Client_Side_Rendering_Is_Not_So_Easy.pdf

Transcript

1. from 2010 to now... Client Side Rendering is Not So Easy
2. Nuria Ruiz @pantojacoder
3. What is client side rendering? A fine idea...
5. <div class="entry"> <h1>{{title}}</h1> <div class="body"> {{{value}}} </div> </div> { "title": "Pretty title", "value": 10000, }
6. To move rendering to the client you need two things: 1. Template Engine 2. Templates Loads of Javascript in the client.
8. Couple of things about About 1 billion page requests every day. 10% on IE7, 0.5% on IE6.
9. We have a loading bar.
10. We have a thick Javascript client.
11. We offer several languages: Spanish, English, Catalan...
12. Back to loads of Javascript in the client... Remember that loading bar? 500 K compressed, 23 requests ~ 3300 K of Javascript !!!!
13. Performance Problem #1 Eager loading of Javascript. Async !=Lazy
14. <div class="footer"> <div> <a class="hide" href="%sectionLink%"> <fw:translate id="Video.video_view_more_link"> %(video_view_more_link)View more... </fw:translate> </a> </div> Performance Problem #2 and #3 Templates were plain HTML documents.
15. We needed to do ajax to retrieve templates, which are HTML docs (cannot use <script>). AND Loads of walking the DOM to insert data.
17. Faster on IE7 than Chrome. We tried a "new" templating technology to solve the DOM issue.
18. XSLT
19. XSLT was faster but had many problems. Browser Implementation is 1.0. It does not support dynamic subtemplating. Adding translations was a major pain.
20. STEP BACK
21. With as much Javascript we had in the client nothing is going to go fast. Fact #1 We need to load Javascript lazily.
23. How does the YUI lazy loading work?
25. <a href="#m=Albums&f=index" onclick=​"Bootloader('t-albums- showcase','Request.click','?m=Albums&f=index')​;​return false;​" title=​"My photo albums">​…​</a>​ Each link does an HTTP request to retrieve the Javascript needed. YUI().use('t-albums')
27. We can remove the loading bar.
28. Fact #2 We need to start from scratch on the template engine.
30. works using a Lexical Parser. Based on Jison, a Javascript parser generator.
31. <div class="entry"> <h1>{{title}}</h1> <div class="body"> {{{body}}} </div> </div> Template: Compilation: $ npm install handlebars $ /usr/bin/handlebars sample_template.js Builds a grammar based on HTML that compiles to Javascript.
32. (function() { var template = Handlebars. template['sample_template.js'] =function (Handlebars,depth0,helpers,partials,data) { helpers = helpers || Handlebars.helpers; var self = this; buffer += "<div class=\"entry\">\n <h1>"; ..... } buffer += escapeExpression(stack1) + "</h1>\n <div class=\"body\">\n ” .... buffer += escapeExpression(stack1) + "\n </div>\n </div>\n"; return buffer; }); })()
33. DOM manipulation.
34. Why Handlebars? If/else constructors. Handlebars is actively worked on. Compilation available.
35. How do we download templates? With YUI, just like anything else, templates now are Javascript. <a href="#m=Albums&f=index" onclick=​"Bootloader('t-photo','Request.click', '?m=Albums&f=index)​;​ return false;​" title=​"My photo albums">​…​</a>​
36. YUI walks the dependency tree.
38. Translations client side. {{{translate "Photos" "%(photo_save_title) Save"}}} We hope to open source our I18N for Handlebars.
39. Do we use Client Side Rendering for everything? No. 1. Features that exist only client side, like overlays, autocomplete, spinners, chat UI. 2. Features for which there are significant CPU savings to be done, e.g. high traffic pages like photos.
40. What's next? Server Side.
41. Last Thoughts.
42. Do not think about problems in isolation.
43. Use the right tool for the job.
44. Measure Everything.
45. 5 times faster
46. Questions?