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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:
#
# * <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>
# * <tt>formatted_polymorphic_url</tt>, <tt>formatted_polymorphic_path</tt>
#
# 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
#
# * <tt>:action</tt> - Specifies the action prefix for the named route:
# <tt>:new</tt>, <tt>:edit</tt>, or <tt>:formatted</tt>. Default is no prefix.
# * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
# Default is <tt>:url</tt>.
#
# ==== 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.dup
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)
send!(named_route, *args)
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 = {})
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)
polymorphic_url(record_or_hash, :action => "#{action}")
end
def #{action}_polymorphic_path(record_or_hash)
polymorphic_url(record_or_hash, :action => "#{action}", :routing_type => :path)
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, 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
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