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.
- #
- B
- C
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- M
- U
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
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
- Symbol of HTTP verb. Supported verbs are:post
,:get
,:delete
and:put
. By default it will be:post
. -
:disabled
- If set to true, it will generate a disabled button. -
: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 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
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 "New", :action => "new", :form_class => "new-thing" %> # => "<form method="post" action="/controller/new" class="new-thing"> # <div><input value="New" type="submit" /></div> # </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"> # <div><input value="Create" 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>" #
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
Let’s say we’re in the /products
action with method POST in
case of invalid product.
current_page?(:controller => 'product', :action => 'index') # => false
# File actionpack/lib/action_view/helpers/url_helper.rb, line 588 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? 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, 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 :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 forpost?
,delete?
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
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 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>
# File actionpack/lib/action_view/helpers/url_helper.rb, line 231 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) href = html_options['href'] tag_options = tag_options(html_options) href_attr = "href=\"#{ERB::Util.html_escape(url)}\"" unless href "<a #{href_attr}#{tag_options}>#{ERB::Util.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,
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>
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 actionpack/lib/action_view/helpers/url_helper.rb, line 420 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 %>
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 theemail_address
before outputting the mailto link. -
:replace_at
- When the linkname
isn't provided, theemail_address
is used for the link label. You can use this option to obfuscate theemail_address
by substituting the @ sign with the string given as the value. -
:replace_dot
- When the linkname
isn't provided, theemail_address
is used for the link label. You can use this option to obfuscate theemail_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 additional 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>
# File actionpack/lib/action_view/helpers/url_helper.rb, line 498 def mail_to(email_address, name = nil, html_options = {}) email_address = ERB::Util.html_escape(email_address) html_options = html_options.stringify_keys encode = html_options.delete("encode").to_s extras = %w{ cc bcc body subject }.map { |item| option = html_options.delete(item) || next "#{item}=#{Rack::Utils.escape(option).gsub("+", "%20")}" }.compact extras = extras.empty? ? '' : '?' + ERB::Util.html_escape(extras.join('&')) email_address_obfuscated = email_address.to_str email_address_obfuscated.gsub!(/@/, html_options.delete("replace_at")) if html_options.key?("replace_at") email_address_obfuscated.gsub!(/\./, html_options.delete("replace_dot")) if html_options.key?("replace_dot") case encode when "javascript" string = '' html = content_tag("a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe)) html = escape_javascript(html.to_str) "document.write('#{html}');".each_byte do |c| string << sprintf("%%%x", c) end "<script type=\"#{Mime::JS}\">eval(decodeURIComponent('#{string}'))</script>".html_safe when "hex" email_address_encoded = email_address_obfuscated.unpack('C*').map {|c| sprintf("&#%d;", c) }.join string = 'mailto:'.unpack('C*').map { |c| sprintf("&#%d;", c) }.join + email_address.unpack('C*').map { |c| char = c.chr char =~ /\w/ ? sprintf("%%%x", c) : char }.join content_tag "a", name || email_address_encoded.html_safe, html_options.merge("href" => "#{string}#{extras}".html_safe) else content_tag "a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe) end end
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
Passing a record (like an Active Record or Active Resource) instead of a Hash as the options parameter will 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.example.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_param which by default returns the id # => /workshops/5 # to_param can be re-defined in a model to provide different URL names: # => /workshops/1-workshop-name <%= 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()
# File actionpack/lib/action_view/helpers/url_helper.rb, line 100 def url_for(options = {}) options ||= {} 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 end
Need to map default url options to controller one. def default_url_options(*args) #:nodoc:
controller.send(:default_url_options, *args)
end