mysql数据库连接程序

时间：2015-01-23 来源：西部数据作者：西部数据

这里提供的数据库连接类程序,后面还提供了一个sql安全检测函数与sql语句完整性检测函数,实例代码如下:

class db_mysql {

var $connid;

var $querynum = 0;

var $expires;

var $cursor = 0;

var $cache_id = '';

var $cache_file = '';

var $cache_expires = '';

var $halt = 0;

var $result = array();

function connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect = 0) {

  global $cfg;

  $this->expires = $cfg['db_expires'];

  $func = $pconnect == 1 ? 'mysql_pconnect' : 'mysql_connect';

  if(!$this->connid = $func($dbhost, $dbuser, $dbpw)) {

   $this->halt('can not connect to mysql server');

  }

  if($this->version() > '4.1' && $cfg['db_charset']) {

   mysql_query("set names '".$cfg['db_charset']."'" , $this->connid);

  }

  if($this->version() > '5.0') {

   mysql_query("set sql_mode=''" , $this->connid);

  }

  if($dbname) {

   if(!mysql_select_db($dbname , $this->connid)) {

    $this->halt('cannot use database '.$dbname);

   }

  }

  return $this->connid;

}

function select_db($dbname) {

  return mysql_select_db($dbname , $this->connid);

}

function query($sql , $type = '', $expires = 0, $save_id = false) {

        $sql=checksql($sql);

  if($type == 'cache' && stristr($sql, 'select')) {

   $this->cursor = 0;

   $this->cache_id = md5($sql);

   $this->result = array();

   $this->cache_expires = $expires ? $expires + mt_rand(-9, 9) : $this->expires;

   return $this->_query($sql);

  }

  if(!$save_id) $this->cache_id = 0;

  $func = $type == 'unbuffered' ? 'mysql_unbuffered_query' : 'mysql_query';

  if(!($query = $func($sql , $this->connid)) && $this->halt) {

   $this->halt('mysql query error', $sql);

  }

  $this->querynum++;

  return $query;

}

function get_one($sql, $type = '', $expires = 0) {

  $query = $this->query($sql, $type, $expires);

  $r = $this->fetch_array($query);

  $this->free_result($query);

  return $r ;

}



function counter($table, $condition = '', $type = '', $expires = 0) {

  global $cfg;

  $table = strpos($table, $cfg['tb_pre']) === false ? $cfg['tb_pre'].$table : $table;

  $sql = "select count(*) as num from {$table}";

  if($condition) $sql .= " where $condition";

  $r = $this->get_one($sql, $type, $expires);

  return $r ? $r['num'] : 0;

}

function fetch_array($query, $result_type = mysql_assoc) {

  return $this->cache_id ? $this->_fetch_array($query) : @mysql_fetch_array($query, $result_type);

}

function affected_rows() {

  return mysql_affected_rows($this->connid);

}

function num_rows($query) {

  return mysql_num_rows($query);

}

function num_fields($query) {

  return mysql_num_fields($query);

}

function escape_string($str){

  return mysql_escape_string($str);

}

function result($query, $row) {

  return @mysql_result($query, $row);

}

function free_result($query) {

  return @mysql_free_result($query);

}

function insert_id() {

  return mysql_insert_id($this->connid);

}

function fetch_row($query) {

  return mysql_fetch_row($query);

}

function version() {

  return mysql_get_server_info($this->connid);

}

function close() {

  return mysql_close($this->connid);

}

function error() {

  return @mysql_error($this->connid);

}

function errno() {

  return intval(@mysql_errno($this->connid)) ;

}

function halt($message = '', $sql = '') {

  global $cfg;

  if($message) {

   if($cfg['errlog']) {

    $log = "query:$sql|errno:".$this->errno()."|error:".$this->error()."|errmsg:$message";

    log_write($log, 'sql');

   }

  }

        showmsg("mysqlerror:$message",'-1');

        exit();

}

function _query($sql) {

  global $fr_time;

  $this->cache_file = cache_root.'/sql/'.substr($this->cache_id, 0, 2).'/'.$this->cache_id.'.php教程';

  if(!is_file($this->cache_file) || ($fr_time - @filemtime($this->cache_file) > $this->cache_expires)) {

   $tmp = array();

   $result = $this->query($sql, '', '', true);

   while($r = mysql_fetch_array($result, mysql_assoc)) {

    $tmp[] = $r;

   }

   $this->result = $tmp;

   $this->free_result($result);

   file_put($this->cache_file, "<?php /*".( $fr_time+$this->cache_expires)."*/ return ".var_export($this->result, true).";n?>");

  } else {

      $this->result = include $this->cache_file;

  }

  return $this->result;

}

function _fetch_array($query = array()) {

  if($query) $this->result = $query;

  if(isset($this->result[$this->cursor])) {

   return $this->result[$this->cursor++];

  } else {

   $this->cursor = $this->cache_id = 0;

   return array();

  }

}

}

function checksql($dbstr,$querytype='select'){

$clean = '';

$old_pos = 0;

$pos = -1;

//普通语句，直接过滤特殊语法

if($querytype=='select'){

  $nastr = "/[^0-9a-z@._-]{1,}(union|sleep|benchmark|load_file|outfile)[^0-9a-z@.-]{1,}/i";

  if(preg_match($nastr,$dbstr)){

            log_write($dbstr,'sql');

            showmsg('safeerror:10001', '网页特效:;');

            exit();

  }

}

//完整的sql检查

while (true){

  $pos = strpos($dbstr, ''', $pos + 1);

  if ($pos === false){

   break;

  }

  $clean .= substr($dbstr, $old_pos, $pos - $old_pos);

  while (true){

   $pos1 = strpos($dbstr, ''', $pos + 1);

   $pos2 = strpos($dbstr, '', $pos + 1);

   if ($pos1 === false){

    break;

   }

   elseif ($pos2 == false || $pos2 > $pos1){

    $pos = $pos1;

    break;

   }

   $pos = $pos2 + 1;

  }

  $clean .= '$s$';

  $old_pos = $pos + 1;

}

$clean .= substr($dbstr, $old_pos);

$clean = trim(strtolower(preg_replace(array('~s+~s' ), array(' '), $clean)));

if (strpos($clean, 'union') !== false && preg_match('~(^|[^a-z])union($|[^[a-z])~s', $clean) != 0){

  $fail = true;

}

elseif (strpos($clean, '/*') > 2 || strpos($clean, '--') !== false || strpos($clean, '#') !== false){

  $fail = true;

}

elseif (strpos($clean, 'sleep') !== false && preg_match('~(^|[^a-z])sleep($|[^[a-z])~s', $clean) != 0){

  $fail = true;

}

elseif (strpos($clean, 'benchmark') !== false && preg_match('~(^|[^a-z])benchmark($|[^[a-z])~s', $clean) != 0){

  $fail = true;

}

elseif (strpos($clean, 'load_file') !== false && preg_match('~(^|[^a-z])load_file($|[^[a-z])~s', $clean) != 0){

  $fail = true;

}

elseif (strpos($clean, 'into outfile') !== false && preg_match('~(^|[^a-z])intos+outfile($|[^[a-z])~s', $clean) != 0){

  $fail = true;

}

elseif (preg_match('~([^)]*?select~s', $clean) != 0){

  $fail = true;

}

if (!emptyempty($fail)){

        log_write($dbstr,'sql');

        showmsg('safeerror:10002', 'javascript：;');exit;

}//开源代码phpfensi.com

else

{

  return $dbstr;

}

}