Introduce suspenders:email generator

NEWS.md

@@ -13,6 +13,7 @@ Unreleased
 * Introduce `suspenders:setup` generator
 * Introduce `suspenders:tasks` generator
 * Introduce `suspenders:db:migrate` task
+* Introduce `suspenders:email` generator
 
 20230113.0 (January, 13, 2023)
 

README.md

@@ -159,6 +159,20 @@ bin/rails suspenders:rake
 bin/rails suspenders:db:migrate
 ```
 
+### Email
+
+Intercepts emails in non-production environments by setting `INTERCEPTOR_ADDRESSES`.
+
+```sh
+INTERCEPTOR_ADDRESSES="user_1@example.com,user_2@example.com" bin/rails s
+```
+
+Configures `default_url_options` in `test` and `development`.
+
+```
+bin/rails g suspenders:email
+```
+
 ## Contributing
 
 See the [CONTRIBUTING] document.

lib/generators/suspenders/email_generator.rb

@@ -0,0 +1,52 @@
+module Suspenders
+  module Generators
+    class EmailGenerator < Rails::Generators::Base
+      source_root File.expand_path("../../templates/email", __FILE__)
+      desc <<~TEXT
+        Intercepts emails in non-production environments by setting `INTERCEPTOR_ADDRESSES`.
+
+        ```sh
+        INTERCEPTOR_ADDRESSES="user_1@example.com,user_2@example.com" bin/rails s
+        ```
+
+        Configures `default_url_options` in `test` and `development`.
+      TEXT
+
+      def create_email_interceptor
+        copy_file "email_interceptor.rb", "app/mailers/email_interceptor.rb"
+      end
+
+      def create_email_interceptor_initializer
+        initializer "email_interceptor.rb", <<~RUBY
+          Rails.application.configure do
+            if ENV["INTERCEPTOR_ADDRESSES"].present?
+              config.action_mailer.interceptors = %w[EmailInterceptor]
+            end
+          end
+        RUBY
+      end
+
+      def configure_email_interceptor
+        environment do
+          %(
+            config.to_prepare do
+              EmailInterceptor.config.interceptor_addresses = ENV.fetch("INTERCEPTOR_ADDRESSES", "").split(",")
+            end
+          )
+        end
+      end
+
+      # TODO: Remove once https://github.com/rails/rails/pull/51191 is in latest
+      # Rails release
+      def configure_development_environment
+        environment %(config.action_mailer.default_url_options = { host: "localhost", port: 3000 }), env: "development"
+      end
+
+      # TODO: Remove once https://github.com/rails/rails/pull/51191 is in latest
+      # Rails release
+      def configure_test_environment
+        environment %(config.action_mailer.default_url_options = { host: "www.example.com" }), env: "test"
+      end
+    end
+  end
+end

lib/generators/templates/email/email_interceptor.rb

@@ -0,0 +1,11 @@
+class EmailInterceptor
+  include ActiveSupport::Configurable
+
+  config_accessor :interceptor_addresses, default: []
+
+  def self.delivering_email(message)
+    to = interceptor_addresses
+
+    message.to = to if to.any?
+  end
+end

test/generators/suspenders/email_generator_test.rb

@@ -0,0 +1,91 @@
+require "test_helper"
+require "generators/suspenders/email_generator"
+
+module Suspenders
+  module Generators
+    class EmailGeneratorTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::EmailGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "creates a mailer intercepter" do
+        expected = <<~RUBY
+          class EmailInterceptor
+            include ActiveSupport::Configurable
+
+            config_accessor :interceptor_addresses, default: []
+
+            def self.delivering_email(message)
+              to = interceptor_addresses
+
+              message.to = to if to.any?
+            end
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("app/mailers/email_interceptor.rb") do |file|
+          assert_equal expected, file
+        end
+      end
+
+      test "creates initializer" do
+        expected = <<~RUBY
+          Rails.application.configure do
+            if ENV["INTERCEPTOR_ADDRESSES"].present?
+              config.action_mailer.interceptors = %w[EmailInterceptor]
+            end
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("config/initializers/email_interceptor.rb") do |file|
+          assert_equal expected, file
+        end
+      end
+
+      test "configures application to user email intercepter" do
+        run_generator
+
+        assert_file app_root("config/application.rb"), /config\.to_prepare\s*do.\s*EmailInterceptor\.config\.interceptor_addresses\s*=\s*ENV\.fetch\("INTERCEPTOR_ADDRESSES",\s*\"\"\)\.split\(\",\"\).\s*end/m
+      end
+
+      test "configures action mailer in development" do
+        run_generator
+
+        assert_file app_root("config/environments/development.rb"), /config\.action_mailer\.default_url_options\s*=\s*{\s*host:\s*"localhost",\s*port:\s*3000\s*}/
+      end
+
+      test "configures action mailer in test" do
+        run_generator
+
+        assert_file app_root("config/environments/test.rb"), /config\.action_mailer\.default_url_options\s*=\s*{\s*host:\s*"www\.example\.com"\s*}/
+      end
+
+      test "has custom description" do
+        assert_no_match(/Description/, generator_class.desc)
+      end
+
+      private
+
+      def prepare_destination
+        backup_file "config/application.rb"
+        backup_file "config/environments/development.rb"
+        backup_file "config/environments/test.rb"
+      end
+
+      def restore_destination
+        restore_file "config/application.rb"
+        restore_file "config/environments/development.rb"
+        restore_file "config/environments/test.rb"
+        remove_file_if_exists "app/mailers/email_interceptor.rb"
+        remove_file_if_exists "config/initializers/email_interceptor.rb"
+      end
+    end
+  end
+end