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AJAX in Ruby-on-Rails

AJAX in Ruby-on-Rails. Ruby on Rails and AJAX. AJAX can be done with just Javascript Easier if you use libraries Prototype SAJAX jQuery Libraries only handle the client side Ruby on Rails also makes it easy on the server side. Simple Consistent Model. A trigger action occurs

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AJAX in Ruby-on-Rails

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  1. AJAX in Ruby-on-Rails

  2. Ruby on Rails and AJAX • AJAX can be done with just Javascript • Easier if you use libraries • Prototype • SAJAX • jQuery • Libraries only handle the client side • Ruby on Rails also makes it easy on the server side

  3. Simple Consistent Model • A trigger action occurs • button or link, javascript event • Data is sent asynchronously • Server side action handler takes some action and returns data • may be HTML partial • Client side receives the data/HTML and updates the view

  4. Client Side • Based on the prototype library • Simple Ruby functions • link_to_remote • form_remote_tag • periodically_call_remote • submit_to_remote • remote_function • View uses these functions which generate appropriate HTML tags and javascript function calls

  5. View <html> <head> <title>Ajax Demo</title> <%= javascript_include_tag :defaults %> </head> <body> <h1>What time is it?</h1> <div id="time_div"> I don't have the time, but <%= link_to_remote( "click here", :update => "time_div", :url =>{ :action => :say_when }) %> and I will look it up. </div> </body> </html>

  6. Details • javascript_include_tag • includes the appropriate javascript libraries • :defaults includes a few • may also just include specific libraries • link_to_remote (can be complex) • most often need • text for link name • id of the DOM element to update • url • may also specify • :method - default is POST • :position - must be one of :before, :top, :bottom, :after • :complete, :success, :failure • javascript callback functions

  7. Server Side • AJAX calls are treated just like any other HTTP request • However, we don’t want full response • layout, css, etc. • To suppress full response use • render(:text => “string”) • may also use render_text • render(:layout => false) • .js.rjs file with partial • controller with no layout

  8. Example class DemoController < ApplicationController def index end def say_when render_text "<p>The time is <b>" + DateTime.now.to_s + "</b></p>” end end In this case, there is no view connected to the action method

  9. form_remote_tag <% form_remote_tag :url => { :action => :add_to_cart, :id => product } do -%> <%= submit_tag "Add to Cart" %> <% end -%>

  10. More complex <%= link_to_remote("Logout", :url => {:controller => "Ajax", :action => "logout" }, :update => 'loginmessage', :complete => remote_function( :url => {:controller => "Ajax", :action => "menu"}, :update => 'sidemenu', :complete => remote_function( :url => {:controller => "Main", :action => "index"} ) ) )

  11. .js.rjs templates • Controller action methods are paired by name with view files • in app/views/controller_name directory • Typically, .html.erb files • May also be .js.rjs • ruby javascript • javascript to be executed on load • allows for multiple page updates • written in Ruby • Paired with controller action method that doesn’t contain calls to render

  12. .js.rjs example view code <%= link_to_remote("Test out RJS!", :url =>{ :controller => "shop", :action => "hello" }) %> controller code def hello end hello.js.rjs - goes into app/views/shop page.alert "Hello from RJS!"

  13. Updating the DOM with .js.rjs • Mark the location to be updated • <div id=“someid”> or <span id=“someid”> • </div> or </span> • Now replace the stuff in that location using page.replace_html • page.replace_html “someid”, “<b>HI</b>” • .js.rjs file is interpreted into javascript and the javascript is executed when it is loaded

  14. Other page methods • alert(message) • replace_html(id, *options_for_render) • options for render may be string with html • insert_html(position, id, *options_for_render) • position must be :before, :after, :top, :bottom • show( *ids ), hide( *ids ), & toggle( *ids ) • toggles the visibility of the html elements • visual_effect(effectname, id, options) • page.visual_effect(:fade, ‘someid’, :duration => 0.5) • page.visual_effect(:appear, ‘someid’, :duration => 0.5) • page.visual_effect(:highlight, ‘someid’, :duration => 1)

  15. .js.rjs • Much of what you can do is based on the scriptaculous library • http://script.aculo.us/ • Also look at the Ruby on Rails api • ActionView::Helpers::ScriptaculousHelper • ActionView::Helpers::PrototypeHelper

  16. Another Example - View • Dynamically populate form elements <% form_remote_tag(:update => "sel_con",:url => { :action => :create_select }, :position => "top", :success => "$('sel_con').innerHTML=''" ) do -%> <p> Please select a sports category: </p> <p> <%= select_tag "categories", "<option>Team</option><option>Individual</option>" %> </p> <div id="sel_con"></div> <p> <%= submit_tag "Show Sports" %> </p> <% end %>

  17. Another Example cont - controller def create_select indArr=["Nordic Skiing", "Inline Skating","Tennis", "Triathlon","Road Racing","Figure Skating", "Weight Lifting","Speed Skating","Snowboarding"]; teamArr=["Soccer","Basketball","Football","Hockey", "Baseball","Lacrosse"]; str=""; if (params[:categories].index('Team') != nil) render :partial => "options", :locals => { :sports => teamArr,:sptype => "team"} elsif (params[:categories].index('Individual') != nil) render :partial => "options", :locals => { :sports => indArr, :sptype => "individual" } else str="<select id='individual' name='individual'> <option>unknown</option></select>"; render :text => str; end end

  18. Another Example cont - partial _options <select id="<%= sptype %>" name="<%= sptype %>"> <% sports.each do |sport| %> <option><%= sport %></option> <% end %> </select>

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