cache|客户端
MemCached的PHP客户端操作类二
/*
* MemCached PHP client
* Copyright (c) 2003
* Ryan Gilfether
* http://www.gilfether.com
*
* Originally translated from Brad Fitzpatrick's
* See the memcached website:
* http://www.danga.com/memcached/
*
* This module is Copyright (c) 2003 Ryan Gilfether.
* All rights reserved.
* You may distribute under the terms of the GNU General Public License
* This is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.
*
*/
/**
* version string
*/
define("MC_VERSION", "1.0.10");
/**
* int, buffer size used for sending and receiving
* data from sockets
*/
define("MC_BUFFER_SZ", 1024);
/**
* MemCached error numbers
*/
define("MC_ERR_NOT_ACTIVE", 1001); // no active servers
define("MC_ERR_SOCKET_WRITE", 1002); // socket_write() failed
define("MC_ERR_SOCKET_READ", 1003); // socket_read() failed
define("MC_ERR_SOCKET_CONNECT", 1004); // failed to connect to host
define("MC_ERR_DELETE", 1005); // delete() did not recieve DELETED command
define("MC_ERR_HOST_FORMAT", 1006); // sock_to_host() invalid host format
define("MC_ERR_HOST_DEAD", 1007); // sock_to_host() host is dead
define("MC_ERR_GET_SOCK", 1008); // get_sock() failed to find a valid socket
define("MC_ERR_SET", 1009); // _set() failed to receive the STORED response
define("MC_ERR_GET_KEY", 1010); // _load_items no values returned for key(s)
define("MC_ERR_LOADITEM_END", 1011); // _load_items failed to receive END response
define("MC_ERR_LOADITEM_BYTES", 1012); // _load_items bytes read larger than bytes available
/**
* MemCached PHP client Class.
*
* Communicates with the MemCached server, and executes the MemCached protocol
* MemCached available at http://www.danga.com/memcached
*
* @author Ryan Gilfether
* @package MemCachedClient
* @access public
* @version 1.0.10
*/
class MemCachedClient
{
/**
* array of servers no long available
* @var array
*/
var $host_dead;
/**
* array of open sockets
* @var array
*/
var $cache_sock;
/**
* determine if debugging is either on or off
* @var bool
*/
var $debug;
/**
* array of servers to attempt to use, "host:port" string format
* @var array
*/
var $servers;
/**
* count of currently active connections to servers
* @var int
*/
var $active;
/**
* error code if one is set
* @var int
*/
var $errno;
/**
* string describing error
* @var string
*/
var $errstr;
/**
* size of val to force compression; 0 turns off; defaults 1
* @ var int
*/
var $compress = 1;
/**
* temp flag to turn compression on/off; defaults on
* @ var int
*/
var $comp_active = 1;
/**
* array that contains parsed out buckets
* @ var array
*/
var $bucket;
/**
* Constructor
*
* Creates a new MemCachedClient object
* Takes one parameter, a array of options. The most important key is
* $options["servers"], but that can also be set later with the set_servers()
* method. The servers must be an array of hosts, each of which is
* either a scalar of the form or an array of the
* former and an integer weight value. (the default weight if
* unspecified is 1.) It's recommended that weight values be kept as low
* as possible, as this module currently allocates memory for bucket
* distribution proportional to the total host weights.
* $options["debug"] turns the debugging on if set to true
*
* @access public
* @param array $option an array of servers and debug status
* @return object MemCachedClient the new MemCachedClient object
*/
function MemCachedClient($options = 0)
{
if(is_array($options))
{
$this->set_servers($options["servers"]);
$this->debug = $options["debug"];
$this->compress = $options["compress"];
$this->cache_sock = array();
}
$this->errno = 0;
$this->errstr = "";
}
/**
* sets up the list of servers and the ports to connect to
* takes an array of servers in the same format as in the constructor
*
* @access public
* @param array $servers array of servers in the format described in the constructor
*/
function set_servers($servers)
{
$this->servers = $servers;
$this->active = count($this->servers);
}
/**
* if $do_debug is set to true, will print out
* debugging info, else debug is turned off
*
* @access public
* @param bool $do_debug set to true to turn debugging on, false to turn off
*/
function set_debug($do_debug)
{
$this->debug = $do_debug;
}
/**
* remove all cached hosts that are no longer good
*
* @access public
*/
function forget_dead_hosts()
{
unset($this->host_dead);
}
/**
* disconnects from all servers
*
* @access public
*/
function disconnect_all()
{
foreach($this->cache_sock as $sock)
socket_close($sock);
unset($this->cache_sock);
$this->active = 0;
}
/**
* removes the key from the MemCache
* $time is the amount of time in seconds (or Unix time) until which
* the client wishes the server to refuse "add" and "replace" commands
* with this key. For this amount of item, the item is put into a
* delete queue, which means that it won't possible to retrieve it by
* the "get" command, but "add" and "replace" command with this key
* will also fail (the "set" command will succeed, however). After the
* time passes, the item is finally deleted from server memory.
* The parameter $time is optional, and, if absent, defaults to 0
* (which means that the item will be deleted immediately and further
* storage commands with this key will succeed).
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_DELETE
*
* @access public
* @param string $key the key to delete
* @param timestamp $time optional, the amount of time server will refuse commands on key
* @return bool TRUE on success, FALSE if key does not exist
*/
function delete($key, $time = 0)
{
if(!$this->active)
{
$this->errno = MC_ERR_NOT_ACTIVE;
$this->errstr = "No active servers are available";
if($this->debug)
$this->_debug("delete(): There are no active servers available.");
return FALSE;
}
$sock = $this->get_sock($key);
if(!is_resource($sock))
{
$this->errno = MC_ERR_GET_SOCK;
$this->errstr = "Unable to retrieve a valid socket.";
if($this->debug)
$this->_debug("delete(): get_sock() returned an invalid socket.");
return FALSE;
}
if(is_array($key))
$key = $key[1];
$cmd = "delete $key $time\r\n";
$cmd_len = strlen($cmd);
$offset = 0;
// now send the command
while($offset {
$result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);
if($result !== FALSE)
$offset += $result;
else if($offset {
$this->errno = MC_ERR_SOCKET_WRITE;
$this->errstr = "Failed to write to socket.";
if($this->debug)
{
$sockerr = socket_last_error($sock);
$this->_debug("delete(): socket_write() returned FALSE. Socket Error $sockerr: ".socket_strerror($sockerr));
}
return FALSE;
}
}
// now read the server's response
if(($retval = socket_read($sock, MC_BUFFER_SZ, PHP_NORMAL_READ)) === FALSE)
{
$this->errno = MC_ERR_SOCKET_READ;
$this->errstr = "Failed to read from socket.";
if($this->debug)
{
$sockerr = socket_last_error($sock);
$this->_debug("delete(): socket_read() returned FALSE. Socket Error $sockerr: ".socket_strerror($sockerr));
}
return FALSE;
}
// remove the \r\n from the end
$retval = rtrim($retval);
// now read the server's response
if($retval == "DELETED")
return TRUE;
else
{
// something went wrong, create the error
$this->errno = MC_ERR_DELETE;
$this->errstr = "Failed to receive DELETED response from server.";
if($this->debug)
$this->_debug("delete(): Failed to receive DELETED response from server. Received $retval instead.");
return FALSE;
}
}
/**
* Like set(), but only stores in memcache if the key doesn't already exist.
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_SET
*
* @access public
* @param string $key the key to set
* @param mixed $val the value of the key
* @param timestamp $exptime optional, the to to live of the key
* @return bool TRUE on success, else FALSE
*/
function add($key, $val, $exptime = 0)
{
return $this->_set("add", $key, $val, $exptime);
}
/**
* Like set(), but only stores in memcache if the key already exists.
* returns TRUE on success else FALSE
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_SET
*
* @access public
* @param string $key the key to set
* @param mixed $val the value of the key
* @param timestamp $exptime optional, the to to live of the key
* @return bool TRUE on success, else FALSE
*/
function replace($key, $val, $exptime = 0)
{
return $this->_set("replace", $key, $val, $exptime);
}
/**
* Unconditionally sets a key to a given value in the memcache. Returns true
* if it was stored successfully.
* The $key can optionally be an arrayref, with the first element being the
* hash value, as described above.
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_SET
*
* @access public
* @param string $key the key to set
* @param mixed $val the value of the key
* @param timestamp $exptime optional, the to to live of the key
* @return bool TRUE on success, else FALSE
*/
function set($key, $val, $exptime = 0)
{
return $this->_set("set", $key, $val, $exptime);
}
/**
* Retrieves a key from the memcache. Returns the value (automatically
* unserialized, if necessary) or FALSE if it fails.
* The $key can optionally be an array, with the first element being the
* hash value, if you want to avoid making this module calculate a hash
* value. You may prefer, for example, to keep all of a given user's
* objects on the same memcache server, so you could use the user's
* unique id as the hash value.
* Possible errors set are:
* MC_ERR_GET_KEY
*
* @access public
* @param string $key the key to retrieve
* @return mixed the value of the key, FALSE on error
*/
function get($key)
{
$val =& $this->get_multi($key);
if(!$val)
{
$this->errno = MC_ERR_GET_KEY;
$this->errstr = "No value found for key $key";
if($this->debug)
$this->_debug("get(): No value found for key $key");
return FALSE;
}
return $val[$key];
}
/**
* just like get(), but takes an array of keys, returns FALSE on error
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
*
* @access public
* @param array $keys the keys to retrieve
* @return array the value of each key, FALSE on error
*/
function get_multi($keys)
{
$sock_keys = array();
$socks = array();
$val = 0;
if(!$this->active)
{
$this->errno = MC_ERR_NOT_ACTIVE;
$this->errstr = "No active servers are available";
if($this->debug)
$this->_debug("get_multi(): There are no active servers available.");
return FALSE;
}
if(!is_array($keys))
{
$arr[] = $keys;
$keys = $arr;
}
foreach($keys as $k)
{
$sock = $this->get_sock($k);
if($sock)
{
$k = is_array($k) ? $k[1] : $k;
if(@!is_array($sock_keys[$sock]))
$sock_keys[$sock] = array();
// if $sock_keys[$sock] doesn't exist, create it
if(!$sock_keys[$sock])
$socks[] = $sock;
$sock_keys[$sock][] = $k;
}
}
if(!is_array($socks))
{
$arr[] = $socks;
$socks = $arr;
}
foreach($socks as $s)
{
$this->_load_items($s, $val, $sock_keys[$sock]);
}
if($this->debug)
{
while(list($k, $v) = @each($val))
$this->_debug("MemCache: got $k = $v\n");
}
return $val;
}
/**
* Sends a command to the server to atomically increment the value for
* $key by $value, or by 1 if $value is undefined. Returns FALSE if $key
* doesn't exist on server, otherwise it returns the new value after
* incrementing. Value should be zero or greater. Overflow on server
* is not checked. Be aware of values approaching 2**32. See decr.
* ONLY WORKS WITH NUMERIC VALUES
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
*
* @access public
* @param string $key the keys to increment
* @param int $value the amount to increment the key bye
* @return int the new value of the key, else FALSE
*/
function incr($key, $value = 1)
{
return $this->_incrdecr("incr", $key, $value);
}
/**
* Like incr, but decrements. Unlike incr, underflow is checked and new
* values are capped at 0. If server value is 1, a decrement of 2
* returns 0, not -1.
* ONLY WORKS WITH NUMERIC VALUES
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
*
* @access public
* @param string $key the keys to increment
* @param int $value the amount to increment the key bye
* @return int the new value of the key, else FALSE
*/
function decr($key, $value = 1)
{
return $this->_incrdecr("decr", $key, $value);
}
/**
* When a function returns FALSE, an error code is set.
* This funtion will return the error code.
* See error_string()
*
* @access public
* @return int the value of the last error code
*/
function error()
{
return $this->errno;
}
/**
* Returns a string describing the error set in error()
* See error()
*
* @access public
* @return int a string describing the error code given
*/
function error_string()
{
return $this->errstr;
}
/**
* Resets the error number and error string
*
* @access public
*/
function error_clear()
{
// reset to no error
$this->errno = 0;
$this->errstr = "";
}
/**
* temporarily sets compression on or off
* turning it off, and then back on will result in the compression threshold going
* back to the original setting from $options
* @param int $setting setting of compression (0=off|1=on)
*/
function set_compression($setting=1) {
if ($setting != 0) {
$this->comp_active = 1;
} else {
$this->comp_active = 0;
}
}
/*
* PRIVATE FUNCTIONS
*/
/**
* connects to a server
* The $host may either a string int the form of host:port or an array of the
* former and an integer weight value. (the default weight if
* unspecified is 1.) See the constructor for details
* Possible errors set are:
* MC_ERR_HOST_FORMAT
* MC_ERR_HOST_DEAD
* MC_ERR_SOCKET_CONNECT
*
* @access private
* @param mixed $host either an array or a string
* @return resource the socket of the new connection, else FALSE
*/
function sock_to_host($host)
{
if(is_array($host))
$host = array_shift($host);
$now = time();
// seperate the ip from the port, index 0 = ip, index 1 = port
$conn = explode(":", $host);
if(count($conn) != 2)
{
$this->errno = MC_ERR_HOST_FORMAT;
$this->errstr = "Host address was not in the format of host:port";
if($this->debug)
$this->_debug("sock_to_host(): Host address was not in the format of host:port");
return FALSE;
}
if(@($this->host_dead[$host] && $this->host_dead[$host] > $now) ||
@($this->host_dead[$conn[0]] && $this->host_dead[$conn[0]] > $now))
{
$this->errno = MC_ERR_HOST_DEAD;
$this->errstr = "Host $host is not available.";
if($this->debug)
$this->_debug("sock_to_host(): Host $host is not available.");
return FALSE;
}
// connect to the server, if it fails, add it to the host_dead below
$sock = socket_create (AF_INET, SOCK_STREAM, getprotobyname("TCP"));
// we need surpress the error message if a connection fails
if(!@socket_connect($sock, $conn[0], $conn[1]))
{
$this->host_dead[$host]=$this->host_dead[$conn[0]]=$now+60+intval(rand(0, 10));
$this->errno = MC_ERR_SOCKET_CONNECT;
$this->errstr = "Failed to connect to ".$conn[0].":".$conn[1];
if($this->debug)
$this->_debug("sock_to_host(): Failed to connect to ".$conn[0].":".$conn[1]);
return FALSE;
}
// success, add to the list of sockets
$cache_sock[$host] = $sock;
return $sock;
}
/**
* retrieves the socket associated with a key
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
*
* @access private
* @param string $key the key to retrieve the socket from
* @return resource the socket of the connection, else FALSE
*/
function get_sock($key)
{
if(!$this->active)
{
$this->errno = MC_ERR_NOT_ACTIVE;
$this->errstr = "No active servers are available";
if($this->debug)
$this->_debug("get_sock(): There are no active servers available.");
return FALSE;
}
$hv = is_array($key) ? intval($key[0]) : $this->_hashfunc($key);
if(!$this->buckets)
{
$bu = $this->buckets = array();
foreach($this->servers as $v)
{
if(is_array($v))
{
for($i = 1; $i $bu[] = $v[0];
}
else
$bu[] = $v;
}
$this->buckets = $bu;
}
$real_key = is_array($key) ? $key[1] : $key;
$tries = 0;
while($tries {
$host = @$this->buckets[$hv % count($this->buckets)];
$sock = $this->sock_to_host($host);
if(is_resource($sock))
return $sock;
$hv += $this->_hashfunc($tries.$real_key);
++$tries;
}
$this->errno = MC_ERR_GET_SOCK;
$this->errstr = "Unable to retrieve a valid socket.";
if($this->debug)
$this->_debug("get_sock(): Unable to retrieve a valid socket.");
return FALSE;
}
/**
* increments or decrements a numerical value in memcached. this function is
* called from incr() and decr()
* ONLY WORKS WITH NUMERIC VALUES
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
*
* @access private
* @param string $cmdname the command to send, either incr or decr
* @param string $key the key to perform the command on
* @param mixed $value the value to incr or decr the key value by
* @return int the new value of the key, FALSE if something went wrong
*/
function _incrdecr($cmdname, $key, $value)
{
if(!$this->active)
{
$this->errno = MC_ERR_NOT_ACTIVE;
$this->errstr = "No active servers are available";
if($this->debug)
$this->_debug("_incrdecr(): There are no active servers available.");
return FALSE;
}
$sock = $this->get_sock($key);
if(!is_resource($sock))
{
$this->errno = MC_ERR_GET_SOCK;
$this->errstr = "Unable to retrieve a valid socket.";
if($this->debug)
$this->_debug("_incrdecr(): Invalid socket returned by get_sock().");
return FALSE;
}
if($value == "")
$value = 1;
$cmd = "$cmdname $key $value\r\n";
$cmd_len = strlen($cmd);
$offset = 0;
// write the command to the server
while($offset {
$result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);
if($result !== FALSE)
$offset += $result;
else if($offset {
$this->errno = MC_ERR_SOCKET_WRITE;
$this->errstr = "Failed to write to socket.";
if($this->debug)
{
$sockerr = socket_last_error($sock);
$this->_debug("_incrdecr(): socket_write() returned FALSE. Error $errno: ".socket_strerror($sockerr));
}
return FALSE;
}
}
// now read the server's response
if(($retval = socket_read($sock, MC_BUFFER_SZ, PHP_NORMAL_READ)) === FALSE)
{
$this->errno = MC_ERR_SOCKET_READ;
$this->errstr = "Failed to read from socket.";
if($this->debug)
{
$sockerr = socket_last_error($sock);
$this->_debug("_incrdecr(): socket_read() returned FALSE. Socket Error $errno: ".socket_strerror($sockerr));
}
return FALSE;
}
// strip the /r/n from the end and return value
return trim($retval);
&nbs, p; }
/**
* sends the command to the server
* Possible errors set are:
* MC_ERR_NOT_ACTIVE
* MC_ERR_GET_SOCK
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_SET
*
* @access private
* @param string $cmdname the command to send, either incr or decr
* @param string $key the key to perform the command on
* @param mixed $value the value to set the key to
* @param timestamp $exptime expiration time of the key
* @return bool TRUE on success, else FALSE
*/
function _set($cmdname, $key, $val, $exptime = 0)
{
if(!$this->active)
{
$this->errno = MC_ERR_NOT_ACTIVE;
$this->errstr = "No active servers are available";
if($this->debug)
$this->_debug("_set(): No active servers are available.");
return FALSE;
}
$sock = $this->get_sock($key);
if(!is_resource($sock))
{
$this->errno = MC_ERR_GET_SOCK;
$this->errstr = "Unable to retrieve a valid socket.";
if($this->debug)
$this->_debug("_set(): Invalid socket returned by get_sock().");
return FALSE;
}
$flags = 0;
$key = is_array($key) ? $key[1] : $key;
$raw_val = $val;
// if the value is not scalar, we need to serialize it
if(!is_scalar($val))
{
$val = serialize($val);
$flags |= 1;
}
if (($this->compress_active) && ($this->compress > 0) && (strlen($val) > $this->compress)) {
$this->_debug("_set(): compressing data. size in:".strlen($val));
$cval=gzcompress($val);
$this->_debug("_set(): done compressing data. size out:".strlen($cval));
if ((strlen($cval) 2048)){
$flags |= 2;
$val=$cval;
}
unset($cval);
}
$len = strlen($val);
if (!is_int($exptime))
$exptime = 0;
// send off the request
$cmd = "$cmdname $key $flags $exptime $len\r\n$val\r\n";
$cmd_len = strlen($cmd);
$offset = 0;
// write the command to the server
while($offset {
$result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);
if($result !== FALSE)
$offset += $result;
else if($offset {
$this->errno = MC_ERR_SOCKET_WRITE;
$this->errstr = "Failed to write to socket.";
if($this->debug)
{
$errno = socket_last_error($sock);
$this->_debug("_set(): socket_write() returned FALSE. Error $errno: ".socket_strerror($errno));
}
return FALSE;
}
}
// now read the server's response
if(($l_szResponse = socket_read($sock, 6, PHP_NORMAL_READ)) === FALSE)
{
$this->errno = MC_ERR_SOCKET_READ;
$this->errstr = "Failed to read from socket.";
if($this->debug)
{
$errno = socket_last_error($sock);
$this->_debug("_set(): socket_read() returned FALSE. Error $errno: ".socket_strerror($errno));
}
return FALSE;
}
if($l_szResponse == "STORED")
{
if($this->debug)
$this->_debug("MemCache: $cmdname $key = $raw_val");
return TRUE;
}
$this->errno = MC_ERR_SET;
$this->errstr = "Failed to receive the STORED response from the server.";
if($this->debug)
$this->_debug("_set(): Did not receive STORED as the server response! Received $l_szResponse instead.");
return FALSE;
}
/**
* retrieves the value, and returns it unserialized
* Possible errors set are:
* MC_ERR_SOCKET_WRITE
* MC_ERR_SOCKET_READ
* MC_ERR_GET_KEY
* MC_ERR_LOADITEM_END
* MC_ERR_LOADITEM_BYTES
*
* @access private
* @param resource $sock the socket to connection we are retriving from
* @param array $val reference to the values retrieved
* @param mixed $sock_keys either a string or an array of keys to retrieve
* @return array TRUE on success, else FALSE
*/
function _load_items($sock, &$val, $sock_keys)
{
$val = array();
$cmd = "get ";
if(!is_array($sock_keys))
{
$arr[] = $sock_keys;
$sock_keys = $arr;
}
foreach($sock_keys as $sk)
$cmd .= $sk." ";
$cmd .="\r\n";
$cmd_len = strlen($cmd);
$offset = 0;
// write the command to the server
while($offset {
$result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);
if($result !== FALSE)
$offset += $result;
else if($offset {
$this->errno = MC_ERR_SOCKET_WRITE;
$this->errstr = "Failed to write to socket.";
if($this->debug)
{
$errno = socket_last_error($sock);
$this->_debug("_load_items(): socket_write() returned FALSE. Error $errno: ".socket_strerror($errno));
}
return FALSE;
}
}
$len = 0;
$buf = "";
$flags_array = array();
// now read the response from the server
while($line = socket_read($sock, MC_BUFFER_SZ, PHP_BINARY_READ))
{
// check for a socket_read error
if($line === FALSE)
{
$this->errno = MC_ERR_SOCKET_READ;
$this->errstr = "Failed to read from socket.";
if($this->debug)
{
$errno = socket_last_error($sock);
$this->_debug("_load_items(): socket_read() returned FALSE. Error $errno: ".socket_strerror($errno));
