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 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. def link_to_remote(name, options = {}, html_options = {}) link_to_function(name, remote_function(options), html_options) end # Periodically calls the specified url (options[:url]) every # options[:frequency] seconds (default is 10). Usually used to # update a specified div (options[:update]) 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 # Works like form_remote_tag, but uses form_for semantics. def remote_form_for(object_name, object, options = {}, &proc) concat form_remote_tag(options), proc.binding fields_for(object_name, object, options, &proc) concat '', proc.binding end alias_method :form_remote_for, :remote_form_for # Returns a button input tag that will submit form using XMLHttpRequest # in the background instead of regular reloading POST arrangement. # options argument is the same as in form_remote_tag. 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. # # * :content: The content to use for updating. Can be left out # if using block, see example. # * :action: Valid options are :update (assumed by default), # :empty, :remove # * :position 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 => "
New product!
")) %> # # <% replacement_function = update_element_function("products") do %> #Product 1
#Product 2
# <% 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 => "New Product: #{@product.name}
")) %> # <% 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: # 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: # :url:: +url_for+-style options for the action to call # when the field has changed. # # Additional options are: # :frequency:: 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. # :update:: Specifies the DOM ID of the element whose # innerHTML should be updated with the # XMLHttpRequest response text. # :with:: A JavaScript expression specifying the # parameters for the XMLHttpRequest. This defaults # to 'value', which in the evaluated context # refers to the new field value. # :on:: Specifies which event handler to observe. By default, # it's set to "changed" for text fields and areas and # "click" for radio buttons and checkboxes. With this, # you can specify it instead to be "blur" or "focus" or # any other event. # # Additionally, you may specify any of the options documented in # link_to_remote. def observe_field(field_id, options = {}) if options[:frequency] && 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 :with 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