Ensure users can’t be spammed with password resets

app/mailers/user_mailer.rb

@@ -20,6 +20,9 @@ class UserMailer < ApplicationMailer
     @user = params[:user]
     @token = params[:token]
 
+    return if @user.password_reset_last_sent_at&.after?(10.minutes.ago)
+
+    @user.update(password_reset_last_sent_at: Time.zone.now)
     mail(to: @user.email, subject: t(".password_reset.subject"))
   end
 end

db/migrate/20240605132327_add_password_reset_last_sent_at_to_user.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddPasswordResetLastSentAtToUser < ActiveRecord::Migration[7.1]
+  def change
+    add_column :users, :password_reset_last_sent_at, :datetime
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_05_30_073852) do
+ActiveRecord::Schema[7.1].define(version: 2024_06_05_132327) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -221,6 +221,7 @@ ActiveRecord::Schema[7.1].define(version: 2024_05_30_073852) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.boolean "verified", default: false, null: false
+    t.datetime "password_reset_last_sent_at"
     t.index ["email"], name: "index_users_on_email", unique: true
     t.index ["username"], name: "index_users_on_username", unique: true
     t.index ["verified"], name: "index_users_on_verified"

test/mailers/user_mailer_test.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class UserMailerTest < ActionMailer::TestCase
+  test "password resets can’t be resent within 10 minutes" do
+    user = users(:trevor)
+    assert_emails(+1) do
+      UserMailer.with(user: user, token: user.generate_token_for(:password_reset)).password_reset.deliver_now
+    end
+    assert_emails(0) do
+      UserMailer.with(user: user, token: user.generate_token_for(:password_reset)).password_reset.deliver_now
+    end
+    travel 11.minutes
+    assert_emails(+1) do
+      UserMailer.with(user: user, token: user.generate_token_for(:password_reset)).password_reset.deliver_now
+    end
+  end
+end