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 false.
• :protocol The protocol to connect to. Defaults to ‘http’.
• :host Specifies the host the link should be targetted at. If :only_path is false, this option must be provided either explicitly, or via default_url_options.
• :port Optionally specify the port to connect to.
• :anchor An anchor name to be appended to the path.
• :skip_relative_url_root If true, the url is not constructed using the relative_url_root set in ActionController::AbstractRequest.relative_url_root.

Any other key(:controller, :action, etc…) given to url_for is forwarded to the Routes module.

Examples:

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', :host=>'somehost.org', :number => '33'  # => 'http://somehost.org/tasks/testing?number=33'

Source Code

# File action_controller/url_rewriter.rb, line 47
def url_for(options)
  options = self.class.default_url_options.merge(options)

  url = ''

  unless options.delete(:only_path)
    url << (options.delete(:protocol) || 'http')
    url << '://' unless url.match("://")

    raise "Missing host to link to! Please provide :host parameter or set default_url_options[:host]" unless options[:host]

    url << options.delete(:host)
    url << ":#{options.delete(:port)}" if options.key?(:port)
  else
    # Delete the unused options to prevent their appearance in the query string.
    [:protocol, :host, :port, :skip_relative_url_root].each { |k| options.delete(k) }
  end

  url << ActionController::AbstractRequest.relative_url_root.to_s unless options[:skip_relative_url_root]
  anchor = "##{CGI.escape options.delete(:anchor).to_param.to_s}" if options[:anchor]
  url << Routing::Routes.generate(options, {})
  url << anchor if anchor

  url
end