Front End Website Optimization

Optimising The Front-EndUsing YSlow

And PHP(In A Continuous Integration Environment)

Gerard Sychayphp|works 2008 Atlanta, GA, USA

Who am I?

Gerard SychayTechnology Director

Zipscene.comCincinnati, OH, USA

Who am I?

IRL Cool Web 2.0 Avatar

"In sampling the top ten U.S. websites, all but one spend less than 20% of the total response time

getting the HTML document."

- http://developer.yahoo.com/performance/rules.html

Why Optimise Front-End?

Why Optimise Front-End?

•

Why Optimise Front-End?

34 YSlow Rules1. Make fewer HTTP Requests

2. Use a Content Delivery Network

3. Add an Expires or a Cache-Control Header

4. Gzip Components

5. Put Stylesheets at the Top

6. Put Scripts at the Bottom

7. Avoid CSS Expressions

8. Make JavaScript and CSS External

9. Reduce DNS Lookups

10. Minify JavaScript and CSS

11. Avoid Redirects

12. Remove Duplicate Scripts

13. Configure ETags

14. Make Ajax Cacheable

15. Flush the Buffer Early

16. Use GET for Ajax Requests

17. Post-load Components

18. Preload Components

19. Reduce the Number of DOM Elements

20. Split Components Across Domains

21. Minimize the Number of iframes

22. No 404s

23. Reduce Cookie Size

24. Use Cookie-free Domains for Components

25. Minimize DOM Access

26. Develop Smart Event Handlers

27. Choose <link> over @import

28. Avoid Filters

29. Optimize Images

30. Optimize CSS Sprites

31. Don’t Scale Images in HTML

32. Make favicon.ico Small and Cacheable

33. Keep Components under 25K

34. Pack Components into a Multipart Document

34 8 YSlow Rules1. Make fewer HTTP Requests

2. Use a Content Delivery Network

3. Add an Expires or a Cache-Control Header

4. Gzip Components

5. Put Stylesheets at the Top

6. Put Scripts at the Bottom

7. Avoid CSS Expressions

8. Make JavaScript and CSS External

9. Reduce DNS Lookups

10. Minify JavaScript and CSS

11. Avoid Redirects

12. Remove Duplicate Scripts

13. Configure ETags

14. Make Ajax Cacheable

15. Flush the Buffer Early

16. Use GET for Ajax Requests

17. Post-load Components

18. Preload Components

19. Reduce the Number of DOM Elements

20. Split Components Across Domains

21. Minimize the Number of iframes

22. No 404s

23. Reduce Cookie Size

24. Use Cookie-free Domains for Components

25. Minimize DOM Access

26. Develop Smart Event Handlers

27. Choose <link> over @import

28. Avoid Filters

29. Optimize Images

30. Optimize CSS Sprites

31. Don’t Scale Images in HTML

32. Make favicon.ico Small and Cacheable

33. Keep Components under 25K

34. Pack Components into a Multipart Document

Rule 1: Make Fewer HTTP RequestsInstead of:

<script type="text/javascript" src="/javascript/foo.js"></script><script type="text/javascript" src="/javascript/bar.js"></script>

Can we make it:

<script type="text/javascript" src="/javascript/foobar.js"></script>

Instead of:

<link rel=“stylesheet” type=“text/css” href=“/css/foo.css” /><link rel=“stylesheet” type=“text/css” href=“/css/bar.css” />

Can we make it:

<link rel=“stylesheet” type=“text/css” href=“/css/foobar.css” />

What about images?

Rule 3: Add An Expires Header

Rule 3: Add An Expires Header

Rule 3: Add An Expires Header

<Directory "/var/www/html/css"> ExpiresActive On ExpiresByType text/css "access plus 1 year”</Directory>

Rule 3: Add An Expires Header

Rule 3: Add An Expires Header

Rule 3: Add An Expires Header

So what if the file changes?

<link ref=“stylesheet” type=“text/css” href=“main.css” />

<link ref=“stylesheet” type=“text/css” href=“main.css?1207641610” />

<link ref=“stylesheet” type=“text/css” href=“main-1207641610.css” />

Rules 9,20,24: Domains

Rules 9,20,24: Domains

"Avoiding DNS lookups cuts response times, but reducing parallel downloads

may increase response times. [A] guideline is to split these components

across at least two but no more than four hostnames."

Rules 9,20,24: Domains

http://static0.example.com http://static1.example.com ...

BONUS! Optimise subdomains for static contentCookiesHTTP Keep-AliveAllowOverride

Rules 10,29: Minify

Javascript/* Prototype JavaScript framework, version 1.5.1.1 * (c) 2005-2007 Sam Stephenson * * Prototype is freely distributable under the terms of an MIT-style license. * For details, see the Prototype web site: http://www.prototypejs.org/ */*--------------------------------------------------------------------------*/var Prototype = { Version: '1.5.1.1', Browser: { IE: !!(window.attachEvent && !window.opera), Opera: !!window.opera, WebKit: navigator.userAgent.indexOf('AppleWebKit/') > -1, Gecko: navigator.userAgent.indexOf('Gecko') > -1 && navigator.userAgent.indexOf('KHTML') == -1 },...

var Prototype={Version:"1.5.1.1",Browser:{IE:!!(window.attachEvent&&!window.opera),Opera:!!window.opera,WebKit:navigator.userAgent.indexOf("AppleWebKit/")>-1,Gecko:navigator.userAgent.indexOf("Gecko")>-1&&navigator.userAgent.indexOf("KHTML")==-1},BrowserFeatures:{XPath:!!document.evaluate,ElementExtensions:!!window.HTMLElement,SpecificElementExtensions:(document.createElement("div").__proto__!==document.createElement("form").__proto__)}...

Rules 10,29: Minify

Javascript

JSMinDojo Shrinksafe, YUI CompressorPacker

Rules 10,29: Minify

CSS

Pretty much just whitespace and comments

Rules 10,29: Minify

Images

jpegtranoptipng

Rule 12: Remove Duplicate Scripts

Can We Do All These At Once?

Let's Find Out...

First Attempt: Template Function

<html> <head> <?php insert_js('/javascript/foo.js', '/javascript/bar.js'); ?> <?php insert_css('/css/foo.css', '/css/bar.css'); ?> </head> <body> <?php insert_img('/images/foo.jpg'); ?> ...

First Attempt: Template Functionfunction insert_js($args){ static $alreadyLoaded = array(); $files = func_get_args(); // get array of javascript files $bundlefile = str_replace('/javascript/', '', join('', $files)); $bundlefile = str_replace('.js', '', $bundlefile); $buffer = ''; $latest = 0; foreach ($files as $file) { if (isset($alreadyLoaded[$file])) continue; else $alreadyLoaded[$file] = true;

$mtime = filemtime(APP_ROOT . $file); if ($mtime > $latest) $latest = $mtime; // get the latest modification time $minified = YuiCompress::compress(APP_ROOT . $file); // minify content $buffer .= "$minified\n"; }

$handle = fopen(APP_ROOT . "/cache/$bundlefile-$latest.js", 'w'); // open bundle fwrite($handle, $buffer); // write minified content to bundle file fclose($handle); $twoBitValue = 0x3 & crc32("$bundlefile.js"); // generate subdomain $path = "http://static{$twoBitValue}.example.com/cache/$bundlefile-$latest.js"; echo "<script type=\"text/javascript\" src=\"$path\"></script>";}

✓Combine✓Expires✓Subdomain✓Minify✓Remove duplicate

First Attempt: Template Function

Instead of:

<script type=“text/javascript” src=“/javascript/foo.js”></script>

<script type=“text/javascript” src=“/javascript/bar.js”></script>

We now have:

<script type=“text/javascript” src=“http://static2.example.com/cache/foobar-1207762384.js”>

</script>

First Attempt: Template Function

Not bad, but… Multiple stat() calls What about CSS (e.g. background-image: url(‘…’))? AND IT MAKES THIS GUY SAD

Second Attempt: Phing

PHP build system similar to make Port of ant to PHP

Second Attempt: PhingCSS

$pattern = ‘/(<link.*href=“[^”]*”.*\/>\s*)+/’;

$buffer = preg_replace_callback($pattern, “insert_css”, $buffer);

Javascript

$pattern = ‘/(<script.*src=“[^”]*”.”></script>s*)+/’;

$buffer = preg_replace_callback($pattern, “insert_js”, $buffer);

Second Attempt: Phing

Images

$pattern = ‘/src=“([^”]*[gif|jpg|png])”’;

$buffer = preg_replace_callback($pattern, “insert_img”, $buffer);

$pattern = ‘/url\(‘?.*[gif|jpg|png]’?\)/”;

$buffer = preg_replace_callback($pattern, “insert_cssimg”,

$buffer);

Beyond Phing: Continuous Integration

Automatic front-end optimisations Automatic unit testing with coverage Automatic syntax checking (with `php -l`) Automatic standards checking (with

PHPCodeSniffer) Automatic deployment to integration Automatic deployment to any environment History of builds

Fin

Summary

Why the front-end is important 34 8 YSlow rules Template functions Continuous deployment

Fin

Links

34 Rules for High Perfomance Websites: http://developer.yahoo.com/performance/rules.html

YSlow homepage: http://developer.yahoo.com/yslow/

Cal Henderson Flickr article: http://www.thinkvitamin.com/features/webapps/serving-javascript-fast

Sitepoint article: http://www.sitepoint.com/article/web-site-optimization-steps/

Fin

Thanks!

Questions!

Comments!

gerard.sychay@zipscene.com

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