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Instance Public methods
Also aliased as: default_url_options
# File actionpack/lib/action_dispatch/routing/mapper.rb, line 627
def default_url_options=(options)
  @set.default_url_options = options

Query if the following named route was already defined.

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 639
def has_named_route?(name)
  @set.named_routes.key? name
match(path, options=nil)

Matches a url pattern to one or more routes.

You should not use the match method in your router without specifying an HTTP method.

If you want to expose your action to both GET and POST, use:

# sets :controller, :action and :id in params
match ':controller/:action/:id', via: [:get, :post]

Note that :controller, :action and :id are interpreted as url query parameters and thus available through params in an action.

If you want to expose your action to GET, use get in the router:

Instead of:

match ":controller/:action/:id"


get ":controller/:action/:id"

Two of these symbols are special, :controller maps to the controller and :action to the controller's action. A pattern can also map wildcard segments (globs) to params:

get 'songs/*category/:title', to: 'songs#show'

# 'songs/rock/classic/stairway-to-heaven' sets
#  params[:category] = 'rock/classic'
#  params[:title] = 'stairway-to-heaven'

To match a wildcard parameter, it must have a name assigned to it. Without a variable name to attach the glob parameter to, the route can't be parsed.

When a pattern points to an internal route, the route's :action and :controller should be set in options or hash shorthand. Examples:

match 'photos/:id' => 'photos#show', via: :get
match 'photos/:id', to: 'photos#show', via: :get
match 'photos/:id', controller: 'photos', action: 'show', via: :get

A pattern can also point to a Rack endpoint i.e. anything that responds to call:

match 'photos/:id', to: -> (hash) { [200, {}, ["Coming soon"]] }, via: :get
match 'photos/:id', to: PhotoRackApp, via: :get
# Yes, controller actions are just rack endpoints
match 'photos/:id', to: PhotosController.action(:show), via: :get

Because requesting various HTTP verbs with a single action has security implications, you must either specify the actions in the via options or use one of the HttpHelpers instead match


Any options not seen here are passed on as params with the url.


The route's controller.


The route's action.


Overrides the default resource identifier :id (name of the dynamic segment used to generate the routes). You can access that segment from your controller using params[<:param>]. In your router:

resources :user, param: :name

You can override ActiveRecord::Base#to_param of a related model to construct a URL:

class User < ActiveRecord::Base
  def to_param

user = User.find_by(name: 'Phusion') user_path(user) # => “/users/Phusion”


The path prefix for the routes.


The namespace for :controller.

match 'path', to: 'c#a', module: 'sekret', controller: 'posts', via: :get
# => Sekret::PostsController

See Scoping#namespace for its scope equivalent.


The name used to generate routing helpers.


Allowed HTTP verb(s) for route.

match 'path', to: 'c#a', via: :get
match 'path', to: 'c#a', via: [:get, :post]
match 'path', to: 'c#a', via: :all

Points to a Rack endpoint. Can be an object that responds to call or a string representing a controller's action.

match 'path', to: 'controller#action', via: :get
match 'path', to: -> (env) { [200, {}, ["Success!"]] }, via: :get
match 'path', to: RackApp, via: :get

Shorthand for wrapping routes in a specific RESTful context. Valid values are :member, :collection, and :new. Only use within resource(s) block. For example:

resource :bar do
  match 'foo', to: 'c#a', on: :member, via: [:get, :post]

Is equivalent to:

resource :bar do
  member do
    match 'foo', to: 'c#a', via: [:get, :post]

Constrains parameters with a hash of regular expressions or an object that responds to matches?. In addition, constraints other than path can also be specified with any object that responds to === (eg. String, Array, Range, etc.).

match 'path/:id', constraints: { id: /[A-Z]\d{5}/ }, via: :get

match 'json_only', constraints: { format: 'json' }, via: :get

class Whitelist
  def matches?(request) request.remote_ip == '' end
match 'path', to: 'c#a', constraints: Whitelist.new, via: :get

See Scoping#constraints for more examples with its scope equivalent.


Sets defaults for parameters

# Sets params[:format] to 'jpg' by default
match 'path', to: 'c#a', defaults: { format: 'jpg' }, via: :get

See Scoping#defaults for its scope equivalent.


Boolean to anchor a match pattern. Default is true. When set to false, the pattern matches any request prefixed with the given path.

# Matches any request starting with 'path'
match 'path', to: 'c#a', anchor: false, via: :get

Allows you to specify the default value for optional format segment or disable it by supplying false.

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 578
def match(path, options=nil)
mount(app, options = nil)

Mount a Rack-based application to be used within the application.

mount SomeRackApp, at: "some_route"


mount(SomeRackApp => "some_route")

For options, see match, as mount uses it internally.

All mounted applications come with routing helpers to access them. These are named after the class specified, so for the above example the helper is either some_rack_app_path or some_rack_app_url. To customize this helper's name, use the :as option:

mount(SomeRackApp => "some_route", as: "exciting")

This will generate the exciting_path and exciting_url helpers which can be used to navigate to this mounted app.

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 600
def mount(app, options = nil)
  if options
    path = options.delete(:at)
    unless Hash === app
      raise ArgumentError, "must be called with mount point"

    options = app
    app, path = options.find { |k, _| k.respond_to?(:call) }
    options.delete(app) if app

  raise "A rack application must be specified" unless path

  rails_app = rails_app? app
  options[:as] ||= app_name(app, rails_app)

  target_as       = name_for_action(options[:as], path)
  options[:via] ||= :all

  match(path, options.merge(:to => app, :anchor => false, :format => false))

  define_generate_prefix(app, target_as) if rails_app
root(options = {})

You can specify what Rails should route “/” to with the root method:

root to: 'pages#main'

For options, see match, as root uses it internally.

You can also pass a string which will expand

root 'pages#main'

You should put the root route at the top of config/routes.rb, because this means it will be matched first. As this is the most popular route of most Rails applications, this is beneficial.

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 403
def root(options = {})
  name = has_named_route?(:root) ? nil : :root
  match '/', { as: name, via:  :get }.merge!(options)
with_default_scope(scope, &block)
# File actionpack/lib/action_dispatch/routing/mapper.rb, line 632
def with_default_scope(scope, &block)
  scope(scope) do