method

link_to_remote

Importance_5
v1.1.6 - Show latest stable - 4 notes - Class: ActionView::Helpers::PrototypeHelper
link_to_remote(name, options = {}, html_options = {}) public

Returns a link to a remote action defined by options[:url] (using the url_for format) that’s called in the background using XMLHttpRequest. The result of that request can then be inserted into a DOM object whose id can be specified with options[:update]. Usually, the result would be a partial prepared by the controller with either render_partial or render_partial_collection.

Examples: 

  link_to_remote "Delete this post", :update => "posts",
    :url => { :action => "destroy", :id => post.id }
  link_to_remote(image_tag("refresh"), :update => "emails",
    :url => { :action => "list_emails" })

You can also specify a hash for options[:update] to allow for easy redirection of output to an other DOM element if a server-side error occurs:

Example: 

  link_to_remote "Delete this post",
    :url => { :action => "destroy", :id => post.id },
    :update => { :success => "posts", :failure => "error" }

Optionally, you can use the options[:position] parameter to influence how the target DOM element is updated. It must be one of :before, :top, :bottom, or :after.

By default, these remote requests are processed asynchronous during which various JavaScript callbacks can be triggered (for progress indicators and the likes). All callbacks get access to the request object, which holds the underlying XMLHttpRequest.

To access the server response, use request.responseText, to find out the HTTP status, use request.status.

Example: 

  link_to_remote word,
    :url => { :action => "undo", :n => word_counter },
    :complete => "undoRequestCompleted(request)"

The callbacks that may be specified are (in order):

:loading:Called when the remote document is being loaded with data by the browser.
:loaded:Called when the browser has finished loading the remote document.
:interactive:Called when the user can interact with the remote document, even though it has not finished loading.
:success:Called when the XMLHttpRequest is completed, and the HTTP status code is in the 2XX range.
:failure:Called when the XMLHttpRequest is completed, and the HTTP status code is not in the 2XX range.
:complete:Called when the XMLHttpRequest is complete (fires after success/failure if they are present).

You can further refine :success and :failure by adding additional callbacks for specific status codes.

Example: 

  link_to_remote word,
    :url => { :action => "action" },
    404 => "alert('Not found...? Wrong URL...?')",
    :failure => "alert('HTTP Error ' + request.status + '!')"

A status code callback overrides the success/failure handlers if present.

If you for some reason or another need synchronous processing (that’ll block the browser while the request is happening), you can specify options[:type] = :synchronous.

You can customize further browser side call logic by passing in JavaScript code snippets via some optional parameters. In their order of use these are:

:confirm:Adds confirmation dialog.
:condition:Perform remote request conditionally by this expression. Use this to describe browser-side conditions when request should not be initiated.
:before:Called before request is initiated.
:after:Called immediately after request was initiated and before :loading.
:submit:Specifies the DOM element ID that’s used as the parent of the form elements. By default this is the current form, but it could just as well be the ID of a table row or any other DOM element.
Show source
Register or log in to add new notes.
March 14, 2009
2 thanks

link_to_remote renders javascript as text

If you want to render an RJS file with link to remote you shouldn’t specify the :update function. Using this:

link_to_remote('add',:update=> 'someId', :url => {:controller => 'my_controller', :action => 'new'} )
# assume having 'my_controller/new.rjs'

will return something like

try { Element.update("someElement\n"); } 
catch (e) { alert('RJS error:\n\n' + e.toString());  
alert('Element.update(\"someId\", \"item\\n\");');
throw e }

You should be specifying the id you are updating in the RJS file, not in link_to_remote. This will render correctly:

link_to_remote('add',:url => {:controller => 'my_controller', :action => 'new'} )
# assume having 'my_controller/new.rjs'

Only use :update when rendering html.

July 4, 2008
0 thanks

Add if before Ajax.request

Use link_to_remote’s before

link_to_remote(“watcher”, {:url => “/watchers/add”, :before => “if($F(‘user_id’)==”){return false;}” })

<a onclick=“if($F(‘user_id’)==”){return false;}; new Ajax.Request(‘/watchers/add’, {asynchronous:true, evalScripts:true, parameters:”}); return false;”>添加订阅人

March 31, 2010
0 thanks

Always gracefully degrade if JS isn't available

If you always want to degrade when JS isn’t available you can add something like to environment.rb

module ActionView
  module Helpers
    module PrototypeHelper
      def link_to_remote(name, options = {}, html_options = nil)
         html_options ||= {}
         html_options[:href] ||= options[:url]
         link_to_function(name, remote_function(options), html_options || options.delete(:html))
      end
    end
  end
end