Implement unsubscribe functionality and add tests for email unsubscription

app/controllers/members_controller.rb

@@ -58,10 +58,13 @@ class MembersController < ApplicationController
 
   def unsubscribe
     verifier = ActiveSupport::MessageVerifier.new(ENV.fetch('RAILS_SECRET_TOKEN', nil))
-    decrypted_message = verifier.verify(params[:message])
+    # The message is JSON, so its keys and the type come back as strings.
+    decrypted_message = verifier.verify(params[:message]).with_indifferent_access
 
     @member = Member.find(decrypted_message[:member_id])
-    @type = decrypted_message[:type]
+    @type = decrypted_message[:type].to_sym
+    raise ActiveSupport::MessageVerifier::InvalidSignature unless EMAIL_TYPE_STRING.key?(@type)
+
     @member.update(@type => false)
 
     flash.now[:notice] = I18n.t('members.unsubscribed', email_type: EMAIL_TYPE_STRING[@type])

spec/requests/unsubscribe_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Unsubscribing from emails' do
+  let(:member) { create(:member) }
+  let(:verifier) { ActiveSupport::MessageVerifier.new(ENV.fetch('RAILS_SECRET_TOKEN', nil)) }
+
+  def link_in(mail, text)
+    Nokogiri::HTML(mail.body.encoded).css('a').find { |anchor| anchor.text.include?(text) }['href']
+  end
+
+  def unsubscribe_via(mail, text)
+    get URI(link_in(mail, text)).request_uri
+  end
+
+  context 'with the link in the planting reminder' do
+    before { unsubscribe_via(NotifierMailer.planting_reminder(member), 'Unsubscribe from planting reminders') }
+
+    it { expect(response).to have_http_status(:ok) }
+    it { expect(response.body).to include 'unsubscribed from planting reminders' }
+    it { expect(member.reload.send_planting_reminder).to be false }
+    it { expect(member.reload.send_harvest_reminder).to be true }
+    it { expect(member.reload.send_notification_email).to be true }
+  end
+
+  context 'with the link in the harvest reminder' do
+    let(:crop) { create(:crop, median_days_to_first_harvest: 20) }
+
+    before do
+      create(:planting, owner: member, crop:, planted_at: 15.days.ago)
+      unsubscribe_via(NotifierMailer.harvest_reminder(member), 'Unsubscribe from harvest reminders')
+    end
+
+    it { expect(member.reload.send_harvest_reminder).to be false }
+    it { expect(member.reload.send_planting_reminder).to be true }
+  end
+
+  context 'with a signed message for a column that is not an email setting' do
+    before { get unsubscribe_member_path(verifier.generate({ member_id: member.id, type: :email })) }
+
+    it { expect(response.body).to include 'there was an error' }
+    it { expect(member.reload.email).to eq member.email }
+  end
+
+  context 'with a message that was not signed by us' do
+    before { get unsubscribe_member_path('not-signed') }
+
+    it { expect(response.body).to include 'there was an error' }
+  end
+end