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

   1 module ActionController
   2   # In <b>routes.rb</b> one defines URL-to-controller mappings, but the reverse
   3   # is also possible: an URL can be generated from one of your routing definitions.
   4   # URL generation functionality is centralized in this module.
   5   #
   6   # See ActionController::Routing and ActionController::Resources for general
   7   # information about routing and routes.rb.
   8   #
   9   # <b>Tip:</b> If you need to generate URLs from your models or some other place,
  10   # then ActionController::UrlWriter is what you're looking for. Read on for
  11   # an introduction.
  12   #
  13   # == URL generation from parameters
  14   #
  15   # As you may know, some functions - such as ActionController::Base#url_for
  16   # and ActionView::Helpers::UrlHelper#link_to, can generate URLs given a set
  17   # of parameters. For example, you've probably had the chance to write code
  18   # like this in one of your views:
  19   #
  20   #   <%= link_to('Click here', :controller => 'users',
  21   #           :action => 'new', :message => 'Welcome!') %>
  22   #
  23   #   #=> Generates a link to: /users/new?message=Welcome%21
  24   #
  25   # link_to, and all other functions that require URL generation functionality,
  26   # actually use ActionController::UrlWriter under the hood. And in particular,
  27   # they use the ActionController::UrlWriter#url_for method. One can generate
  28   # the same path as the above example by using the following code:
  29   #
  30   #   include UrlWriter
  31   #   url_for(:controller => 'users',
  32   #           :action => 'new',
  33   #           :message => 'Welcome!',
  34   #           :only_path => true)
  35   #   # => "/users/new?message=Welcome%21"
  36   #
  37   # Notice the <tt>:only_path => true</tt> part. This is because UrlWriter has no
  38   # information about the website hostname that your Rails app is serving. So if you
  39   # want to include the hostname as well, then you must also pass the <tt>:host</tt>
  40   # argument:
  41   #
  42   #   include UrlWriter
  43   #   url_for(:controller => 'users',
  44   #           :action => 'new',
  45   #           :message => 'Welcome!',
  46   #           :host => 'www.example.com')        # Changed this.
  47   #   # => "http://www.example.com/users/new?message=Welcome%21"
  48   #
  49   # By default, all controllers and views have access to a special version of url_for,
  50   # that already knows what the current hostname is. So if you use url_for in your
  51   # controllers or your views, then you don't need to explicitly pass the <tt>:host</tt>
  52   # argument.
  53   #
  54   # For convenience reasons, mailers provide a shortcut for ActionController::UrlWriter#url_for.
  55   # So within mailers, you only have to type 'url_for' instead of 'ActionController::UrlWriter#url_for'
  56   # in full. However, mailers don't have hostname information, and what's why you'll still
  57   # have to specify the <tt>:host</tt> argument when generating URLs in mailers.
  58   #
  59   #
  60   # == URL generation for named routes
  61   #
  62   # UrlWriter also allows one to access methods that have been auto-generated from
  63   # named routes. For example, suppose that you have a 'users' resource in your
  64   # <b>routes.rb</b>:
  65   #
  66   #   map.resources :users
  67   #
  68   # This generates, among other things, the method <tt>users_path</tt>. By default,
  69   # this method is accessible from your controllers, views and mailers. If you need
  70   # to access this auto-generated method from other places (such as a model), then
  71   # you can do that in two ways.
  72   #
  73   # The first way is to include ActionController::UrlWriter in your class:
  74   #
  75   #   class User < ActiveRecord::Base
  76   #     include ActionController::UrlWriter         # !!!
  77   #
  78   #     def name=(value)
  79   #       write_attribute('name', value)
  80   #       write_attribute('base_uri', users_path)   # !!!
  81   #     end
  82   #   end
  83   #
  84   # The second way is to access them through ActionController::UrlWriter.
  85   # The autogenerated named routes methods are available as class methods:
  86   #
  87   #   class User < ActiveRecord::Base
  88   #     def name=(value)
  89   #       write_attribute('name', value)
  90   #       path = ActionController::UrlWriter.users_path   # !!!
  91   #       write_attribute('base_uri', path)               # !!!
  92   #     end
  93   #   end
  94   module UrlWriter
  95     # The default options for urls written by this writer. Typically a <tt>:host</tt>
  96     # pair is provided.
  97     mattr_accessor :default_url_options
  98     self.default_url_options = {}
  99
 100     def self.included(base) #:nodoc:
 101       ActionController::Routing::Routes.install_helpers(base)
 102       base.mattr_accessor :default_url_options
 103       base.default_url_options ||= default_url_options
 104     end
 105
 106     # Generate a url based on the options provided, default_url_options and the
 107     # routes defined in routes.rb.  The following options are supported:
 108     #
 109     # * <tt>:only_path</tt> - If true, the relative url is returned. Defaults to +false+.
 110     # * <tt>:protocol</tt> - The protocol to connect to. Defaults to 'http'.
 111     # * <tt>:host</tt> - Specifies the host the link should be targetted at.
 112     #   If <tt>:only_path</tt> is false, this option must be
 113     #   provided either explicitly, or via +default_url_options+.
 114     # * <tt>:port</tt> - Optionally specify the port to connect to.
 115     # * <tt>:anchor</tt> - An anchor name to be appended to the path.
 116     # * <tt>:skip_relative_url_root</tt> - If true, the url is not constructed using the
 117     #   +relative_url_root+ set in ActionController::Base.relative_url_root.
 118     # * <tt>:trailing_slash</tt> - If true, adds a trailing slash, as in "/archive/2009/"
 119     #
 120     # Any other key (<tt>:controller</tt>, <tt>:action</tt>, etc.) given to
 121     # +url_for+ is forwarded to the Routes module.
 122     #
 123     # Examples:
 124     #
 125     #    url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :port=>'8080'    # => 'http://somehost.org:8080/tasks/testing'
 126     #    url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :anchor => 'ok', :only_path => true    # => '/tasks/testing#ok'
 127     #    url_for :controller => 'tasks', :action => 'testing', :trailing_slash=>true  # => 'http://somehost.org/tasks/testing/'
 128     #    url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :number => '33'  # => 'http://somehost.org/tasks/testing?number=33'
 129     def url_for(options)
 130       options = self.class.default_url_options.merge(options)
 131
 132       url = ''
 133
 134       unless options.delete(:only_path)
 135         url << (options.delete(:protocol) || 'http')
 136         url << '://' unless url.match("://")
 137
 138         raise "Missing host to link to! Please provide :host parameter or set default_url_options[:host]" unless options[:host]
 139
 140         url << options.delete(:host)
 141         url << ":#{options.delete(:port)}" if options.key?(:port)
 142       else
 143         # Delete the unused options to prevent their appearance in the query string.
 144         [:protocol, :host, :port, :skip_relative_url_root].each { |k| options.delete(k) }
 145       end
 146       trailing_slash = options.delete(:trailing_slash) if options.key?(:trailing_slash)
 147       url << ActionController::Base.relative_url_root.to_s unless options[:skip_relative_url_root]
 148       anchor = "##{CGI.escape options.delete(:anchor).to_param.to_s}" if options[:anchor]
 149       generated = Routing::Routes.generate(options, {})
 150       url << (trailing_slash ? generated.sub(/\?|\z/) { "/" + $& } : generated)
 151       url << anchor if anchor
 152
 153       url
 154     end
 155   end
 156
 157   # Rewrites URLs for Base.redirect_to and Base.url_for in the controller.
 158   class UrlRewriter #:nodoc:
 159     RESERVED_OPTIONS = [:anchor, :params, :only_path, :host, :protocol, :port, :trailing_slash, :skip_relative_url_root]
 160     def initialize(request, parameters)
 161       @request, @parameters = request, parameters
 162     end
 163
 164     def rewrite(options = {})
 165       rewrite_url(options)
 166     end
 167
 168     def to_str
 169       "#{@request.protocol}, #{@request.host_with_port}, #{@request.path}, #{@parameters[:controller]}, #{@parameters[:action]}, #{@request.parameters.inspect}"
 170     end
 171
 172     alias_method :to_s, :to_str
 173
 174     private
 175       # Given a path and options, returns a rewritten URL string
 176       def rewrite_url(options)
 177         rewritten_url = ""
 178
 179         unless options[:only_path]
 180           rewritten_url << (options[:protocol] || @request.protocol)
 181           rewritten_url << "://" unless rewritten_url.match("://")
 182           rewritten_url << rewrite_authentication(options)
 183           rewritten_url << (options[:host] || @request.host_with_port)
 184           rewritten_url << ":#{options.delete(:port)}" if options.key?(:port)
 185         end
 186
 187         path = rewrite_path(options)
 188         rewritten_url << ActionController::Base.relative_url_root.to_s unless options[:skip_relative_url_root]
 189         rewritten_url << (options[:trailing_slash] ? path.sub(/\?|\z/) { "/" + $& } : path)
 190         rewritten_url << "##{options[:anchor]}" if options[:anchor]
 191
 192         rewritten_url
 193       end
 194
 195       # Given a Hash of options, generates a route
 196       def rewrite_path(options)
 197         options = options.symbolize_keys
 198         options.update(options[:params].symbolize_keys) if options[:params]
 199
 200         if (overwrite = options.delete(:overwrite_params))
 201           options.update(@parameters.symbolize_keys)
 202           options.update(overwrite.symbolize_keys)
 203         end
 204
 205         RESERVED_OPTIONS.each { |k| options.delete(k) }
 206
 207         # Generates the query string, too
 208         Routing::Routes.generate(options, @request.symbolized_path_parameters)
 209       end
 210
 211       def rewrite_authentication(options)
 212         if options[:user] && options[:password]
 213           "#{CGI.escape(options.delete(:user))}:#{CGI.escape(options.delete(:password))}@"
 214         else
 215           ""
 216         end
 217       end
 218   end
 219 end