Merge pull request #38169 from gsamokovarov/rails-middleware-move-before-after

Delayed middleware delete does not allow move operations

actionpack/lib/action_dispatch/middleware/stack.rb

@@ -122,6 +122,24 @@ module ActionDispatch
       middlewares.delete_if { |m| m.klass == target }
     end
 
+    def move(target, source)
+      source_index = assert_index(source, :before)
+      source_middleware = middlewares.delete_at(source_index)
+
+      target_index = assert_index(target, :before)
+      middlewares.insert(target_index, source_middleware)
+    end
+
+    alias_method :move_before, :move
+
+    def move_after(target, source)
+      source_index = assert_index(source, :after)
+      source_middleware = middlewares.delete_at(source_index)
+
+      target_index = assert_index(target, :after)
+      middlewares.insert(target_index + 1, source_middleware)
+    end
+
     def use(klass, *args, &block)
       middlewares.push(build_middleware(klass, args, block))
     end

actionpack/test/dispatch/middleware_stack_test.rb

@@ -93,6 +93,60 @@ class MiddlewareStackTest < ActiveSupport::TestCase
     assert_equal FooMiddleware, @stack[0].klass
   end
 
+  test "move moves middleware at the integer index" do
+    @stack.move(0, BarMiddleware)
+    assert_equal BarMiddleware, @stack[0].klass
+    assert_equal FooMiddleware, @stack[1].klass
+  end
+
+  test "move requires the moved middleware to be in the stack" do
+    assert_raises RuntimeError do
+      @stack.move(0, BazMiddleware)
+    end
+  end
+
+  test "move preserves the arguments of the moved middleware" do
+    @stack.use BazMiddleware, true, foo: "bar"
+    @stack.move_before(FooMiddleware, BazMiddleware)
+
+    assert_equal [true, foo: "bar"], @stack.first.args
+  end
+
+  test "move_before moves middleware before another middleware class" do
+    @stack.move_before(FooMiddleware, BarMiddleware)
+    assert_equal BarMiddleware, @stack[0].klass
+    assert_equal FooMiddleware, @stack[1].klass
+  end
+
+  test "move_after requires the moved middleware to be in the stack" do
+    assert_raises RuntimeError do
+      @stack.move_after(BarMiddleware, BazMiddleware)
+    end
+  end
+
+  test "move_after moves middleware after the integer index" do
+    @stack.insert_after(BarMiddleware, BazMiddleware)
+    @stack.move_after(0, BazMiddleware)
+    assert_equal FooMiddleware, @stack[0].klass
+    assert_equal BazMiddleware, @stack[1].klass
+    assert_equal BarMiddleware, @stack[2].klass
+  end
+
+  test "move_after moves middleware after another middleware class" do
+    @stack.insert_after(BarMiddleware, BazMiddleware)
+    @stack.move_after(BarMiddleware, FooMiddleware)
+    assert_equal BarMiddleware, @stack[0].klass
+    assert_equal FooMiddleware, @stack[1].klass
+    assert_equal BazMiddleware, @stack[2].klass
+  end
+
+  test "move_afters preserves the arguments of the moved middleware" do
+    @stack.use BazMiddleware, true, foo: "bar"
+    @stack.move_after(FooMiddleware, BazMiddleware)
+
+    assert_equal [true, foo: "bar"], @stack[1].args
+  end
+
   test "unshift adds a new middleware at the beginning of the stack" do
     @stack.unshift MiddlewareStackTest::BazMiddleware
     assert_equal BazMiddleware, @stack.first.klass

guides/source/configuring.md

@@ -317,6 +317,19 @@ Middlewares can also be completely swapped out and replaced with others:
 config.middleware.swap ActionController::Failsafe, Lifo::Failsafe
 ```
 
+Middlewares can be moved from one place to another:
+
+```ruby
+config.middleware.move_before ActionDispatch::Flash, Magical::Unicorns
+```
+
+This will move the `Magical::Unicorns` middleware before
+`ActionDispatch::Flash`. You can also move it after:
+
+```ruby
+config.middleware.move_after ActionDispatch::Flash, Magical::Unicorns
+```
+
 They can also be removed from the stack completely:
 
 ```ruby

railties/CHANGELOG.md

@@ -1,3 +1,21 @@
+*   Introduce middleware move operations
+
+    With this change, you no longer need to delete and reinsert a middleware to
+    move it from one place to another in the stack:
+
+    ```ruby
+    config.middleware.move_before ActionDispatch::Flash, Magical::Unicorns
+    ```
+
+    This will move the `Magical::Unicorns` middleware before
+    `ActionDispatch::Flash`. You can also move it after with:
+
+    ```ruby
+    config.middleware.move_after ActionDispatch::Flash, Magical::Unicorns
+    ```
+
+    *Genadi Samokovarov*
+
 *   Generators that inherit from NamedBase respect `--force` option
 
     *Josh Brody*

railties/lib/rails/configuration.rb

@@ -30,6 +30,15 @@ module Rails
     #
     #     config.middleware.swap ActionDispatch::Flash, Magical::Unicorns
     #
+    # Middlewares can be moved from one place to another:
+    #
+    #     config.middleware.move_before ActionDispatch::Flash, Magical::Unicorns
+    #
+    # This will move the <tt>Magical::Unicorns</tt> middleware before the
+    # <tt>ActionDispatch::Flash</tt>. You can also move it after:
+    #
+    #     config.middleware.move_after ActionDispatch::Flash, Magical::Unicorns
+    #
     # And finally they can also be removed from the stack completely:
     #
     #     config.middleware.delete ActionDispatch::Flash
@@ -66,6 +75,16 @@ module Rails
         @delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
       end
 
+      def move_before(*args, &block)
+        @delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
+      end
+
+      alias :move :move_before
+
+      def move_after(*args, &block)
+        @delete_operations << -> middleware { middleware.send(__method__, *args, &block) }
+      end
+
       def unshift(*args, &block)
         @operations << -> middleware { middleware.send(__method__, *args, &block) }
       end

railties/test/configuration/middleware_stack_proxy_test.rb

@@ -18,6 +18,11 @@ module Rails
         assert_playback :insert_before, :foo
       end
 
+      def test_playback_insert
+        @stack.insert :foo
+        assert_playback :insert_before, :foo
+      end
+
       def test_playback_insert_after
         @stack.insert_after :foo
         assert_playback :insert_after, :foo
@@ -38,6 +43,21 @@ module Rails
         assert_playback :delete, :foo
       end
 
+      def test_playback_move_before
+        @stack.move_before :foo
+        assert_playback :move_before, :foo
+      end
+
+      def test_playback_move
+        @stack.move :foo
+        assert_playback :move_before, :foo
+      end
+
+      def test_playback_move_after
+        @stack.move_after :foo
+        assert_playback :move_after, :foo
+      end
+
       def test_order
         @stack.swap :foo
         @stack.delete :foo