Example of stream used with databases :
Requirement :
A MySQL database with a table named data structured as follow :
CREATE TABLE IF NOT EXISTS `data` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`data` varchar(255) NOT NULL,
`when_inserted` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
Now with the stream implementation :
<?php
class DBStream {
private $_pdo;
private $_ps;
private $_rowId = 0;
function stream_open($path, $mode, $options, &$opath)
{
$url = parse_url($path);
$url['path'] = substr($url['path'], 1);
try{
$this->_pdo = new PDO("mysql:host={$url['host']};dbname={$url['path']}", $url['user'], isset($url['pass'])? $url['pass'] : '', array());
} catch(PDOException $e){ return false; }
switch ($mode){
case 'w' :
$this->_ps = $this->_pdo->prepare('INSERT INTO data VALUES(null, ?, NOW())');
break;
case 'r' :
$this->_ps = $this->_pdo->prepare('SELECT id, data FROM data WHERE id > ? LIMIT 1');
break;
default : return false;
}
return true;
}
function stream_read()
{
$this->_ps->execute(array($this->_rowId));
if($this->_ps->rowCount() == 0) return false;
$this->_ps->bindcolumn(1, $this->_rowId);
$this->_ps->bindcolumn(2, $ret);
$this->_ps->fetch();
return $ret;
}
function stream_write($data)
{
$this->_ps->execute(array($data));
return strlen($data);
}
function stream_tell()
{
return $this->_rowId;
}
function stream_eof()
{
$this->_ps->execute(array($this->_rowId));
return (bool) $this->_ps->rowCount();
}
function stream_seek($offset, $step)
{
}
}
stream_register_wrapper('db', 'DBStream');
$fr = fopen('db://testuser@localhost/testdb', 'r');
$fw = fopen('db://testuser:testpassword@localhost/testdb', 'w');
$alg = hash_algos();
$al = $alg[array_rand($alg)];
$data = hash($al, rand(rand(0, 9), rand(10, 999))); fwrite($fw, $data); while($a = fread($fr, 256)){ echo $a . '<br />';
}
?>
Hope it helps, cheers ;)