6个超级有用的PHP代码片段

对于老程序员来说，他们的有道笔记、印象笔记等一定收藏了很多代码片段，代码段总是能节省大量宝贵的时间
并提高编码效率。今天，我要分享一些超级有用的PHP代码片段。

生成随机颜色

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();

从网络中下载文件

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);

显示Alexa/Google Page Rank

function page_rank($page, $type = 'alexa'){ 
    switch($type){ 
        case 'alexa': 
            $url = 'http://alexa.com/siteinfo/'; 
            $handle = fopen($url.$page, 'r'); 
        break; 
        case 'google': 
            $url = 'http://google.com/search?client=navclient-auto&ch=6-1484155081&features=Rank&q=info:'; 
            $handle = fopen($url.'http://'.$page, 'r'); 
        break; 
    } 
    $content = stream_get_contents($handle); 
    fclose($handle); 
    $content = preg_replace("~(\n|\t|\s\s+)~",'', $content); 
    switch($type){ 
        case 'alexa': 
            if(preg_match('~\<div class=\"data (down|up)\"\>\<img.+?\>(.+?)\ <\/div\>~im',$content,$matches)){ 
                return $matches[2]; 
            }else{ 
                return FALSE; 
            } 
        break; 
        case 'google': 
            $rank = explode(':',$content); 
            if($rank[2] != '') 
                return $rank[2]; 
            else 
                return FALSE; 
        break; 
        default: 
            return FALSE; 
        break; 
    } 
} 

// Alexa Page Rank: 
echo 'Alexa Rank: '.page_rank('phpsnips.com'); 
echo ''; 

// Google Page Rank 
echo 'Google Rank: '.page_rank('phpsnips.com', 'google');

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; 
}

生成图片

$filename= "test.jpg";
list($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);

检查一个站点是否可以访问

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";

标签：php代码片段