Web Components for Rails.
Do you need an interactive user interface for your Rails application? A cool Rich Client Application with dashboards, portlets and AJAX, Drag&Drop and jQuery?
Is your controller gettin’ fat? And your partial-helper-AJAX pile is getting out of control?
Do you want a framework to make the implementation easier? You want Apotomo.
Apotomo is based on Cells, the popular View Components framework for Rails.
It gives you widgets and encapsulation, bubbling events, AJAX page updates, rock-solid testing and more. Check out apotomo.de for a bunch of tutorials and a nice web 2.0 logo.
Easy as hell.
gem install apotomo
gem install apotomo -v 0.1.4
Don’t forget to load the gem in your app, either in your Gemfile or environment.rb.
A shitty example is worse a shitty framework, so let’s choose wisely…
Say you had a blog application. The page showing the post should have a comments block, with a list of comments and a form to post a new comment. Submitting should validate and send back the updated comments list, via AJAX.
Let’s wrap that comments block in a widget.
Go and generate a widget stub.
$ rails generate apotomo:widget CommentsWidget display write -e haml create app/cells/ create app/cells/comments_widget create app/cells/comments_widget.rb create app/cells/comments_widget/display.html.haml create app/cells/comments_widget/write.html.haml create test/widgets/comments_widget_test.rb
Nothing special.
You now tell your controller about the new widget.
class PostsController < ApplicationController
include Apotomo::Rails::ControllerMethods
has_widgets do |root|
root << widget('comments_widget', 'post-comments', :post => @post)
end
The widget is named post-comments. We pass the current post into the widget - the block is executed in controller instance context, that’s were @post comes from. Handy, isn’t it?
Rendering usually happens in your controller view, views/posts/show.haml, for instance.
%h1 @post.title %p @post.body %p = render_widget 'post-comments'
A widget is like a cell which is like a mini-controller.
class CommentsWidget < Apotomo::Widget
responds_to_event :submit, :with => :write
def display(args)
@comments = args[:post].comments # the parameter from outside.
render
end
Having display as the default state when rendering, this method collects comments to show and renders its view.
And look at line 2 - if encountering a :submit event we invoke write, which is simply another state. How cool is that?
def write(evt)
@comment = Comment.new(:post_id => evt[:post_id])
@comment.update_attributes evt[:comment] # a bit like params[].
update :state => :display
end
end
The event is processes with three steps in our widget:
-
create the new comment
-
re-render the
displaystate -
update itself on the page.
Apotomo helps you focusing on your app and takes away the pain of action dispatching and page updating.
So how and where is the :submit event triggered?
Take a look at the widget’s view display.html.haml.
= widget_div do
%ul
- for c in @comments
%li c.text
- form_for :comment, @comment, :html => {"data-event-url" => url_for_event(:submit)} do |f|
= f.error_messages
= f.text_field :text
= submit_tag "Don't be shy, comment!"
That’s a lot of familiar view code, almost looks like a partial.
The view also contains a bit of JavaScript.
:javascript
var form = $("##{widget_id} form");
form.submit(function() {
$.ajax({url: form.attr("data-event-url"), data: form.serialize()})
return false;
});
Triggering happens by sending an AJAX request to an address that the Apotomo helper url_for_event generated for us.
Now what happens when the event request is sent? Apotomo - again - does three things for you, it
-
accepts the request on a special event route it adds to your app
-
triggers the event in your ruby widget tree, which will invoke the
#processstate in our comment widget -
sends back the page updates your widgets rendered
In this example, we use jQuery for triggering. We could also use Prototype, RightJS, YUI, or a self-baked framework, that’s up to you.
Also, updating the page is in your hands. Where Apotomo provides handy helpers as #replace, you could also emit your own JavaScript.
Look, replace basically generates
$("post-comments").replaceWith(<the rendered view>);
If that’s not what you want, do
def write(evt) if evt[:comment][:text].explicit? render :text => 'alert("Hey, you wanted to submit a pervert comment!");' end end
Apotomo doesn’t depend on any JS framework - you choose!
Apotomo comes with its own test case and assertions to build rock-solid web components.
class CommentsWidgetTest < Apotomo::TestCase has_widgets do |root| root << widget(:comments_widget, 'me', :post => @pervert_post) end def test_render render_widget 'me' assert_select "li#me" trigger :submit, :comment => {:text => "Sex on the beach"} assert_response 'alert("Hey, you wanted to submit a pervert comment!");' end end
You can render your widgets, spec the markup, trigger events and assert the event responses, so far. If you need more, let us know!
There’s even more, too much for a simple README.
- Statefulness
-
Deriving your widget from
StatefulWidgetgives you free statefulness. - Composability
-
Widgets can range from small standalone components to nested widget trees like complex dashboards.
- Bubbling events
-
Events bubble up from their triggering source to root and thus can be observed, providing a way to implement loosely coupled, distributable components.
- Team-friendly
-
Widgets encourage encapsulation and help having different developers working on different components without getting out of bounds.
Give it a try- you will love the power and simplicity of real web components!
Please visit apotomo.de, the official project page with lots of examples.
If you have questions, visit us in the IRC channel #cells at irc.freenode.org.
If you wanna be cool, subscribe to our feed!
Copyright © 2007-2011 Nick Sutterer <apotonick@gmail.com> under the MIT License