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