Summary of 4 practical PHP custom functions

This article mainly introduces several practical custom functions of PHP, and combines examples to summarize and analyze PHP network operations, string operations, time operations and regular expressions usage, etc. For tips, friends in need can refer to

1. Get the client IP

function getOnlineIp() {
  $strOnlineIp = "";
  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);
  $strOnlineIp = $onlineipmatches[0] ? $onlineipmatches[0] : 'unknown';
  return $strOnlineIp;
}

Here, if you use a multi-level proxy, the real IP cannot be obtained .

2, String interception, support Chinese

function getStrTruncate($string, $length = 80, $etc = ''){
  if ($length == 0) return '';
  mb_internal_encoding("UTF-8");
  $string = str_replace("\n","",$string);
  $strlen = mb_strwidth($string);
  if ($strlen > $length) {
    $etclen = mb_strwidth($etc);
    $length = $length - $etclen;
    $str=''; $n = 0;
    for($i=0; $i<$length; $i++) {
      $c = mb_substr($string, $i, 1);
      $n += mb_strwidth($c);
      if ($n>$length) { break; }
      $str .= $c;
    }
    return $str.$etc;
  } else {
    return $string;
  }
}
echo getStrTruncate("博客",7); //结果是海底苍，utf8一个汉字对应二个字符

3, How long ago time function, commonly used in forums and blogs

function timeFromNow($dateline) {
  if(emptyempty($dateline)) return false;
  $seconds = time() - $dateline;
  if ($seconds < 60){
    return "1分钟前";
  }elseif($seconds < 3600){
    return floor($seconds/60)."分钟前";
  }elseif($seconds < 24*3600){
    return floor($seconds/3600)."小时前";
  }elseif($seconds < 48*3600){
    return date("昨天 H:i", $dateline)."";
  }else{
    return date(&#39;Y-m-d&#39;, $dateline);
  }
}
echo timeFromNow(strtotime("2012-07-07 14:15:13")); //昨天 14:15
echo timeFromNow(strtotime("2012-07-08 14:15:13")); //1小前

4. Filter some tags

function delTags($str)
{
  $farr = array(
  "/<(\/?)(script|i?frame|style|html|body|title|link|meta|form|input|embed|object|textarea|\?|\%)([^>]*?)>/isU",
  "/(<[^>]*)on[a-zA-Z]+\s*=([^>]*>)/isU"
  );
  $tarr = array(
  "",
  ""
  );
  $str = preg_replace( $farr,$tarr,$str);
  return $str;
}
$str = "<a href=&#39;#&#39;>asdfasdfsd</a>====<script>alert(1111)</script>";
echo delTags($str);  //结果：<a href=&#39;#&#39;>asdfasdfsd</a>====alert(1111)
echo strip_tags($str); //结果：sdfasdfsd====alert(1111)

If you want to filter all tags strip_tags is enough.

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