HowTo: Search Engine Friendly URL in PHP

URL is one of the most important things when it comes to search engine indexing. Compare http://www.yourdomain.com/category/name_of_article_with_keywords to http://www.yourdomain.com/text.php?id=237364. Which one has more chances to be better indexed? Obviously, the one with keywords in URL.
I’m going to explain how to do it in PHP, provide example source code and explain how it works.

There are two easy steps.

1. Redirect all requests to your PHP class

There are two ways of sending all requests to specific PHP file.

a) Simple way. It can be done via managing of 404 error processing (when user requests virtual directory it triggers error 404, which your script should be able to process and render requested page).

Open httpd.conf file, insert the following line (there is a section with other ErrorDocument settings), save the file and restart Apache:

ErrorDocument 404 /index.php

b) Correct way. If your Apache has mod_rewrite installed (in most cases it has), redirection can be setup via this module.

Open httpd.conf file, insert or uncomment the following block (there is a section which starts with “<IfModule mod_rewrite.c>” string), save the file and restart Apache:

<IfModule mod_rewrite.c>
RewriteEngine on
# we don’t want to redirect requests for static images from /graph/ directory
RewriteRule /(graph.*) /$1 [skip=10]
# we also can skip file types by extension
RewriteRule /(.*\.(jpg|gif|swf|pps|ppt|doc|zip|png|pdf)) /$1 [skip=10]
# make webalizer stats accessible the standard way
RewriteRule /(statistics.*) /$1 [skip=10]
# …and redirect all the rest to index.php
RewriteRule /.* /index.php
</IfModule>

Now, when all the requests are being redirected to your index.php file, on the next steps let’s see the source code.

2. Process The Request

I’m assuming the following directory structure:

/index.php
/include.php
/project/engine.php

index.php:

BODY();
?>

include.php:

engine.php:

DEF = new def();
$this->PARSEURL();
}

function PARSEURL() {
if (
($GLOBALS["HTTP_SERVER_VARS"]["CONTENT_LENGTH"]) ||
($GLOBALS["_SERVER"]["CONTENT_LENGTH"]))
{
// В В В  processing POST data
} else {
if ($this->INSTALLATION == “IIS”) {
$URI = $GLOBALS["HTTP_SERVER_VARS"]["HTTP_REFERER"];
} else
if (isset($GLOBALS["HTTP_SERVER_VARS"]["REQUEST_URI"])) {
$URI = $GLOBALS["HTTP_SERVER_VARS"]["REQUEST_URI"];
} else {
$URI = $GLOBALS["_SERVER"]["REQUEST_URI"];
}

$this->URL = $URI;

$URI = ereg_replace(”^/”, “”, $URI);
$URI = ereg_replace(”$upath/$”, “”, $URI);

if (!$URI) $URI = “/”;

if ($URI) {
$URIarray = split(”/”,$URI);
$num = count($URIarray);

$this->URIarray = $URIarray;

// setting global navigation variables
//
$this->SECTION =
($URIarray[0]?strtolower($URIarray[0]):$this->DEF->SECTION);

if ( in_array($this->SECTION,$this->DEF->SECTIONS) ) {
$this->CATEGORY =
($URIarray[1]?strtolower($URIarray[1]):$this->DEF->CATEGORY);
$this->PAGE =
($URIarray[2]?strtolower($URIarray[2]):$this->DEF->PAGE);

} else {
// В В В  section is not known, process it as 404 error
$this->SECTION = “404″;
}
}
}
} // PARSEURL

function BODY() {

$body = ‘‘.
‘‘.
‘‘.
‘‘.
‘‘.
‘
‘.
”.
‘URL: ‘.
$this->URL .
‘

‘ .
”.
‘SECTION: ‘.
$this->SECTION .
‘

‘ .
”.
‘CATEGORY: ‘.
$this->CATEGORY .
‘

‘ .
”.
‘PAGE: ‘.
$this->PAGE .
‘

‘ .
‘

‘.
‘
‘.
‘this example is provided by ‘.
‘ontoinfo.com’.
‘

‘.
‘‘.
‘‘;

echo $body;
} // BODY
}
?>

Conclusion

The example above is extremely simple yet effective way to incorporate search engine friendly URL in PHP-based web site. You may copy and paste appropriate source code into your files or you can download the example.