Refactored JavaScriptHelper into PrototypeHelper and ScriptaculousHelper. Added PrototypeHelper::JavaScriptGenerator and PrototypeHelper#update_page for easily modifying multiple elements in an Ajax response.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3036 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 522 insertions, 0 deletions

diff --git a/actionpack/lib/action_view/helpers/prototype_helper.rb b/actionpack/lib/action_view/helpers/prototype_helper.rb
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+require File.dirname(__FILE__) + '/javascript_helper'
+
+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    = [ :uninitialized, :loading, :loaded, :interactive, 
+                         :complete, :failure, :success ] + (100..599).to_a
+        AJAX_OPTIONS = [ :before, :after, :condition, :url, :asynchronous, 
+                         :method, :insertion, :position, :form, :with, :update,
+                         :script ] + 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
+      
+      # 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 * $/
+        end
+  
+        # Inserts HTML at the specified +position+ relative to the DOM element
+        # identified by the given +id+.
+        # 
+        # +position+ may be one of:
+        # 
+        # <tt>:top</tt>::    HTML is inserted inside the element, before the 
+        #                    element's existing content.
+        # <tt>:bottom</tt>:: HTML is inserted inside the element, after the
+        #                    element's existing content.
+        # <tt>:before</tt>:: HTML is inserted immediately preceeding the element.
+        # <tt>:after</tt>::  HTML is inserted immediately following the element.
+        #
+        # +options_for_render+ may be either a string of HTML to insert, or a hash
+        # of options to be passed to ActionView::Base#render.  For example:
+        #
+        #   # Insert the rendered 'navigation' partial just before the DOM
+        #   # element with ID 'content'.
+        #   insert_html :before, 'content', :partial => 'navigation'
+        #
+        #   # Add a list item to the bottom of the <ul> with ID 'list'.
+        #   insert_html :bottom, 'list', '<li>Last item</li>'
+        #
+        def insert_html(position, id, *options_for_render)
+          html = render(*options_for_render)
+          record "new Insertion.#{position.to_s.camelize}(#{id.inspect}, #{html.inspect})"
+        end
+  
+        # Replaces the inner HTML of the DOM element with the given +id+.
+        #
+        # +options_for_render+ may be either a string of HTML to insert, or a hash
+        # of options to be passed to ActionView::Base#render.  For example:
+        #
+        #   # Replace the HTML of the DOM element having ID 'person-45' with the
+        #   # 'person' partial for the appropriate object.
+        #   replace_html 'person-45', :partial => 'person', :object => @person
+        #
+        def replace_html(id, *options_for_render)
+          html = render(*options_for_render)
+          record "$(#{id.inspect}).innerHTML = #{html.inspect}"
+        end
+  
+        # Removes the DOM elements with the given +ids+ from the page.
+        def remove(*ids)
+          record "#{ids.inspect}.each(Element.remove)"
+        end
+  
+        # Shows hidden DOM elements with the given +ids+.
+        def show(*ids)
+          record "#{ids.inspect}.each(Element.show)"
+        end
+  
+        # Hides the visible DOM elements with the given +ids+.
+        def hide(*ids)
+          record "#{ids.inspect}.each(Element.hide)"
+        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
+            @lines << 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
+      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