instance method url_for

Generate a URL based on the options provided, default_url_options, and the routes defined in config/routes.rb. The following options are supported:

• :only_path - If true, the relative URL is returned. Defaults to false.

• :protocol - The protocol to connect to. Defaults to "http".

• :host - Specifies the host the link should be targeted at. If :only_path is false, this option must be provided either explicitly, or via default_url_options.

• :subdomain - Specifies the subdomain of the link, using the tld_length to 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_length to split the domain from the host.

• :tld_length - Number of labels the TLD id composed of, only used if :subdomain or :domain are 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.

• :params - The query parameters to be appended to the path.

• :path_params - The query parameters that will only be used for the named dynamic segments of path. If unused, they will be discarded.

• :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 (:controller, :action, etc.) given to 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'

Missing routes keys may be filled in from the current request’s parameters (e.g. :controller, :action, :id, and any other parameters that are placed in the path). Given that the current action has been reached through GET /users/1:

url_for(only_path: true)                        # => '/users/1'
url_for(only_path: true, action: 'edit')        # => '/users/1/edit'
url_for(only_path: true, action: 'edit', id: 2) # => '/users/2/edit'

Notice that no :id parameter was provided to the first url_for call and the helper used the one from the route’s path. Any path parameter implicitly used by url_for can always be overwritten like shown on the last url_for calls.