5. 用 PHP 源码操作 memcache(2)

   如何使用PHP源码来操作memcached服务
如果管理员不让我们去加载 memcache.dll 文件，我们可以直接通过源码操作.

先关闭扩展.

<?php

require_once './memcached.php';

$mc = new memcached(array(
'servers' => array('127.0.0.1:11211'),//连接memcache 的 ip 和端口
'debug'   => false, //是否debug
'compress_threshold' => 10240,  //最大压缩
'persistant' => true));//是否是持久连接

$mc->add('key2','hello');
//  $mc->replace('key', 'some random string');
$val = $mc->get('key2');
echo $val;
//修改
$mc->set('key1','北京');
$val1 = $mc->get('key1');
var_dump($val1);

//删除
$mc->delete('key1');
$val2 = $mc->get('key1');
var_dump($val2);

<?php
//
// +---------------------------------------------------------------------------+
// | memcached client, PHP                                                     |
// +---------------------------------------------------------------------------+
// | Copyright (c) 2003 Ryan T. Dean <rtdean@cytherianage.net>                 |
// | All rights reserved.                                                      |
// |                                                                           |
// | Redistribution and use in source and binary forms, with or without        |
// | modification, are permitted provided that the following conditions        |
// | are met:                                                                  |
// |                                                                           |
// | 1. Redistributions of source code must retain the above copyright         |
// |    notice, this list of conditions and the following disclaimer.          |
// | 2. Redistributions in binary form must reproduce the above copyright      |
// |    notice, this list of conditions and the following disclaimer in the    |
// |    documentation and/or other materials provided with the distribution.   |
// |                                                                           |
// | THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR      |
// | IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
// | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.   |
// | IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,          |
// | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT  |
// | NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
// | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY     |
// | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT       |
// | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF  |
// | THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.         |
// +---------------------------------------------------------------------------+
// | Author: Ryan T. Dean <rtdean@cytherianage.net>                            |
// | Heavily influenced by the Perl memcached client by Brad Fitzpatrick.      |
// |   Permission granted by Brad Fitzpatrick for relicense of ported Perl     |
// |   client logic under 2-clause BSD license.                                |
// +---------------------------------------------------------------------------+
//
// $TCAnet$
//

/**
* This is the PHP client for memcached - a distributed memory cache daemon.
* More information is available at http://www.danga.com/memcached/ *
* Usage example:
*
* require_once 'memcached.php';
*
* $mc = new memcached(array(
*              'servers' => array('127.0.0.1:10000',
*                                 array('192.0.0.1:10010', 2),
*                                 '127.0.0.1:10020'),
*              'debug'   => false,
*              'compress_threshold' => 10240,
*              'persistant' => true));
*
* $mc->add('key', array('some', 'array'));
* $mc->replace('key', 'some random string');
* $val = $mc->get('key');
*
* @author  Ryan T. Dean <rtdean@cytherianage.net>
* @package memcached-client
* @version 0.1.2
*/

// {{{ requirements
// }}}

// {{{ constants
// {{{ flags

/**
* Flag: indicates data is serialized
*/
define("MEMCACHE_SERIALIZED", 1<<0);

/**
* Flag: indicates data is compressed
*/
define("MEMCACHE_COMPRESSED", 1<<1);

// }}}

/**
* Minimum savings to store data compressed
*/
define("COMPRESSION_SAVINGS", 0.20);

// }}}

// {{{ class memcached
/**
* memcached client class implemented using (p)fsockopen()
*
* @author  Ryan T. Dean <rtdean@cytherianage.net>
* @package memcached-client
*/
class memcached
{
// {{{ properties
// {{{ public

/**
* Command statistics
*
* @var     array
* @access  public
*/
var $stats;

// }}}
// {{{ private

/**
* Cached Sockets that are connected
*
* @var     array
* @access  private
*/
var $_cache_sock;

/**
* Current debug status; 0 - none to 9 - profiling
*
* @var     boolean
* @access  private
*/
var $_debug;

/**
* Dead hosts, assoc array, 'host'=>'unixtime when ok to check again'
*
* @var     array
* @access  private
*/
var $_host_dead;

/**
* Is compression available?
*
* @var     boolean
* @access  private
*/
var $_have_zlib;

/**
* Do we want to use compression?
*
* @var     boolean
* @access  private
*/
var $_compress_enable;

/**
* At how many bytes should we compress?
*
* @var     interger
* @access  private
*/
var $_compress_threshold;

/**
* Are we using persistant links?
*
* @var     boolean
* @access  private
*/
var $_persistant;

/**
* If only using one server; contains ip:port to connect to
*
* @var     string
* @access  private
*/
var $_single_sock;

/**
* Array containing ip:port or array(ip:port, weight)
*
* @var     array
* @access  private
*/
var $_servers;

/**
* Our bit buckets
*
* @var     array
* @access  private
*/
var $_buckets;

/**
* Total # of bit buckets we have
*
* @var     interger
* @access  private
*/
var $_bucketcount;

/**
* # of total servers we have
*
* @var     interger
* @access  private
*/
var $_active;

// }}}
// }}}
// {{{ methods
// {{{ public functions
// {{{ memcached()

/**
* Memcache initializer
*
* @param   array    $args    Associative array of settings
*
* @return  mixed
* @access  public
*/
public function __construct ($args)
{
$this->set_servers($args['servers']);
$this->_debug = $args['debug'];
$this->stats = array();
$this->_compress_threshold = $args['compress_threshold'];
$this->_persistant = isset($args['persistant']) ? $args['persistant'] : false;
$this->_compress_enable = true;
$this->_have_zlib = function_exists("gzcompress");

$this->_cache_sock = array();
$this->_host_dead = array();
}

// }}}
// {{{ add()

/**
* Adds a key/value to the memcache server if one isn't already set with
* that key
*
* @param   string   $key     Key to set with data
* @param   mixed    $val     Value to store
* @param   interger $exp     (optional) Time to expire data at
*
* @return  boolean
* @access  public
*/
function add ($key, $val, $exp = 0)
{
return $this->_set('add', $key, $val, $exp);
}

// }}}
// {{{ decr()

/**
* Decriment a value stored on the memcache server
*
* @param   string   $key     Key to decriment
* @param   interger $amt     (optional) Amount to decriment
*
* @return  mixed    FALSE on failure, value on success
* @access  public
*/
function decr ($key, $amt=1)
{
return $this->_incrdecr('decr', $key, $amt);
}

// }}}
// {{{ delete()

/**
* Deletes a key from the server, optionally after $time
*
* @param   string   $key     Key to delete
* @param   interger $time    (optional) How long to wait before deleting
*
* @return  boolean  TRUE on success, FALSE on failure
* @access  public
*/
function delete ($key, $time = 0)
{
if (!$this->_active)
return false;

$sock = $this->get_sock($key);
if (!is_resource($sock))
return false;

$key = is_array($key) ? $key[1] : $key;

$this->stats['delete']++;
$cmd = "delete $key $time\r\n";
if(!fwrite($sock, $cmd, strlen($cmd)))
{
$this->_dead_sock($sock);
return false;
}
$res = trim(fgets($sock));

if ($this->_debug)
printf("MemCache: delete %s (%s)\n", $key, $res);

if ($res == "DELETED")
return true;
return false;
}

// }}}
// {{{ disconnect_all()

/**
* Disconnects all connected sockets
*
* @access  public
*/
function disconnect_all ()
{
foreach ($this->_cache_sock as $sock)
fclose($sock);

$this->_cache_sock = array();
}

// }}}
// {{{ enable_compress()

/**
* Enable / Disable compression
*
* @param   boolean  $enable  TRUE to enable, FALSE to disable
*
* @access  public
*/
function enable_compress ($enable)
{
$this->_compress_enable = $enable;
}

// }}}
// {{{ forget_dead_hosts()

/**
* Forget about all of the dead hosts
*
* @access  public
*/
function forget_dead_hosts ()
{
$this->_host_dead = array();
}

// }}}
// {{{ get()

/**
* Retrieves the value associated with the key from the memcache server
*
* @param  string   $key     Key to retrieve
*
* @return  mixed
* @access  public
*/
function get ($key)
{
if (!$this->_active)
return false;

$sock = $this->get_sock($key);

if (!is_resource($sock))
return false;

$this->stats['get']++;

$cmd = "get $key\r\n";
if (!fwrite($sock, $cmd, strlen($cmd)))
{
$this->_dead_sock($sock);
return false;
}

$val = array();
$this->_load_items($sock, $val);

if ($this->_debug)
foreach ($val as $k => $v)
printf("MemCache: sock %s got %s => %s\r\n", $sock, $k, $v);

return $val[$key];
}

// }}}
// {{{ get_multi()

/**
* Get multiple keys from the server(s)
*
* @param   array    $keys    Keys to retrieve
*
* @return  array
* @access  public
*  get('key1')   keys=array('key1','key2');
*/
function get_multi ($keys)
{
if (!$this->_active)
return false;

$this->stats['get_multi']++;

foreach ($keys as $key)
{
$sock = $this->get_sock($key);
if (!is_resource($sock)) continue;
$key = is_array($key) ? $key[1] : $key;
if (!isset($sock_keys[$sock]))
{
$sock_keys[$sock] = array();
$socks[] = $sock;
}
$sock_keys[$sock][] = $key;
}

// Send out the requests
foreach ($socks as $sock)
{
$cmd = "get";
foreach ($sock_keys[$sock] as $key)
{
$cmd .= " ". $key;
}
$cmd .= "\r\n";

if (fwrite($sock, $cmd, strlen($cmd)))
{
$gather[] = $sock;
} else
{
$this->_dead_sock($sock);
}
}

// Parse responses
$val = array();
foreach ($gather as $sock)
{
$this->_load_items($sock, $val);
}

if ($this->_debug)
foreach ($val as $k => $v)
printf("MemCache: got %s => %s\r\n", $k, $v);

return $val;
}

// }}}
// {{{ incr()

/**
* Increments $key (optionally) by $amt
*
* @param   string   $key     Key to increment
* @param   interger $amt     (optional) amount to increment
*
* @return  interger New key value?
* @access  public
*/
function incr ($key, $amt=1)
{
return $this->_incrdecr('incr', $key, $amt);
}

// }}}
// {{{ replace()

/**
* Overwrites an existing value for key; only works if key is already set
*
* @param   string   $key     Key to set value as
* @param   mixed    $value   Value to store
* @param   interger $exp     (optional) Experiation time
*
* @return  boolean
* @access  public
*/
function replace ($key, $value, $exp=0)
{
return $this->_set('replace', $key, $value, $exp);
}

// }}}
// {{{ run_command()

/**
* Passes through $cmd to the memcache server connected by $sock; returns
* output as an array (null array if no output)
*
* NOTE: due to a possible bug in how PHP reads while using fgets(), each
*       line may not be terminated by a \r\n.  More specifically, my testing
*       has shown that, on FreeBSD at least, each line is terminated only
*       with a \n.  This is with the PHP flag auto_detect_line_endings set
*       to falase (the default).
*
* @param   resource $sock    Socket to send command on
* @param   string   $cmd     Command to run
*
* @return  array    Output array
* @access  public
*/
function run_command ($sock, $cmd)
{
if (!is_resource($sock))
return array();

if (!fwrite($sock, $cmd, strlen($cmd)))
return array();

while (true)
{
$res = fgets($sock);
$ret[] = $res;
if (preg_match('/^END/', $res))
break;
if (strlen($res) == 0)
break;
}
return $ret;
}

// }}}
// {{{ set()

/**
* Unconditionally sets a key to a given value in the memcache.  Returns true
* if set successfully.
*
* @param   string   $key     Key to set value as
* @param   mixed    $value   Value to set
* @param   interger $exp     (optional) Experiation time
*
* @return  boolean  TRUE on success
* @access  public
*/
function set ($key, $value, $exp=0)
{
return $this->_set('set', $key, $value, $exp);
}

// }}}
// {{{ set_compress_threshold()

/**
* Sets the compression threshold
*
* @param   interger $thresh  Threshold to compress if larger than
*
* @access  public
*/
function set_compress_threshold ($thresh)
{
$this->_compress_threshold = $thresh;
}

// }}}
// {{{ set_debug()

/**
* Sets the debug flag
*
* @param   boolean  $dbg     TRUE for debugging, FALSE otherwise
*
* @access  public
*
* @see     memcahced::memcached
*/
function set_debug ($dbg)
{
$this->_debug = $dbg;
}

// }}}
// {{{ set_servers()

/**
* Sets the server list to distribute key gets and puts between
*
* @param   array    $list    Array of servers to connect to
*
* @access  public
*
* @see     memcached::memcached()
*/
function set_servers ($list)
{
$this->_servers = $list;
$this->_active = count($list);
$this->_buckets = null;
$this->_bucketcount = 0;

$this->_single_sock = null;
if ($this->_active == 1)
$this->_single_sock = $this->_servers[0];
}

// }}}
// }}}
// {{{ private methods
// {{{ _close_sock()

/**
* Close the specified socket
*
* @param   string   $sock    Socket to close
*
* @access  private
*/
function _close_sock ($sock)
{
$host = array_search($sock, $this->_cache_sock);
fclose($this->_cache_sock[$host]);
unset($this->_cache_sock[$host]);
}

// }}}
// {{{ _connect_sock()

/**
* Connects $sock to $host, timing out after $timeout
*
* @param   interger $sock    Socket to connect
* @param   string   $host    Host:IP to connect to
* @param   float    $timeout (optional) Timeout value, defaults to 0.25s
*
* @return  boolean
* @access  private
*/
function _connect_sock (&$sock, $host, $timeout = 0.25)
{
list ($ip, $port) = explode(":", $host);
if ($this->_persistant == 1)
{
$sock = @pfsockopen($ip, $port, $errno, $errstr, $timeout);
} else
{
$sock = @fsockopen($ip, $port, $errno, $errstr, $timeout);
}

if (!$sock)
return false;
return true;
}

// }}}
// {{{ _dead_sock()

/**
* Marks a host as dead until 30-40 seconds in the future
*
* @param   string   $sock    Socket to mark as dead
*
* @access  private
*/
function _dead_sock ($sock)
{
$host = array_search($sock, $this->_cache_sock);
list ($ip, $port) = explode(":", $host);
$this->_host_dead[$ip] = time() + 30 + intval(rand(0, 10));
$this->_host_dead[$host] = $this->_host_dead[$ip];
unset($this->_cache_sock[$host]);
}

// }}}
// {{{ get_sock()

/**
* get_sock
*
* @param   string   $key     Key to retrieve value for;
*
* @return  mixed    resource on success, false on failure
* @access  private
*/
function get_sock ($key)
{
if (!$this->_active)
return false;

if ($this->_single_sock !== null)
return $this->sock_to_host($this->_single_sock);

$hv = is_array($key) ? intval($key[0]) : $this->_hashfunc($key);

if ($this->_buckets === null)
{
foreach ($this->_servers as $v)
{
if (is_array($v))
{
for ($i=0; $i<$v[1]; $i++)
$bu[] = $v[0];
} else
{
$bu[] = $v;
}
}
$this->_buckets = $bu;
$this->_bucketcount = count($bu);
}

$realkey = is_array($key) ? $key[1] : $key;
for ($tries = 0; $tries<20; $tries++)
{
$host = $this->_buckets[$hv % $this->_bucketcount];
$sock = $this->sock_to_host($host);
if (is_resource($sock))
return $sock;
$hv += $this->_hashfunc($tries . $realkey);
}

return false;
}

// }}}
// {{{ _hashfunc()

/**
* Creates a hash interger based on the $key
*
* @param   string   $key     Key to hash
*
* @return  interger Hash value
* @access  private
*/
function _hashfunc ($key)
{
$hash = 0;
for ($i=0; $i<strlen($key); $i++)
{
$hash = $hash*33 + ord($key[$i]);
}

return $hash;
}

// }}}
// {{{ _incrdecr()

/**
* Perform increment/decriment on $key
*
* @param   string   $cmd     Command to perform
* @param   string   $key     Key to perform it on
* @param   interger $amt     Amount to adjust
*
* @return  interger    New value of $key
* @access  private
*/
function _incrdecr ($cmd, $key, $amt=1)
{
if (!$this->_active)
return null;

$sock = $this->get_sock($key);
if (!is_resource($sock))
return null;

$key = is_array($key) ? $key[1] : $key;
$this->stats[$cmd]++;
if (!fwrite($sock, "$cmd $key $amt\r\n"))
return $this->_dead_sock($sock);

stream_set_timeout($sock, 1, 0);
$line = fgets($sock);
if (!preg_match('/^(\d+)/', $line, $match))
return null;
return $match[1];
}

// }}}
// {{{ _load_items()

/**
* Load items into $ret from $sock
*
* @param   resource $sock    Socket to read from
* @param   array    $ret     Returned values
*
* @access  private
*/
function _load_items ($sock, &$ret)
{
while (1)
{
$decl = fgets($sock);
if ($decl == "END\r\n")
{
return true;
} elseif (preg_match('/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match))
{
list($rkey, $flags, $len) = array($match[1], $match[2], $match[3]);
$bneed = $len+2;
$offset = 0;

while ($bneed > 0)
{
$data = fread($sock, $bneed);
$n = strlen($data);
if ($n == 0)
break;
$offset += $n;
$bneed -= $n;
$ret[$rkey] .= $data;
}

if ($offset != $len+2)
{
// Something is borked!
if ($this->_debug)
printf("Something is borked!  key %s expecting %d got %d length\n", $rkey, $len+2, $offset);

unset($ret[$rkey]);
$this->_close_sock($sock);
return false;
}

$ret[$rkey] = rtrim($ret[$rkey]);

if ($this->_have_zlib && $flags & MEMCACHE_COMPRESSED)
$ret[$rkey] = gzuncompress($ret[$rkey]);

if ($flags & MEMCACHE_SERIALIZED)
$ret[$rkey] = unserialize($ret[$rkey]);

} else
{
if ($this->_debug)
print("Error parsing memcached response\n");
return 0;
}
}
}

// }}}
// {{{ _set()

/**
* Performs the requested storage operation to the memcache server
*
* @param   string   $cmd     Command to perform
* @param   string   $key     Key to act on
* @param   mixed    $val     What we need to store
* @param   interger $exp     When it should expire
*
* @return  boolean
* @access  private
*/
function _set ($cmd, $key, $val, $exp)
{
if (!$this->_active)
return false;
//get_sock就是去获取到memcached服务器连接
$sock = $this->get_sock($key);
if (!is_resource($sock))
return false;

$this->stats[$cmd]++;

$flags = 0;

if (!is_scalar($val))
{
$val = serialize($val);
$flags |= MEMCACHE_SERIALIZED;
if ($this->_debug)
printf("client: serializing data as it is not scalar\n");
}

$len = strlen($val);

if ($this->_have_zlib && $this->_compress_enable &&
$this->_compress_threshold && $len >= $this->_compress_threshold)
{
$c_val = gzcompress($val, 9);
$c_len = strlen($c_val);

if ($c_len < $len*(1 - COMPRESS_SAVINGS))
{
if ($this->_debug)
printf("client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len);
$val = $c_val;
$len = $c_len;
$flags |= MEMCACHE_COMPRESSED;
}
}
if (!fwrite($sock, "$cmd $key $flags $exp $len\r\n$val\r\n"))
return $this->_dead_sock($sock);

$line = trim(fgets($sock));

if ($this->_debug)
{
if ($flags & MEMCACHE_COMPRESSED)
$val = 'compressed data';
printf("MemCache: %s %s => %s (%s)\n", $cmd, $key, $val, $line);
}
if ($line == "STORED")
return true;
return false;
}

// }}}
// {{{ sock_to_host()

/**
* Returns the socket for the host
*
* @param   string   $host    Host:IP to get socket for
*
* @return  mixed    IO Stream or false
* @access  private
*/
function sock_to_host ($host)

{

if (isset($this->_cache_sock[$host]))
return $this->_cache_sock[$host];

$now = time();
list ($ip, $port) = explode (":", $host);
if (isset($this->_host_dead[$host]) && $this->_host_dead[$host] > $now ||
isset($this->_host_dead[$ip]) && $this->_host_dead[$ip] > $now)
return null;

if (!$this->_connect_sock($sock, $host))
return $this->_dead_sock($host);

// Do not buffer writes
stream_set_write_buffer($sock, 0);

$this->_cache_sock[$host] = $sock;

return $this->_cache_sock[$host];
}

// }}}
// }}}
// }}}
}

// }}}
?>