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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 include the Prototype JavaScript Framework and for some functions
# script.aculo.us (which both come with Rails) on your pages. Choose one of these options:
#
# * Use <tt><%= javascript_include_tag :defaults %></tt> in the HEAD section of your page (recommended):
# The function will return references to the JavaScript files created by the +rails+ command in your
# <tt>public/javascripts</tt> directory. Using it is recommended as the browser can then cache the libraries
# instead of fetching all the functions anew on every request.
# * Use <tt><%= javascript_include_tag 'prototype' %></tt>: As above, but will only include the Prototype core library,
# which means you are able to use all basic AJAX functionality. For the script.aculo.us-based JavaScript helpers,
# like visual effects, autocompletion, drag and drop and so on, you should use the method described above.
# * Use <tt><%= define_javascript_functions %></tt>: this will copy all the JavaScript support functions within a single
# script block.
#
# For documentation on +javascript_include_tag+ see ActionView::Helpers::AssetTagHelper.
#
# 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, :success].push((100..599).to_a).flatten
AJAX_OPTIONS = [ :before, :after, :condition, :url, :asynchronous, :method,
:insertion, :position, :form, :with, :update, :script ].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 (in order):
#
# <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>:success</tt>:: Called when the XMLHttpRequest is completed,
# and the HTTP status code is in the 2XX range.
# <tt>:failure</tt>:: Called when the XMLHttpRequest is completed,
# and the HTTP status code is not in the 2XX
# range.
# <tt>:complete</tt>:: Called when the XMLHttpRequest is complete
# (fires after success/failure if they are present).,
#
# You can further refine <tt>:success</tt> and <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 + '!')"
#
# 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
# <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>.
# <tt>:submit</tt>:: 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.
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})"
javascript_tag(code)
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") }
# The Hash passed to the :html key is equivalent to the options (2nd) argument in the FormTagHelper.form_tag method.
#
# 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
# Returns a Javascript function (or expression) that'll update a DOM element according to the options passed.
#
# * <tt>:content</tt>: The content to use for updating. Can be left out if using block, see example.
# * <tt>:action</tt>: Valid options are :update (assumed by default), :empty, :remove
# * <tt>:position</tt> If the :action is :update, you can optionally specify one of the following positions: :before, :top, :bottom, :after.
#
# Examples:
# <%= javascript_tag(update_element_function(
# "products", :position => :bottom, :content => "<p>New product!</p>")) %>
#
# <% replacement_function = update_element_function("products") do %>
# <p>Product 1</p>
# <p>Product 2</p>
# <% end %>
# <%= javascript_tag(replacement_function) %>
#
# This method can also be used in combination with remote method call where the result is evaluated afterwards to cause
# multiple updates on a page. Example:
#
# # Calling view
# <%= form_remote_tag :url => { :action => "buy" }, :complete => evaluate_remote_response %>
# all the inputs here...
#
# # Controller action
# def buy
# @product = Product.find(1)
# end
#
# # Returning view
# <%= update_element_function(
# "cart", :action => :update, :position => :bottom,
# :content => "<p>New Product: #{@product.name}</p>")) %>
# <% update_element_function("status", :binding => binding) do %>
# You've bought a new product!
# <% end %>
#
# Notice how the second call doesn't need to be in an ERb output block since it uses a block and passes in the binding
# to render directly. This trick will however only work in ERb (not Builder or other template forms).
def update_element_function(element_id, options = {}, &block)
content = escape_javascript(options[:content] || '')
content = escape_javascript(capture(&block)) if block
javascript_function = case (options[:action] || :update)
when :update
if options[:position]
"new Insertion.#{options[:position].to_s.camelize}('#{element_id}','#{content}')"
else
"$('#{element_id}').innerHTML = '#{content}'"
end
when :empty
"$('#{element_id}').innerHTML = ''"
when :remove
"Element.remove('#{element_id}')"
else
raise ArgumentError, "Invalid action, choose one of :update, :remove, :empty"
end
javascript_function << ";\n"
options[:binding] ? concat(javascript_function, options[:binding]) : javascript_function
end
# Returns 'eval(request.responseText)' which is the Javascript function that form_remote_tag can call in :complete to
# evaluate a multiple update return document using update_element_function calls.
def evaluate_remote_response
"eval(request.responseText)"
end
# Returns the javascript needed for a remote function.
# Takes the same arguments as link_to_remote.
#
# Example:
# <select id="options" onchange="<%= remote_function(:update => "options", :url => { :action => :update_options }) %>">
# <option value="0">Hello</option>
# <option value="1">World</option>
# </select>
def remote_function(options)
javascript_options = options_for_ajax(options)
update = ''
if options[:update] and options[:update].is_a?Hash
update = []
update << "success:'#{options[:update][:success]}'" if options[:update][:success]
update << "failure:'#{options[:update][:failure]}'" if options[:update][:failure]
update = '{' + update.join(',') + '}'
elsif options[:update]
update << "'#{options[:update]}'"
end
function = update.empty? ?
"new Ajax.Request(" :
"new Ajax.Updater(#{update}, "
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. Not setting this
# option at all or to a value equal to or less than
# zero will use event based observation instead of
# time 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] and options[:frequency] > 0
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
# Returns a JavaScript snippet to be used on the AJAX callbacks for starting
# visual effects.
#
# This method requires the inclusion of the script.aculo.us JavaScript library.
#
# Example:
# <%= link_to_remote "Reload", :update => "posts",
# :url => { :action => "reload" },
# :complete => visual_effect(:highlight, "posts", :duration => 0.5 )
#
# If no element_id is given, it assumes "element" which should be a local
# variable in the generated JavaScript execution context. This can be used
# for example with drop_receiving_element:
#
# <%= drop_receving_element (...), :loading => visual_effect(:fade) %>
#
# This would fade the element that was dropped on the drop receiving element.
#
# You can change the behaviour with various options, see
# http://script.aculo.us for more documentation.
def visual_effect(name, element_id = false, js_options = {})
element = element_id ? "'#{element_id}'" : "element"
js_options[:queue] = "'#{js_options[:queue]}'" if js_options[:queue]
"new Effect.#{name.to_s.camelize}(#{element},#{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.
#
# This method requires the inclusion of the script.aculo.us JavaScript library.
#
# Example:
# <%= sortable_element("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) }
[:tag, :overlap, :constraint, :handle].each do |option|
options[option] = "'#{options[option]}'" if options[option]
end
options[:containment] = array_or_string_for_javascript(options[:containment]) if options[:containment]
options[:only] = array_or_string_for_javascript(options[:only]) if options[:only]
javascript_tag("Sortable.create('#{element_id}', #{options_for_javascript(options)})")
end
# Makes the element with the DOM ID specified by +element_id+ draggable.
#
# This method requires the inclusion of the script.aculo.us JavaScript library.
#
# Example:
# <%= draggable_element("my_image", :revert => true)
#
# You can change the behaviour with various options, see
# http://script.aculo.us for more documentation.
def draggable_element(element_id, options = {})
javascript_tag("new Draggable('#{element_id}', #{options_for_javascript(options)})")
end
# Makes the element with the DOM ID specified by +element_id+ receive
# dropped draggable elements (created by draggable_element).
# and make an AJAX call By default, the action called gets the DOM ID of the
# element as parameter.
#
# This method requires the inclusion of the script.aculo.us JavaScript library.
#
# Example:
# <%= drop_receiving_element("my_cart", :url => { :controller => "cart", :action => "add" }) %>
#
# You can change the behaviour with various options, see
# http://script.aculo.us for more documentation.
def drop_receiving_element(element_id, options = {})
options[:with] ||= "'id=' + encodeURIComponent(element.id)"
options[:onDrop] ||= "function(element){" + remote_function(options) + "}"
options.delete_if { |key, value| AJAX_OPTIONS.include?(key) }
options[:accept] = array_or_string_for_javascript(options[:accept]) if options[:accept]
options[:hoverclass] = "'#{options[:hoverclass]}'" if options[:hoverclass]
javascript_tag("Droppables.add('#{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", javascript_cdata_section(content), :type => "text/javascript")
end
def javascript_cdata_section(content) #:nodoc:
"\n//#{cdata_section("\n#{content}\n//")}\n"
end
private
def options_for_javascript(options)
'{' + options.map {|k, v| "#{k}:#{v}"}.sort.join(', ') + '}'
end
def array_or_string_for_javascript(option)
js_option = if option.kind_of?(Array)
"['#{option.join('\',\'')}']"
elsif !option.nil?
"'#{option}'"
end
js_option
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].nil? || options[:script]
if options[:form]
js_options['parameters'] = 'Form.serialize(this)'
elsif options[:submit]
js_options['parameters'] = "Form.serialize(document.getElementById('#{options[:submit]}'))"
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 = "new #{klass}('#{name}', "
javascript << "#{options[:frequency]}, " if options[:frequency]
javascript << "function(element, value) {"
javascript << "#{callback}})"
javascript_tag(javascript)
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
end
JavascriptHelper = JavaScriptHelper unless const_defined? :JavascriptHelper
end
end
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