vendor/rails/actionpack/lib/action_controller/scaffolding.rb

   1 module ActionController
   2   module Scaffolding # :nodoc:
   3     def self.included(base)
   4       base.extend(ClassMethods)
   5     end
   6
   7     # Scaffolding is a way to quickly put an Active Record class online by providing a series of standardized actions
   8     # for listing, showing, creating, updating, and destroying objects of the class. These standardized actions come
   9     # with both controller logic and default templates that through introspection already know which fields to display
  10     # and which input types to use. Example:
  11     #
  12     #  class WeblogController < ActionController::Base
  13     #    scaffold :entry
  14     #  end
  15     #
  16     # This tiny piece of code will add all of the following methods to the controller:
  17     #
  18     #  class WeblogController < ActionController::Base
  19     #    verify :method => :post, :only => [ :destroy, :create, :update ],
  20     #           :redirect_to => { :action => :list }
  21     #
  22     #    def index
  23     #      list
  24     #    end
  25     #
  26     #    def list
  27     #      @entries = Entry.find(:all)
  28     #      render_scaffold "list"
  29     #    end
  30     #
  31     #    def show
  32     #      @entry = Entry.find(params[:id])
  33     #      render_scaffold
  34     #    end
  35     #
  36     #    def destroy
  37     #      Entry.find(params[:id]).destroy
  38     #      redirect_to :action => "list"
  39     #    end
  40     #
  41     #    def new
  42     #      @entry = Entry.new
  43     #      render_scaffold
  44     #    end
  45     #
  46     #    def create
  47     #      @entry = Entry.new(params[:entry])
  48     #      if @entry.save
  49     #        flash[:notice] = "Entry was successfully created"
  50     #        redirect_to :action => "list"
  51     #      else
  52     #        render_scaffold('new')
  53     #      end
  54     #    end
  55     #
  56     #    def edit
  57     #      @entry = Entry.find(params[:id])
  58     #      render_scaffold
  59     #    end
  60     #
  61     #    def update
  62     #      @entry = Entry.find(params[:id])
  63     #      @entry.attributes = params[:entry]
  64     #
  65     #      if @entry.save
  66     #        flash[:notice] = "Entry was successfully updated"
  67     #        redirect_to :action => "show", :id => @entry
  68     #      else
  69     #        render_scaffold('edit')
  70     #      end
  71     #    end
  72     #  end
  73     #
  74     # The <tt>render_scaffold</tt> method will first check to see if you've made your own template (like "weblog/show.erb" for
  75     # the show action) and if not, then render the generic template for that action. This gives you the possibility of using the
  76     # scaffold while you're building your specific application. Start out with a totally generic setup, then replace one template
  77     # and one action at a time while relying on the rest of the scaffolded templates and actions.
  78     module ClassMethods
  79       # Adds a swath of generic CRUD actions to the controller. The +model_id+ is automatically converted into a class name unless
  80       # one is specifically provide through <tt>options[:class_name]</tt>. So <tt>scaffold :post</tt> would use Post as the class
  81       # and @post/@posts for the instance variables.
  82       #
  83       # It's possible to use more than one scaffold in a single controller by specifying <tt>options[:suffix] = true</tt>. This will
  84       # make <tt>scaffold :post, :suffix => true</tt> use method names like list_post, show_post, and create_post
  85       # instead of just list, show, and post. If suffix is used, then no index method is added.
  86       def scaffold(model_id, options = {})
  87         options.assert_valid_keys(:class_name, :suffix)
  88
  89         singular_name = model_id.to_s
  90         class_name    = options[:class_name] || singular_name.camelize
  91         plural_name   = singular_name.pluralize
  92         suffix        = options[:suffix] ? "_#{singular_name}" : ""
  93
  94         unless options[:suffix]
  95           module_eval <<-"end_eval", __FILE__, __LINE__
  96             def index
  97               list
  98             end
  99           end_eval
 100         end
 101
 102         module_eval <<-"end_eval", __FILE__, __LINE__
 103
 104           verify :method => :post, :only => [ :destroy#{suffix}, :create#{suffix}, :update#{suffix} ],
 105                  :redirect_to => { :action => :list#{suffix} }
 106
 107
 108           def list#{suffix}
 109             @#{singular_name}_pages, @#{plural_name} = paginate :#{plural_name}, :per_page => 10
 110             render#{suffix}_scaffold "list#{suffix}"
 111           end
 112
 113           def show#{suffix}
 114             @#{singular_name} = #{class_name}.find(params[:id])
 115             render#{suffix}_scaffold
 116           end
 117
 118           def destroy#{suffix}
 119             #{class_name}.find(params[:id]).destroy
 120             redirect_to :action => "list#{suffix}"
 121           end
 122
 123           def new#{suffix}
 124             @#{singular_name} = #{class_name}.new
 125             render#{suffix}_scaffold
 126           end
 127
 128           def create#{suffix}
 129             @#{singular_name} = #{class_name}.new(params[:#{singular_name}])
 130             if @#{singular_name}.save
 131               flash[:notice] = "#{class_name} was successfully created"
 132               redirect_to :action => "list#{suffix}"
 133             else
 134               render#{suffix}_scaffold('new')
 135             end
 136           end
 137
 138           def edit#{suffix}
 139             @#{singular_name} = #{class_name}.find(params[:id])
 140             render#{suffix}_scaffold
 141           end
 142
 143           def update#{suffix}
 144             @#{singular_name} = #{class_name}.find(params[:id])
 145             @#{singular_name}.attributes = params[:#{singular_name}]
 146
 147             if @#{singular_name}.save
 148               flash[:notice] = "#{class_name} was successfully updated"
 149               redirect_to :action => "show#{suffix}", :id => @#{singular_name}
 150             else
 151               render#{suffix}_scaffold('edit')
 152             end
 153           end
 154
 155           private
 156             def render#{suffix}_scaffold(action=nil)
 157               action ||= caller_method_name(caller)
 158               # logger.info ("testing template:" + "\#{self.class.controller_path}/\#{action}") if logger
 159
 160               if template_exists?("\#{self.class.controller_path}/\#{action}")
 161                 render :action => action
 162               else
 163                 @scaffold_class = #{class_name}
 164                 @scaffold_singular_name, @scaffold_plural_name = "#{singular_name}", "#{plural_name}"
 165                 @scaffold_suffix = "#{suffix}"
 166                 add_instance_variables_to_assigns
 167
 168                 @template.instance_variable_set("@content_for_layout", @template.render_file(scaffold_path(action.sub(/#{suffix}$/, "")), false))
 169
 170                 if !active_layout.nil?
 171                   render :file => active_layout, :use_full_path => true
 172                 else
 173                   render :file => scaffold_path('layout')
 174                 end
 175               end
 176             end
 177
 178             def scaffold_path(template_name)
 179               File.dirname(__FILE__) + "/templates/scaffolds/" + template_name + ".erb"
 180             end
 181
 182             def caller_method_name(caller)
 183               caller.first.scan(/`(.*)'/).first.first # ' ruby-mode
 184             end
 185         end_eval
 186       end
 187
 188       deprecate :scaffold => 'Controller scaffolding will be moved to a plugin in Rails 2.0. Switch to the generator or `script/plugin install scaffolding`'
 189     end
 190   end
 191 end