module ActionDispatch
module Routing
# 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
#
# Example usage:
#
# edit_polymorphic_path(@post) # => "/posts/1/edit"
# polymorphic_path(@post, :format => :pdf) # => "/posts/1.pdf"
#
# == Using with mounted engines
#
# If you use mounted engine, there is a possibility that you will need to use
# polymorphic_url pointing at engine's routes. To do that, just pass proxy used
# to reach engine's routes as a first argument:
#
# For example:
#
# polymorphic_url([blog, @post]) # it will call blog.post_path(@post)
# form_for([blog, @post]) # => "/blog/posts/1
#
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"
# polymorphic_url(Comment) # => "http://example.com/comments"
#
# ==== Options
#
# * :action - Specifies the action prefix for the named route:
# :new or :edit. 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()
#
# # the class of a record will also map to the collection
# polymorphic_url(Comment) # 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
if record_or_hash_or_array.first.is_a?(ActionDispatch::Routing::RoutesProxy)
proxy = record_or_hash_or_array.shift
end
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)
record = record.to_model if record.respond_to?(:to_model)
args = Array === record_or_hash_or_array ?
record_or_hash_or_array.dup :
[ record_or_hash_or_array ]
inflection = if options[:action] && options[:action].to_s == "new"
args.pop
:singular
elsif (record.respond_to?(:persisted?) && !record.persisted?)
args.pop
:plural
elsif record.is_a?(Class)
args.pop
:plural
else
:singular
end
args.delete_if {|arg| arg.is_a?(Symbol) || arg.is_a?(String)}
named_route = build_named_route_call(record_or_hash_or_array, inflection, options)
url_options = options.except(:action, :routing_type)
unless url_options.empty?
args.last.kind_of?(Hash) ? args.last.merge!(url_options) : args << url_options
end
if proxy
proxy.send(named_route, *args)
else
# we need to use url_for, because polymorphic_url can be used in context of other than
# current routes (e.g. engine's routes). As named routes from engine are not included
# calling engine's named route directly would fail.
url_for _routes.url_helpers.__send__("hash_for_#{named_route}", *args)
end
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 = {})
polymorphic_url(record_or_hash_or_array, options.merge(:routing_type => :path))
end
%w(edit new).each do |action|
module_eval <<-EOT, __FILE__, __LINE__ + 1
def #{action}_polymorphic_url(record_or_hash, options = {}) # def edit_polymorphic_url(record_or_hash, options = {})
polymorphic_url( # polymorphic_url(
record_or_hash, # record_or_hash,
options.merge(:action => "#{action}")) # options.merge(:action => "edit"))
end # end
#
def #{action}_polymorphic_path(record_or_hash, options = {}) # def edit_polymorphic_path(record_or_hash, options = {})
polymorphic_url( # polymorphic_url(
record_or_hash, # record_or_hash,
options.merge(:action => "#{action}", :routing_type => :path)) # options.merge(:action => "edit", :routing_type => :path))
end # end
EOT
end
private
def action_prefix(options)
options[:action] ? "#{options[:action]}_" : ''
end
def routing_type(options)
options[:routing_type] || :url
end
def build_named_route_call(records, inflection, options = {})
if records.is_a?(Array)
record = records.pop
route = records.map do |parent|
if parent.is_a?(Symbol) || parent.is_a?(String)
parent
else
ActiveModel::Naming.route_key(parent).singularize
end
end
else
record = extract_record(records)
route = []
end
if record.is_a?(Symbol) || record.is_a?(String)
route << record
elsif record
route << ActiveModel::Naming.route_key(record)
route = [route.join("_").singularize] if inflection == :singular
route << "index" if ActiveModel::Naming.uncountable?(record) && inflection == :plural
else
raise ArgumentError, "Nil location provided. Can't build URI."
end
route << routing_type(options)
action_prefix(options) + route.join("_")
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
end
end
end