Skip to content
This repository
tree: 61d236d941
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

executable file 471 lines (327 sloc) 15.197 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471
= Action Pack -- On rails from request to response

Action Pack splits the response to a web request into a controller part
(performing the logic) and a view part (rendering a template). This two-step
approach is known as an action, which will normally create, read, update, or
delete (CRUD for short) some sort of model part (often backed by a database)
before choosing either to render a template or redirecting to another action.

Action Pack implements these actions as public methods on Action Controllers
and uses Action Views to implement the template rendering. Action Controllers
are then responsible for handling all the actions relating to a certain part
of an application. This grouping usually consists of actions for lists and for
CRUDs revolving around a single (or a few) model objects. So ContactController
would be responsible for listing contacts, creating, deleting, and updating
contacts. A WeblogController could be responsible for both posts and comments.

Action View templates are written using embedded Ruby in tags mingled in with
the HTML. To avoid cluttering the templates with code, a bunch of helper
classes provide common behavior for forms, dates, and strings. And it's easy
to add specific helpers to keep the separation as the application evolves.

Note: Some of the features, such as scaffolding and form building, are tied to
ActiveRecord[http://activerecord.rubyonrails.org] (an object-relational
mapping package), but that doesn't mean that Action Pack depends on Active
Record. Action Pack is an independent package that can be used with any sort
of backend (Instiki[http://www.instiki.org], which is based on an older version
of Action Pack, uses Madeleine for example). Read more about the role Action
Pack can play when used together with Active Record on
http://www.rubyonrails.org.

A short rundown of the major features:

* Actions grouped in controller as methods instead of separate command objects
  and can therefore helper share methods.

    BlogController < ActionController::Base
      def display
        @customer = find_customer
      end
      
      def update
        @customer = find_customer
        @customer.attributes = @params["customer"]
        @customer.save ?
          redirect_to(:action => "display") :
          render("customer/edit")
      end
      
      private
        def find_customer() Customer.find(@params["id"]) end
    end

  {Learn more}[link:classes/ActionController/Base.html]


* Embedded Ruby for templates (no new "easy" template language)

    <% for post in @posts %>
      Title: <%= post.title %>
    <% end %>

    All post titles: <%= @post.collect{ |p| p.title }.join ", " %>

    <% unless @person.is_client? %>
      Not for clients to see...
    <% end %>
  
  {Learn more}[link:classes/ActionView.html]


* Builder-based templates (great for XML content, like RSS)

    xml.rss("version" => "2.0") do
      xml.channel do
        xml.title(@feed_title)
        xml.link(@url)
        xml.description "Basecamp: Recent items"
        xml.language "en-us"
        xml.ttl "40"

        for item in @recent_items
          xml.item do
            xml.title(item_title(item))
            xml.description(item_description(item))
            xml.pubDate(item_pubDate(item))
            xml.guid(@recent_items.url(item))
            xml.link(@recent_items.url(item))
          end
        end
      end
    end

  {Learn more}[link:classes/ActionView/Base.html]


* Filters for pre and post processing of the response (as methods, procs, and classes)

    class WeblogController < ActionController::Base
      before_filter :authenticate, :cache, :audit
      after_filter { |c| c.response.body = GZip::compress(c.response.body) }
      after_filter LocalizeFilter
      
      def list
        # Before this action is run, the user will be authenticated, the cache
        # will be examined to see if a valid copy of the results already
        # exist, and the action will be logged for auditing.
        
        # After this action has run, the output will first be localized then
        # compressed to minimize bandwith usage
      end
      
      private
        def authenticate
          # Implement the filter will full access to both request and response
        end
    end
  
  {Learn more}[link:classes/ActionController/Filters/ClassMethods.html]
  

* Helpers for forms, dates, action links, and text

    <%= text_field "post", "title", "size" => 30 %>
    <%= html_date_select(Date.today) %>
    <%= link_to "New post", :controller => "post", :action => "new" %>
    <%= truncate(post.title, 25) %>
 
  {Learn more}[link:classes/ActionView/Helpers.html]


* Layout sharing for template reuse (think simple version of Struts
  Tiles[http://jakarta.apache.org/struts/userGuide/dev_tiles.html])

    class WeblogController < ActionController::Base
      layout "weblog_layout"
      
      def hello_world
      end
    end

    Layout file (called weblog_layout):
      <html><body><%= @content_for_layout %></body></html>
    
    Template for hello_world action:
      <h1>Hello world</h1>
    
    Result of running hello_world action:
      <html><body><h1>Hello world</h1></body></html>

  {Learn more}[link:classes/ActionController/Layout/ClassMethods.html]


* Routing makes pretty urls incredibly easy

    map.connect 'clients/:client_name/:project_name/:controller/:action'

    Accessing /clients/37signals/basecamp/project/dash calls ProjectController#dash with
    { "client_name" => "37signals", "project_name" => "basecamp" } in @params["params"]
    
    From that URL, you can rewrite the redirect in a number of ways:
    
    redirect_to(:action => "edit") =>
      /clients/37signals/basecamp/project/dash

    redirect_to(:client_name => "nextangle", :project_name => "rails") =>
      /clients/nextangle/rails/project/dash

  {Learn more}[link:classes/ActionController/Base.html]


* Javascript and Ajax integration.

    link_to_function "Greeting", "alert('Hello world!')"
    link_to_remote "Delete this post", :update => "posts",
                   :url => { :action => "destroy", :id => post.id }
  
  {Learn more}[link:classes/ActionView/Helpers/JavascriptHelper.html]


* Pagination for navigating lists of results.

    # controller
    def list
      @pages, @people =
        paginate :people, :order_by => 'last_name, first_name'
    end

    # view
    <%= link_to "Previous page", { :page => @pages.current.previous } if @pages.current.previous %>
    <%= link_to "Next page", { :page => @pages.current.next } of @pages.current.next =%>

  {Learn more}[link:classes/ActionController/Pagination.html]


* Easy testing of both controller and template result through TestRequest/Response

    class LoginControllerTest < Test::Unit::TestCase
      def setup
        @controller = LoginController.new
        @request = ActionController::TestRequest.new
        @response = ActionController::TestResponse.new
      end

      def test_failing_authenticate
        process :authenticate, "user_name" => "nop", "password" => ""
        assert_flash_has 'alert'
        assert_redirected_to :action => "index"
      end
    end

  {Learn more}[link:classes/ActionController/TestRequest.html]


* Automated benchmarking and integrated logging

    Processing WeblogController#index (for 127.0.0.1 at Fri May 28 00:41:55)
    Parameters: {"action"=>"index", "controller"=>"weblog"}
    Rendering weblog/index (200 OK)
    Completed in 0.029281 (34 reqs/sec)

    If Active Record is used as the model, you'll have the database debugging
as well:

Processing WeblogController#create (for 127.0.0.1 at Sat Jun 19 14:04:23)
Params: {"controller"=>"weblog", "action"=>"create",
"post"=>{"title"=>"this is good"} }
SQL (0.000627) INSERT INTO posts (title) VALUES('this is good')
Redirected to http://test/weblog/display/5
Completed in 0.221764 (4 reqs/sec) | DB: 0.059920 (27%)

You specify a logger through a class method, such as:

ActionController::Base.logger = Logger.new("Application Log")
ActionController::Base.logger = Log4r::Logger.new("Application Log")


* Caching at three levels of granularity (page, action, fragment)

class WeblogController < ActionController::Base
caches_page :show
caches_action :account
def show
# the output of the method will be cached as
# ActionController::Base.page_cache_directory + "/weblog/show/n.html"
# and the web server will pick it up without even hitting Rails
end
def account
# the output of the method will be cached in the fragment store
# but Rails is hit to retrieve it, so filters are run
end
def update
List.update(@params["list"]["id"], @params["list"])
expire_page :action => "show", :id => @params["list"]["id"]
expire_action :action => "account"
redirect_to :action => "show", :id => @params["list"]["id"]
end
end

{Learn more}[link:classes/ActionController/Caching.html]


* Component requests from one controller to another

class WeblogController < ActionController::Base
# Performs a method and then lets hello_world output its render
def delegate_action
do_other_stuff_before_hello_world
render_component :controller => "greeter", :action => "hello_world"
end
end
class GreeterController < ActionController::Base
def hello_world
render_text "Hello World!"
end
end
The same can be done in a view to do a partial rendering:
Let's see a greeting:
      <%= render_component :controller => "greeter", :action => "hello_world" %>

  {Learn more}[link:classes/ActionController/Components.html]
  

* Powerful debugging mechanism for local requests

    All exceptions raised on actions performed on the request of a local user
    will be presented with a tailored debugging screen that includes exception
    message, stack trace, request parameters, session contents, and the
    half-finished response.

  {Learn more}[link:classes/ActionController/Rescue.html]


* Scaffolding for Action Record model objects

    require 'account' # must be an Active Record class
    class AccountController < ActionController::Base
      scaffold :account
    end
    
    The AccountController now has the full CRUD range of actions and default
    templates: list, show, destroy, new, create, edit, update
    
  {Learn more}link:classes/ActionController/Scaffolding/ClassMethods.html


* Form building for Active Record model objects

    The post object has a title (varchar), content (text), and
    written_on (date)

    <%= form "post" %>
    
    ...will generate something like (the selects will have more options of
    course):
    
    <form action="create" method="POST">
      <p>
        <b>Title:</b><br/>
        <input type="text" name="post[title]" value="<%= @post.title %>" />
      </p>
      <p>
        <b>Content:</b><br/>
        <textarea name="post[content]"><%= @post.title %></textarea>
      </p>
      <p>
        <b>Written on:</b><br/>
        <select name='post[written_on(3i)]'><option>18</option></select>
        <select name='post[written_on(2i)]'><option value='7'>July</option></select>
        <select name='post[written_on(1i)]'><option>2004</option></select>
      </p>

      <input type="submit" value="Create">
    </form>

    This form generates a @params["post"] array that can be used directly in a save action:
    
    class WeblogController < ActionController::Base
      def save
        post = Post.create(@params["post"])
        redirect_to :action => "display", :path_params => { "id" => post.id }
      end
    end

  {Learn more}[link:classes/ActionView/Helpers/ActiveRecordHelper.html]


* Runs on top of WEBrick, CGI, FCGI, and mod_ruby


== Simple example

This example will implement a simple weblog system using inline templates and
an Active Record model. So let's build that WeblogController with just a few
methods:

require 'action_controller'
require 'post'

class WeblogController < ActionController::Base
layout "weblog/layout"
def index
@posts = Post.find_all
end
def display
@post = Post.find(@params["id"])
end
def new
@post = Post.new
end
def create
@post = Post.create(@params["post"])
redirect_to :action => "display", :id => @post.id
end
end

WeblogController::Base.template_root = File.dirname(__FILE__)
WeblogController.process_cgi if $0 == __FILE__

The last two lines are responsible for telling ActionController where the
template files are located and actually running the controller on a new
request from the web-server (like to be Apache).

And the templates look like this:

weblog/layout.rhtml:
<html><body>
<%= @content_for_layout %>
</body></html>

weblog/index.rhtml:
<% for post in @posts %>
<p><%= link_to(post.title, :action => "display", :id => post.id %></p>
<% end %>

weblog/display.rhtml:
<p>
<b><%= post.title %></b><br/>
<b><%= post.content %></b>
</p>

weblog/new.rhtml:
<%= form "post" %>
This simple setup will list all the posts in the system on the index page,
which is called by accessing /weblog/. It uses the form builder for the Active
Record model to make the new screen, which in turns hand everything over to
the create action (that's the default target for the form builder when given a
new model). After creating the post, it'll redirect to the display page using
an URL such as /weblog/display/5 (where 5 is the id of the post).


== Examples

Action Pack ships with three examples that all demonstrate an increasingly
detailed view of the possibilities. First is blog_controller that is just a
single file for the whole MVC (but still split into separate parts). Second is
the debate_controller that uses separate template files and multiple screens.
Third is the address_book_controller that uses the layout feature to separate
template casing from content.

Please note that you might need to change the "shebang" line to
#!/usr/local/env ruby, if your Ruby is not placed in /usr/local/bin/ruby


== Download

The latest version of Action Pack can be found at

* http://rubyforge.org/project/showfiles.php?group_id=249

Documentation can be found at

* http://ap.rubyonrails.com


== Installation

You can install Action Pack with the following command.

  % [sudo] ruby install.rb

from its distribution directory.


== License

Action Pack is released under the MIT license.


== Support

The Action Pack homepage is http://www.rubyonrails.com. You can find
the Action Pack RubyForge page at http://rubyforge.org/projects/actionpack.
And as Jim from Rake says:

   Feel free to submit commits or feature requests. If you send a patch,
   remember to update the corresponding unit tests. If fact, I prefer
   new feature to be submitted in the form of new unit tests.

For other information, feel free to ask on the ruby-talk mailing list (which
is mirrored to comp.lang.ruby) or contact mailto:david@loudthinking.com.
Something went wrong with that request. Please try again.