Permalink
Switch branches/tags
Find file
Fetching contributors…
Cannot retrieve contributors at this time
448 lines (405 sloc) 20.9 KB
require File.dirname(__FILE__) + '/tag_helper'
module ActionView
module Helpers
# Provides a set of helpers for calling JavaScript functions and, most importantly, to call remote methods using what has
# been labelled Ajax[http://www.adaptivepath.com/publications/essays/archives/000385.php]. This means that you can call
# actions in your controllers without reloading the page, but still update certain parts of it using injections into the
# DOM. The common use case is having a form that adds a new element to a list without reloading the page.
#
# To be able to use the JavaScript helpers, you must either call <tt><%= define_javascript_functions %></tt> (which returns all
# the JavaScript support functions in a <script> block) or reference the JavaScript library using
# <tt><%= javascript_include_tag "prototype" %></tt> (which looks for the library in /javascripts/prototype.js). The latter is
# recommended as the browser can then cache the library instead of fetching all the functions anew on every request.
#
# If you're the visual type, there's an Ajax movie[http://www.rubyonrails.com/media/video/rails-ajax.mov] demonstrating
# the use of form_remote_tag.
module JavaScriptHelper
unless const_defined? :CALLBACKS
CALLBACKS =
[:uninitialized, :loading, :loaded, :interactive, :complete, :failure].push((100..599).to_a).flatten
AJAX_OPTIONS = [ :url, :asynchronous, :method, :insertion, :form, :with, :update ].concat(CALLBACKS)
JAVASCRIPT_PATH = File.join(File.dirname(__FILE__), 'javascripts')
end
# Returns a link that'll trigger a javascript +function+ using the
# onclick handler and return false after the fact.
#
# Examples:
# link_to_function "Greeting", "alert('Hello world!')"
# link_to_function(image_tag("delete"), "if confirm('Really?'){ do_delete(); }")
def link_to_function(name, function, html_options = {})
content_tag(
"a", name,
{:href => "#", :onclick => "#{function}; return false;"}.merge(html_options.symbolize_keys)
)
end
# Returns a link to a remote action defined by <tt>options[:url]</tt>
# (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 <tt>options[:update]</tt>.
# 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 <tt>options[:update]</tt> 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 <tt>options[:position]</tt> parameter to influence
# how the target DOM element is updated. It must be one of
# <tt>:before</tt>, <tt>:top</tt>, <tt>:bottom</tt>, or <tt>:after</tt>.
#
# 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 <tt>request</tt> object,
# which holds the underlying XMLHttpRequest.
#
# To access the server response, use <tt>request.responseText</tt>, to
# find out the HTTP status, use <tt>request.status</tt>.
#
# Example:
# link_to_remote word,
# :url => { :action => "undo", :n => word_counter },
# :complete => "undoRequestCompleted(request)"
#
# The callbacks that may be specified are:
#
# <tt>:loading</tt>:: Called when the remote document is being
# loaded with data by the browser.
# <tt>:loaded</tt>:: Called when the browser has finished loading
# the remote document.
# <tt>:interactive</tt>:: Called when the user can interact with the
# remote document, even though it has not
# finished loading.
# <tt>:complete</tt>:: Called when the XMLHttpRequest is complete,
# and the HTTP status code is 200 OK.
# <tt>:failure</tt>:: Called when the XMLHttpRequest is complete,
# and the HTTP status code is anything other than
# 200 OK.
#
# You can further refine <tt>:failure</tt> 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 + '!')"
#
#
# If you for some reason or another need synchronous processing (that'll
# block the browser while the request is happening), you can specify
# <tt>options[:type] = :synchronous</tt>.
#
# 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:
#
# <tt>:confirm</tt>:: Adds confirmation dialog.
# <tt>:condition</tt>:: Perform remote request conditionally
# by this expression. Use this to
# describe browser-side conditions when
# request should not be initiated.
# <tt>:before</tt>:: Called before request is initiated.
# <tt>:after</tt>:: Called immediately after request was
# initiated and before <tt>:loading</tt>.
def link_to_remote(name, options = {}, html_options = {})
link_to_function(name, remote_function(options), html_options)
end
# Periodically calls the specified url (<tt>options[:url]</tt>) every <tt>options[:frequency]</tt> seconds (default is 10).
# Usually used to update a specified div (<tt>options[:update]</tt>) with the results of the remote call.
# The options for specifying the target with :url and defining callbacks is the same as link_to_remote.
def periodically_call_remote(options = {})
frequency = options[:frequency] || 10 # every ten seconds by default
code = "new PeriodicalExecuter(function() {#{remote_function(options)}}, #{frequency})"
content_tag("script", code, options[:html_options] || {})
end
# Returns a form tag that will submit using XMLHttpRequest in the background instead of the regular
# reloading POST arrangement. Even though it's using JavaScript to serialize the form elements, the form submission
# will work just like a regular submission as viewed by the receiving side (all elements available in @params).
# The options for specifying the target with :url and defining callbacks is the same as link_to_remote.
#
# A "fall-through" target for browsers that doesn't do JavaScript can be specified with the :action/:method options on :html
#
# form_remote_tag :html => { :action => url_for(:controller => "some", :action => "place") }
#
# By default the fall-through action is the same as the one specified in the :url (and the default method is :post).
def form_remote_tag(options = {})
options[:form] = true
options[:html] ||= {}
options[:html][:onsubmit] = "#{remote_function(options)}; return false;"
options[:html][:action] = options[:html][:action] || url_for(options[:url])
options[:html][:method] = options[:html][:method] || "post"
tag("form", options[:html], true)
end
# Returns a button input tag that will submit form using XMLHttpRequest in the background instead of regular
# reloading POST arrangement. <tt>options</tt> argument is the same as in <tt>form_remote_tag</tt>
def submit_to_remote(name, value, options = {})
options[:with] = 'Form.serialize(this.form)'
options[:html] ||= {}
options[:html][:type] = 'button'
options[:html][:onclick] = "#{remote_function(options)}; return false;"
options[:html][:name] = name
options[:html][:value] = value
tag("input", options[:html], false)
end
def remote_function(options) #:nodoc: for now
javascript_options = options_for_ajax(options)
update = []
if options[:update] and options[:update].is_a?Hash
update << "success:'#{options[:update][:success]}'" if options[:update][:success]
update << "failure:'#{options[:update][:failure]}'" if options[:update][:failure]
elsif options[:update]
update << "success:'#{options[:update]}'"
end
function = update.empty? ?
"new Ajax.Request(" :
"new Ajax.Updater({#{update.join(',')}}, "
function << "'#{url_for(options[:url])}'"
function << ", #{javascript_options})"
function = "#{options[:before]}; #{function}" if options[:before]
function = "#{function}; #{options[:after]}" if options[:after]
function = "if (#{options[:condition]}) { #{function}; }" if options[:condition]
function = "if (confirm('#{escape_javascript(options[:confirm])}')) { #{function}; }" if options[:confirm]
return function
end
# Includes the Action Pack JavaScript libraries inside a single <script>
# tag. The function first includes prototype.js and then its core extensions,
# (determined by filenames starting with "prototype").
# Afterwards, any additional scripts will be included in random order.
#
# Note: The recommended approach is to copy the contents of
# lib/action_view/helpers/javascripts/ into your application's
# public/javascripts/ directory, and use +javascript_include_tag+ to
# create remote <script> links.
def define_javascript_functions
javascript = '<script type="text/javascript">'
# load prototype.js and its extensions first
prototype_libs = Dir.glob(File.join(JAVASCRIPT_PATH, 'prototype*')).sort.reverse
prototype_libs.each do |filename|
javascript << "\n" << IO.read(filename)
end
# load other librairies
(Dir.glob(File.join(JAVASCRIPT_PATH, '*')) - prototype_libs).each do |filename|
javascript << "\n" << IO.read(filename)
end
javascript << '</script>'
end
# Observes the field with the DOM ID specified by +field_id+ and makes
# an Ajax call when its contents have changed.
#
# Required +options+ are:
# <tt>:url</tt>:: +url_for+-style options for the action to call
# when the field has changed.
#
# Additional options are:
# <tt>:frequency</tt>:: The frequency (in seconds) at which changes to
# this field will be detected. Set this to a value
# greater than zero to use time based observation
# instead of event based observation.
# <tt>:update</tt>:: Specifies the DOM ID of the element whose
# innerHTML should be updated with the
# XMLHttpRequest response text.
# <tt>:with</tt>:: A JavaScript expression specifying the
# parameters for the XMLHttpRequest. This defaults
# to 'value', which in the evaluated context
# refers to the new field value.
#
# Additionally, you may specify any of the options documented in
# +link_to_remote.
def observe_field(field_id, options = {})
if options[:frequency]
build_observer('Form.Element.Observer', field_id, options)
else
build_observer('Form.Element.EventObserver', field_id, options)
end
end
# Like +observe_field+, but operates on an entire form identified by the
# DOM ID +form_id+. +options+ are the same as +observe_field+, except
# the default value of the <tt>:with</tt> option evaluates to the
# serialized (request string) value of the form.
def observe_form(form_id, options = {})
if options[:frequency]
build_observer('Form.Observer', form_id, options)
else
build_observer('Form.EventObserver', form_id, options)
end
end
# Adds Ajax autocomplete functionality to the text input field with the
# DOM ID specified by +field_id+.
#
# This function expects that the called action returns a HTML <ul> list,
# or nothing if no entries should be displayed for autocompletion.
#
# You'll probably want to turn the browser's built-in autocompletion off,
# su be sure to include a autocomplete="off" attribute with your text
# input field.
#
# Required +options+ are:
# <tt>:url</tt>:: Specifies the DOM ID of the element whose
# innerHTML should be updated with the autocomplete
# entries returned by XMLHttpRequest.
#
# Addtional +options+ are:
# <tt>:update</tt>:: Specifies the DOM ID of the element whose
# innerHTML should be updated with the autocomplete
# entries returned by the Ajax request.
# Defaults to field_id + '_auto_complete'
# <tt>:with</tt>:: A JavaScript expression specifying the
# parameters for the XMLHttpRequest. This defaults
# to 'value', which in the evaluated context
# refers to the new field value.
# <tt>:indicator</tt>:: Specifies the DOM ID of an elment which will be
# displayed while autocomplete is running.
def auto_complete_field(field_id, options = {})
function = "new Ajax.Autocompleter("
function << "'#{field_id}', "
function << "'" + (options[:update] || "#{field_id}_auto_complete") + "', "
function << "'#{url_for(options[:url])}'"
js_options = {}
js_options[:callback] = "function(element, value) { return #{options[:with]} }" if options[:with]
js_options[:indicator] = "'#{options[:indicator]}'" if options[:indicator]
function << (', ' + options_for_javascript(js_options) + ')')
javascript_tag(function)
end
# Use this method in your view to generate a return for the Ajax automplete requests.
#
# Example action:
#
# def auto_complete_for_item_title
# @items = Item.find(:all, :conditions => [ 'LOWER(description) LIKE ?',
# '%' + params[:for].downcase + '%' ], 'description ASC')
# render :inline => '<%= auto_complete_result(@items, 'description') %>'
# end
#
# The auto_complete_result can of course also be called from a view belonging to the
# auto_complete action if you need to decorate it further.
def auto_complete_result(entries, field, phrase = nil)
return unless entries
items = entries.map { |entry| content_tag("li", phrase ? highlight(entry[field], phrase) : h(entry[field])) }
content_tag("ul", items)
end
def text_field_with_auto_complete(object, method, tag_options = {}, completion_options = {})
(completion_options[:skip_style] ? "" : auto_complete_stylesheet) +
text_field(object, method, { :autocomplete => "off" }.merge!(tag_options)) +
content_tag("div", "", :id => "#{object}_#{method}_auto_complete", :class => "auto_complete") +
auto_complete_field("#{object}_#{method}", { :url => { :action => "auto_complete_for_#{object}_#{method}" } }.update(completion_options))
end
# Returns a JavaScript snippet to be used on the Ajax callbacks for starting
# visual effects.
#
# Example:
# <%= link_to_remote "Reload", :update => "posts",
# :url => { :action => "reload" },
# :complete => visual_effect(:highlight, "posts", :duration => 0.5 )
#
# You can change the behaviour with various options, see
# http://script.aculo.us for more documentation.
def visual_effect(name, element_id, js_options = {})
"new Effect.#{name.to_s.capitalize}('#{element_id}',#{options_for_javascript(js_options)});"
end
# Makes the element with the DOM ID specified by +element_id+ sortable
# by drag-and-drop and make an Ajax call whenever the sort order has
# changed. By default, the action called gets the serialized sortable
# element as parameters.
#
# Example:
# <%= remote_sortable("my_list", :url => { :action => "order" }) %>
#
# In the example, the action gets a "my_list" array parameter
# containing the values of the ids of elements the sortable consists
# of, in the current order.
#
# You can change the behaviour with various options, see
# http://script.aculo.us for more documentation.
def sortable_element(element_id, options = {})
options[:with] ||= "Sortable.serialize('#{element_id}')"
options[:onUpdate] ||= "function(){" + remote_function(options) + "}"
options.delete_if { |key, value| AJAX_OPTIONS.include?(key) }
javascript_tag("Sortable.create('#{element_id}', #{options_for_javascript(options)})")
end
# Escape carrier returns and single and double quotes for JavaScript segments.
def escape_javascript(javascript)
(javascript || '').gsub(/\r\n|\n|\r/, "\\n").gsub(/["']/) { |m| "\\#{m}" }
end
# Returns a JavaScript tag with the +content+ inside. Example:
# javascript_tag "alert('All is good')" # => <script type="text/javascript">alert('All is good')</script>
def javascript_tag(content)
content_tag("script", content, :type => "text/javascript")
end
private
def options_for_javascript(options)
'{' + options.map {|k, v| "#{k}:#{v}"}.join(', ') + '}'
end
def options_for_ajax(options)
js_options = build_callbacks(options)
js_options['asynchronous'] = options[:type] != :synchronous
js_options['method'] = method_option_to_s(options[:method]) if options[:method]
js_options['insertion'] = "Insertion.#{options[:position].to_s.camelize}" if options[:position]
js_options['evalScripts'] = options[:script] == true if options[:script]
if options[:form]
js_options['parameters'] = 'Form.serialize(this)'
elsif options[:with]
js_options['parameters'] = options[:with]
end
options_for_javascript(js_options)
end
def method_option_to_s(method)
(method.is_a?(String) and !method.index("'").nil?) ? method : "'#{method}'"
end
def build_observer(klass, name, options = {})
options[:with] ||= 'value' if options[:update]
callback = remote_function(options)
javascript = '<script type="text/javascript">'
javascript << "new #{klass}('#{name}', "
javascript << "#{options[:frequency]}, " if options[:frequency]
javascript << "function(element, value) {"
javascript << "#{callback}})</script>"
end
def build_callbacks(options)
callbacks = {}
options.each do |callback, code|
if CALLBACKS.include?(callback)
name = 'on' + callback.to_s.capitalize
callbacks[name] = "function(request){#{code}}"
end
end
callbacks
end
def auto_complete_stylesheet
content_tag("style", <<-EOT
div.auto_complete {
width: 350px;
}
div.auto_complete ul {
border:1px solid #888;
margin:0;
padding:0;
width:100%;
list-style-type:none;
}
div.auto_complete ul li {
margin:0;
padding:3px;
}
div.auto_complete ul li.selected {
background-color: #ffb;
}
div.auto_complete ul strong.highlight {
color: #800;
margin:0;
padding:0;
}
EOT
)
end
end
JavascriptHelper = JavaScriptHelper unless const_defined? :JavascriptHelper
end
end