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Ajax and Rails

Ajax and Rails

Presentation given during the genevarb meetup, in Geneva (Switzerland)


Vincent Pochet

December 12, 2012


  1. Ajax and Rails by Vincent Pochet @vin100pochet

  2. Ajax and Rails • Standard rendering • json messages ◦

    as_json ◦ json templates • Rendering HTML ◦ pjax ◦ turbolinks
  3. Standard rendering The old way! Each action render the full

    page markup: • layout • external scripts and css files • page content A POST action send data and receive response as a new HTML page => full rendering on every action
  4. as_json Model Controller class Model < ActiveRecord::Base def as_json(options =

    {}) super({only: [:id, :name]}.merge!(options)) end end class ModelsController < ApplicationController def show model = Model.find(params[:id]) render json: model end end Easy for simple data/message transfer Did not scale (multiple output format...) Models should not be responsible of their presentation
  5. The MVC way jbuilder Model View (show.json.jbuilder) Controller class Model

    < ActiveRecord::Base end json.(@model, :id, :name) json.other @model.compute_something class ModelsController < ApplicationController def show @model = Model.find(params[:id]) end end We use templates like we do for html rendering Partial templates Multiple presentation for models, depending of the action Advanced rendering
  6. The MVC way jbuilder (json) Builder (xml) rabl

    (json and xml)
  7. HTML rendering PJAX ( HTML / Javascript Controller class ModelsController

    < ApplicationController def show @model = Model.find(params[:id]) render layout: false if request.headers['X-PJAX'] end end Simple jquery extension Reload only portions of web pages on navigation PushState support You keep the control on how links are rendered <a href='/explore' data-pjax='#main'>Explore</a> <script type="text/javascript"> $(document).pjax('a[data-pjax]'); </scrript>
  8. HTML rendering Turbolinks ( Mix of the standard HTML rendering

    with a javascript based application. Similar to PJAX with differences: • A rails project (part of Rails 4) • Replace the entire body and the title tag content • Not dependant on jQuery • Used by default for all internal links
  9. Questions ?