前段时间对短域名做了点小研究，其实大体上无非是用更大的进制来对10进制数值进行缩短，并存入一个kvdb中，到时候直接提取即可。
这里我使用的是Memcache(也可以使用Mongodb或者redis等)
以下是主要代码：
<?php
/**
* 短域名生成&解析类
* @version 1.0 2013-5-12
*/
class ShortURL {
private $mem;
private $base_url = 'http://it300.com/';
public function __construct() {
$mem_conf = array(
array(
'host' => '192.168.10.90',
'port' => '10086'
),
array(
'host' => '192.168.10.91',
'port' => '10086'
),
);
$this->mem = new Memcache();
foreach ($mem_conf as $v) {
$this->mem->addServer($v['host'], $v['port']);
}
}
public function encode($url) {
$url = trim($url);
if(!preg_match("#^[http://|https://|ftp://]#iS", $url)) {
return false;
}
$md5 = md5($url);
$aid = $this->mem->get($md5);
if(!$aid) {
if(($aid = $this->mem->increment('auto_increment_id')) === false) {
$this->mem->set('auto_increment_id', 10000);
$aid = $this->mem->increment('auto_increment_id');
}
$this->mem->set($md5, $aid);
$key = $this->dec2str($aid);
$this->mem->set($key, $url);
} else {
$key = $this->dec2any($aid);
}
return $this->base_url.$key;
}
public function decode($url) {
$key = str_replace($this->base_url, '', trim($url));
return $this->mem->get($key);
}
private function dec2str($num, $base=62, $index=false) {
$out = '';
if (! $base ) {
$base = strlen($index);
} else if (! $index ) {
$index = substr("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" ,0 ,$base);
}
$t = ($num == 0) ? 0 : floor(log10($num) / log10($base));
for ($t; $t >= 0; $t--) {
$a = floor($num / pow( $base, $t ));
$out = $out . substr($index, $a, 1);
$num = $num - ($a * pow( $base, $t ));
}
return $out;
}
}
$app = new ShortURL();
$url = array(
'http://www.it300.com',
'http://www.it300.com/cphp.html',
'http://www.it300.com/cjs.html',
'http://www.it300.com/clinux.html',
'http://www.it300.com/article-15316.html'
);
foreach ($url as $v) {
$sort = $app->encode($v);
echo "sort link: ".$sort."\n";
$original = $app->decode($sort);
echo "original: ".$original."\n";
}
?> 输出结果如下：
sort link: http://it300.com/2Bj
original: http://www.it300.com
sort link: http://it300.com/2Bk
original: http://www.it300.com/cphp.html
sort link: http://it300.com/2Bl
original: http://www.it300.com/cjs.html
sort link: http://it300.com/2Bm
original: http://www.it300.com/clinux.html
sort link: http://it300.com/2Bn
original: http://www.it300.com/article-15316.html
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