Custom fonts in your Rails app

There are numerous free fonts available on the Internet, and most of them are also available on Google Fonts. Using fonts available on Google is an extremely simple and straight forward thing. You can use any of the following techniques

• Link it to them in your HTML file.

 <link href="https://fonts.googleapis.com/css2?family=Roboto" rel="stylesheet">

• Import the font in your css file.

@import url('https://fonts.googleapis.com/css2?family=Roboto');

However, there are times when fonts you want to use are not available on Google Fonts and other online font foundries - it may be because that particular font is not yet added there or it is a commerically licensed font. In those cases, you receive font files which can be in TrueType Format (.ttf), OpenType Format (.otf), Web Open Font Format (.woff or .woff2)

There can be more than one file for any particular font you are trying to use - they differ on font weight (normal, thin, medium, semibold, bold which are usually represented with numbers between 100 and 900) or font style (italic, normal etc.)

Here are sequence of steps you can follow to add these font files and corresponding css in your project:

• In your rails app, create a directory called fonts in app/assets/ directory
• Copy all the font files in this directory
• In your app/assets/stylesheets directory, create a new file, let’s call it fonts.css
• In fonts.css, add css explaining your fonts. Here is an example

@font-face {
  font-family: "HK Grotesk";
  src: url("./HKGrotesk-Regular.woff2") format("woff2"),
    url("./HKGrotesk-Regular.woff") format("woff");
  font-weight: normal;
  font-style: normal;
}

@font-face {
  font-family: "HK Grotesk";
  src: url("./HKGrotesk-ExtraBold.woff2") format("woff2"),
    url("./HKGrotesk-ExtraBold.woff") format("woff");
  font-weight: 800;
  font-style: normal;
}

• In application config (present in config/application.rb) add the following line in Application class

class Application < Rails::Application
  # Precompile fonts.
  config.assets.paths << Rails.root.join('app/assets/fonts')
end

• And done; start using the new font by specifiying it in the font-family. In the above example, I am trying to use “HK Grotesk” font which is a good font, but still not available on Google font.

font-family: 'HK Grotesk', sans-serif;

• Normally these steps should work, in case they don’t, please also check your Content Security Policy (present in config/initializers/content_security_policy.rb)