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 ActionController::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 at 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 onclick="return confirm('Are you sure?');" # value="Delete" type="submit" /> # </div> # </form>"
True if the current request URI was generated by the given options.
Let‘s say we‘re in the /shop/checkout action.
current_page?(:action => 'process') # => false current_page?(:controller => 'shop', :action => 'checkout') # => true 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.
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, your should check for it in your controller‘s action by using the request object‘s methods for post?, delete? or put?.
You can mix and match the html_options with the exception of :popup and :method which will raise an ActionView::ActionViewError exception.
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>
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 three options specfic to link_to (:confirm, :popup, 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/" onclick="return confirm('Are you sure?');">Visit Other Site</a> link_to "Help", { :action => "help" }, :popup => true # => <a href="/testing/help/" onclick="window.open(this.href);return false;">Help</a> link_to "View Image", @image, :popup => ['new_window_name', 'height=300,width=600'] # => <a href="/images/9" onclick="window.open(this.href,'new_window_name','height=300,width=600');return false;">View Image</a> link_to "Delete Image", @image, :confirm => "Are you sure?", :method => :delete # => <a href="/images/9" onclick="if (confirm('Are you sure?')) { var f = document.createElement('form'); f.style.display = 'none'; this.parentNode.appendChild(f); f.method = 'POST'; f.action = this.href; var m = document.createElement('input'); m.setAttribute('type', 'hidden'); m.setAttribute('name', '_method'); m.setAttribute('value', 'delete'); f.appendChild(m);f.submit(); };return false;">Delete Image</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(unescape('%64%6f%63...%6d%65%6e'))</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.
When called from a view, url_for returns an HTML escaped url. If you need an unescaped url, pass :escape => false in the options.
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 => 'checkout', :anchor => 'tax&ship') %> # => /testing/jump/#tax&ship <%= url_for(:action => 'checkout', :anchor => 'tax&ship', :escape => false) %> # => /testing/jump/#tax&ship <%= url_for(Workshop.new) %> # relies on Workshop answering a new_record? call (and in this case returning true) # => /workshops <%= url_for(@workshop) %> # calls @workshop.to_s # => /workshops/5