Rails 3.1 Load CSS in Particular Order

Rails 3.1 Load css in particular order

It is better to specify the order of each and every files manually:

/*
 * This is a manifest file that'll automatically include all the stylesheets available in this directory
 * and any sub-directories. You're free to add application-wide styles to this file and they'll appear at
 * the top of the compiled file, but it's generally better to create a new file per style scope.
 *= require_self
 *= require reset
 *= require groups
 *= require the_last
*

Is it possible to control the order .CSS files are read by Rails or is it fixed by convention?

SCSS

I believe the require_tree directive loads the files in alphabetical order

If you want to load the files in your own order, you may be interested in looking into using the @import functionality of scss (the Rails default CSS preprocessor)

You'll be able to do the following:

#app/assets/stylesheets/application.css.scss
@import bootstrap
@import todo
@import **/* /* Directory Globbing ;-) */

--

This will allow you to load the individual files / directories you require in the order you require

How does one load a CSS framework in Rails 3.1?

Even though Rails 3.1 (RC) allows use of SASS files-- it doesn't force it.
Files in your /public/stylesheets will still be served just fine.

If you wish to activate the SASS parser (and utilize the new framework), rename your my_styles.css to be my_styles.css.scss and put it in the /app/assets/stylesheets folder. Then include just your application.css in your application.erb.html after uncommenting out the require_self / require_tree lines in it.

For more info, here is a blog i pulled up after a quick google search: http://www.rubyinside.com/how-to-rails-3-1-coffeescript-howto-4695.html

As for the IE 8 thing. There was a bug in IE not not always executing conditions, so try


<!--[if IE 8.000]><!-->
<link href='./design/style-ie-8.css' rel='stylesheet' type='text/css' />
<!--<![endif]-->


its a bit of hackery to try and reset the parser to execute the rule

Javascript and CSS specific files, how to include them by convention ? Rails 3.1

In the application.css and application.js file, be sure to remove the line \\= require tree.

Then, manually list all the css/js files you want included in each manifest file, for example:

// application.js
//= global.js
//= everywhere.js

Then, I would setup a yield in your header or your closing body tag for your application layout file, for instance (in haml)

%head
  %title Some Page
  = stylesheet_link_tag 'application'
  = yield :stylesheets

Then in your particular view, say _example_partial.html.haml, do this:

- content_for :stylesheets do
  = stylesheet_link_tag 'example_partial'

-# the rest of your view goes here

You do the exact same thing with Javascript files, just using javascript_include_tag instead of stylesheet_link_tag.

This will let you quickly and easily assemble view-specific javascript / css payloads. There may be a more sophisticated way to handle this using the asset pipeline, but I would suggest that if the asset pipeline is already minifying and merging you major stylesheets that this kind of +1 css / js file per view is not going to cause a major performance hit. Just try to make sure you don't overdo it with dozens of separate files loading into a single view.

Adding page-specific CSS to Rails Asset Pipeline

I found this blog post to be very helpful: http://blog.seancarpenter.net/2012/11/05/page-specific-javascript-with-the-asset-pipeline/. My answer paraphrases what this blogger already wrote and fills in a few missing details.

---

First, it's important that you've read and understood the Rails Guide to the Asset Pipeline. Unfortunately, this guide doesn't clearly explain how to add action-specific assets, but it does cover some concepts you need to know. Made sure you understand these ideas:

• That the asset pipeline compiles Javascript, CSS, and other assets so that Rails servers can cache assets for better performance.
• That manifest files use commands like require, require_tree, and require_self to indicate which files are compiled together.
• That in order for the asset pipeline to work properly in production, you need to manually run rake assets:precompile to produce the compiled, minified assets in the public directory.

These ideas are the minimum "need-to-know" pieces of information about the asset pipeline. If you don't already understand these ideas, you don't have an "expert or enthusiast" level of knowledge about the pipeline, and unfortunately, SO isn't the right place to learn this stuff. Fortunately, the the Rails Guide to the Asset Pipeline is a short 15-minute read and can get you up to speed quickly if you need it.

---

Second, these are the changes you need to make in order to ensure that the asset pipeline correctly sees and handles your new print.css file.

Follow these steps:

1. Add your print.css file to app/assets/css.
2. You'll need to create a manifest file that will show Rails where to find print.css. You need to do this, even though you only have a single CSS file you're adding. This is an easy step:
   
   
   • Add a file called print.js to app/assets/javascript.
   • Add this line to print.js:

//= require print

This will be the only line in the entire print.js file. If I understand correctly, Rails expects manifest files to have the file extension .js, which is why we aren't using print.css as the manifest file.

3. We now need to instruct Rails to find and use the print.js manifest. Add the following line in your config/application.rb file:

config.assets.precompile += %w( print.js )

4. We're almost finished! However, the already-present application.js manifest includes the line //= require_tree . which means that it will include your print.css file. This will cause your print.css styling to affect your entire site, not just the single view. There are two ways of dealing with this:
   
   
   • If application.js and print.js do not share any assets, you can use the stub command in your application.js to exclude the assets used in print.js. What this does is instruct application.js to remove any of the assets that print.js references from its own list of referenced files. Our modified application.js looks like:

(snip...)
require_tree .
stub print

See this answer for more information.

• If your print.js and application.js files share some assets, you'll need to move all of the assets used by application.js into subdirectories. I didn't do this myself, so I'm not the most help in this area. Look at this answer for instructions.

---

Now we have included print.css in the asset pipeline. We now need to direct Rails to use print.css in your specific view.

Let's say your action is in the reports controller, and that the action is named print_reports. This means we have a reports_controller.rb file and a print_reports.html.erb (or .haml) file. We need to make several changes to these files.

1. To start, add a new layout in app/views/layouts. Perhaps call it print.html.erb. We'll use this new layout for your print_reports.html.erb file. Set it up as you desire. For a page intended to be printed, this will likely be very simple, such as

<html>
    <head>
        <title="Print">
    </head>
    <body>
        <%= yield %>
    </body>
</html>

Using a separate layout the disadvantage that it's difficult to keep this layout and the layout used by the rest of the application in sync, but if you are using separate CSS files for the action, it's unlikely that you want the layout to be the same anyway.

2. Add a stylesheet_link_tag in the layout's header pointing to your print.css:

<html>
    <head>
        <title="Print"/>
        <%= stylesheet_link_tag "print" %>
    </head>
    <body>
        <%= yield %>
    </body>
</html>

3. In the controller, we'll tell Rails to use our new layout for the action. Add the line layout 'print', only: [:print_reports] to your controller:

class reports_controller < ApplicationController
    layout 'print', only: [:print_reports]

    #snip

See this question for more information and a few different approaches.

At this point, when you run the app, your print_reports action should be using print.css correctly!

---

Remember to run rake assets:precompile before deploying on the server.

How do you properly include a conditional css file for IE in Rails 3.1+ (asset pipeline) and haml?

/[if IE] 
  = stylesheet_link_tag 'ie'

CSS Require Order - Asset Pipeline

Scss variables are processed at compile time, the order you use them doesn't actually matter for variables since, by the time the code links to the .css file, the variables were already replaces by the scss compiler on the assets pipeline, feeds.css.scss doesn't know what $red means since it's defined in another file.

You have to include the variables on every .scss file that uses them.

_colors.css.scss

$red: #ff0000;
$blue: #0000ff;
$gree: #00ff00;

default_app.css.scss

@import('colors');
.something {
  color: $red;
}

feeds.css.scss

@import('colors');
.other_thing {
  color: $red;
  background: $blue;
}

---

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