require 'action_controller/model_naming'
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:
#
# * <tt>url_for</tt>, so you can use it with a record as the argument, e.g.
# <tt>url_for(@article)</tt>;
# * ActionView::Helpers::FormHelper uses <tt>polymorphic_path</tt>, so you can write
# <tt>form_for(@article)</tt> without having to specify <tt>:url</tt> parameter for the form
# action;
# * <tt>redirect_to</tt> (which, in fact, uses <tt>url_for</tt>) so you can write
# <tt>redirect_to(post)</tt> in your controllers;
# * ActionView::Helpers::AtomFeedHelper, so you don't have to explicitly specify URLs
# for feed entries.
#
# == Prefixed polymorphic helpers
#
# In addition to <tt>polymorphic_url</tt> and <tt>polymorphic_path</tt> methods, a
# number of prefixed helpers are available as a shorthand to <tt>action: "..."</tt>
# in options. Those are:
#
# * <tt>edit_polymorphic_url</tt>, <tt>edit_polymorphic_path</tt>
# * <tt>new_polymorphic_url</tt>, <tt>new_polymorphic_path</tt>
#
# Example usage:
#
# edit_polymorphic_path(@post) # => "/posts/1/edit"
# polymorphic_path(@post, format: :pdf) # => "/posts/1.pdf"
#
# == Usage with mounted engines
#
# If you are using a mounted engine and you need to use a polymorphic_url
# pointing at the engine's routes, pass in the engine's route proxy as the first
# argument to the method. For example:
#
# polymorphic_url([blog, @post]) # calls blog.post_path(@post)
# form_for([blog, @post]) # => "/blog/posts/1"
#
module PolymorphicRoutes
include ActionController::ModelNaming
# 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
#
# * <tt>:action</tt> - Specifies the action prefix for the named route:
# <tt>:new</tt> or <tt>:edit</tt>. Default is no prefix.
# * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
# Default is <tt>:url</tt>.
#
# Also includes all the options from <tt>url_for</tt>. These include such
# things as <tt>:anchor</tt> or <tt>:trailing_slash</tt>. Example usage
# is given below:
#
# polymorphic_url([blog, post], anchor: 'my_anchor')
# # => "http://example.com/blogs/1/posts/1#my_anchor"
# polymorphic_url([blog, post], anchor: 'my_anchor', script_name: "/my_app")
# # => "http://example.com/my_app/blogs/1/posts/1#my_anchor"
#
# For all of these options, see the documentation for <tt>url_for</tt>.
#
# ==== Functionality
#
# # 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 = {})
recipient = self
opts = options.except(:action, :routing_type)
case record_or_hash_or_array
when Array
if record_or_hash_or_array.empty? || record_or_hash_or_array.any?(&:nil?)
raise ArgumentError, "Nil location provided. Can't build URI."
end
if record_or_hash_or_array.first.is_a?(ActionDispatch::Routing::RoutesProxy)
recipient = record_or_hash_or_array.shift
end
record_list = record_or_hash_or_array.dup
record = record_list.pop
when Hash
unless record_or_hash_or_array[:id]
raise ArgumentError, "Nil location provided. Can't build URI."
end
opts = record_or_hash_or_array.dup.merge!(opts)
record_list = []
record = opts.delete(:id)
when nil
raise ArgumentError, "Nil location provided. Can't build URI."
else
record_list = []
record = record_or_hash_or_array
end
if options[:action] == 'new'
inflection = lambda { |name| name.singular_route_key }
else
inflection = lambda { |name| name.route_key }
end
args = []
route = record_list.map { |parent|
case parent
when Symbol, String
parent.to_s
when Class
args << parent
parent.model_name.singular_route_key
else
args << parent.to_model
parent.to_model.class.model_name.singular_route_key
end
}
route <<
case record
when Symbol, String
record.to_s
when Class
inflection.call record.model_name
else
if record.persisted?
args << record.to_model
record.to_model.class.model_name.singular_route_key
else
inflection.call record.to_model.class.model_name
end
end
route << routing_type(options)
named_route = action_prefix(options) + route.join("_")
if opts.empty?
recipient.send(named_route, *args)
else
recipient.send(named_route, *args, opts)
end
end
# Returns the path component of a URL for the given record. It uses
# <tt>polymorphic_url</tt> with <tt>routing_type: :path</tt>.
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
end
end
end
