Respond with 422 Unprocessable Entity for non-GET HTML/JS requests with errors

CHANGELOG.md

@@ -1,8 +1,9 @@
 ## Unreleased
 
-* Add support for Ruby 3.0, drop support for Ruby < 2.5
-* Add support for Rails 6.1, drop support for Rails < 5.2
-* Move CI to GitHub Actions
+* Responding to an `HTML` or `JS` request that has errors on the resource now sets the status to `422 Unprocessable Entity`. (instead of the default of `200 OK`.) This makes it more consistent with other statuses more commonly used in APIs (JSON/XML for example), and works by default with Turbo/Hotwire which expects a 422 on form error HTML responses. Note that this change may break your application if you're relying on the previous 2xx status to handle error cases.
+* Add support for Ruby 3.0, drop support for Ruby < 2.5.
+* Add support for Rails 6.1, drop support for Rails < 5.2.
+* Move CI to GitHub Actions.
 
 ## 3.0.1
 

README.md

@@ -212,7 +212,8 @@ assertions on this behavior for your controllers.
 def create
   @widget = Widget.new(widget_params)
   @widget.errors.add(:base, :invalid)
-  # `respond_with` will render the `new` template again.
+  # `respond_with` will render the `new` template again,
+  # and set the status to `422 Unprocessable Entity`.
   respond_with @widget
 end
 ```

lib/action_controller/respond_with.rb

@@ -95,7 +95,8 @@ def clear_respond_to
     #      i.e. its +show+ action.
     #   2. If there are validation errors, the response
     #      renders a default action, which is <tt>:new</tt> for a
-    #      +post+ request or <tt>:edit</tt> for +patch+ or +put+.
+    #      +post+ request or <tt>:edit</tt> for +patch+ or +put+,
+    #      and the status is set to <tt>422 Unprocessable Entity</tt>.
     #   Thus an example like this -
     #
     #     respond_to :html, :xml
@@ -116,8 +117,8 @@ def clear_respond_to
     #           format.html { redirect_to(@user) }
     #           format.xml { render xml: @user }
     #         else
-    #           format.html { render action: "new" }
-    #           format.xml { render xml: @user }
+    #           format.html { render action: "new", status: :unprocessable_entity }
+    #           format.xml { render xml: @user, status: :unprocessable_entity }
     #         end
     #       end
     #     end
@@ -194,7 +195,7 @@ def clear_respond_to
     #    need to render a template which is outside of controller's path or you
     #    want to override the default http <tt>:status</tt> code, e.g.
     #
-    #    respond_with(resource, render: { template: 'path/to/template', status: 422 })
+    #    respond_with(resource, render: { template: 'path/to/template', status: 418 })
     def respond_with(*resources, &block)
       if self.class.mimes_for_respond_to.empty?
         raise "In order to use respond_with, first you need to declare the " \

lib/action_controller/responder.rb

@@ -49,7 +49,7 @@ module ActionController #:nodoc:
   #         format.html { redirect_to(@user) }
   #         format.xml { render xml: @user, status: :created, location: @user }
   #       else
-  #         format.html { render action: "new" }
+  #         format.html { render action: "new", status: :unprocessable_entity }
   #         format.xml { render xml: @user.errors, status: :unprocessable_entity }
   #       end
   #     end
@@ -113,7 +113,7 @@ module ActionController #:nodoc:
   #       if @task.save
   #         flash[:notice] = 'Task was successfully created.'
   #       else
-  #         format.html { render "some_special_template" }
+  #         format.html { render "some_special_template", status: :unprocessable_entity }
   #       end
   #     end
   #   end
@@ -202,7 +202,7 @@ def navigation_behavior(error)
       if get?
         raise error
       elsif has_errors? && default_action
-        render rendering_options
+        render error_rendering_options
       else
         redirect_to navigation_location
       end
@@ -236,6 +236,8 @@ def resource_location
     def default_render
       if @default_response
         @default_response.call(options)
+      elsif !get? && has_errors?
+        controller.render(options.merge(status: :unprocessable_entity))
       else
         controller.render(options)
       end
@@ -300,11 +302,11 @@ def response_overridden?
       @default_response.present?
     end
 
-    def rendering_options
+    def error_rendering_options
       if options[:render]
         options[:render]
       else
-        { action: default_action }
+        { action: default_action, status: :unprocessable_entity }
       end
     end
   end

test/action_controller/respond_with_test.rb

@@ -170,6 +170,17 @@ def test_using_resource_with_js_simply_tries_to_render_the_template
     get :using_resource
     assert_equal "text/javascript", @response.media_type
     assert_equal "alert(\"Hi\");", @response.body
+    assert_equal 200, @response.status
+  end
+
+  def test_using_resource_for_post_with_js_renders_the_template_and_yields_unprocessable_entity_on_failure
+    @request.accept = "text/javascript"
+    errors = { name: :invalid }
+    Customer.any_instance.stubs(:errors).returns(errors)
+    post :using_resource
+    assert_equal "text/javascript", @response.media_type
+    assert_equal "alert(\"Hi\");", @response.body
+    assert_equal 422, @response.status
   end
 
   def test_using_hash_resource_with_js_raises_an_error_if_template_cant_be_found
@@ -245,13 +256,13 @@ def test_using_resource_for_post_with_html_redirects_on_success
     end
   end
 
-  def test_using_resource_for_post_with_html_rerender_on_failure
+  def test_using_resource_for_post_with_html_rerender_and_yields_unprocessable_entity_on_failure
     with_test_route_set do
       errors = { name: :invalid }
       Customer.any_instance.stubs(:errors).returns(errors)
       post :using_resource
       assert_equal "text/html", @response.media_type
-      assert_equal 200, @response.status
+      assert_equal 422, @response.status
       assert_equal "New world!\n", @response.body
       assert_nil @response.location
     end
@@ -305,26 +316,26 @@ def test_using_resource_for_patch_with_html_redirects_on_success
     end
   end
 
-  def test_using_resource_for_patch_with_html_rerender_on_failure
+  def test_using_resource_for_patch_with_html_rerender_and_yields_unprocessable_entity_on_failure
     with_test_route_set do
       errors = { name: :invalid }
       Customer.any_instance.stubs(:errors).returns(errors)
       patch :using_resource
       assert_equal "text/html", @response.media_type
-      assert_equal 200, @response.status
+      assert_equal 422, @response.status
       assert_equal "Edit world!\n", @response.body
       assert_nil @response.location
     end
   end
 
-  def test_using_resource_for_patch_with_html_rerender_on_failure_even_on_method_override
+  def test_using_resource_for_patch_with_html_rerender_and_yields_unprocessable_entity_on_failure_even_on_method_override
     with_test_route_set do
       errors = { name: :invalid }
       Customer.any_instance.stubs(:errors).returns(errors)
       @request.env["rack.methodoverride.original_method"] = "POST"
       patch :using_resource
       assert_equal "text/html", @response.media_type
-      assert_equal 200, @response.status
+      assert_equal 422, @response.status
       assert_equal "Edit world!\n", @response.body
       assert_nil @response.location
     end
@@ -340,27 +351,27 @@ def test_using_resource_for_put_with_html_redirects_on_success
     end
   end
 
-  def test_using_resource_for_put_with_html_rerender_on_failure
+  def test_using_resource_for_put_with_html_rerender_and_yields_unprocessable_entity_on_failure
     with_test_route_set do
       errors = { name: :invalid }
       Customer.any_instance.stubs(:errors).returns(errors)
       put :using_resource
 
       assert_equal "text/html", @response.media_type
-      assert_equal 200, @response.status
+      assert_equal 422, @response.status
       assert_equal "Edit world!\n", @response.body
       assert_nil @response.location
     end
   end
 
-  def test_using_resource_for_put_with_html_rerender_on_failure_even_on_method_override
+  def test_using_resource_for_put_with_html_rerender_and_yields_unprocessable_entity_on_failure_even_on_method_override
     with_test_route_set do
       errors = { name: :invalid }
       Customer.any_instance.stubs(:errors).returns(errors)
       @request.env["rack.methodoverride.original_method"] = "POST"
       put :using_resource
       assert_equal "text/html", @response.media_type
-      assert_equal 200, @response.status
+      assert_equal 422, @response.status
       assert_equal "Edit world!\n", @response.body
       assert_nil @response.location
     end