module PrototypeHelper # Creates a button with an onclick event which calls a remote action # via XMLHttpRequest # The options for specifying the target with :url # and defining callbacks is the same as link_to_remote. def button_to_remote(name, options = {}, html_options = {}) button_to_function(name, remote_function(options), html_options) end # Returns a button input tag with the element name of +name+ and a value (i.e., display text) of +value+ # that will submit form using XMLHttpRequest in the background instead of a regular POST request that # reloads the page. # # # Create a button that submits to the create action # # # # Generates: # <%= submit_to_remote 'create_btn', 'Create', :url => { :action => 'create' } %> # # # Submit to the remote action update and update the DIV succeed or fail based # # on the success or failure of the request # # # # Generates: # <%= submit_to_remote 'update_btn', 'Update', :url => { :action => 'update' }, # :update => { :success => "succeed", :failure => "fail" } # # options argument is the same as in form_remote_tag. def submit_to_remote(name, value, options = {}) options[:with] ||= 'Form.serialize(this.form)' html_options = options.delete(:html) || {} html_options[:name] = name button_to_remote(value, options, html_options) 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 # render :partial. # # Examples: # # Generates: Delete this post # link_to_remote "Delete this post", :update => "posts", # :url => { :action => "destroy", :id => post.id } # # # Generates:

# link_to_remote(image_tag("refresh"), :update => "emails", # :url => { :action => "list_emails" }) # # You can override the generated HTML options by specifying a hash in # options[:html]. # # link_to_remote "Delete this post", :update => "posts", # :url => post_url(@post), :method => :delete, # :html => { :class => "destructive" } # # 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: # # Generates: Delete this post # 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. # # The method used is by default POST. You can also specify GET or you # can simulate PUT or DELETE over POST. All specified with options[:method] # # Example: # # Generates: Destroy # link_to_remote "Destroy", :url => person_url(:id => person), :method => :delete # # 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: # # Generates: hello # word = 'hello' # 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: # # Generates: hello # 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. # :with:: A JavaScript expression specifying # the parameters for the XMLHttpRequest. # Any expressions should return a valid # URL query string. # # Example: # # :with => "'name=' + $('name').value" # # You can generate a link that uses AJAX in the general case, while # degrading gracefully to plain link behavior in the absence of # JavaScript by setting html_options[:href] to an alternate URL. # Note the extra curly braces around the options hash separate # it as the second parameter from html_options, the third. # # Example: # link_to_remote "Delete this post", # { :update => "posts", :url => { :action => "destroy", :id => post.id } }, # :href => url_for(:action => "destroy", :id => post.id) def link_to_remote(name, options = {}, html_options = nil) link_to_function(name, remote_function(options), html_options || options.delete(:html)) 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: # # Generates: # # # <%= form_remote_tag :url => '/posts' do -%> #

<%= submit_tag 'Save' %>

# <% end -%> def form_remote_tag(options = {}, &block) options[:form] = true options[:html] ||= {} options[:html][:onsubmit] = (options[:html][:onsubmit] ? options[:html][:onsubmit] + "; " : "") + "#{remote_function(options)}; return false;" form_tag(options[:html].delete(:action) || url_for(options[:url]), options[:html], &block) end # Creates a form that will submit using XMLHttpRequest in the background # instead of the regular reloading POST arrangement and a scope around a # specific resource that is used as a base for questioning about # values for the fields. # # === Resource # # Example: # <% remote_form_for(@post) do |f| %> # ... # <% end %> # # This will expand to be the same as: # # <% remote_form_for :post, @post, :url => post_path(@post), :html => { :method => :put, :class => "edit_post", :id => "edit_post_45" } do |f| %> # ... # <% end %> # # === Nested Resource # # Example: # <% remote_form_for([@post, @comment]) do |f| %> # ... # <% end %> # # This will expand to be the same as: # # <% remote_form_for :comment, @comment, :url => post_comment_path(@post, @comment), :html => { :method => :put, :class => "edit_comment", :id => "edit_comment_45" } do |f| %> # ... # <% end %> # # If you don't need to attach a form to a resource, then check out form_remote_tag. # # See FormHelper#form_for for additional semantics. def remote_form_for(record_or_name_or_array, *args, &proc) options = args.extract_options! case record_or_name_or_array when String, Symbol object_name = record_or_name_or_array when Array object = record_or_name_or_array.last object_name = ActiveModel::Naming.singular(object) apply_form_for_options!(record_or_name_or_array, options) args.unshift object else object = record_or_name_or_array object_name = ActiveModel::Naming.singular(record_or_name_or_array) apply_form_for_options!(object, options) args.unshift object end form_remote_tag options do fields_for object_name, *(args << options), &proc end end alias_method :form_remote_for, :remote_form_for # 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 # Observes the field with the DOM ID specified by +field_id+ and calls a # callback when its contents have changed. The default callback is an # Ajax call. By default the value of the observed field is sent as a # parameter with the Ajax call. # # Example: # # Generates: new Form.Element.Observer('suggest', 0.25, function(element, value) {new Ajax.Updater('suggest', # # '/testing/find_suggestion', {asynchronous:true, evalScripts:true, parameters:'q=' + value})}) # <%= observe_field :suggest, :url => { :action => :find_suggestion }, # :frequency => 0.25, # :update => :suggest, # :with => 'q' # %> # # Required +options+ are either of: # :url:: +url_for+-style options for the action to call # when the field has changed. # :function:: Instead of making a remote call to a URL, you # can specify javascript code to be called instead. # Note that the value of this option is used as the # *body* of the javascript function, a function definition # with parameters named element and value will be generated for you # for example: # observe_field("glass", :frequency => 1, :function => "alert('Element changed')") # will generate: # new Form.Element.Observer('glass', 1, function(element, value) {alert('Element changed')}) # The element parameter is the DOM element being observed, and the value is its value at the # time the observer is triggered. # # 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. The default is to send the # key and value of the observed field. Any custom # expressions should return a valid URL query string. # The value of the field is stored in the JavaScript # variable +value+. # # Examples # # :with => "'my_custom_key=' + value" # :with => "'person[name]=' + prompt('New name')" # :with => "Form.Element.serialize('other-field')" # # Finally # :with => 'name' # is shorthand for # :with => "'name=' + value" # This essentially just changes the key of the parameter. # # Additionally, you may specify any of the options documented in the # Common options section at the top of this document. # # Example: # # # Sends params: {:title => 'Title of the book'} when the book_title input # # field is changed. # observe_field 'book_title', # :url => 'http://example.com/books/edit/1', # :with => 'title' # # 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 # Observes the form with the DOM ID specified by +form_id+ and calls a # callback when its contents have changed. The default callback is an # Ajax call. By default all fields of the observed field are sent as # parameters with the Ajax call. # # The +options+ for +observe_form+ are the same as the options for # +observe_field+. The JavaScript variable +value+ available to the # :with option is set to the serialized form by default. 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 # 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. # Examples: # # Call get_averages and put its results in 'avg' every 10 seconds # # Generates: # # new PeriodicalExecuter(function() {new Ajax.Updater('avg', '/grades/get_averages', # # {asynchronous:true, evalScripts:true})}, 10) # periodically_call_remote(:url => { :action => 'get_averages' }, :update => 'avg') # # # Call invoice every 10 seconds with the id of the customer # # If it succeeds, update the invoice DIV; if it fails, update the error DIV # # Generates: # # new PeriodicalExecuter(function() {new Ajax.Updater({success:'invoice',failure:'error'}, # # '/testing/invoice/16', {asynchronous:true, evalScripts:true})}, 10) # periodically_call_remote(:url => { :action => 'invoice', :id => customer.id }, # :update => { :success => "invoice", :failure => "error" } # # # Call update every 20 seconds and update the new_block DIV # # Generates: # # new PeriodicalExecuter(function() {new Ajax.Updater('news_block', 'update', {asynchronous:true, evalScripts:true})}, 20) # periodically_call_remote(:url => 'update', :frequency => '20', :update => 'news_block') # 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 protected def build_observer(klass, name, options = {}) if options[:with] && (options[:with] !~ /[\{=(.]/) options[:with] = "'#{options[:with]}=' + encodeURIComponent(value)" else options[:with] ||= 'value' unless options[:function] end callback = options[:function] || remote_function(options) javascript = "new #{klass}('#{name}', " javascript << "#{options[:frequency]}, " if options[:frequency] javascript << "function(element, value) {" javascript << "#{callback}}" javascript << ")" javascript_tag(javascript) end end