10个超实用的PHP代码片段

在正确的时间拥有正确的代码片段，绝对是是Web开发人员的救星。今天，为大家已经收集了10个很棒的PHP代码片段，希望对您的开发有所帮助。
Super simple page caching
当你的项目没有基于CMS框架搭建时，利用下面这段代码就能够在你的页面上实现一个简单的缓存系统。非常适合于小型网站。

<?php
    // define the path and name of cached file
    $cachefile = 'cached-files/'.date('M-d-Y').'.php';
    // define how long we want to keep the file in seconds. I set mine to 5 hours.
    $cachetime = 18000;
    // Check if the cached file is still fresh. If it is, serve it up and exit.
    if (file_exists($cachefile) && time() - $cachetime < filemtime($cachefile)) {
    include($cachefile);
        exit;
    }
    // if there is either no file OR the file to too old, render the page and capture the HTML.
    ob_start();
?>
    <html>
        output all your html here.
    </html>
<?php
    // We're done! Save the cached content to a file
    $fp = fopen($cachefile, 'w');
    fwrite($fp, ob_get_contents());
    fclose($fp);
    // finally send browser output
    ob_end_flush();
?>
Calculate distances in PHP
这里是一个非常方便的功能，使用经度和纬度来计算从A点到B点的距离。该函数可以返回英里，公里，海里的距离。

function distance($lat1, $lon1, $lat2, $lon2, $unit) {

$theta = $lon1 - $lon2;
$dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
$dist = acos($dist);
$dist = rad2deg($dist);
$miles = $dist * 60 * 1.1515;
$unit = strtoupper($unit);

if ($unit == "K") {
    return ($miles * 1.609344);
} else if ($unit == "N") {
      return ($miles * 0.8684);
    } else {
        return $miles;
      }
}
Usage:

echo distance(32.9697, -96.80322, 29.46786, -98.53506, "k")." kilometers";
Convert seconds to time (years, months, days, hours…)
这个方法用于将秒数转换成年，月，周，日等。

function Sec2Time($time){
if(is_numeric($time)){
    $value = array(
      "years" => 0, "days" => 0, "hours" => 0,
      "minutes" => 0, "seconds" => 0,
    );
    if($time >= 31556926){
      $value["years"] = floor($time/31556926);
      $time = ($time%31556926);
    }
    if($time >= 86400){
      $value["days"] = floor($time/86400);
      $time = ($time%86400);
    }
    if($time >= 3600){
      $value["hours"] = floor($time/3600);
      $time = ($time%3600);
    }
    if($time >= 60){
      $value["minutes"] = floor($time/60);
      $time = ($time%60);
    }
    $value["seconds"] = floor($time);
    return (array) $value;
}else{
    return (bool) FALSE;
}
}
Force file download
有一些文件，比较mp3，通常会直接在客户端浏览器中播放。假如你希望强制下载这些文件，没有问题，下面这些代码将能够帮助你实现这个功能。

function downloadFile($file){
        $file_name = $file;
        $mime = 'application/force-download';
   header('Pragma: public');    // required
   header('Expires: 0');       // no cache
   header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
   header('Cache-Control: private',false);
   header('Content-Type: '.$mime);
   header('Content-Disposition: attachment; filename="'.basename($file_name).'"');
   header('Content-Transfer-Encoding: binary');
   header('Connection: close');
   readfile($file_name);       // push it out
   exit();
}
Get current weather using Google API
你是否想知道今天的天气？利用下面这段代码，只有3行代码能够实现。将第一段代码中的ADDRESS替换成想知道的地方。

$xml = simplexml_load_file('http://www.google.com/ig/api?weather=ADDRESS');
$information = $xml->xpath("/xml_api_reply/weather/current_conditions/condition");
echo $information[0]->attributes();
Basic PHP whois
利用下面这段代码可以取得一个域名的注册基本信息包括：所有者、创建时间，注册情况等信息。但需要在你的服务器上安装whois unix command，这段代码才能起作用。

$domains = array('home.pl', 'w3c.org');

function creation_date($domain) {
    $lines = explode("\n", `whois $domain`);
    foreach($lines as $line) {
        if(strpos(strtolower($line), 'created') !== false) {
            return $line;
        }
    }

    return false;
}

foreach($domains as $d) {
    echo creation_date($d) . "\n";
}
Get latitude and longitude from an adress
利用下面这段代码可以从Google Maps API取得一个地方的经度和纬度。

function getLatLong($address){
   if (!is_string($address))die("All Addresses must be passed as a string");
   $_url = sprintf('http://maps.google.com/maps?output=js&q=%s',rawurlencode($address));
   $_result = false;
   if($_result = file_get_contents($_url)) {
       if(strpos($_result,'errortips') > 1 || strpos($_result,'Did you mean:') !== false) return false;
       preg_match('!center:\s*{lat:\s*(-?\d+\.\d+),lng:\s*(-?\d+\.\d+)}!U', $_result, $_match);
       $_coords['lat'] = $_match[1];
       $_coords['long'] = $_match[2];
   }
   return $_coords;
}
Get domain favicon using PHP and Google
最近，有许多网站或Web应用使用Google提供的服务来获取网站的favicons图标。下面这段代码，可以帮助您实现这个功能。

function get_favicon($url){
$url = str_replace("http://",'',$url);
return "http://www.google.com/s2/favicons?domain=".$url;
}
Calculate Paypal fees
Ah, Paypal fees. Every person who ever used the popular online payment service had to pay their fees. So what about a PHP function to easily calculate the fee for a specific amount?

function paypalFees($sub_total, $round_fee) {

   // Set Fee Rate Variables
   $fee_percent = '3.4'; // Paypal's percentage rate per transaction (3.4% in UK)
   $fee_cash    = '0.20'; // Paypal's set cash amount per transaction (£0.20 in UK)

   // Calculate Fees
   $paypal_fee = ((($sub_total / 100) * $fee_percent) + $fee_cash);

   if ($round_fee == true) {
       $paypal_fee = ceil($paypal_fee);
   }

   // Calculate Grand Total
   $grand_total = ($sub_total + $paypal_fee);

   // Tidy Up Numbers
   $sub_total   = number_format($sub_total, 2, '.', ',');
   $paypal_fee = number_format($paypal_fee, 2, '.', ',');
   $grand_total = number_format($grand_total, 2, '.', ',');

   // Return Array
   return array('grand_total'=>$grand_total, 'paypal_fee'=>$paypal_fee, 'sub_total'=>$sub_total);
}

10个超实用的PHP代码片段

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