module ActionController # Polymorphic URL helpers are methods for smart resolution to a named route call when # given an Active Record model instance. They are to be used in combination with # ActionController::Resources. # # These methods are useful when you want to generate correct URL or path to a RESTful # resource without having to know the exact type of the record in question. # # Nested resources and/or namespaces are also supported, as illustrated in the example: # # polymorphic_url([:admin, @article, @comment]) # # results in: # # admin_article_comment_url(@article, @comment) # # == Usage within the framework # # Polymorphic URL helpers are used in a number of places throughout the Rails framework: # # * url_for, so you can use it with a record as the argument, e.g. # url_for(@article); # * ActionView::Helpers::FormHelper uses polymorphic_path, so you can write # form_for(@article) without having to specify :url parameter for the form # action; # * redirect_to (which, in fact, uses url_for) so you can write # redirect_to(post) in your controllers; # * ActionView::Helpers::AtomFeedHelper, so you don't have to explicitly specify URLs # for feed entries. # # == Prefixed polymorphic helpers # # In addition to polymorphic_url and polymorphic_path methods, a # number of prefixed helpers are available as a shorthand to :action => "..." # in options. Those are: # # * edit_polymorphic_url, edit_polymorphic_path # * new_polymorphic_url, new_polymorphic_path # * formatted_polymorphic_url, formatted_polymorphic_path # # Example usage: # # edit_polymorphic_path(@post) # => "/posts/1/edit" # formatted_polymorphic_path([@post, :pdf]) # => "/posts/1.pdf" module PolymorphicRoutes # Constructs a call to a named RESTful route for the given record and returns the # resulting URL string. For example: # # # calls post_url(post) # polymorphic_url(post) # => "http://example.com/posts/1" # polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1" # polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1" # polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1" # # ==== Options # # * :action - Specifies the action prefix for the named route: # :new, :edit, or :formatted. Default is no prefix. # * :routing_type - Allowed values are :path or :url. # Default is :url. # # ==== Examples # # # an Article record # polymorphic_url(record) # same as article_url(record) # # # a Comment record # polymorphic_url(record) # same as comment_url(record) # # # it recognizes new records and maps to the collection # record = Comment.new # polymorphic_url(record) # same as comments_url() # def polymorphic_url(record_or_hash_or_array, options = {}) if record_or_hash_or_array.kind_of?(Array) record_or_hash_or_array = record_or_hash_or_array.compact record_or_hash_or_array = record_or_hash_or_array[0] if record_or_hash_or_array.size == 1 end record = extract_record(record_or_hash_or_array) format = extract_format(record_or_hash_or_array, options) namespace = extract_namespace(record_or_hash_or_array) args = case record_or_hash_or_array when Hash; [ record_or_hash_or_array ] when Array; record_or_hash_or_array.dup else [ record_or_hash_or_array ] end inflection = case when options[:action].to_s == "new" args.pop :singular when record.respond_to?(:new_record?) && record.new_record? args.pop :plural else :singular end args.delete_if {|arg| arg.is_a?(Symbol) || arg.is_a?(String)} args << format if format named_route = build_named_route_call(record_or_hash_or_array, namespace, inflection, options) url_options = options.except(:action, :routing_type, :format) unless url_options.empty? args.last.kind_of?(Hash) ? args.last.merge!(url_options) : args << url_options end __send__(named_route, *args) end # Returns the path component of a URL for the given record. It uses # polymorphic_url with :routing_type => :path. def polymorphic_path(record_or_hash_or_array, options = {}) options[:routing_type] = :path polymorphic_url(record_or_hash_or_array, options) end %w(edit new formatted).each do |action| module_eval <<-EOT, __FILE__, __LINE__ def #{action}_polymorphic_url(record_or_hash, options = {}) polymorphic_url(record_or_hash, options.merge(:action => "#{action}")) end def #{action}_polymorphic_path(record_or_hash, options = {}) polymorphic_url(record_or_hash, options.merge(:action => "#{action}", :routing_type => :path)) end EOT end private def action_prefix(options) options[:action] ? "#{options[:action]}_" : options[:format] ? "formatted_" : "" end def routing_type(options) options[:routing_type] || :url end def build_named_route_call(records, namespace, inflection, options = {}) unless records.is_a?(Array) record = extract_record(records) route = '' else record = records.pop route = records.inject("") do |string, parent| if parent.is_a?(Symbol) || parent.is_a?(String) string << "#{parent}_" else string << "#{RecordIdentifier.__send__("singular_class_name", parent)}_" end end end if record.is_a?(Symbol) || record.is_a?(String) route << "#{record}_" else route << "#{RecordIdentifier.__send__("#{inflection}_class_name", record)}_" end action_prefix(options) + namespace + route + routing_type(options).to_s end def extract_record(record_or_hash_or_array) case record_or_hash_or_array when Array; record_or_hash_or_array.last when Hash; record_or_hash_or_array[:id] else record_or_hash_or_array end end def extract_format(record_or_hash_or_array, options) if options[:action].to_s == "formatted" && record_or_hash_or_array.is_a?(Array) record_or_hash_or_array.pop elsif options[:format] options[:format] else nil end end # Remove the first symbols from the array and return the url prefix # implied by those symbols. def extract_namespace(record_or_hash_or_array) return "" unless record_or_hash_or_array.is_a?(Array) namespace_keys = [] while (key = record_or_hash_or_array.first) && key.is_a?(String) || key.is_a?(Symbol) namespace_keys << record_or_hash_or_array.shift end namespace_keys.map {|k| "#{k}_"}.join end end end