Module: ActionView::Helpers::UrlHelper

Extended by:
ActiveSupport::Concern
Includes:
ActionDispatch::Routing::UrlFor, TagHelper
Included in:
ActionView::Helpers, FormHelper, FormTagHelper
Defined in:
actionpack/lib/action_view/helpers/url_helper.rb

Overview

Provides a set of methods for making links and getting URLs that depend on the routing subsystem (see ActionDispatch::Routing). This allows you to use the same format for links in views and controllers.

Constant Summary

Constant Summary

Constants included from TagHelper

TagHelper::BOOLEAN_ATTRIBUTES

Constants included from ERB::Util

ERB::Util::HTML_ESCAPE, ERB::Util::JSON_ESCAPE

Instance Method Summary collapse

Methods included from ActiveSupport::Concern

append_features, extended, included

Methods included from TagHelper

#cdata_section, #content_tag, #escape_once, #tag

Methods included from CaptureHelper

#capture, #content_for, #content_for?, #flush_output_buffer, #with_output_buffer

Methods included from ERB::Util

h, html_escape, j, json_escape

Methods included from ActionDispatch::Routing::PolymorphicRoutes

#polymorphic_path, #polymorphic_url

Instance Method Details

#button_to(name, options = {}, html_options = {}) ⇒ Object

Generates a form containing a single button that submits to the URL created by the set of options. This is the safest method to ensure links that cause changes to your data are not triggered by search bots or accelerators. If the HTML button does not work with your layout, you can also consider using the link_to method with the :method modifier as described in the link_to documentation.

The generated form element has a class name of button_to to allow styling of the form itself and its children. You can control the form submission and input element behavior using html_options. This method accepts the :method and :confirm modifiers described in the link_to documentation. If no :method modifier is given, it will default to performing a POST operation. You can also disable the button by passing :disabled => true in html_options. If you are using RESTful routes, you can pass the :method to change the HTTP verb used to submit the form.

Options

The options hash accepts the same options as url_for.

There are a few special html_options:

  • :method - Specifies the anchor name to be appended to the path.

  • :disabled - Specifies the anchor name to be appended to the path.

  • :confirm - This will use the unobtrusive JavaScript driver to prompt with the question specified. If the user accepts, the link is processed normally, otherwise no action is taken.

  • :remote - If set to true, will allow the Unobtrusive JavaScript drivers to control the submit behaviour. By default this behaviour is an ajax submit.

Examples

<%= button_to "New", :action => "new" %>
# => "<form method="post" action="/controller/new" class="button_to">
#      <div><input value="New" type="submit" /></div>
#    </form>"

<%= button_to "Delete Image", { :action => "delete", :id => @image.id },
          :confirm => "Are you sure?", :method => :delete %>
# => "<form method="post" action="/images/delete/1" class="button_to">
#      <div>
#        <input type="hidden" name="_method" value="delete" />
#        <input data-confirm='Are you sure?' value="Delete" type="submit" />
#      </div>
#    </form>"

<%= button_to('Destroy', 'http://www.example.com', :confirm => 'Are you sure?',
          :method => "delete", :remote => true, :disable_with => 'loading...') %>
# => "<form class='button_to' method='post' action='http://www.example.com' data-remote='true'>
#       <div>
#         <input name='_method' value='delete' type='hidden' />
#         <input value='Destroy' type='submit' disable_with='loading...' data-confirm='Are you sure?' />
#       </div>
#     </form>"
#


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 306

def button_to(name, options = {}, html_options = {})
  html_options = html_options.stringify_keys
  convert_boolean_attributes!(html_options, %w( disabled ))

  method_tag = ''
  if (method = html_options.delete('method')) && %w{put delete}.include?(method.to_s)
    method_tag = tag('input', :type => 'hidden', :name => '_method', :value => method.to_s)
  end

  form_method = method.to_s == 'get' ? 'get' : 'post'

  remote = html_options.delete('remote')

  request_token_tag = ''
  if form_method == 'post' && protect_against_forgery?
    request_token_tag = tag(:input, :type => "hidden", :name => request_forgery_protection_token.to_s, :value => form_authenticity_token)
  end

  url = options.is_a?(String) ? options : self.url_for(options)
  name ||= url

  html_options = convert_options_to_data_attributes(options, html_options)

  html_options.merge!("type" => "submit", "value" => name)

  ("<form method=\"#{form_method}\" action=\"#{html_escape(url)}\" #{"data-remote=\"true\"" if remote} class=\"button_to\"><div>" +
    method_tag + tag("input", html_options) + request_token_tag + "</div></form>").html_safe
end

#current_page?(options) ⇒ Boolean

True if the current request URI was generated by the given options.

Examples

Let's say we're in the /shop/checkout?order=desc action.

current_page?(:action => 'process')
# => false

current_page?(:controller => 'shop', :action => 'checkout')
# => true

current_page?(:controller => 'shop', :action => 'checkout', :order => 'asc')
# => false

current_page?(:action => 'checkout')
# => true

current_page?(:controller => 'library', :action => 'checkout')
# => false

Let's say we're in the /shop/checkout?order=desc&page=1 action.

current_page?(:action => 'process')
# => false

current_page?(:controller => 'shop', :action => 'checkout')
# => true

current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page=>'1')
# => true

current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page=>'2')
# => false

current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc')
# => false

current_page?(:action => 'checkout')
# => true

current_page?(:controller => 'library', :action => 'checkout')
# => false

Returns:

  • (Boolean)


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 562

def current_page?(options)
  unless request
    raise "You cannot use helpers that need to determine the current " \
          "page unless your view context provides a Request object " \
          "in a #request method"
  end

  url_string = url_for(options)

  # We ignore any extra parameters in the request_uri if the
  # submitted url doesn't have any either.  This lets the function
  # work with things like ?order=asc
  if url_string.index("?")
    request_uri = request.fullpath
  else
    request_uri = request.path
  end

  if url_string =~ /^\w+:\/\//
    url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}"
  else
    url_string == request_uri
  end
end

Creates a link tag of the given name using a URL created by the set of options. See the valid options in the documentation for url_for. It's also possible to pass a string instead of an options hash to get a link tag that uses the value of the string as the href for the link, or use :back to link to the referrer - a JavaScript back link will be used in place of a referrer if none exists. If nil is passed as a name, the link itself will become the name.

Signatures

link_to(body, url, html_options = {})
  # url is a String; you can use URL helpers like
  # posts_path

link_to(body, url_options = {}, html_options = {})
  # url_options, except :confirm or :method,
  # is passed to url_for

link_to(options = {}, html_options = {}) do
  # name
end

link_to(url, html_options = {}) do
  # name
end

Options

  • :confirm => 'question?' - This will allow the unobtrusive JavaScript driver to prompt with the question specified. If the user accepts, the link is processed normally, otherwise no action is taken.

  • :method => symbol of HTTP verb - This modifier will dynamically create an HTML form and immediately submit the form for processing using the HTTP verb specified. Useful for having links perform a POST operation in dangerous actions like deleting a record (which search bots can follow while spidering your site). Supported verbs are :post, :delete and :put. Note that if the user has JavaScript disabled, the request will fall back to using GET. If :href => '#' is used and the user has JavaScript disabled clicking the link will have no effect. If you are relying on the POST behavior, you should check for it in your controller's action by using the request object's methods for post?, delete? or put?.

  • :remote => true - This will allow the unobtrusive JavaScript driver to make an Ajax request to the URL in question instead of following the link. The drivers each provide mechanisms for listening for the completion of the Ajax request and performing JavaScript operations once they're complete

Examples

Because it relies on url_for, link_to supports both older-style controller/action/id arguments and newer RESTful routes. Current Rails style favors RESTful routes whenever possible, so base your application on resources and use

link_to "Profile", profile_path(@profile)
# => <a href="/profiles/1">Profile</a>

or the even pithier

link_to "Profile", @profile
# => <a href="/profiles/1">Profile</a>

in place of the older more verbose, non-resource-oriented

link_to "Profile", :controller => "profiles", :action => "show", :id => @profile
# => <a href="/profiles/show/1">Profile</a>

Similarly,

link_to "Profiles", profiles_path
# => <a href="/profiles">Profiles</a>

is better than

link_to "Profiles", :controller => "profiles"
# => <a href="/profiles">Profiles</a>

You can use a block as well if your link target is hard to fit into the name parameter. ERb example:

<%= link_to(@profile) do %>
  <strong><%= @profile.name %></strong> -- <span>Check it out!</span>
<% end %>
# => <a href="/profiles/1">
       <strong>David</strong> -- <span>Check it out!</span>
     </a>

Classes and ids for CSS are easy to produce:

link_to "Articles", articles_path, :id => "news", :class => "article"
# => <a href="/articles" class="article" id="news">Articles</a>

Be careful when using the older argument style, as an extra literal hash is needed:

link_to "Articles", { :controller => "articles" }, :id => "news", :class => "article"
# => <a href="/articles" class="article" id="news">Articles</a>

Leaving the hash off gives the wrong link:

link_to "WRONG!", :controller => "articles", :id => "news", :class => "article"
# => <a href="/articles/index/news?class=article">WRONG!</a>

link_to can also produce links with anchors or query strings:

link_to "Comment wall", profile_path(@profile, :anchor => "wall")
# => <a href="/profiles/1#wall">Comment wall</a>

link_to "Ruby on Rails search", :controller => "searches", :query => "ruby on rails"
# => <a href="/searches?query=ruby+on+rails">Ruby on Rails search</a>

link_to "Nonsense search", searches_path(:foo => "bar", :baz => "quux")
# => <a href="/searches?foo=bar&amp;baz=quux">Nonsense search</a>

The two options specific to link_to (:confirm and :method) are used as follows:

link_to "Visit Other Site", "http://www.rubyonrails.org/", :confirm => "Are you sure?"
# => <a href="http://www.rubyonrails.org/" data-confirm="Are you sure?"">Visit Other Site</a>

link_to("Destroy", "http://www.example.com", :method => :delete, :confirm => "Are you sure?")
# => <a href='http://www.example.com' rel="nofollow" data-method="delete" data-confirm="Are you sure?">Destroy</a>


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 225

def link_to(*args, &block)
  if block_given?
    options      = args.first || {}
    html_options = args.second
    link_to(capture(&block), options, html_options)
  else
    name         = args[0]
    options      = args[1] || {}
    html_options = args[2]

    html_options = convert_options_to_data_attributes(options, html_options)
    url = url_for(options)

    if html_options
      html_options = html_options.stringify_keys
      href = html_options['href']
      tag_options = tag_options(html_options)
    else
      tag_options = nil
    end

    href_attr = "href=\"#{html_escape(url)}\"" unless href
    "<a #{href_attr}#{tag_options}>#{html_escape(name || url)}</a>".html_safe
  end
end

Creates a link tag of the given name using a URL created by the set of options if condition is true, in which case only the name is returned. To specialize the default behavior, you can pass a block that accepts the name or the full argument list for link_to_unless (see the examples in link_to_unless).

Examples

<%= link_to_if(@current_user.nil?, "Login", { :controller => "sessions", :action => "new" }) %>
# If the user isn't logged in...
# => <a href="/sessions/new/">Login</a>

<%=
   link_to_if(@current_user.nil?, "Login", { :controller => "sessions", :action => "new" }) do
     link_to(@current_user.login, { :controller => "accounts", :action => "show", :id => @current_user })
   end
%>
# If the user isn't logged in...
# => <a href="/sessions/new/">Login</a>
# If they are logged in...
# => <a href="/accounts/show/3">my_username</a>


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 430

def link_to_if(condition, name, options = {}, html_options = {}, &block)
  link_to_unless !condition, name, options, html_options, &block
end

Creates a link tag of the given name using a URL created by the set of options unless condition is true, in which case only the name is returned. To specialize the default behavior (i.e., show a login link rather than just the plaintext link text), you can pass a block that accepts the name or the full argument list for link_to_unless.

Examples

<%= link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) %>
# If the user is logged in...
# => <a href="/controller/reply/">Reply</a>

<%=
   link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) do |name|
     link_to(name, { :controller => "accounts", :action => "signup" })
   end
%>
# If the user is logged in...
# => <a href="/controller/reply/">Reply</a>
# If not...
# => <a href="/accounts/signup">Reply</a>


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 398

def link_to_unless(condition, name, options = {}, html_options = {}, &block)
  if condition
    if block_given?
      block.arity <= 1 ? capture(name, &block) : capture(name, options, html_options, &block)
    else
      name
    end
  else
    link_to(name, options, html_options)
  end
end

Creates a link tag of the given name using a URL created by the set of options unless the current request URI is the same as the links, in which case only the name is returned (or the given block is yielded, if one exists). You can give link_to_unless_current a block which will specialize the default behavior (e.g., show a “Start Here” link rather than the link's text).

Examples

Let's say you have a navigation menu…

<ul id="navbar">
  <li><%= link_to_unless_current("Home", { :action => "index" }) %></li>
  <li><%= link_to_unless_current("About Us", { :action => "about" }) %></li>
</ul>

If in the “about” action, it will render…

<ul id="navbar">
  <li><a href="/controller/index">Home</a></li>
  <li>About Us</li>
</ul>

…but if in the “index” action, it will render:

<ul id="navbar">
  <li>Home</li>
  <li><a href="/controller/about">About Us</a></li>
</ul>

The implicit block given to link_to_unless_current is evaluated if the current action is the action given. So, if we had a comments page and wanted to render a “Go Back” link instead of a link to the comments page, we could do something like this…

<%=
    link_to_unless_current("Comment", { :controller => "comments", :action => "new" }) do
       link_to("Go back", { :controller => "posts", :action => "index" })
    end
 %>


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 374

def link_to_unless_current(name, options = {}, html_options = {}, &block)
  link_to_unless current_page?(options), name, options, html_options, &block
end

#mail_to(email_address, name = nil, html_options = {}) ⇒ Object

Creates a mailto link tag to the specified email_address, which is also used as the name of the link unless name is specified. Additional HTML attributes for the link can be passed in html_options.

mail_to has several methods for hindering email harvesters and customizing the email itself by passing special keys to html_options.

Options

  • :encode - This key will accept the strings “javascript” or “hex”. Passing “javascript” will dynamically create and encode the mailto link then eval it into the DOM of the page. This method will not show the link on the page if the user has JavaScript disabled. Passing “hex” will hex encode the email_address before outputting the mailto link.

  • :replace_at - When the link name isn't provided, the email_address is used for the link label. You can use this option to obfuscate the email_address by substituting the @ sign with the string given as the value.

  • :replace_dot - When the link name isn't provided, the email_address is used for the link label. You can use this option to obfuscate the email_address by substituting the . in the email with the string given as the value.

  • :subject - Preset the subject line of the email.

  • :body - Preset the body of the email.

  • :cc - Carbon Copy addition recipients on the email.

  • :bcc - Blind Carbon Copy additional recipients on the email.

Examples

mail_to "me@domain.com"
# => <a href="mailto:me@domain.com">me@domain.com</a>

mail_to "me@domain.com", "My email", :encode => "javascript"
# => <script type="text/javascript">eval(decodeURIComponent('%64%6f%63...%27%29%3b'))</script>

mail_to "me@domain.com", "My email", :encode => "hex"
# => <a href="mailto:%6d%65@%64%6f%6d%61%69%6e.%63%6f%6d">My email</a>

mail_to "me@domain.com", nil, :replace_at => "_at_", :replace_dot => "_dot_", :class => "email"
# => <a href="mailto:me@domain.com" class="email">me_at_domain_dot_com</a>

mail_to "me@domain.com", "My email", :cc => "ccaddress@domain.com",
         :subject => "This is an example email"
# => <a href="mailto:me@domain.com?cc=ccaddress@domain.com&subject=This%20is%20an%20example%20email">My email</a>


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 476

def mail_to(email_address, name = nil, html_options = {})
  email_address = html_escape(email_address)

  html_options = html_options.stringify_keys
  encode = html_options.delete("encode").to_s
  cc, bcc, subject, body = html_options.delete("cc"), html_options.delete("bcc"), html_options.delete("subject"), html_options.delete("body")

  extras = []
  extras << "cc=#{Rack::Utils.escape(cc).gsub("+", "%20")}" unless cc.nil?
  extras << "bcc=#{Rack::Utils.escape(bcc).gsub("+", "%20")}" unless bcc.nil?
  extras << "body=#{Rack::Utils.escape(body).gsub("+", "%20")}" unless body.nil?
  extras << "subject=#{Rack::Utils.escape(subject).gsub("+", "%20")}" unless subject.nil?
  extras = extras.empty? ? '' : '?' + html_escape(extras.join('&'))

  email_address_obfuscated = email_address.dup
  email_address_obfuscated.gsub!(/@/, html_options.delete("replace_at")) if html_options.has_key?("replace_at")
  email_address_obfuscated.gsub!(/\./, html_options.delete("replace_dot")) if html_options.has_key?("replace_dot")

  string = ''

  if encode == "javascript"
    "document.write('#{("a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe))}');".each_byte do |c|
      string << sprintf("%%%x", c)
    end
    "<script type=\"#{Mime::JS}\">eval(decodeURIComponent('#{string}'))</script>".html_safe
  elsif encode == "hex"
    email_address_encoded = ''
    email_address_obfuscated.each_byte do |c|
      email_address_encoded << sprintf("&#%d;", c)
    end

    protocol = 'mailto:'
    protocol.each_byte { |c| string << sprintf("&#%d;", c) }

    email_address.each_byte do |c|
      char = c.chr
      string << (char =~ /\w/ ? sprintf("%%%x", c) : char)
    end
     "a", name || email_address_encoded.html_safe, html_options.merge("href" => "#{string}#{extras}".html_safe)
  else
     "a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe)
  end
end

#url_for(options = {}) ⇒ Object

Returns the URL for the set of options provided. This takes the same options as url_for in Action Controller (see the documentation for ActionController::Base#url_for). Note that by default :only_path is true so you'll get the relative “/controller/action” instead of the fully qualified URL like “example.com/controller/action”.

Options

  • :anchor - Specifies the anchor name to be appended to the path.

  • :only_path - If true, returns the relative URL (omitting the protocol, host name, and port) (true by default unless :host is specified).

  • :trailing_slash - If true, adds a trailing slash, as in “/archive/2005/”. Note that this is currently not recommended since it breaks caching.

  • :host - Overrides the default (current) host if provided.

  • :protocol - Overrides the default (current) protocol if provided.

  • :user - Inline HTTP authentication (only plucked out if :password is also present).

  • :password - Inline HTTP authentication (only plucked out if :user is also present).

Relying on named routes

If you instead of a hash pass a record (like an Active Record or Active Resource) as the options parameter, you'll trigger the named route for that record. The lookup will happen on the name of the class. So passing a Workshop object will attempt to use the workshop_path route. If you have a nested route, such as admin_workshop_path you'll have to call that explicitly (it's impossible for url_for to guess that route).

Examples

<%= url_for(:action => 'index') %>
# => /blog/

<%= url_for(:action => 'find', :controller => 'books') %>
# => /books/find

<%= url_for(:action => 'login', :controller => 'members', :only_path => false, :protocol => 'https') %>
# => https://www.railsapplication.com/members/login/

<%= url_for(:action => 'play', :anchor => 'player') %>
# => /messages/play/#player

<%= url_for(:action => 'jump', :anchor => 'tax&ship') %>
# => /testing/jump/#tax&ship

<%= url_for(Workshop.new) %>
# relies on Workshop answering a persisted? call (and in this case returning false)
# => /workshops

<%= url_for(@workshop) %>
# calls @workshop.to_s
# => /workshops/5

<%= url_for("http://www.example.com") %>
# => http://www.example.com

<%= url_for(:back) %>
# if request.env["HTTP_REFERER"] is set to "http://www.example.com"
# => http://www.example.com

<%= url_for(:back) %>
# if request.env["HTTP_REFERER"] is not set or is blank
# => javascript:history.back()


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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 92

def url_for(options = {})
  options ||= {}
  url = case options
  when String
    options
  when Hash
    options = options.symbolize_keys.reverse_merge!(:only_path => options[:host].nil?)
    super
  when :back
    controller.request.env["HTTP_REFERER"] || 'javascript:history.back()'
  else
    polymorphic_path(options)
  end

  url
end

#url_optionsObject

Need to map default url options to controller one. def default_url_options(*args) #:nodoc:

controller.send(:default_url_options, *args)

end



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# File 'actionpack/lib/action_view/helpers/url_helper.rb', line 30

def url_options
  return super unless controller.respond_to?(:url_options)
  controller.url_options
end