Module | ActionView::Helpers::UrlHelper |
In: |
lib/action_view/helpers/url_helper.rb
|
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.
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.
The generated form element has a class name of button_to to allow styling of the form itself and its children. 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.
The options hash accepts the same options as url_for.
There are a few special html_options:
<%= button_to "New", :action => "new" %> # => "<form method="post" action="/controller/new" class="button_to"> # <div><input value="New" 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.
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
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
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>
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>
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>
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 %>
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.
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>
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".
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()