module ActionView::Helpers::UrlHelper
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.
Constants
- BUTTON_TAG_METHOD_VERBS
This helper may be included in any class that includes the URL helpers of a routes (routes.url_helpers). Some methods provided here will only work in the context of a request (link_to_unless_current, for instance), which must be provided as a method called request on the context.
Public Instance Methods
True if the current request URI was generated by the given
options
.
Examples¶ ↑
Let's say we're in the
http://www.example.com/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 current_page?('http://www.example.com/shop/checkout') # => true current_page?('/shop/checkout') # => true
Let's say we're in the
http://www.example.com/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
Let's say we're in the http://www.example.com/products
action with method POST in case of invalid product.
current_page?(controller: 'product', action: 'index') # => false
# File lib/action_view/helpers/url_helper.rb, line 526 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 return false unless request.get? || request.head? url_string = URI.parser.unescape(url_for(options)).force_encoding(Encoding::BINARY) # 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 request_uri = url_string.index("?") ? request.fullpath : request.path request_uri = URI.parser.unescape(request_uri).force_encoding(Encoding::BINARY) 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, which generates a link tag that uses the value of the
String as the href for the link. Using a :back
Symbol instead
of an options hash will generate a link to the referrer (a JavaScript back
link will be used in place of a referrer if none exists). If
nil
is passed as the name the value of 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 :method, is passed to url_for link_to(options = {}, html_options = {}) do # name end link_to(url, html_options = {}) do # name end
Options¶ ↑
-
:data
- This option can be used to add custom data attributes. -
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
,:patch
, and:put
. Note that if the user has JavaScript disabled, the request will fall back to using GET. Ifhref: '#'
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 forpost?
,delete?
,patch?
, orput?
. -
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
Data attributes¶ ↑
-
confirm: 'question?'
- This will allow the unobtrusive JavaScript driver to prompt with the question specified (in this case, the resulting text would bequestion?
. If the user accepts, the link is processed normally, otherwise no action is taken. -
:disable_with
- Value of this parameter will be used as the value for a disabled version of the submit button when the form is submitted. This feature is provided by the unobtrusive JavaScript driver.
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&baz=quux">Nonsense search</a>
The only option specific to link_to
(:method
) is
used as follows:
link_to("Destroy", "http://www.example.com", method: :delete) # => <a href='http://www.example.com' rel="nofollow" data-method="delete">Destroy</a>
You can also use custom data attributes using the :data
option:
link_to "Visit Other Site", "http://www.rubyonrails.org/", data: { confirm: "Are you sure?" } # => <a href="http://www.rubyonrails.org/" data-confirm="Are you sure?">Visit Other Site</a>
# File lib/action_view/helpers/url_helper.rb, line 175 def link_to(name = nil, options = nil, html_options = nil, &block) html_options, options, name = options, name, block if block_given? options ||= {} html_options = convert_options_to_data_attributes(options, html_options) url = url_for(options) html_options['href'] ||= url content_tag(:a, name || url, html_options, &block) end
Creates a link tag of the given name
using a URL created by
the set of options
if condition
is true,
otherwise 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>
# File lib/action_view/helpers/url_helper.rb, line 407 def link_to_if(condition, name, options = {}, html_options = {}, &block) if condition link_to(name, options, html_options) else if block_given? block.arity <= 1 ? capture(name, &block) : capture(name, options, html_options, &block) else ERB::Util.html_escape(name) end end 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>
# File lib/action_view/helpers/url_helper.rb, line 383 def link_to_unless(condition, name, options = {}, html_options = {}, &block) link_to_if !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 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 %>
# File lib/action_view/helpers/url_helper.rb, line 359 def link_to_unless_current(name, options = {}, html_options = {}, &block) link_to_unless current_page?(options), name, options, html_options, &block end
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 customizing the email itself
by passing special keys to html_options
.
Options¶ ↑
-
:subject
- Preset the subject line of the email. -
:body
- Preset the body of the email. -
:cc
- Carbon Copy additional recipients on the email. -
:bcc
- Blind Carbon Copy additional recipients on the email.
Obfuscation¶ ↑
Prior to Rails 4.0, mail_to
provided options for encoding the
address in order to hinder email harvesters. To take advantage of these
options, install the actionview-encoded_mail_to
gem.
Examples¶ ↑
mail_to "me@domain.com" # => <a href="mailto:me@domain.com">me@domain.com</a> mail_to "me@domain.com", "My email" # => <a href="mailto:me@domain.com">My email</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>
You can use a block as well if your link target is hard to fit into the name parameter. ERB example:
<%= mail_to "me@domain.com" do %> <strong>Email me:</strong> <span>me@domain.com</span> <% end %> # => <a href="mailto:me@domain.com"> <strong>Email me:</strong> <span>me@domain.com</span> </a>
# File lib/action_view/helpers/url_helper.rb, line 456 def mail_to(email_address, name = nil, html_options = {}, &block) html_options, name = name, nil if block_given? html_options = (html_options || {}).stringify_keys extras = %w{ cc bcc body subject }.map! { |item| option = html_options.delete(item) || next "#{item}=#{Rack::Utils.escape_path(option)}" }.compact extras = extras.empty? ? '' : '?' + extras.join('&') encoded_email_address = ERB::Util.url_encode(email_address ? email_address.to_str : '').gsub("%40", "@") html_options["href"] = "mailto:#{encoded_email_address}#{extras}" content_tag(:a, name || email_address, html_options, &block) end
Private Instance Methods
# File lib/action_view/helpers/url_helper.rb, line 572 def add_method_to_attributes!(html_options, method) if method && method.to_s.downcase != "get" && html_options["rel"] !~ /nofollow/ html_options["rel"] = "#{html_options["rel"]} nofollow".lstrip end html_options["data-method"] = method end
Processes the html_options
hash, converting the boolean
attributes from true/false form into the form required by HTML/XHTML. (An
attribute is considered to be boolean if its name is listed in the given
bool_attrs
array.)
More specifically, for each boolean attribute in html_options
given as:
"attr" => bool_value
if the associated bool_value
evaluates to true, it is replaced
with the attribute's name; otherwise the attribute is removed from the
html_options
hash. (See the XHTML 1.0 spec, section 4.5
“Attribute Minimization” for more: www.w3.org/TR/xhtml1/#h-4.5)
Returns the updated html_options
hash, which is also modified
in place.
Example:
convert_boolean_attributes!( html_options, %w( checked disabled readonly ) )
# File lib/action_view/helpers/url_helper.rb, line 602 def convert_boolean_attributes!(html_options, bool_attrs) bool_attrs.each { |x| html_options[x] = x if html_options.delete(x) } html_options end
# File lib/action_view/helpers/url_helper.rb, line 551 def convert_options_to_data_attributes(options, html_options) if html_options html_options = html_options.stringify_keys html_options['data-remote'] = 'true' if link_to_remote_options?(options) || link_to_remote_options?(html_options) method = html_options.delete('method') add_method_to_attributes!(html_options, method) if method html_options else link_to_remote_options?(options) ? {'data-remote' => 'true'} : {} end end
# File lib/action_view/helpers/url_helper.rb, line 566 def link_to_remote_options?(options) if options.is_a?(Hash) options.delete('remote') || options.delete(:remote) end end
# File lib/action_view/helpers/url_helper.rb, line 616 def method_tag(method) tag('input', type: 'hidden', name: '_method', value: method.to_s) end
# File lib/action_view/helpers/url_helper.rb, line 607 def token_tag(token=nil) if token != false && protect_against_forgery? token ||= form_authenticity_token tag(:input, type: "hidden", name: request_forgery_protection_token.to_s, value: token) else '' end end