- Extended by:
- Included in:
- , , , ,
- Defined in:
config/routes.rb you define URL-to-controller mappings, but
the reverse is also possible: an URL can be generated from one of your
routing definitions. URL generation functionality is centralized in this
See ActionDispatch::Routing for general information about routing and routes.rb.
Tip: If you need to generate URLs from your models or some other place, then ActionController::UrlFor is what you're looking for. Read on for an introduction. In general, this module should not be included on its own, as it is usually included by url_helpers (as in Rails.application.routes.url_helpers).
URL generation from parameters
As you may know, some functions, such as ActionController::Base#url_for and ActionView::Helpers::UrlHelper#link_to, can generate URLs given a set of parameters. For example, you've probably had the chance to write code like this in one of your views:
<%= link_to('Click here', controller: 'users', action: 'new', message: 'Welcome!') %> # => "/users/new?message=Welcome%21"
link_to, and all other functions that require URL generation functionality, actually use ActionController::UrlFor under the hood. And in particular, they use the ActionController::UrlFor#url_for method. One can generate the same path as the above example by using the following code:
include UrlFor url_for(controller: 'users', action: 'new', message: 'Welcome!', only_path: true) # => "/users/new?message=Welcome%21"
only_path: true part. This is because UrlFor has no
information about the website hostname that your Rails app is serving. So
if you want to include the hostname as well, then you must also pass the
include UrlFor url_for(controller: 'users', action: 'new', message: 'Welcome!', host: 'www.example.com') # => "http://www.example.com/users/new?message=Welcome%21"
By default, all controllers and views have access to a special version of
url_for, that already knows what the current hostname is. So if you use
url_for in your controllers or your views, then you don't need to
explicitly pass the
For convenience reasons, mailers provide a shortcut for
ActionController::UrlFor#url_for. So within mailers, you only have to type
'url_for' instead of 'ActionController::UrlFor#url_for' in
full. However, mailers don't have hostname information, and that's
why you'll still have to specify the
:host argument when
generating URLs in mailers.
URL generation for named routes
UrlFor also allows one to access methods that have been auto-generated from
named routes. For example, suppose that you have a 'users' resource
This generates, among other things, the method
default, this method is accessible from your controllers, views and
mailers. If you need to access this auto-generated method from other places
(such as a model), then you can do that by including
Rails.application.routes.url_helpers in your class:
class User < ActiveRecord::Base include Rails.application.routes.url_helpers def base_uri user_path(self) end end User.find(1).base_uri # => "/users/1"
Instance Method Summary collapse
- #initialize ⇒ Object
#url_for(options = nil) ⇒ Object
Generate a url based on the options provided, default_url_options and the routes defined in routes.rb.
#url_options ⇒ Object
Hook overridden in controller to add request information with `default_url_options`.
Methods included from
Methods included from
Methods included from
Instance Method Details
102 103 104 105
# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 102 def initialize(*) @_routes = nil super end
#url_for(options = nil) ⇒
Generate a url based on the options provided, default_url_options and the routes defined in routes.rb. The following options are supported:
:only_path- If true, the relative url is returned. Defaults to
:protocol- The protocol to connect to. Defaults to 'http'.
:host- Specifies the host the link should be targeted at. If
:only_pathis false, this option must be provided either explicitly, or via
:subdomain- Specifies the subdomain of the link, using the
tld_lengthto split the subdomain from the host. If false, removes all subdomains from the host part of the link.
:domain- Specifies the domain of the link, using the
tld_lengthto split the domain from the host.
:tld_length- Number of labels the TLD id composed of, only used if
:domainare supplied. Defaults to
ActionDispatch::Http::URL.tld_length, which in turn defaults to 1.
:port- Optionally specify the port to connect to.
:anchor- An anchor name to be appended to the path.
:trailing_slash- If true, adds a trailing slash, as in “/archive/2009/”
:script_name- Specifies application path relative to domain root. If provided, prepends application path.
Any other key (
:action, etc.) given
url_for is forwarded to the Routes module.
url_for controller: 'tasks', action: 'testing', host: 'somehost.org', port: '8080' # => 'http://somehost.org:8080/tasks/testing' url_for controller: 'tasks', action: 'testing', host: 'somehost.org', anchor: 'ok', only_path: true # => '/tasks/testing#ok' url_for controller: 'tasks', action: 'testing', trailing_slash: true # => 'http://somehost.org/tasks/testing/' url_for controller: 'tasks', action: 'testing', host: 'somehost.org', number: '33' # => 'http://somehost.org/tasks/testing?number=33' url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp" # => 'http://somehost.org/myapp/tasks/testing' url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp", only_path: true # => '/myapp/tasks/testing'
150 151 152 153 154 155 156 157 158 159 160 161
# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 150 def url_for( = nil) case when nil _routes.url_for(.symbolize_keys) when Hash _routes.url_for(.symbolize_keys.reverse_merge!()) when String else polymorphic_url() end end
Hook overridden in controller to add request information with `default_url_options`. Application logic should not go into url_options.
110 111 112
# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 110 def end