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