6个超实用的PHP代码片段

一、黑名单过滤

function is_spam($text, $file, $split = ':', $regex = false){
  $handle = fopen($file, 'rb');
  $contents = fread($handle, filesize($file));
  fclose($handle);
  $lines = explode("n", $contents);
$arr = array();
foreach($lines as $line){
list($word, $count) = explode($split, $line);
if($regex)
$arr[$word] = $count;
else
$arr[preg_quote($word)] = $count;
}
preg_match_all("~".implode('|', array_keys($arr))."~", $text, $matches);
$temp = array();
foreach($matches[0] as $match){
if(!in_array($match, $temp)){
$temp[$match] = $temp[$match] + 1;
if($temp[$match] >= $arr[$word])
return true;
}
}
return false;
} 

$file = 'spam.txt';
$str = 'This string has cat, dog word';
if(is_spam($str, $file))
echo 'this is spam';
else
echo 'this is not spam'; 

ab:3
dog:3
cat:2
monkey:2 

二、随机颜色生成器

function randomColor() {
  $str = '#';
  for($i = 0 ; $i < 6 ; $i++) {
    $randNum = rand(0 , 15);
    switch ($randNum) {
      case 10: $randNum = 'A'; break;
      case 11: $randNum = 'B'; break;
      case 12: $randNum = 'C'; break;
      case 13: $randNum = 'D'; break;
      case 14: $randNum = 'E'; break;
      case 15: $randNum = 'F'; break;
    }
    $str .= $randNum;
  }
  return $str;
}
$color = randomColor();

三、从网上下载文件

set_time_limit(0);
// Supports all file types
// URL Here:
$url = 'http://somsite.com/some_video.flv';
$pi = pathinfo($url);
$ext = $pi['extension'];
$name = $pi['filename']; 

// create a new cURL resource
$ch = curl_init(); 

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
curl_setopt($ch, CURLOPT_AUTOREFERER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 

// grab URL and pass it to the browser
$opt = curl_exec($ch); 

// close cURL resource, and free up system resources
curl_close($ch); 

$saveFile = $name.'.'.$ext;
if(preg_match("/[^0-9a-z._-]/i", $saveFile))
$saveFile = md5(microtime(true)).'.'.$ext; 

$handle = fopen($saveFile, 'wb');
fwrite($handle, $opt);
fclose($handle);

四、强制下载文件

$filename = $_GET['file']; //Get the fileid from the URL
// Query the file ID
$query = sprintf("SELECT * FROM tableName WHERE id = '%s'",mysql_real_escape_string($filename));
$sql = mysql_query($query);
if(mysql_num_rows($sql) > 0){
$row = mysql_fetch_array($sql);
// Set some headers
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Disposition: attachment; filename=".basename($row['FileName']).";");
header("Content-Transfer-Encoding: binary");
header("Content-Length: ".filesize($row['FileName'])); 

@readfile($row['FileName']);
exit(0);
}else{
header("Location: /");
exit;
}

五、截取图片

$filename= "test.jpg";
list($w, $h, $type, $attr) = getimagesize($filename);
$src_im = imagecreatefromjpeg($filename); 

$src_x = '0'; // begin x
$src_y = '0'; // begin y
$src_w = '100'; // width
$src_h = '100'; // height
$dst_x = '0'; // destination x
$dst_y = '0'; // destination y 

$dst_im = imagecreatetruecolor($src_w, $src_h);
$white = imagecolorallocate($dst_im, 255, 255, 255);
imagefill($dst_im, 0, 0, $white); 

imagecopy($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h); 

header("Content-type: image/png");
imagepng($dst_im);
imagedestroy($dst_im);

六、检查网站是否宕机

function Visit($url){
    $agent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";$ch=curl_init();
curl_setopt ($ch, CURLOPT_URL,$url );
curl_setopt($ch, CURLOPT_USERAGENT, $agent);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch,CURLOPT_VERBOSE,false);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch,CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch,CURLOPT_SSLVERSION,3);
curl_setopt($ch,CURLOPT_SSL_VERIFYHOST, FALSE);
$page=curl_exec($ch);
//echo curl_error($ch);
$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if($httpcode>=200 && $httpcode<300) return true;
else return false;
}
if (Visit("http://www.google.com"))
echo "Website OK"."n";
else
echo "Website DOWN";

以上就是6个超实用的PHP代码样例，希望对大家学习PHP编程有所帮助，果断收藏吧