Responders
A set of responders modules to dry up your Rails app.
Installation
Add the responders gem to your Gemfile:
gem "responders"
Update your bundle and run the install generator:
$ bundle install
$ rails g responders:install
If you are including this gem to support backwards compatibilty for responders in previous releases of Rails, you only need to include the gem and bundle.
$ bundle install
Responders Types
FlashResponder
Sets the flash based on the controller action and resource status.
For instance, if you do: respond_with(@post)
on a POST request and the resource @post
does not contain errors, it will automatically set the flash message to
"Post was successfully created"
as long as you configure your I18n file:
yaml
flash:
actions:
create:
notice: "%{resource_name} was successfully created."
update:
notice: "%{resource_name} was successfully updated."
destroy:
notice: "%{resource_name} was successfully destroyed."
alert: "%{resource_name} could not be destroyed."
In case the resource contains errors, you should use the failure key on I18n. This is
useful to dry up flash messages from your controllers. Note: by default alerts for update
and destroy
actions are commented in generated I18n file. If you need a specific message
for a controller, let’s say, for PostsController
, you can also do:
yaml
flash:
posts:
create:
notice: "Your post was created and will be published soon"
This responder is activated in all non get requests. By default it will use the keys
:notice
and :alert
, but they can be changed in your application:
ruby
config.responders.flash_keys = [ :success, :failure ]
You can also have embedded HTML. Just create a _html
scope.
yaml
flash:
actions:
create:
alert_html: "<strong>OH NOES!</strong> You did it wrong!"
posts:
create:
notice_html: "<strong>Yay!</strong> You did it!"
See also the namespace_lookup
option to search the full hierarchy of possible keys.
HttpCacheResponder
Automatically adds Last-Modified headers to API requests. This allows clients to easily query the server if a resource changed and if the client tries to retrieve a resource that has not been modified, it returns not_modified status.
CollectionResponder
Makes your create and update action redirect to the collection on success.
LocationResponder
This responder allows you to use callable objects as the redirect location.
Useful when you want to use the respond_with
method with
a custom route that requires persisted objects, but the validation may fail.
Note: this responder is included by default, and doesn’t need to be included on the top of your controller (including it will issue a deprecation warning).
```ruby class ThingsController < ApplicationController respond_to :html
def create @thing = Thing.create(params[:thing]) respond_with @thing, location: -> { thing_path(@thing) } end end ```
Dealing with namespaced routes
In order for the LocationResponder to find the correct route helper for namespaced routes you need to pass the namespaces to respond_with
:
```ruby class Api::V1::ThingsController < ApplicationController respond_to :json
# POST /api/v1/things def create @thing = Thing.create(thing_params) respond_with :api, :v1, @thing end end ```
Configuring your own responder
Responders only provides a set of modules and to use them you have to create your own responder. After you run the install command, the following responder will be generated in your application:
ruby
# lib/application_responder.rb
class ApplicationResponder < ActionController::Responder
include Responders::FlashResponder
include Responders::HttpCacheResponder
end
Your application also needs to be configured to use it:
```ruby # app/controllers/application_controller.rb require “application_responder”
class ApplicationController < ActionController::Base self.responder = ApplicationResponder respond_to :html end ```
Controller method
This gem also includes the controller method responders
, which allows you to cherry-pick which
responders you want included in your controller.
ruby
class InvitationsController < ApplicationController
responders :flash, :http_cache
end
Interpolation Options
You can pass in extra interpolation options for the translation by adding an flash_interpolation_options
method to your controller:
```ruby class InvitationsController < ApplicationController responders :flash, :http_cache
def create @invitation = Invitation.create(params[:invitation]) respond_with @invitation end
private
def flash_interpolation_options { resource_name: @invitation.email } end end ```
Now you would see the message "[email protected] was successfully created"
instead of the default "Invitation was successfully created."
Generator
This gem also includes a responders controller generator, so your scaffold can be customized
to use respond_with
instead of default respond_to
blocks. From 2.1, you need to explicitly opt-in to use this generator by adding the following to your config/application.rb
:
ruby
config.app_generators.scaffold_controller :responders_controller
Failure handling
Responders don’t use valid?
to check for errors in models to figure out if
the request was successful or not, and relies on your controllers to call
save
or create
to trigger the validations.
ruby
def create
@widget = Widget.new(widget_params)
# @widget will be a valid record for responders, as we haven't called `save`
# on it, and will always redirect to the `widgets_path`.
respond_with @widget, location: -> { widgets_path }
end
Responders will check if the errors
object in your model is empty or not. Take
this in consideration when implementing different actions or writing test
assertions on this behavior for your controllers.
ruby
def create
@widget = Widget.new(widget_params)
@widget.errors.add(:base, :invalid)
# `respond_with` will render the `new` template again.
respond_with @widget
end
Verifying request formats
respond_with
will raise an ActionController::UnknownFormat
if the request
MIME type was not configured through the class level respond_to
, but the
action will still be executed and any side effects (like creating a new record)
will still occur. To raise the UnknownFormat
exception before your action
is invoked you can set the verify_requested_format!
method as a before_action
on your controller.
```ruby class WidgetsController < ApplicationController respond_to :json before_action :verify_requested_format!
# POST /widgets.html won’t reach the create
action.
def create
widget = Widget.create(widget_params)
respond_with widget
end
end
```
Examples
Want more examples ? Check out these blog posts:
- Embracing REST with mind, body and soul
- Three reasons to love ActionController::Responder
- My five favorite things about Rails 3
Bugs and Feedback
If you discover any bugs or want to drop a line, feel free to create an issue on GitHub.
MIT License. Copyright 2020 Rafael França, Carlos Antônio da Silva. Copyright 2009-2019 Plataformatec.