root/branches/1-2-stable/actionpack/lib/action_controller/routing.rb

require 'cgi'

class Object
  def to_param
    to_s
  end
end

class TrueClass
  def to_param
    self
  end
end

class FalseClass
  def to_param
    self
  end
end

class NilClass
  def to_param
    self
  end
end

class Regexp #:nodoc:
  def number_of_captures
    Regexp.new("|#{source}").match('').captures.length
  end
  
  class << self
    def optionalize(pattern)
      case unoptionalize(pattern)
        when /\A(.|\(.*\))\Z/ then "#{pattern}?"
        else "(?:#{pattern})?"
      end
    end
    
    def unoptionalize(pattern)
      [/\A\(\?:(.*)\)\?\Z/, /\A(.|\(.*\))\?\Z/].each do |regexp|
        return $1 if regexp =~ pattern
      end
      return pattern
    end
  end
end

module ActionController
  # == Routing 
  #
  # The routing module provides URL rewriting in native Ruby. It's a way to
  # redirect incoming requests to controllers and actions. This replaces
  # mod_rewrite rules. Best of all Rails' Routing works with any web server. 
  # Routes are defined in routes.rb in your RAILS_ROOT/config directory.
  #
  # Consider the following route, installed by Rails when you generate your 
  # application:
  #
  #   map.connect ':controller/:action/:id'
  #
  # This route states that it expects requests to consist of a 
  # :controller followed by an :action that in turns is fed by some :id 
  #
  # Suppose you get an incoming request for <tt>/blog/edit/22</tt>, you'll end up 
  # with:
  #
  #   params = { :controller => 'blog',
  #              :action     => 'edit' 
  #              :id         => '22'
  #           }
  #
  # Think of creating routes as drawing a map for your requests. The map tells 
  # them where to go based on some predefined pattern:
  #
  #  ActionController::Routing::Routes.draw do |map|
  #   Pattern 1 tells some request to go to one place
  #   Pattern 2 tell them to go to another
  #   ...
  #  end
  #
  # The following symbols are special:
  #
  #   :controller maps to your controller name
  #   :action     maps to an action with your controllers
  #   
  # Other names simply map to a parameter as in the case of +:id+.
  #    
  # == Route priority
  #
  # Not all routes are created equally. Routes have priority defined by the 
  # order of appearance of the routes in the routes.rb file. The priority goes
  # from top to bottom. The last route in that file is at the lowest priority
  # will be applied last. If no route matches, 404 is returned.
  #
  # Within blocks, the empty pattern goes first i.e. is at the highest priority.
  # In practice this works out nicely:
  #
  #  ActionController::Routing::Routes.draw do |map| 
  #    map.with_options :controller => 'blog' do |blog|
  #      blog.show    '',  :action => 'list'
  #    end
  #    map.connect ':controller/:action/:view 
  #  end
  #
  # In this case, invoking blog controller (with an URL like '/blog/') 
  # without parameters will activate the 'list' action by default.
  #
  # == Defaults routes and default parameters
  #
  # Setting a default route is straightforward in Rails because by appending a
  # Hash to the end of your mapping you can set default parameters.
  #
  # Example:
  #  ActionController::Routing:Routes.draw do |map|
  #    map.connect ':controller/:action/:id', :controller => 'blog'
  #  end
  #
  # This sets up  +blog+ as the default controller if no other is specified. 
  # This means visiting '/' would invoke the blog controller.
  #
  # More formally, you can define defaults in a route with the +:defaults+ key.
  #   
  #   map.connect ':controller/:id/:action', :action => 'show', :defaults => { :page => 'Dashboard' }
  #
  # == Named routes
  #
  # Routes can be named with the syntax <tt>map.name_of_route options</tt>,
  # allowing for easy reference within your source as +name_of_route_url+
  # for the full URL and +name_of_route_path+ for the URI path.
  #
  # Example:
  #   # In routes.rb
  #   map.login 'login', :controller => 'accounts', :action => 'login'
  #
  #   # With render, redirect_to, tests, etc.
  #   redirect_to login_url
  #
  # Arguments can be passed as well.
  #
  #   redirect_to show_item_path(:id => 25)
  #
  # Use <tt>map.root</tt> as a shorthand to name a route for the root path ""
  #
  #   # In routes.rb
  #   map.root :controller => 'blogs'
  #
  #   # would recognize http://www.example.com/ as
  #   params = { :controller => 'blogs', :action => 'index' }
  #
  #   # and provide these named routes
  #   root_url   # => 'http://www.example.com/'
  #   root_path  # => ''
  #
  # Note: when using +with_options+, the route is simply named after the
  # method you call on the block parameter rather than map.
  #
  #   # In routes.rb
  #   map.with_options :controller => 'blog' do |blog|
  #     blog.show    '',            :action  => 'list'
  #     blog.delete  'delete/:id',  :action  => 'delete',
  #     blog.edit    'edit/:id',    :action  => 'edit'
  #   end
  #
  #   # provides named routes for show, delete, and edit
  #   link_to @article.title, show_path(:id => @article.id) 
  #
  # == Pretty URLs
  #
  # Routes can generate pretty URLs. For example:
  #
  #  map.connect 'articles/:year/:month/:day',
  #              :controller => 'articles', 
  #              :action     => 'find_by_date',
  #              :year       => /\d{4}/,
  #              :month => /\d{1,2}/, 
  #              :day   => /\d{1,2}/
  #  
  #  # Using the route above, the url below maps to:
  #  # params = {:year => '2005', :month => '11', :day => '06'}
  #  # http://localhost:3000/articles/2005/11/06
  #
  # == Regular Expressions and parameters
  # You can specify a reqular expression to define a format for a parameter.
  #
  #  map.geocode 'geocode/:postalcode', :controller => 'geocode',
  #              :action => 'show', :postalcode => /\d{5}(-\d{4})?/
  #
  # or  more formally:
  #
  #   map.geocode 'geocode/:postalcode', :controller => 'geocode', 
  #                      :action => 'show', 
  #                      :requirements { :postalcode => /\d{5}(-\d{4})?/ }
  #
  # == Route globbing
  #
  # Specifying <tt>*[string]</tt> as part of a rule like :
  #
  #  map.connect '*path' , :controller => 'blog' , :action => 'unrecognized?'
  #
  # will glob all remaining parts of the route that were not recognized earlier. This idiom must appear at the end of the path. The globbed values are in <tt>params[:path]</tt> in this case.  
  #
  # == Reloading routes
  #
  # You can reload routes if you feel you must:
  #
  #  Action::Controller::Routes.reload
  #
  # This will clear all named routes and reload routes.rb
  #
  # == Testing Routes
  #
  # The two main methods for testing your routes:
  #
  # === +assert_routing+
  # 
  #  def test_movie_route_properly_splits
  #   opts = {:controller => "plugin", :action => "checkout", :id => "2"}
  #   assert_routing "plugin/checkout/2", opts
  #  end
  #  
  # +assert_routing+ lets you test whether or not the route properly resolves into options.
  #
  # === +assert_recognizes+
  #
  #  def test_route_has_options
  #   opts = {:controller => "plugin", :action => "show", :id => "12"}
  #   assert_recognizes opts, "/plugins/show/12" 
  #  end
  # 
  # Note the subtle difference between the two: +assert_routing+ tests that
  # an URL fits options while +assert_recognizes+ tests that an URL
  # breaks into parameters properly.
  #
  # In tests you can simply pass the URL or named route to +get+ or +post+.
  #
  #  def send_to_jail
  #    get '/jail'
  #    assert_response :success
  #    assert_template "jail/front"
  #  end
  #
  #  def goes_to_login
  #    get login_url
  #    #...
  #  end
  #
  module Routing
    SEPARATORS = %w( / ; . , ? )

    # The root paths which may contain controller files
    mattr_accessor :controller_paths
    self.controller_paths = []

    class << self
      def with_controllers(names)
        prior_controllers = @possible_controllers
        use_controllers! names
        yield
      ensure
        use_controllers! prior_controllers
      end

      def normalize_paths(paths)
        # do the hokey-pokey of path normalization...
        paths = paths.collect do |path|
          path = path.
            gsub("//", "/").           # replace double / chars with a single
            gsub("\\\\", "\\").        # replace double \ chars with a single
            gsub(%r{(.)[\\/]$}, '\1')  # drop final / or \ if path ends with it

          # eliminate .. paths where possible
          re = %r{\w+[/\\]\.\.[/\\]}
          path.gsub!(%r{\w+[/\\]\.\.[/\\]}, "") while path.match(re)
          path
        end

        # start with longest path, first
        paths = paths.uniq.sort_by { |path| - path.length }
      end

      def possible_controllers
        unless @possible_controllers
          @possible_controllers = []
        
          paths = controller_paths.select { |path| File.directory?(path) && path != "." }

          seen_paths = Hash.new {|h, k| h[k] = true; false}
          normalize_paths(paths).each do |load_path|
            Dir["#{load_path}/**/*_controller.rb"].collect do |path|
              next if seen_paths[path.gsub(%r{^\.[/\\]}, "")]
              
              controller_name = path[(load_path.length + 1)..-1]
              
              controller_name.gsub!(/_controller\.rb\Z/, '')
              @possible_controllers << controller_name
            end
          end

          # remove duplicates
          @possible_controllers.uniq!
        end
        @possible_controllers
      end

      def use_controllers!(controller_names)
        @possible_controllers = controller_names
      end

      def controller_relative_to(controller, previous)
        if controller.nil?           then previous
        elsif controller[0] == ?/    then controller[1..-1]
        elsif %r{^(.*)/} =~ previous then "#{$1}/#{controller}"
        else controller
        end     
      end     
    end
  
    class Route #:nodoc:
      attr_accessor :segments, :requirements, :conditions
      
      def initialize
        @segments = []
        @requirements = {}
        @conditions = {}
      end
  
      # Write and compile a +generate+ method for this Route.
      def write_generation
        # Build the main body of the generation
        body = "expired = false\n#{generation_extraction}\n#{generation_structure}"
    
        # If we have conditions that must be tested first, nest the body inside an if
        body = "if #{generation_requirements}\n#{body}\nend" if generation_requirements
        args = "options, hash, expire_on = {}"

        # Nest the body inside of a def block, and then compile it.
        raw_method = method_decl = "def generate_raw(#{args})\npath = begin\n#{body}\nend\n[path, hash]\nend"
        instance_eval method_decl, "generated code (#{__FILE__}:#{__LINE__})"

        # expire_on.keys == recall.keys; in other words, the keys in the expire_on hash
        # are the same as the keys that were recalled from the previous request. Thus,
        # we can use the expire_on.keys to determine which keys ought to be used to build
        # the query string. (Never use keys from the recalled request when building the
        # query string.)

        method_decl = "def generate(#{args})\npath, hash = generate_raw(options, hash, expire_on)\nappend_query_string(path, hash, extra_keys(options))\nend"
        instance_eval method_decl, "generated code (#{__FILE__}:#{__LINE__})"

        method_decl = "def generate_extras(#{args})\npath, hash = generate_raw(options, hash, expire_on)\n[path, extra_keys(options)]\nend"
        instance_eval method_decl, "generated code (#{__FILE__}:#{__LINE__})"
        raw_method
      end
  
      # Build several lines of code that extract values from the options hash. If any
      # of the values are missing or rejected then a return will be executed.
      def generation_extraction
        segments.collect do |segment|
          segment.extraction_code
        end.compact * "\n"
      end
  
      # Produce a condition expression that will check the requirements of this route
      # upon generation.
      def generation_requirements
        requirement_conditions = requirements.collect do |key, req|
          if req.is_a? Regexp
            value_regexp = Regexp.new "\\A#{req.source}\\Z"
            "hash[:#{key}] && #{value_regexp.inspect} =~ options[:#{key}]"
          else
            "hash[:#{key}] == #{req.inspect}"
          end
        end
        requirement_conditions * ' && ' unless requirement_conditions.empty?
      end
      def generation_structure
        segments.last.string_structure segments[0..-2]
      end
  
      # Write and compile a +recognize+ method for this Route.
      def write_recognition
        # Create an if structure to extract the params from a match if it occurs.
        body = "params = parameter_shell.dup\n#{recognition_extraction * "\n"}\nparams"
        body = "if #{recognition_conditions.join(" && ")}\n#{body}\nend"
    
        # Build the method declaration and compile it
        method_decl = "def recognize(path, env={})\n#{body}\nend"
        instance_eval method_decl, "generated code (#{__FILE__}:#{__LINE__})"
        method_decl
      end

      # Plugins may override this method to add other conditions, like checks on
      # host, subdomain, and so forth. Note that changes here only affect route
      # recognition, not generation.
      def recognition_conditions
        result = ["(match = #{Regexp.new(recognition_pattern).inspect}.match(path))"]
        result << "conditions[:method] === env[:method]" if conditions[:method]
        result
      end

      # Build the regular expression pattern that will match this route.
      def recognition_pattern(wrap = true)
        pattern = ''
        segments.reverse_each do |segment|
          pattern = segment.build_pattern pattern
        end
        wrap ? ("\\A" + pattern + "\\Z") : pattern
      end
      
      # Write the code to extract the parameters from a matched route.
      def recognition_extraction
        next_capture = 1
        extraction = segments.collect do |segment|
          x = segment.match_extraction next_capture
          next_capture += Regexp.new(segment.regexp_chunk).number_of_captures
          x
        end
        extraction.compact
      end
  
      # Write the real generation implementation and then resend the message.
      def generate(options, hash, expire_on = {})
        write_generation
        generate options, hash, expire_on
      end

      def generate_extras(options, hash, expire_on = {})
        write_generation
        generate_extras options, hash, expire_on
      end

      # Generate the query string with any extra keys in the hash and append
      # it to the given path, returning the new path.
      def append_query_string(path, hash, query_keys=nil)
        return nil unless path
        query_keys ||= extra_keys(hash)
        "#{path}#{build_query_string(hash, query_keys)}"
      end

      # Determine which keys in the given hash are "extra". Extra keys are
      # those that were not used to generate a particular route. The extra
      # keys also do not include those recalled from the prior request, nor
      # do they include any keys that were implied in the route (like a
      # :controller that is required, but not explicitly used in the text of
      # the route.)
      def extra_keys(hash, recall={})
        (hash || {}).keys.map { |k| k.to_sym } - (recall || {}).keys - significant_keys
      end

      # Build a query string from the keys of the given hash. If +only_keys+
      # is given (as an array), only the keys indicated will be used to build
      # the query string. The query string will correctly build array parameter
      # values.
      def build_query_string(hash, only_keys = nil)
        elements = []
        
        (only_keys || hash.keys).each do |key|
          if value = hash[key]
            elements << value.to_query(key)
          end
        end
        elements.empty? ? '' : "?#{elements.sort * '&'}"
      end

      # Write the real recognition implementation and then resend the message.
      def recognize(path, environment={})
        write_recognition
        recognize path, environment
      end
  
      # A route's parameter shell contains parameter values that are not in the
      # route's path, but should be placed in the recognized hash.
      # 
      # For example, +{:controller => 'pages', :action => 'show'} is the shell for the route:
      # 
      #   map.connect '/page/:id', :controller => 'pages', :action => 'show', :id => /\d+/
      # 
      def parameter_shell
        @parameter_shell ||= returning({}) do |shell|
          requirements.each do |key, requirement|
            shell[key] = requirement unless requirement.is_a? Regexp
          end
        end
      end
  
      # Return an array containing all the keys that are used in this route. This
      # includes keys that appear inside the path, and keys that have requirements
      # placed upon them.
      def significant_keys
        @significant_keys ||= returning [] do |sk|
          segments.each { |segment| sk << segment.key if segment.respond_to? :key }
          sk.concat requirements.keys
          sk.uniq!
        end
      end

      # Return a hash of key/value pairs representing the keys in the route that
      # have defaults, or which are specified by non-regexp requirements.
      def defaults
        @defaults ||= returning({}) do |hash|
          segments.each do |segment|
            next unless segment.respond_to? :default
            hash[segment.key] = segment.default unless segment.default.nil?
          end
          requirements.each do |key,req|
            next if Regexp === req || req.nil?
            hash[key] = req
          end
        end
      end
  
      def matches_controller_and_action?(controller, action)
        unless @matching_prepared
          @controller_requirement = requirement_for(:controller)
          @action_requirement = requirement_for(:action)
          @matching_prepared = true
        end

        (@controller_requirement.nil? || @controller_requirement === controller) &&
        (@action_requirement.nil? || @action_requirement === action)
      end

      def to_s
        @to_s ||= begin
          segs = segments.inject("") { |str,s| str << s.to_s }
          "%-6s %-40s %s" % [(conditions[:method] || :any).to_s.upcase, segs, requirements.inspect]
        end
      end
  
    protected
      def requirement_for(key)
        return requirements[key] if requirements.key? key
        segments.each do |segment|
          return segment.regexp if segment.respond_to?(:key) && segment.key == key
        end
        nil
      end
  
    end

    class Segment #:nodoc:
      attr_accessor :is_optional
      alias_method :optional?, :is_optional

      def initialize
        self.is_optional = false
      end

      def extraction_code
        nil
      end
  
      # Continue generating string for the prior segments.
      def continue_string_structure(prior_segments)
        if prior_segments.empty?
          interpolation_statement(prior_segments)
        else
          new_priors = prior_segments[0..-2]
          prior_segments.last.string_structure(new_priors)
        end
      end
  
      # Return a string interpolation statement for this segment and those before it.
      def interpolation_statement(prior_segments)
        chunks = prior_segments.collect { |s| s.interpolation_chunk }
        chunks << interpolation_chunk
        "\"#{chunks * ''}\"#{all_optionals_available_condition(prior_segments)}"
      end
  
      def string_structure(prior_segments)
        optional? ? continue_string_structure(prior_segments) : interpolation_statement(prior_segments)
      end
  
      # Return an if condition that is true if all the prior segments can be generated.
      # If there are no optional segments before this one, then nil is returned.
      def all_optionals_available_condition(prior_segments)
        optional_locals = prior_segments.collect { |s| s.local_name if s.optional? && s.respond_to?(:local_name) }.compact
        optional_locals.empty? ? nil : " if #{optional_locals * ' && '}"
      end
  
      # Recognition
  
      def match_extraction(next_capture)
        nil
      end
  
      # Warning
  
      # Returns true if this segment is optional? because of a default. If so, then
      # no warning will be emitted regarding this segment.
      def optionality_implied?
        false
      end
    end

    class StaticSegment < Segment #:nodoc:
      attr_accessor :value, :raw
      alias_method :raw?, :raw
  
      def initialize(value = nil)
        super()
        self.value = value
      end
  
      def interpolation_chunk
        raw? ? value : CGI.escape(value)
      end
  
      def regexp_chunk
        chunk = Regexp.escape value
        optional? ? Regexp.optionalize(chunk) : chunk
      end
  
      def build_pattern(pattern)
        escaped = Regexp.escape(value)
        if optional? && ! pattern.empty?
          "(?:#{Regexp.optionalize escaped}\\Z|#{escaped}#{Regexp.unoptionalize pattern})"
        elsif optional?
          Regexp.optionalize escaped
        else
          escaped + pattern
        end
      end
  
      def to_s
        value
      end
    end

    class DividerSegment < StaticSegment #:nodoc:
      def initialize(value = nil)
        super(value)
        self.raw = true
        self.is_optional = true
      end
  
      def optionality_implied?
        true
      end
    end

    class DynamicSegment < Segment #:nodoc:
      attr_accessor :key, :default, :regexp
  
      def initialize(key = nil, options = {})
        super()
        self.key = key
        self.default = options[:default] if options.key? :default
        self.is_optional = true if options[:optional] || options