Set Meta Tags In ERB Views

There are all kinds of meta tags that we may want to set for the pages that our Rails app serves. A lot of these are for SEO and social sharing. Let's look at how to add og:description meta tags to our views.

I'll start with a helper method in app/helpers/application_helper.rb:

module ApplicationHelper
  def meta_description(desc)
    content_for(:description) { desc }
  end
end

Then, I'll update my app/views/layouts/application.html.erb to consume the description when provided.

<!DOCTYPE html>
<html>
  <head>
    <!-- ... -->

    <meta
      property="og:description"
      content="<%= content_for?(:description) ? yield(:description) : 'Default description' %>"
    >

    <!-- ... -->
  </head>

  <!-- ... -->
</html>

Now I have a default description for all my views that I can override as needed with the meta_description helper.

# app/views/posts/show.html.erb
<%= meta_description @post.body.split("\n").first %>

<!-- ... -->

If I reload the page and inspect the meta tags in <head>, I should find the og:description tag with the corresponding value.

This can be extended to apply all the different meta tags (e.g. Open Graph and Twitter) to make links to these pages render well across the internet.