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 562 562: def current_page?(options) 563: unless request 564: raise "You cannot use helpers that need to determine the current " "page unless your view context provides a Request object " "in a #request method" 565: end 566: 567: url_string = url_for(options) 568: 569: # We ignore any extra parameters in the request_uri if the 570: # submitted url doesn't have any either. This lets the function 571: # work with things like ?order=asc 572: if url_string.index("?") 573: request_uri = request.fullpath 574: else 575: request_uri = request.path 576: end 577: 578: if url_string =~ /^\w+:\/\// 579: url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}" 580: else 581: url_string == request_uri 582: end 583: 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 225 225: def link_to(*args, &block) 226: if block_given? 227: options = args.first || {} 228: html_options = args.second 229: link_to(capture(&block), options, html_options) 230: else 231: name = args[0] 232: options = args[1] || {} 233: html_options = args[2] 234: 235: html_options = convert_options_to_data_attributes(options, html_options) 236: url = url_for(options) 237: 238: if html_options 239: html_options = html_options.stringify_keys 240: href = html_options['href'] 241: tag_options = tag_options(html_options) 242: else 243: tag_options = nil 244: end 245: 246: href_attr = "href=\"#{html_escape(url)}\"" unless href 247: "<a #{href_attr}#{tag_options}>#{html_escape(name || url)}</a>".html_safe 248: end 249: 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 430 430: def link_to_if(condition, name, options = {}, html_options = {}, &block) 431: link_to_unless !condition, name, options, html_options, &block 432: 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 398 398: def link_to_unless(condition, name, options = {}, html_options = {}, &block) 399: if condition 400: if block_given? 401: block.arity <= 1 ? capture(name, &block) : capture(name, options, html_options, &block) 402: else 403: name 404: end 405: else 406: link_to(name, options, html_options) 407: end 408: 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 374 374: def link_to_unless_current(name, options = {}, html_options = {}, &block) 375: link_to_unless current_page?(options), name, options, html_options, &block 376: 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 476 476: def mail_to(email_address, name = nil, html_options = {}) 477: email_address = html_escape(email_address) 478: 479: html_options = html_options.stringify_keys 480: encode = html_options.delete("encode").to_s 481: cc, bcc, subject, body = html_options.delete("cc"), html_options.delete("bcc"), html_options.delete("subject"), html_options.delete("body") 482: 483: extras = [] 484: extras << "cc=#{Rack::Utils.escape(cc).gsub("+", "%20")}" unless cc.nil? 485: extras << "bcc=#{Rack::Utils.escape(bcc).gsub("+", "%20")}" unless bcc.nil? 486: extras << "body=#{Rack::Utils.escape(body).gsub("+", "%20")}" unless body.nil? 487: extras << "subject=#{Rack::Utils.escape(subject).gsub("+", "%20")}" unless subject.nil? 488: extras = extras.empty? ? '' : '?' + html_escape(extras.join('&')) 489: 490: email_address_obfuscated = email_address.dup 491: email_address_obfuscated.gsub!(/@/, html_options.delete("replace_at")) if html_options.has_key?("replace_at") 492: email_address_obfuscated.gsub!(/\./, html_options.delete("replace_dot")) if html_options.has_key?("replace_dot") 493: 494: string = '' 495: 496: if encode == "javascript" 497: "document.write('#{content_tag("a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe))}');".each_byte do |c| 498: string << sprintf("%%%x", c) 499: end 500: "<script type=\"#{Mime::JS}\">eval(decodeURIComponent('#{string}'))</script>".html_safe 501: elsif encode == "hex" 502: email_address_encoded = '' 503: email_address_obfuscated.each_byte do |c| 504: email_address_encoded << sprintf("&#%d;", c) 505: end 506: 507: protocol = 'mailto:' 508: protocol.each_byte { |c| string << sprintf("&#%d;", c) } 509: 510: email_address.each_byte do |c| 511: char = c.chr 512: string << (char =~ /\w/ ? sprintf("%%%x", c) : char) 513: end 514: content_tag "a", name || email_address_encoded.html_safe, html_options.merge("href" => "#{string}#{extras}".html_safe) 515: else 516: content_tag "a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe) 517: end 518: 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 92: def url_for(options = {}) 93: options ||= {} 94: url = case options 95: when String 96: options 97: when Hash 98: options = options.symbolize_keys.reverse_merge!(:only_path => options[:host].nil?) 99: super 100: when :back 101: controller.request.env["HTTP_REFERER"] || 'javascript:history.back()' 102: else 103: polymorphic_path(options) 104: end 105: 106: url 107: 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 30: def url_options 31: return super unless controller.respond_to?(:url_options) 32: controller.url_options 33: end
# File lib/action_view/helpers/url_helper.rb, line 610 610: def add_confirm_to_attributes!(html_options, confirm) 611: html_options["data-confirm"] = confirm if confirm 612: end
# File lib/action_view/helpers/url_helper.rb, line 614 614: def add_method_to_attributes!(html_options, method) 615: html_options["rel"] = "nofollow" if method && method.to_s.downcase != "get" 616: html_options["data-method"] = method if method 617: end
# File lib/action_view/helpers/url_helper.rb, line 627 627: def array_or_string_for_javascript(option) 628: if option.kind_of?(Array) 629: "['#{option.join('\',\'')}']" 630: elsif !option.nil? 631: "'#{option}'" 632: end 633: 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 658 658: def convert_boolean_attributes!(html_options, bool_attrs) 659: bool_attrs.each { |x| html_options[x] = x if html_options.delete(x) } 660: html_options 661: end
# File lib/action_view/helpers/url_helper.rb, line 588 588: def convert_options_to_data_attributes(options, html_options) 589: html_options = {} if html_options.nil? 590: html_options = html_options.stringify_keys 591: 592: if (options.is_a?(Hash) && options.key?('remote') && options.delete('remote')) || (html_options.is_a?(Hash) && html_options.key?('remote') && html_options.delete('remote')) 593: html_options['data-remote'] = 'true' 594: end 595: 596: confirm = html_options.delete("confirm") 597: 598: if html_options.key?("popup") 599: ActiveSupport::Deprecation.warn(":popup has been deprecated", caller) 600: end 601: 602: method, href = html_options.delete("method"), html_options['href'] 603: 604: add_confirm_to_attributes!(html_options, confirm) if confirm 605: add_method_to_attributes!(html_options, method) if method 606: 607: html_options 608: end
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