Rails asset pipeline working with fonts and yarn

Question

I have an existing rails application where I am working on a separate branch to implement yarn for managing my vendor assets. My app stack is:

• ruby-2.4.0
• rails 5.1.4
• node 9.4.0
• yarn 1.3.2

After installing yarn, I ran yarn init and it generated a package.json in the project root. After a few packages added, it looks like:

# package.json

{
  "name": "my-project-name",
  "version": "1.0.0",
  "private": true,
  "repository": "my-repo",
  "author": "me",
  "license": "MIT",
  "dependencies": {
    "bootstrap": "3",
    "font-awesome": "^4.7.0",
    "jquery": "^3.3.1",
    "jquery-backstretch": "^2.1.16",
    "jquery-ujs": "^1.2.2",
    "waypoints": "^4.0.1"
  }
}

I created under app/assets a couple of files for including stylesheets and javascripts from node_modules:

# app/assets/javascripts/node_modules.js
//= require jquery
//= require jquery-ujs
//= require bootstrap/dist/js/bootstrap.min.js
//= require waypoints
//= require jquery-backstretch

# app/assets/stylesheets/font_path_overwrite.scss
$fa-font-path: "font-awesome/fonts/";

# app/assets/stylesheets/node_modules.css.scss
/*
 *= require bootstrap/dist/css/bootstrap.min.css
 *= require font_path_overwrite
 *= require font-awesome/scss/font-awesome
*/

I also changed:

# config/initializers/assets.rb
# ...
Rails.application.config.assets.paths << Rails.root.join('node_modules')

Rails.application.config.assets.precompile += %w(*.js *.scss)
Rails.application.config.assets.precompile += %w(*.png *.woff2 *.woff *.ttf *.eot *.jpg *.gif *.svg *.ico)

# Rakefile
# ...
Rake::Task['assets:precompile'].enhance [:js_deps_install]
task :js_deps_install do
  sh 'yarn install'
end

As per SO-43170792, I added a new

heroku buildpacks:set heroku/ruby
heroku buildpacks:add --index 1 heroku/nodejs

In my staging environment I deployed these changes and I suddenly realized that something strange is happening with my assets precompilation node_modules/ folder: whilst everything seems to work fine for js and css files, I am having some issues with fonts (especially font-awesome's fonts).

Debugging in the network inspector the file assets/font-awesome/fonts/fontawesome-webfont.ttf?v=4.7.0 is not found since it was precompiled and not just copied into:

public/assets/font-awesome/fonts/fontawesome-webfont-[hash].ttf

I understand why I am facing this situation (which is very similar to this unaswered question from two months ago).

I am looking for a clean solution or smart workaround (e.g. create a middleware to redirect the plain .ttf request to the rails complaint hashed version and cache the answer for x hours. Would you have any suggestion?

Answer 1

I guess I found the cleanest solution after a few attempts:

Attempt 1: Sass and overwrite fonts directories

I did a pretty extensive refactoring of sass modules in app/assets/stylesheets directory. Here a couple of examples:

For fonts

// sass_font_awesome.scss
$fa-font-path: "font-awesome/fonts";
@import 'font-awesome/scss/font-awesome';
@font-face {
  font-family: 'FontAwesome';
  src: asset-url('#{$fa-font-path}/fontawesome-webfont.eot');
  src: asset-url('#{$fa-font-path}/fontawesome-webfont.eot?#iefix') format('embedded-opentype'),
    asset-url('#{$fa-font-path}/fontawesome-webfont.woff2') format('woff2'),
    asset-url('#{$fa-font-path}/fontawesome-webfont.woff') format('woff'),
    asset-url('#{$fa-font-path}/fontawesome-webfont.ttf') format('truetype'),
    asset-url('#{$fa-font-path}/fontawesome-webfont.svg?#fontawesomeregular') format('svg');
  font-weight: normal;
  font-style: normal;
}

For images

// sass_multiselect.scss
$ms-img-path: 'multiselect/js/img';
@import 'multiselect/css/multi-select';
.ms-container{
  background: transparent asset-url('#{$ms-img-path}/switch.png') no-repeat 50% 50%;
  width: 370px;
}

This approach was still breaking when node_modules folder was precompiled. Actually all the node cli scripts had some issues in terms of syntax for Ugflifier.

Attempt 2: Install Webpack and create a app/javascripts/pack/application.sass

@import '~font-awesome/scss/font-awesome'
@import '~multiselect/css/multi-select'

I was still facing some issues with relative paths. I found the solution in webpacker documentation adding to my config/webpacker/environment.js the following loader:

// webpack/environment.js
const { environment } = require('@rails/webpacker')

// resolve-url-loader must be used before sass-loader
environment.loaders.get('sass').use.splice(-1, 0, {
  loader: 'resolve-url-loader',
  options: {
    attempts: 1
  }
});

Solution: the easiest way

I finally found out the default behaviour of webpacker gem and it was very easy:

// app/javascripts/packs/styles.js
import 'font-awesome/scss/font-awesome.scss';
import 'multiselect/css/multi-select.css';

This compile to a bundled styles.css without needing any additional loader.

It took me quite a lot time to figure it out and I hope it will be helpful to you too!

Answer 2

I made it work by overriding font paths.

application.scss:

$fa-font-path:"font-awesome/fonts";

@import 'font-awesome/scss/font-awesome';

@font-face {
  font-family: 'FontAwesome';
  src: font-url('#{$fa-font-path}/fontawesome-webfont.eot?v=#{$fa-version}');
  src: font-url('#{$fa-font-path}/fontawesome-webfont.eot?#iefix&v=#{$fa-version}') format('embedded-opentype'),
  font-url('#{$fa-font-path}/fontawesome-webfont.woff2?v=#{$fa-version}') format('woff2'),
  font-url('#{$fa-font-path}/fontawesome-webfont.woff?v=#{$fa-version}') format('woff'),
  font-url('#{$fa-font-path}/fontawesome-webfont.ttf?v=#{$fa-version}') format('truetype'),
  font-url('#{$fa-font-path}/fontawesome-webfont.svg?v=#{$fa-version}#fontawesomeregular') format('svg');
  //  src: url('#{$fa-font-path}/FontAwesome.otf') format('opentype'); // used when developing fonts
  font-weight: normal;
  font-style: normal;
}

Run rake assets:precompile and you should see font files in public/assets/font-awesome/fonts with digested file names.

Compiled CSS should access font files from Rails assets:

@font-face{
   font-family:'FontAwesome';
   src:url(/assets/font-awesome/fonts/fontawesome-webfont-7bfcab6db99...979.eot?v=4.7.0)