非常实用的PHP常用函数汇总

<?php
/**
 * 获取客户端IP
 * @return [string] [description]
 */
function getClientIp() {
 $ip = NULL;
 if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
  $arr = explode(',',$_SERVER['HTTP_X_FORWARDED_FOR']);
  $pos = array_search('unknown',$arr);
  if(false !== $pos) unset($arr[$pos]);
  $ip = trim($arr[0]);
 }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
  $ip = $_SERVER['HTTP_CLIENT_IP'];
 }elseif (isset($_SERVER['REMOTE_ADDR'])) {
  $ip = $_SERVER['REMOTE_ADDR'];
 }
 // IP地址合法验证
 $ip = (false !== ip2long($ip)) ? $ip : '0.0.0.0';
 return $ip;
}
/**
 * 获取在线IP
 * @return String
 */
function getOnlineIp($format=0) {
 global $S_GLOBAL;
 if(empty($S_GLOBAL['onlineip'])) {
  if(getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'),'unknown')) {
   $onlineip = getenv('HTTP_CLIENT_IP');
  } elseif(getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'),'unknown')) {
   $onlineip = getenv('HTTP_X_FORWARDED_FOR');
  } elseif(getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'),'unknown')) {
   $onlineip = getenv('REMOTE_ADDR');
  } elseif(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'],'unknown')) {
   $onlineip = $_SERVER['REMOTE_ADDR'];
  }
  preg_match("/[d.]{7,15}/",$onlineip,$onlineipmatches);
  $S_GLOBAL['onlineip'] = $onlineipmatches[0] ? $onlineipmatches[0] : 'unknown';
 }
 if($format) {
  $ips = explode('.',$S_GLOBAL['onlineip']);
  for($i=0;$i<3;$i++) {
   $ips[$i] = intval($ips[$i]);
  }
  return sprintf('%03d%03d%03d',$ips[0],$ips[1],$ips[2]);
 } else {
  return $S_GLOBAL['onlineip'];
 }
}
/**
 * 获取url
 * @return [type] [description]
 */
function getUrl(){
 $pageURL = 'http';
 if (isset($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] == "on") {
 $pageURL .= "s";
 }
 $pageURL .= "://";
 if ($_SERVER["SERVER_PORT"] != "80") {
 $pageURL .= $_SERVER["HTTP_HOST"] . ":" . $_SERVER["SERVER_PORT"] . $_SERVER["REQUEST_URI"];
 } else {
 $pageURL .= $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"];
 }
 return $pageURL;
}
/**
 * 获取当前站点的拜访路径根目录
 * @return [type] [description]
 */
function getSiteUrl() {
 $uri = $_SERVER['REQUEST_URI']?$_SERVER['REQUEST_URI']:($_SERVER['PHP_SELF']?$_SERVER['PHP_SELF']:$_SERVER['SCRIPT_NAME']);
 return 'http://'.$_SERVER['HTTP_HOST'].substr($uri,strrpos($uri,'/')+1);
}
/**
 * 字符串截取,支持中文和其他编码
 * @param [string] $str  [字符串]
 * @param integer $start [起始位置]
 * @param integer $length [截取长度]
 * @param string $charset [字符串编码]
 * @param boolean $suffix [是否有省略号]
 * @return [type]   [description]
 */
function msubstr($str,$start=0,$length=15,$charset="utf-8",$suffix=true) {
 if(function_exists("mb_substr")) {
  return mb_substr($str,$length,$charset);
 } elseif(function_exists('iconv_substr')) {
  return iconv_substr($str,$charset);
 }
 $re['utf-8'] = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff][x80-xbf]{3}/";
 $re['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";
 $re['gbk'] = "/[x01-x7f]|[x81-xfe][x40-xfe]/";
 $re['big5'] = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";
 preg_match_all($re[$charset],$str,$match);
 $slice = join("",array_slice($match[0],$length));
 if($suffix) {
  return $slice."…";
 }
 return $slice;
}
/**
 * php 实现js escape 函数
 * @param [type] $string [description]
 * @param string $encoding [description]
 * @return [type]   [description]
 */
function escape($string,$encoding = 'UTF-8'){
 $return = null;
 for ($x = 0; $x < mb_strlen($string,$encoding);$x ++)
 {
 $str = mb_substr($string,$x,1,$encoding);
 if (strlen($str) > 1) { // 多字节字符
  $return .= "%u" . strtoupper(bin2hex(mb_convert_encoding($str,'UCS-2',$encoding)));
 } else {
  $return .= "%" . strtoupper(bin2hex($str));
 }
 }
 return $return;
}
/**
 * php 实现 js unescape函数
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/(?:%u.{4})|.{4};|d+;|.+/U",$r);
 $ar = $r[0];
 foreach($ar as $k=>$v) {
  if(substr($v,2) == "%u"){
   $ar[$k] = iconv("UCS-2","utf-8//IGNORE",pack("H4",substr($v,-4)));
  } elseif(substr($v,3) == "") {
   $ar[$k] = iconv("UCS-2","utf-8",3,-1)));
  } elseif(substr($v,2) == "") {
   echo substr($v,2,-1)."";
   $ar[$k] = iconv("UCS-2",pack("n",-1)));
  }
 }
 return join("",$ar);
}
/**
 * 数字转人名币
 * @param [type] $num [description]
 * @return [type]  [description]
 */
function num2rmb ($num) {
 $c1 = "零壹贰叁肆伍陆柒捌玖";
 $c2 = "分角元拾佰仟万拾佰仟亿";
 $num = round($num,2);
 $num = $num * 100;
 if (strlen($num) > 10) {
  return "oh,sorry,the number is too long!";
 }
 $i = 0;
 $c = "";
 while (1) {
  if ($i == 0) {
   $n = substr($num,strlen($num)-1,1);
  } else {
   $n = $num % 10;
  }
  $p1 = substr($c1,3 * $n,3);
  $p2 = substr($c2,3 * $i,3);
  if ($n != '0' || ($n == '0' && ($p2 == '亿' || $p2 == '万' || $p2 == '元'))) {
   $c = $p1 . $p2 . $c;
  } else {
   $c = $p1 . $c;
  }
  $i = $i + 1;
  $num = $num / 10;
  $num = (int)$num;
  if ($num == 0) {
   break;
  }
 }
 $j = 0;
 $slen = strlen($c);
 while ($j < $slen) {
  $m = substr($c,$j,6);
  if ($m == '零元' || $m == '零万' || $m == '零亿' || $m == '零零') {
   $left = substr($c,$j);
   $right = substr($c,$j + 3);
   $c = $left . $right;
   $j = $j-3;
   $slen = $slen-3;
  }
  $j = $j + 3;
 }
 if (substr($c,strlen($c)-3,3) == '零') {
  $c = substr($c,strlen($c)-3);
 } // if there is a '0' on the end,chop it out
 return $c . "整";
}
/**
 * 特殊的字符
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function makeSemiangle($str) {
 $arr = array(
  '０' => '0','１' => '1','２' => '2','３' => '3','４' => '4','５' => '5','６' => '6','７' => '7','８' => '8','９' => '9','Ａ' => 'A','Ｂ' => 'B','Ｃ' => 'C','Ｄ' => 'D','Ｅ' => 'E','Ｆ' => 'F','Ｇ' => 'G','Ｈ' => 'H','Ｉ' => 'I','Ｊ' => 'J','Ｋ' => 'K','Ｌ' => 'L','Ｍ' => 'M','Ｎ' => 'N','Ｏ' => 'O','Ｐ' => 'P','Ｑ' => 'Q','Ｒ' => 'R','Ｓ' => 'S','Ｔ' => 'T','Ｕ' => 'U','Ｖ' => 'V','Ｗ' => 'W','Ｘ' => 'X','Ｙ' => 'Y','Ｚ' => 'Z','ａ' => 'a','ｂ' => 'b','ｃ' => 'c','ｄ' => 'd','ｅ' => 'e','ｆ' => 'f','ｇ' => 'g','ｈ' => 'h','ｉ' => 'i','ｊ' => 'j','ｋ' => 'k','ｌ' => 'l','ｍ' => 'm','ｎ' => 'n','ｏ' => 'o','ｐ' => 'p','ｑ' => 'q','ｒ' => 'r','ｓ' => 's','ｔ' => 't','ｕ' => 'u','ｖ' => 'v','ｗ' => 'w','ｘ' => 'x','ｙ' => 'y','ｚ' => 'z','(' => '(',')' => ')','〔' => '[','〕' => ']','【' => '[','】' => ']','〖' => '[','〗' => ']','｛' => '{','｝' => '}','《' => '<','》' => '>','％' => '%','＋' => '+','―' => '-','－' => '-','～' => '-','：' => ':','.' => '.','、' => ',' => '.','、' => '.','；' => ';','?' => '?','!' => '!','…' => '-','‖' => '|','”' => '"','“' => '"',''' => '`','‘' => '`','｜' => '|','〃' => '"','　' => ' ','．' => '.');
 return strtr($str,$arr);
}
/**
 * 下载
 * @param [type] $filename [description]
 * @param string $dir  [description]
 * @return [type]   [description]
 */
function downloads($filename,$dir='./'){
 $filepath = $dir.$filename;
 if (!file_exists($filepath)){
  header("Content-type: text/html; charset=utf-8");
  echo "File not found!";
  exit;
 } else {
  $file = fopen($filepath,"r");
  Header("Content-type: application/octet-stream");
  Header("Accept-Ranges: bytes");
  Header("Accept-Length: ".filesize($filepath));
  Header("Content-Disposition: attachment; filename=".$filename);
  echo fread($file,filesize($filepath));
  fclose($file);
 }
}
/**
 * 创建一个目录树
 * @param [type] $dir [description]
 * @param integer $mode [description]
 * @return [type]  [description]
 */
function mkdirs($dir,$mode = 0777) {
 if (!is_dir($dir)) {
  mkdirs(dirname($dir),$mode);
  return mkdir($dir,$mode);
 }
 return true;
}