Use header-only forgery protection and cache complete responses

test/controllers/fetch_metadata_test.rb

@@ -0,0 +1,91 @@
+require "test_helper"
+
+class FetchMetadataTest < ActionDispatch::IntegrationTest
+  setup do
+    host! "once.campfire.test"
+    @previous_exceptions = Rails.application.env_config["action_dispatch.show_exceptions"]
+    Rails.application.env_config["action_dispatch.show_exceptions"] = :rescuable
+    @previous_forgery = ActionController::Base.allow_forgery_protection
+    ActionController::Base.allow_forgery_protection = true
+  end
+
+  teardown do
+    ActionController::Base.allow_forgery_protection = @previous_forgery
+    Rails.application.env_config["action_dispatch.show_exceptions"] = @previous_exceptions
+  end
+
+  test "login and authenticated forms have no token fields" do
+    get new_session_url
+    assert_response :success
+    assert_select 'meta[name="csrf-token"]', count: 0
+    assert_select 'input[name="authenticity_token"]', count: 0
+    sign_in :david
+    get room_url(rooms(:watercooler))
+    assert_response :success
+    assert_select 'meta[name="csrf-token"]', count: 0
+    assert_select 'input[name="authenticity_token"]', count: 0
+  end
+
+  test "HTTPS login accepts browser metadata without a token" do
+    https!
+    %w[ same-origin same-site ].each do |site|
+      reset!
+      host! "once.campfire.test"
+      https!
+      post session_url, params: credentials, headers: {
+        "Sec-Fetch-Site" => site, "Origin" => "https://once.campfire.test" }
+      assert_response :redirect
+      assert cookies["session_token"].present?
+    end
+  end
+
+  test "HTTPS writes reject missing metadata even with a legacy token parameter" do
+    https!
+    assert_no_difference "Session.count" do
+      post session_url, params: credentials.merge(authenticity_token: "old token"), headers: { "Origin" => "https://once.campfire.test" }
+    end
+    assert_response :unprocessable_entity
+  end
+
+  test "cross-site none and malformed metadata cannot sign in over HTTP or HTTPS" do
+    [ false, true ].each do |tls|
+      https! tls
+      %w[ cross-site none garbage ].each do |site|
+        assert_no_difference "Session.count" do
+          post session_url, params: credentials, headers: { "Sec-Fetch-Site" => site }
+        end
+        assert_response :unprocessable_entity
+      end
+    end
+  end
+
+  test "provided foreign and null origins fail even with same-site metadata" do
+    %w[ https://foreign.example null ].each do |origin|
+      assert_no_difference "Session.count" do
+        post session_url, params: credentials, headers: { "Sec-Fetch-Site" => "same-site", "Origin" => origin }
+      end
+      assert_response :unprocessable_entity
+    end
+  end
+
+  test "plain HTTP retains the missing-header fallback" do
+    post session_url, params: credentials, headers: { "Origin" => "http://once.campfire.test" }
+    assert_response :redirect
+    assert cookies["session_token"].present?
+  end
+
+  test "cross-site reads remain available and method-overridden writes stay protected" do
+    get new_session_url, headers: { "Sec-Fetch-Site" => "cross-site" }
+    assert_response :success
+    sign_in :david
+    assert_no_difference "Room.count" do
+      post room_path(rooms(:watercooler)), params: { _method: "delete" }, headers: { "Sec-Fetch-Site" => "cross-site" }
+    end
+    assert_response :unprocessable_entity
+  end
+
+  private
+    def credentials
+      { email_address: users(:david).email_address, password: "secret123456" }
+    end
+end