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.
True if the current request URI was generated by the given
options
.
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
# File lib/action_view/helpers/url_helper.rb, line 560 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 =~ %r^\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.
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
: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
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 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) href = html_options['href'] tag_options = tag_options(html_options) 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
).
<%= 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 426 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
.
<%= 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 394 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).
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 370 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 hindering email harvesters and
customizing the email itself by passing special keys to
html_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.
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 lib/action_view/helpers/url_helper.rb, line 472 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.to_str email_address_obfuscated.gsub!(%r@/, html_options.delete("replace_at")) if html_options.has_key?("replace_at") email_address_obfuscated.gsub!(%r\./, html_options.delete("replace_dot")) if html_options.has_key?("replace_dot") string = '' if encode == "javascript" html = content_tag("a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe)) html = escape_javascript(html) "document.write('#{html}');".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 =~ %r\w/ ? sprintf("%%%x", c) : char) end 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”.
: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).
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).
<%= 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()
# File 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
Need to map default url options to controller one. def default_url_options(*args) #:nodoc:
controller.send(:default_url_options, *args)
end
# File lib/action_view/helpers/url_helper.rb, line 30 def url_options return super unless controller.respond_to?(:url_options) controller.url_options end