PHP实用代码片段（二）

1. 转换 URL：从字符串变成超链接

如果你正在开发论坛，博客或者是一个常规的表单提交，很多时候都要用户访问一个网站。使用这个函数，URL 字符串就可以自动的转换为超链接。

function makeClickableLinks($text)
{
 $text = eregi_replace('(((f|ht){1}tp://)[-a-zA-Z0-9@:%_+.~#?&//=]+)',
 '<a href="\1">\1</a>', $text);
 $text = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_+.~#?&//=]+)',
 '\1<a href="http://\2">\2</a>', $text);
 $text = eregi_replace('([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})',
 '<a href="mailto:\1">\1</a>', $text);  

return $text;
}

语法：

<?php
$text = "This is my first post on http://blog.koonk.com";
$text = makeClickableLinks($text);
echo $text;
?>

2. 阻止多个 IP 访问你的网站

这个代码片段可以方便你禁止某些特定的 IP 地址访问你的网站。

if ( !file_exists('blocked_ips.txt') ) {
 $deny_ips = array(
  '127.0.0.1',
  '192.168.1.1',
  '83.76.27.9',
  '192.168.1.163'
 );
} else {
 $deny_ips = file('blocked_ips.txt');
}
// read user ip adress:
$ip = isset($_SERVER['REMOTE_ADDR']) ? trim($_SERVER['REMOTE_ADDR']) : '';

// search current IP in $deny_ips array
if ( (array_search($ip, $deny_ips))!== FALSE ) {
 // address is blocked:
 echo 'Your IP adress ('.$ip.') was blocked!';
 exit;
}

3. 强制性文件下载

如果你需要下载特定的文件而不用另开新窗口，下面的代码片段可以帮助你。

function force_download($file)
{
    $dir      = "../log/exports/";
    if ((isset($file))&&(file_exists($dir.$file))) {
       header("Content-type: application/force-download");
       header('Content-Disposition: inline; filename="' . $dir.$file . '"');
       header("Content-Transfer-Encoding: Binary");
       header("Content-length: ".filesize($dir.$file));
       header('Content-Type: application/octet-stream');
       header('Content-Disposition: attachment; filename="' . $file . '"');
       readfile("$dir$file");
    } else {
       echo "No file selected";
    }
}

语法：

<php
force_download("image.jpg");
?>

4. 创建 JSON 数据

使用下面的 PHP 片段可以创建 JSON 数据，可以方便你创建移动应用的 Web 服务。

$json_data = array ('id'=>1,'name'=>"Mohit");
echo json_encode($json_data);

5. 压缩 zip 文件

使用下面的 PHP 片段可以即时压缩 zip 文件。

function create_zip($files = array(),$destination = '',$overwrite = false) {
    //if the zip file already exists and overwrite is false, return false
    if(file_exists($destination) && !$overwrite) { return false; }
    //vars
    $valid_files = array();
    //if files were passed in...
    if(is_array($files)) {
        //cycle through each file
        foreach($files as $file) {
            //make sure the file exists
            if(file_exists($file)) {
                $valid_files[] = $file;
            }
        }
    }
    //if we have good files...
    if(count($valid_files)) {
        //create the archive
        $zip = new ZipArchive();
        if($zip->open($destination,$overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true) {
            return false;
        }
        //add the files
        foreach($valid_files as $file) {
            $zip->addFile($file,$file);
        }
        //debug
        //echo 'The zip archive contains ',$zip->numFiles,' files with a status of ',$zip->status;  

        //close the zip -- done!
        $zip->close();  

        //check to make sure the file exists
        return file_exists($destination);
    }
    else
    {
        return false;
    }
}

语法：

<?php
$files=array('file1.jpg', 'file2.jpg', 'file3.gif');
create_zip($files, 'myzipfile.zip', true);
?>

6. 解压文件

function unzip($location,$newLocation)
{
        if(exec("unzip $location",$arr)){
            mkdir($newLocation);
            for($i = 1;$i< count($arr);$i++){
                $file = trim(preg_replace("~inflating: ~","",$arr[$i]));
                copy($location.'/'.$file,$newLocation.'/'.$file);
                unlink($location.'/'.$file);
            }
            return TRUE;
        }else{
            return FALSE;
        }
}

语法：

<?php
unzip('test.zip','unziped/test'); //File would be unzipped in unziped/test folder
?>

7. 缩放图片

function resize_image($filename, $tmpname, $xmax, $ymax)
{
    $ext = explode(".", $filename);
    $ext = $ext[count($ext)-1];  

    if($ext == "jpg" || $ext == "jpeg")
        $im = imagecreatefromjpeg($tmpname);
    elseif($ext == "png")
        $im = imagecreatefrompng($tmpname);
    elseif($ext == "gif")
        $im = imagecreatefromgif($tmpname);  

    $x = imagesx($im);
    $y = imagesy($im);  

    if($x <= $xmax && $y <= $ymax)
        return $im;  

    if($x >= $y) {
        $newx = $xmax;
        $newy = $newx * $y / $x;
    }
    else {
        $newy = $ymax;
        $newx = $x / $y * $newy;
    }  

    $im2 = imagecreatetruecolor($newx, $newy);
    imagecopyresized($im2, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);
    return $im2;
}

8. 使用 mail() 发送邮件

function send_mail($to,$subject,$body)
{
$headers = "From: KOONK\r\n";
$headers .= "Reply-To: blog@koonk.com\r\n";
$headers .= "Return-Path: blog@koonk.com\r\n";
$headers .= "X-Mailer: PHP5\n";
$headers .= 'MIME-Version: 1.0' . "\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
mail($to,$subject,$body,$headers);
}

语法：

<?php
$to = "admin@koonk.com";
$subject = "This is a test mail";
$body = "Hello World!";
send_mail($to,$subject,$body);
?>

9. 把秒转换成天数，小时数和分钟

function secsToStr($secs) {
    if($secs>=86400){$days=floor($secs/86400);$secs=$secs%86400;$r=$days.' day';if($days<>1){$r.='s';}if($secs>0){$r.=', ';}}
    if($secs>=3600){$hours=floor($secs/3600);$secs=$secs%3600;$r.=$hours.' hour';if($hours<>1){$r.='s';}if($secs>0){$r.=', ';}}
    if($secs>=60){$minutes=floor($secs/60);$secs=$secs%60;$r.=$minutes.' minute';if($minutes<>1){$r.='s';}if($secs>0){$r.=', ';}}
    $r.=$secs.' second';if($secs<>1){$r.='s';}
    return $r;
}

语法：

<?php
$seconds = "56789";
$output = secsToStr($seconds);
echo $output;
?>

10. 数据库连接

连接 MySQL 数据库

<?php
$DBNAME = 'koonk';
$HOST = 'localhost';
$DBUSER = 'root';
$DBPASS = 'koonk';
$CONNECT = mysql_connect($HOST,$DBUSER,$DBPASS);
if(!$CONNECT)
{
    echo 'MySQL Error: '.mysql_error();
}
$SELECT = mysql_select_db($DBNAME);
if(!$SELECT)
{
    echo 'MySQL Error: '.mysql_error();
}
?>