Module | ActionView::Helpers::UrlHelper
In: | lib/action_view/helpers/url_helper.rb

Provides a set of methods for making easy links and getting urls that depend on the controller and action. This means that you can use the same format for links in the views that you do in the controller.

### Methods

button_to current_page? link_image_to link_to link_to_if link_to_image link_to_unless link_to_unless_current mail_to url_for

### Included Modules

JavaScriptHelper

### Public Instance methods

button_to(name, options = {}, html_options = {})

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`.

      button_to "New", :action => "new"

Generates the following HTML:

      <form method="post" action="/controller/new" class="button-to">
        <div><input value="New" type="submit" /></div>
      </form>

If you are using RESTful routes, you can pass the `:method` to change the HTTP verb used to submit the form.

      button_to "Delete Image", { :action => "delete", :id => @image.id },
                :confirm => "Are you sure?", :method => :delete

Which generates the following HTML:

      <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>

current_page?(options)

True if the current request uri was generated by the given `options`.

link_image_to(src, options = {}, html_options = {}, *parameters_for_method_reference)

DEPRECATED. It is reccommended to use the AssetTagHelper::image_tag within a link_to method to generate a linked image.

      link_to(image_tag("rss", :size => "30x45", :border => 0), "http://www.example.com")

link_to(name, options = {}, html_options = nil, *parameters_for_method_reference)

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 ActionController::Base#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. If nil is passed as a name, the link itself will become the name.

The `html_options` will accept a hash of html attributes for the link tag. It also accepts 3 modifiers that specialize the link behavior.

- `:confirm => ‘question?‘`: This will add a JavaScript confirm prompt with the question specified. If the user accepts, the link is processed normally, otherwise no action is taken.
- `:popup => true || array of window options`: This will force the link to open in a popup window. By passing true, a default browser window will be opened with the URL. You can also specify an array of options that are passed-thru to JavaScripts window.open method.
- `: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 you are relying on the POST behavior, your should check for it in your controllers action by using the request objects 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.

      link_to "Visit Other Site", "http://www.rubyonrails.org/", :confirm => "Are you sure?"
      link_to "Help", { :action => "help" }, :popup => true
      link_to "View Image", { :action => "view" }, :popup => ['new_window_name', 'height=300,width=600']
      link_to "Delete Image", { :action => "delete", :id => @image.id }, :confirm => "Are you sure?", :method => :delete

link_to_if(condition, name, options = {}, html_options = {}, *parameters_for_method_reference, &block)

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_image(src, options = {}, html_options = {}, *parameters_for_method_reference)

Alias for link_image_to

link_to_unless(condition, name, options = {}, html_options = {}, *parameters_for_method_reference) {|name| ...}

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, you can pass a block that accepts the name or the full argument list for link_to_unless (see the example).

      <%= link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) %>

This example uses a block to modify the link if the condition isn‘t met.

      <%= link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) do |name|
         link_to(name, { :controller => "accounts", :action => "signup" })
       end %>

link_to_unless_current(name, options = {}, html_options = {}, *parameters_for_method_reference, &block)

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). Refer to the documentation for link_to_unless for block usage.

      <ul id="navbar">
        <li><%= link_to_unless_current("Home", { :action => "index" }) %></li>
        <li><%= link_to_unless_current("About Us", { :action => "about" }) %></li>
      </ul>

This will render the following HTML when on the about us page:

      <ul id="navbar">
        <li><a href="/controller/index">Home</a></li>
        <li>About Us</li>
      </ul>

mail_to(email_address, name = nil, html_options = {})

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 harvestors and customizing the email itself by passing special keys to `html_options`.

Special 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.

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(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>

url_for(options = {}, *parameters_for_method_reference)

Returns the URL for the set of `options` provided. This takes the same options as url_for in action controller. For a list, see the documentation for ActionController::Base#url_for. Note that it‘ll set :only_path => true so you‘ll get the relative /controller/action instead of the fully qualified 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`.

[Validate]