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:
#
# * 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"
#
# == 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
#
# * :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.
#
# Also includes all the options from url_for. These include such
# things as :anchor or :trailing_slash. 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 url_for.
#
# ==== 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)
prefix = action_prefix options
suffix = routing_type options
if options[:action] == 'new'
inflection = SINGULAR_ROUTE_KEY
builder = HelperMethodBuilder.singular
else
inflection = ROUTE_KEY
builder = HelperMethodBuilder.plural
end
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
method, args = builder.handle_list record_or_hash_or_array,
prefix,
suffix
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 = opts.delete(:id)
method, args = builder.handle_model record, prefix, suffix
when String, Symbol
method, args = builder.handle_string record_or_hash_or_array,
prefix,
suffix
when Class
method, args = builder.handle_class record_or_hash_or_array,
prefix,
suffix
when nil
raise ArgumentError, "Nil location provided. Can't build URI."
else
method, args = builder.handle_model record_or_hash_or_array,
prefix,
suffix
end
if opts.empty?
recipient.send(method, *args)
else
recipient.send(method, *args, opts)
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
class HelperMethodBuilder # :nodoc:
def self.singular
new(->(name) { name.singular_route_key })
end
def self.plural
new(->(name) { name.route_key })
end
def initialize(key_strategy)
@key_strategy = key_strategy
end
def handle_string(record, prefix, suffix)
method = prefix + "#{record}_#{suffix}"
[method, []]
end
def handle_class(klass, prefix, suffix)
name = @key_strategy.call klass.model_name
[prefix + "#{name}_#{suffix}", []]
end
def handle_model(record, prefix, suffix)
args = []
model = record.to_model
name = if record.persisted?
args << model
model.class.model_name.singular_route_key
else
@key_strategy.call model.class.model_name
end
named_route = prefix + "#{name}_#{suffix}"
[named_route, args]
end
def handle_list(list, prefix, suffix)
record_list = list.dup
record = record_list.pop
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
@key_strategy.call record.model_name
else
if record.persisted?
args << record.to_model
record.to_model.class.model_name.singular_route_key
else
@key_strategy.call record.to_model.class.model_name
end
end
route << suffix
named_route = prefix + route.join("_")
[named_route, args]
end
end
ROUTE_KEY = lambda { |name| name.route_key }
SINGULAR_ROUTE_KEY = lambda { |name| name.singular_route_key }
def model_path_helper_call(record)
handle_model record, ''.freeze, "path".freeze, ROUTE_KEY
end
def class_path_helper_call(klass)
handle_class klass, ''.freeze, "path".freeze, ROUTE_KEY
end
def action_prefix(options)
options[:action] ? "#{options[:action]}_" : ''
end
def routing_type(options)
options[:routing_type] || :url
end
end
end
end