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.
BUTTON_TAG_METHOD_VERBS | = | %w{patch put delete} |
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. |
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.
By default, the generated form element has a class name of
button_to
to allow styling of the form itself and its
children. This can be changed using the :form_class
modifier
within html_options
. You can control the form submission and
input element behavior using html_options
. This method accepts
the :method
modifier 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
- Symbol of HTTP verb. Supported verbs are:post
,:get
,:delete
,:patch
, and:put
. By default it will be:post
. -
:disabled
- If set to true, it will generate a disabled button. -
:data
- This option can be used to add custom data attributes. -
:remote
- If set to true, will allow the Unobtrusive JavaScript drivers to control the submit behavior. By default this behavior is an ajax submit. -
:form
- This hash will be form attributes -
:form_class
- This controls the class of the form within which the submit button will be placed -
:params
- Hash of parameters to be rendered as hidden fields within the form.
Data attributes
-
: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. -
: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
<%= button_to "New", action: "new" %>
# => "<form method="post" action="/controller/new" class="button_to">
# <input value="New" type="submit" />
# </form>"
<%= button_to "New", new_articles_path %>
# => "<form method="post" action="/articles/new" class="button_to">
# <input value="New" type="submit" />
# </form>"
<%= button_to [:make_happy, @user] do %>
Make happy <strong><%= @user.name %></strong>
<% end %>
# => "<form method="post" action="/users/1/make_happy" class="button_to">
# <button type="submit">
# Make happy <strong><%= @user.name %></strong>
# </button>
# </form>"
<%= button_to "New", { action: "new" }, form_class: "new-thing" %>
# => "<form method="post" action="/controller/new" class="new-thing">
# <input value="New" type="submit" />
# </form>"
<%= button_to "Create", { action: "create" }, remote: true, form: { "data-type" => "json" } %>
# => "<form method="post" action="/images/create" class="button_to" data-remote="true" data-type="json">
# <input value="Create" type="submit" />
# <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
# </form>"
<%= button_to "Delete Image", { action: "delete", id: @image.id },
method: :delete, data: { confirm: "Are you sure?" } %>
# => "<form method="post" action="/images/delete/1" class="button_to">
# <input type="hidden" name="_method" value="delete" />
# <input data-confirm='Are you sure?' value="Delete Image" type="submit" />
# <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
# </form>"
<%= button_to('Destroy', 'http://www.example.com',
method: "delete", remote: true, data: { confirm: 'Are you sure?', disable_with: 'loading...' }) %>
# => "<form class='button_to' method='post' action='http://www.example.com' data-remote='true'>
# <input name='_method' value='delete' type='hidden' />
# <input value='Destroy' type='submit' data-disable-with='loading...' data-confirm='Are you sure?' />
# <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
# </form>"
#
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&page=1
action.
current_page?(action: 'process')
# => false
current_page?(action: 'checkout')
# => true
current_page?(controller: 'library', action: 'checkout')
# => false
current_page?(controller: 'shop', action: 'checkout')
# => true
current_page?(controller: 'shop', action: 'checkout', order: 'asc')
# => false
current_page?(controller: 'shop', action: 'checkout', order: 'desc', page: '1')
# => true
current_page?(controller: 'shop', action: 'checkout', order: 'desc', page: '2')
# => false
current_page?('http://www.example.com/shop/checkout')
# => true
current_page?('http://www.example.com/shop/checkout', check_parameters: true)
# => false
current_page?('/shop/checkout')
# => true
current_page?('http://www.example.com/shop/checkout?order=desc&page=1')
# => true
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
We can also pass in the symbol arguments instead of strings.
# File actionview/lib/action_view/helpers/url_helper.rb, line 536 def current_page?(options, check_parameters: false) 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? check_parameters ||= options.is_a?(Hash) && options.delete(:check_parameters) 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 # the behaviour can be disabled with check_parameters: true request_uri = url_string.index("?") || check_parameters ? request.fullpath : request.path request_uri = URI.parser.unescape(request_uri).force_encoding(Encoding::BINARY) if url_string.start_with?("/") && url_string != "/" url_string.chomp!("/") request_uri.chomp!("/") end if %r{^\w+://}.match?(url_string) url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}" else url_string == request_uri end end
Creates an anchor element 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 an anchor element 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 name for a disabled version of the link. 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>
Also you can set any link attributes such as target
,
rel
, type
:
link_to "External link", "http://www.rubyonrails.org/", target: "_blank", rel: "nofollow"
# => <a href="http://www.rubyonrails.org/" target="_blank" rel="nofollow">External link</a>
# File actionview/lib/action_view/helpers/url_helper.rb, line 189 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".freeze] ||= url content_tag("a".freeze, 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 actionview/lib/action_view/helpers/url_helper.rb, line 425 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>
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
%>
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. -
:reply_to
- Preset the Reply-To field of 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 actionview/lib/action_view/helpers/url_helper.rb, line 475 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 reply_to }.map! { |item| option = html_options.delete(item).presence || next "#{item.dasherize}=#{ERB::Util.url_encode(option)}" }.compact extras = extras.empty? ? "".freeze : "?" + extras.join("&") encoded_email_address = ERB::Util.url_encode(email_address).gsub("%40", "@") html_options["href"] = "mailto:#{encoded_email_address}#{extras}" content_tag("a".freeze, name || email_address, html_options, &block) end