Unsubscribe Links

A subscriber may want to unsubscribe at some point, so let’s build that next.

First, we need a route for unsubscribing that will be the URL we include in emails.

  resource :unsubscribe, only: [ :show ]

Active Record has a feature called generates_token_for that can generate unique tokens to find database records for different purposes. We can use this for generating a unique unsubscribe token to use in the email’s unsubscribe URL.

class Subscriber < ApplicationRecord
  belongs_to :product
  generates_token_for :unsubscribe
end

Our controller will first look up the Subscriber record from the token in the URL. Once the subscriber is found, it will destroy the record and redirect to the homepage. Create app/controllers/unsubscribes_controller.rb and add the following code:

class UnsubscribesController < ApplicationController
  allow_unauthenticated_access
  before_action :set_subscriber

  def show
    @subscriber&.destroy
    redirect_to root_path, notice: "Unsubscribed successfully."
  end

  private

  def set_subscriber
    @subscriber = Subscriber.find_by_token_for(:unsubscribe, params[:token])
  end
end

Last but not least, let’s add the unsubscribe link to our email templates.

In app/views/product_mailer/in_stock.html.erb, add a link_to:

<h1>Good news!</h1>

<p><%= link_to @product.name, product_url(@product) %> is back in stock.</p>

<%= link_to "Unsubscribe", unsubscribe_url(token: params[:subscriber].generate_token_for(:unsubscribe)) %>

In app/views/product_mailer/in_stock.text.erb, add the URL in plain text:

Good news!

<%= @product.name %> is back in stock.
<%= product_url(@product) %>

Unsubscribe: <%= unsubscribe_url(token: params[:subscriber].generate_token_for(:unsubscribe)) %>

When the unsubscribe link is clicked, the subscriber record will be deleted from the database. The controller also safely handles invalid or expired tokens without raising any errors.

Use the Rails console to send another email and test the unsubscribe link in the logs.