memcached-client.php

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<?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.                                |
// +---------------------------------------------------------------------------+
//
// $TCAnet$
//

// {{{ requirements
// }}}

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

define("MEMCACHE_SERIALIZED", 1<<0);

define("MEMCACHE_COMPRESSED", 1<<1);

// }}}

define("COMPRESSION_SAVINGS", 0.20);

// }}}

// {{{ class memcached
class memcached
{
   // {{{ properties
   // {{{ public

   var $stats;
   
   // }}}
   // {{{ private

   var $_cache_sock;
   
   var $_debug;
   
   var $_host_dead;
   
   var $_have_zlib;
   
   var $_compress_enable;
   
   var $_compress_threshold;
   
   var $_persistant;
   
   var $_single_sock;
   
   var $_servers;
   
   var $_buckets;
   
   var $_bucketcount;
   
   var $_active;

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

   function memcached ($args)
   {
      $this->set_servers(@$args['servers']);
      $this->_debug = @$args['debug'];
      $this->stats = array();
      $this->_compress_threshold = @$args['compress_threshold'];
      $this->_persistant = array_key_exists('persistant', $args) ? (@$args['persistant']) : false;
      $this->_compress_enable = true;
      $this->_have_zlib = function_exists("gzcompress");
      
      $this->_cache_sock = array();
      $this->_host_dead = array();
   }

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

   function add ($key, $val, $exp = 0)
   {
      return $this->_set('add', $key, $val, $exp);
   }

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

   function decr ($key, $amt=1)
   {
      return $this->_incrdecr('decr', $key, $amt);
   }

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

   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)
         $this->_debugprint(sprintf("MemCache: delete %s (%s)\n", $key, $res));
      
      if ($res == "DELETED")
         return true;
      return false;
   }

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

   function disconnect_all ()
   {
      foreach ($this->_cache_sock as $sock)
         fclose($sock);

      $this->_cache_sock = array();
   }

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

   function enable_compress ($enable)
   {
      $this->_compress_enable = $enable;
   }

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

   function forget_dead_hosts ()
   {
      $this->_host_dead = array();
   }

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

   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)
            $this->_debugprint(@sprintf("MemCache: sock %s got %s => %s\r\n", serialize($sock), $k, $v));

      return @$val[$key];
   }

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

   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)
            $this->_debugprint(sprintf("MemCache: got %s => %s\r\n", $k, $v));
            
      return $val;
   }

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

   function incr ($key, $amt=1)
   {
      return $this->_incrdecr('incr', $key, $amt);
   }

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

   function replace ($key, $value, $exp=0)
   {
      return $this->_set('replace', $key, $value, $exp);
   }

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

   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()

   function set ($key, $value, $exp=0)
   {
      return $this->_set('set', $key, $value, $exp);
   }

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

   function set_compress_threshold ($thresh)
   {
      $this->_compress_threshold = $thresh;
   }

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

   function set_debug ($dbg)
   {
      $this->_debug = $dbg;
   }

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

   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()

   function _close_sock ($sock)
   {
      $host = array_search($sock, $this->_cache_sock);
      fclose($this->_cache_sock[$host]);
      unset($this->_cache_sock[$host]);
   }

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

   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()

   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()

   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()

   function _hashfunc ($key)
   {
      return crc32($key);
   }

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

   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()

   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)
                  $this->_debugprint(sprintf("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 
         {
            $this->_debugprint("Error parsing memcached response\n");
            return 0;
         }
      }
   }

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

   function _set ($cmd, $key, $val, $exp)
   {
      if (!$this->_active)
         return false;
         
      $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)
            $this->_debugprint(sprintf("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)
               $this->_debugprint(sprintf("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';
         $this->_debugprint(sprintf("MemCache: %s %s => %s (%s)\n", $cmd, $key, $val, $line));
      }
      if ($line == "STORED")
         return true;
      return false;
   }

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

   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];
   }

   function _debugprint($str){
      print($str);
   }

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

// }}}
?>

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