration instead.

Ignoring 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-immutable="true" attribute on style and link tags you do not want to be processed and removed from the document's head. 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 always ignored.

Inlining link tags

Any link element that is part of your email will be linked in. You can exclude them by setting data-immutable as you would on normal style elements. Linked stylesheets for print media is also ignored as you would expect.

If the link tag uses an absolute URL to the stylesheet, it will not be inlined. Use a relative path instead:

<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 -->
  <link rel="stylesheet" type="text/css" href="/assets/jazz.css" media="print">      <!-- Will NOT be inlined -->
  <link rel="stylesheet" type="text/css" href="/ambient.css" data-immutable>         <!-- Will NOT be inlined -->
</head>

Writing your own provider

A provider handles searching CSS files for you. Cou can easily create your own provider for your specific app by subclassing Roadie::AssetProvider. See the API documentation for information about how to build them.

Example Subclassing the AssetPipelineProvider:

# application.rb
config.roadie.provider = UserAssetsProvider.new

# lib/user_assets_provider.rb
class UserAssetsProvider < Roadie::AssetPipelineProvider
  def find(name)
    super
  rescue CSSFileNotFound
    user = User.find_by_name(name)
    raise unless user
    user.custom_css
  end
end

Bugs / TODO

• Improve overall performance
• Clean up stylesheet assignment code
• Assets referenced with digest URLs should be findable
  • Roadie should be able to have multiple asset providers in a specific order

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

• Online documentation for 2.3.0
• Online documentation for master
• Changelog

History and contributors

Major contributors to Roadie:

• Arttu Tervo (arttu) - Original Asset pipeline support

You can see all contributors on GitHub.

This gem was originally developed for Rails 2 use on Purify under the name MailStyle. However, the author stopped maintaining it and a fork took place to make it Rails 3 compatible.

The following people have contributed to the orignal gem:

• Jim Neath (Original author)
• Lars Klevans
• Jonas Grimfelt
• Ben Johnson
• Istvan Hoka
• Voraz

License

(The MIT License)

Copyright (c) 2009-2011

• Jim Neath
• Magnus Bergmark magnus.bergmark@gmail.com

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.