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. The different methods are even named synchronously, so link_to uses that same url as is generated by url_for, which again is the same url used for redirection in redirect_to.

Methods
Included Modules
Public Instance methods
button_to(name, options = {}, html_options = nil)

Generates a form containing a sole button that submits to the URL given by options. Use this method instead of link_to for actions that do not have the safe HTTP GET semantics implied by using a hypertext link.

The parameters are the same as for link_to. Any html_options that you pass will be applied to the inner input element. In particular, pass 

  :disabled => true/false

as part of html_options to control whether the button is disabled. The generated form element is given the class ‘button-to’, to which you can attach CSS styles for display purposes.

Example 1: 

  # inside of controller for "feeds"
  button_to "Edit", :action => 'edit', :id => 3

Generates the following HTML (sans formatting): 

  <form method="post" action="/feeds/edit/3" class="button-to">
    <div><input value="Edit" type="submit" /></div>
  </form>

Example 2: 

  button_to "Destroy", { :action => 'destroy', :id => 3 },
            :confirm => "Are you sure?"

Generates the following HTML (sans formatting): 

  <form method="post" action="/feeds/destroy/3" class="button-to">
    <div><input onclick="return confirm('Are you sure?');"
                value="Destroy" type="submit" />
    </div>
  </form>

NOTE: This method generates HTML code that represents a form. Forms are "block" content, which means that you should not try to insert them into your HTML where only inline content is expected. For example, you can legally insert a form inside of a div or td element or in between p elements, but not in the middle of a run of text, nor can you place a form within another form. (Bottom line: Always validate your HTML before going public.)

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 100
100:       def button_to(name, options = {}, html_options = nil)
101:         html_options = (html_options || {}).stringify_keys
102:         convert_boolean_attributes!(html_options, %w( disabled ))
103:         
104:         if confirm = html_options.delete("confirm")
105:           html_options["onclick"] = "return #{confirm_javascript_function(confirm)};"
106:         end
107: 
108:         url, name = options.is_a?(String) ?
109:           [ options,  name || options ] :
110:           [ url_for(options), name || html_escape(url_for(options)) ]
111: 
112:         html_options.merge!("type" => "submit", "value" => name)
113: 
114:         "<form method=\"post\" action=\"#{h url}\" class=\"button-to\"><div>" +
115:           tag("input", html_options) + "</div></form>"
116:       end
current_page?(options)

Returns true if the current page uri is generated by the options passed (in url_for format).

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 237
237:       def current_page?(options)
238:         url_for(options) == @controller.request.request_uri
239:       end
link_image_to(src, options = {}, html_options = {}, *parameters_for_method_reference)

This tag is deprecated. Combine the link_to and AssetTagHelper::image_tag yourself instead, like: 

  link_to(image_tag("rss", :size => "30x45", :border => 0), "http://www.example.com")
This method is also aliased as link_to_image

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 121
121:       def link_image_to(src, options = {}, html_options = {}, *parameters_for_method_reference)
122:         image_options = { "src" => src.include?("/") ? src : "/images/#{src}" }
123:         image_options["src"] += ".png" unless image_options["src"].include?(".")
124: 
125:         html_options = html_options.stringify_keys
126:         if html_options["alt"]
127:           image_options["alt"] = html_options["alt"]
128:           html_options.delete "alt"
129:         else
130:           image_options["alt"] = src.split("/").last.split(".").first.capitalize
131:         end
132: 
133:         if html_options["size"]
134:           image_options["width"], image_options["height"] = html_options["size"].split("x")
135:           html_options.delete "size"
136:         end
137: 
138:         if html_options["border"]
139:           image_options["border"] = html_options["border"]
140:           html_options.delete "border"
141:         end
142: 
143:         if html_options["align"]
144:           image_options["align"] = html_options["align"]
145:           html_options.delete "align"
146:         end
147: 
148:         link_to(tag("img", image_options), options, html_options, *parameters_for_method_reference)
149:       end
link_to(name, options = {}, html_options = nil, *parameters_for_method_reference)

Creates a link tag of the given name using an URL created by the set of options. See the valid options in classes/ActionView/Helpers/UrlHelper.html#M000304. It’s also possible to pass a string instead of an options hash to get a link tag that just points without consideration. If nil is passed as a name, the link itself will become the name.

The html_options has three special features. One for creating javascript confirm alerts where if you pass :confirm => ‘Are you sure?’, the link will be guarded with a JS popup asking that question. If the user accepts, the link is processed, otherwise not.

Another for creating a popup window, which is done by either passing :popup with true or the options of the window in Javascript form.

And a third for making the link do a POST request (instead of the regular GET) through a dynamically added form element that is instantly submitted. Note that if the user has turned off Javascript, the request will fall back on the GET. So its your responsibility to determine what the action should be once it arrives at the controller. The POST form is turned on by passing :post as true. Note, it’s not possible to use POST requests and popup targets at the same time (an exception will be thrown).

Examples: 

  link_to "Delete this page", { :action => "destroy", :id => @page.id }, :confirm => "Are you sure?"
  link_to "Help", { :action => "help" }, :popup => true
  link_to "Busy loop", { :action => "busy" }, :popup => ['new_window', 'height=300,width=600']
  link_to "Destroy account", { :action => "destroy" }, :confirm => "Are you sure?", :post => true

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 41
41:       def link_to(name, options = {}, html_options = nil, *parameters_for_method_reference)
42:         if html_options
43:           html_options = html_options.stringify_keys
44:           convert_options_to_javascript!(html_options)
45:           tag_options = tag_options(html_options)
46:         else
47:           tag_options = nil
48:         end
49:         url = html_escape(options.is_a?(String) ? options : url_for(options, *parameters_for_method_reference))
50:         "<a href=\"#{url}\"#{tag_options}>#{name||url}</a>"
51:       end
link_to_if(condition, name, options = {}, html_options = {}, *parameters_for_method_reference, &block)

Create a link tag of the given name using an URL created by the set of options, if condition is true, in which case only the name is returned (or the given block is yielded, if one exists).

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 177
177:       def link_to_if(condition, name, options = {}, html_options = {}, *parameters_for_method_reference, &block)
178:         link_to_unless !condition, name, options, html_options, *parameters_for_method_reference, &block
179:       end
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| ...}

Create a link tag of the given name using an URL created by the set of options, unless condition is true, in which case only the name is returned (or the given block is yielded, if one exists).

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 163
163:       def link_to_unless(condition, name, options = {}, html_options = {}, *parameters_for_method_reference, &block)
164:         if condition
165:           if block_given?
166:             block.arity <= 1 ? yield(name) : yield(name, options, html_options, *parameters_for_method_reference)
167:           else
168:             name
169:           end
170:         else
171:           link_to(name, options, html_options, *parameters_for_method_reference)
172:         end  
173:       end
link_to_unless_current(name, options = {}, html_options = {}, *parameters_for_method_reference, &block)

Creates a link tag of the given name using an URL created by the set of options, unless the current request uri is the same as the link’s, in which case only the name is returned (or the given block is yielded, if one exists). This is useful for creating link bars where you don’t want to link to the page currently being viewed.

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 157
157:       def link_to_unless_current(name, options = {}, html_options = {}, *parameters_for_method_reference, &block)
158:         link_to_unless current_page?(options), name, options, html_options, *parameters_for_method_reference, &block
159:       end
mail_to(email_address, name = nil, html_options = {})

Creates a link tag for starting an email to the specified email_address, which is also used as the name of the link unless name is specified. Additional HTML options, such as class or id, can be passed in the html_options hash.

You can also make it difficult for spiders to harvest email address by obfuscating them. Examples: 

  mail_to "me@domain.com", "My email", :encode => "javascript"  # =>
    <script type="text/javascript" language="javascript">eval(unescape('%64%6f%63%75%6d%65%6e%74%2e%77%72%69%74%65%28%27%3c%61%20%68%72%65%66%3d%22%6d%61%69%6c%74%6f%3a%6d%65%40%64%6f%6d%61%69%6e%2e%63%6f%6d%22%3e%4d%79%20%65%6d%61%69%6c%3c%2f%61%3e%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>

You can also specify the cc address, bcc address, subject, and body parts of the message header to create a complex e-mail using the corresponding cc, bcc, subject, and body html_options keys. Each of these options are URI escaped and then appended to the email_address before being output. Be aware that javascript keywords will not be escaped and may break this feature when encoding with javascript. Examples: 

  mail_to "me@domain.com", "My email", :cc => "ccaddress@domain.com", :bcc => "bccaddress@domain.com", :subject => "This is an example email", :body => "This is the body of the message."   # =>
    <a href="mailto:me@domain.com?cc="ccaddress@domain.com"&bcc="bccaddress@domain.com"&body="This%20is%20the%20body%20of%20the%20message."&subject="This%20is%20an%20example%20email">My email</a>

[ show source ]

     # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 199
199:       def mail_to(email_address, name = nil, html_options = {})
200:         html_options = html_options.stringify_keys
201:         encode = html_options.delete("encode")
202:         cc, bcc, subject, body = html_options.delete("cc"), html_options.delete("bcc"), html_options.delete("subject"), html_options.delete("body")
203: 
204:         string = ''
205:         extras = ''
206:         extras << "cc=#{CGI.escape(cc).gsub("+", "%20")}&" unless cc.nil?
207:         extras << "bcc=#{CGI.escape(bcc).gsub("+", "%20")}&" unless bcc.nil?
208:         extras << "body=#{CGI.escape(body).gsub("+", "%20")}&" unless body.nil?
209:         extras << "subject=#{CGI.escape(subject).gsub("+", "%20")}&" unless subject.nil?
210:         extras = "?" << extras.gsub!(/&?$/,"") unless extras.empty?
211: 
212:         email_address_obfuscated = email_address.dup
213:         email_address_obfuscated.gsub!(/@/, html_options.delete("replace_at")) if html_options.has_key?("replace_at")
214:         email_address_obfuscated.gsub!(/\./, html_options.delete("replace_dot")) if html_options.has_key?("replace_dot")
215: 
216:         if encode == 'javascript'
217:           tmp = "document.write('#{content_tag("a", name || email_address, html_options.merge({ "href" => "mailto:"+email_address.to_s+extras }))}');"
218:           for i in 0...tmp.length
219:             string << sprintf("%%%x",tmp[i])
220:           end
221:           "<script type=\"text/javascript\" language=\"javascript\">eval(unescape('#{string}'))</script>"
222:         elsif encode == 'hex'
223:           for i in 0...email_address.length
224:             if email_address[i,1] =~ /\w/
225:               string << sprintf("%%%x",email_address[i])
226:             else
227:               string << email_address[i,1]
228:             end
229:           end
230:           content_tag "a", name || email_address_obfuscated, html_options.merge({ "href" => "mailto:#{string}#{extras}" })
231:         else
232:           content_tag "a", name || email_address_obfuscated, html_options.merge({ "href" => "mailto:#{email_address}#{extras}" })
233:         end
234:       end
url_for(options = {}, *parameters_for_method_reference)

Returns the URL for the set of options provided. This takes the same options as url_for. For a list, see the url_for documentation in classes/ActionController/Base.html#M000079. Note that it’ll set :only_path => true so you’ll get /controller/action instead of the example.com/controller/action part (makes it harder to parse httpd log files)

[ show source ]

    # File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 16
16:       def url_for(options = {}, *parameters_for_method_reference)
17:         options = { :only_path => true }.update(options.symbolize_keys) if options.kind_of? Hash
18:         @controller.send(:url_for, options, *parameters_for_method_reference)
19:       end