require File.dirname(__FILE__) + '/javascript_helper'
require 'set'
module ActionView
module Helpers
# Provides a set of helpers for calling Prototype JavaScript functions,
# including functionality to call remote methods using
# 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 these helpers, you must include the Prototype
# JavaScript framework in your pages. See the documentation for
# ActionView::Helpers::JavaScriptHelper for more information on including
# the necessary JavaScript.
#
# See link_to_remote for documentation of options common to all Ajax
# helpers.
#
# See also ActionView::Helpers::ScriptaculousHelper for helpers which work
# with the Scriptaculous controls and visual effects library.
#
# See JavaScriptGenerator for information on updating multiple elements
# on the page in an Ajax response.
module PrototypeHelper
unless const_defined? :CALLBACKS
CALLBACKS = Set.new([ :uninitialized, :loading, :loaded,
:interactive, :complete, :failure, :success ] +
(100..599).to_a)
AJAX_OPTIONS = Set.new([ :before, :after, :condition, :url,
:asynchronous, :method, :insertion, :position,
:form, :with, :update, :script ]).merge(CALLBACKS)
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.
#
# Example:
# 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
def form_remote_for(object_name, object, options = {}, &proc)
concat(form_remote_tag(options), proc.binding)
fields_for(object_name, object, &proc)
concat(end_form_tag, proc.binding)
end
# Works like form_remote_tag, but uses form_for semantics.
def form_remote_for(object_name, object, options = {}, &proc)
concat(form_remote_tag(options), proc.binding)
fields_for(object_name, object, &proc)
concat(end_form_tag, proc.binding)
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).
#
# See also JavaScriptGenerator and update_page.
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
# 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
# JavaScriptGenerator generates blocks of JavaScript code that allow you
# to change the content and presentation of multiple DOM elements. Use
# this in your Ajax response bodies, either in a <script> tag or as plain
# JavaScript sent with a Content-type of "text/javascript".
#
# Create new instances with PrototypeHelper#update_page, then call
# #insert_html, #replace_html, #remove, #show, or #hide on the yielded
# generator in any order you like to modify the content and appearance of
# the current page. (You can also call other helper methods which
# return JavaScript, such as
# ActionView::Helpers::ScriptaculousHelper#visual_effect.)
#
# Example:
#
# update_page do |page|
# page.insert_html :bottom, 'list', '<li>Last item</li>'
# page.visual_effect :highlight, 'list'
# page.hide 'status-indicator', 'cancel-link'
# end
#
# generates the following JavaScript:
#
# new Insertion.Bottom("list", "<li>Last item</li>");
# new Effect.Highlight("list");
# ["status-indicator", "cancel-link"].each(Element.hide);
#
# You can also use PrototypeHelper#update_page_tag instead of
# PrototypeHelper#update_page to wrap the generated JavaScript in a
# <script> tag.
class JavaScriptGenerator
def initialize(context) #:nodoc:
@context, @lines = context, []
yield self
end
def to_s #:nodoc:
@lines * $/
end
# Inserts HTML at the specified +position+ relative to the DOM element
# identified by the given +id+.
#
# +position+ may be one of:
#
# <tt>:top</tt>:: HTML is inserted inside the element, before the
# element's existing content.
# <tt>:bottom</tt>:: HTML is inserted inside the element, after the
# element's existing content.
# <tt>:before</tt>:: HTML is inserted immediately preceeding the element.
# <tt>:after</tt>:: HTML is inserted immediately following the element.
#
# +options_for_render+ may be either a string of HTML to insert, or a hash
# of options to be passed to ActionView::Base#render. For example:
#
# # Insert the rendered 'navigation' partial just before the DOM
# # element with ID 'content'.
# insert_html :before, 'content', :partial => 'navigation'
#
# # Add a list item to the bottom of the <ul> with ID 'list'.
# insert_html :bottom, 'list', '<li>Last item</li>'
#
def insert_html(position, id, *options_for_render)
insertion = position.to_s.camelize
call "new Insertion.#{insertion}", id, render(*options_for_render)
end
# Replaces the inner HTML of the DOM element with the given +id+.
#
# +options_for_render+ may be either a string of HTML to insert, or a hash
# of options to be passed to ActionView::Base#render. For example:
#
# # Replace the HTML of the DOM element having ID 'person-45' with the
# # 'person' partial for the appropriate object.
# replace_html 'person-45', :partial => 'person', :object => @person
#
def replace_html(id, *options_for_render)
call 'Element.update', id, render(*options_for_render)
end
# Removes the DOM elements with the given +ids+ from the page.
def remove(*ids)
record "#{javascript_object_for(ids)}.each(Element.remove)"
end
# Shows hidden DOM elements with the given +ids+.
def show(*ids)
call 'Element.show', *ids
end
# Hides the visible DOM elements with the given +ids+.
def hide(*ids)
call 'Element.hide', *ids
end
# Toggles the visibility of the DOM elements with the given +ids+.
def toggle(*ids)
call 'Element.toggle', *ids
end
# Displays an alert dialog with the given +message+.
def alert(message)
call 'alert', message
end
# Redirects the browser to the given +location+, in the same form as
# +url_for+.
def redirect_to(location)
assign 'window.location.href', @context.url_for(location)
end
# Calls the JavaScript +function+, optionally with the given
# +arguments+.
def call(function, *arguments)
record "#{function}(#{arguments_for_call(arguments)})"
end
# Assigns the JavaScript +variable+ the given +value+.
def assign(variable, value)
record "#{variable} = #{javascript_object_for(value)}"
end
# Writes raw JavaScript to the page.
def <<(javascript)
@lines << javascript
end
private
def method_missing(method, *arguments, &block)
record @context.send(method, *arguments, &block)
end
def record(line)
returning line = "#{line.to_s.chomp.gsub /\;$/, ''};" do
self << line
end
end
def render(*options_for_render)
Hash === options_for_render.first ?
@context.render(*options_for_render) :
options_for_render.first.to_s
end
def javascript_object_for(object)
object.respond_to?(:to_json) ? object.to_json : object.inspect
end
def arguments_for_call(arguments)
arguments.map { |argument| javascript_object_for(argument) }.join ', '
end
end
# Yields a JavaScriptGenerator and returns the generated JavaScript code.
# Use this to update multiple elements on a page in an Ajax response.
# See JavaScriptGenerator for more information.
def update_page(&block)
JavaScriptGenerator.new(@template, &block).to_s
end
# Works like update_page but wraps the generated JavaScript in a <script>
# tag. Use this to include generated JavaScript in an ERb template.
# See JavaScriptGenerator for more information.
def update_page_tag(&block)
javascript_tag update_page(&block)
end
protected
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('#{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
end
end