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。

01 <?php
02     // define the path and name of cached file
03     $cachefile = 'cached-files/'.date('M-d-Y').'.php';
04     // define how long we want to keep the file in seconds. I set mine to 5 hours.
05     $cachetime = 18000;
06     // Check if the cached file is still fresh. If it is, serve it up and exit.
07     if (file_exists($cachefile) && time() - $cachetime < filemtime($cachefile)) {
08     include($cachefile);
09         exit;
10     }
11     // if there is either no file OR the file to too old, render the page and capture the HTML.
12     ob_start();
13 ?>
14     <html>
15         output all your html here.
16     </html>
17 <?php
18     // We're done! Save the cached content to a file
19     $fp = fopen($cachefile, 'w');
20     fwrite($fp, ob_get_contents());
21     fclose($fp);
22     // finally send browser output
23     ob_end_flush();
24 ?>

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。

01 function distance($lat1, $lon1, $lat2, $lon2, $unit) {
02  
03   $theta = $lon1 - $lon2;
04   $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
05   $dist = acos($dist);
06   $dist = rad2deg($dist);
07   $miles = $dist * 60 * 1.1515;
08   $unit = strtoupper($unit);
09  
10   if ($unit == "K") {
11     return ($miles * 1.609344);
12   } else if ($unit == "N") {
13       return ($miles * 0.8684);
14     } else {
15         return $miles;
16       }
17 }

Usage:

1 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。

01 function Sec2Time($time){
02   if(is_numeric($time)){
03     $value = array(
04       "years" => 0, "days" => 0, "hours" => 0,
05       "minutes" => 0, "seconds" => 0,
06     );
07     if($time >= 31556926){
08       $value["years"] = floor($time/31556926);
09       $time = ($time%31556926);
10     }
11     if($time >= 86400){
12       $value["days"] = floor($time/86400);
13       $time = ($time%86400);
14     }
15     if($time >= 3600){
16       $value["hours"] = floor($time/3600);
17       $time = ($time%3600);
18     }
19     if($time >= 60){
20       $value["minutes"] = floor($time/60);
21       $time = ($time%60);
22     }
23     $value["seconds"] = floor($time);
24     return (array) $value;
25   }else{
26     return (bool) FALSE;
27   }
28 }

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。

01 function downloadFile($file){
02         $file_name = $file;
03         $mime = 'application/force-download';
04     header('Pragma: public');   // required
05     header('Expires: 0');       // no cache
06     header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
07     header('Cache-Control: private',false);
08     header('Content-Type: '.$mime);
09     header('Content-Disposition: attachment; filename="'.basename($file_name).'"');
10     header('Content-Transfer-Encoding: binary');
11     header('Connection: close');
12     readfile($file_name);       // push it out
13     exit();
14 }

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。

1 $xml = simplexml_load_file('http://www.google.com/ig/api?weather=ADDRESS');
2   $information = $xml->xpath("/xml_api_reply/weather/current_conditions/condition");
3   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。

01 $domains = array('home.pl', 'w3c.org');
02  
03 function creation_date($domain) {
04     $lines = explode("\n", `whois $domain`);
05     foreach($lines as $line) {
06         if(strpos(strtolower($line), 'created') !== false) {
07             return $line;
08         }
09     }
10  
11     return false;
12 }
13  
14 foreach($domains as $d) {
15     echo creation_date($d) . "\n";
16 }

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。

01 function getLatLong($address){
02     if (!is_string($address))die("All Addresses must be passed as a string");
03     $_url = sprintf('http://maps.google.com/maps?output=js&q=%s',rawurlencode($address));
04     $_result = false;
05     if($_result = file_get_contents($_url)) {
06         if(strpos($_result,'errortips') > 1 || strpos($_result,'Did you mean:') !== false) return false;
07         preg_match('!center:\s*{lat:\s*(-?\d+\.\d+),lng:\s*(-?\d+\.\d+)}!U', $_result, $_match);
08         $_coords['lat'] = $_match[1];
09         $_coords['long'] = $_match[2];
10     }
11     return $_coords;
12 }

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。

1 function get_favicon($url){
2   $url = str_replace("http://",'',$url);
3   return "http://www.google.com/s2/favicons?domain=".$url;
4 }

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?

01 function paypalFees($sub_total, $round_fee) {
02  
03     // Set Fee Rate Variables
04     $fee_percent = '3.4'; // Paypal's percentage rate per transaction (3.4% in UK)
05     $fee_cash    = '0.20'; // Paypal's set cash amount per transaction (£0.20 in UK)
06  
07     // Calculate Fees
08     $paypal_fee = ((($sub_total / 100) * $fee_percent) + $fee_cash);
09  
10     if ($round_fee == true) {
11         $paypal_fee = ceil($paypal_fee);
12     }
13  
14     // Calculate Grand Total
15     $grand_total = ($sub_total + $paypal_fee);
16  
17     // Tidy Up Numbers
18     $sub_total   = number_format($sub_total, 2, '.', ',');
19     $paypal_fee  = number_format($paypal_fee, 2, '.', ',');
20     $grand_total = number_format($grand_total, 2, '.', ',');
21  
22     // Return Array
23     return array('grand_total'=>$grand_total, 'paypal_fee'=>$paypal_fee, 'sub_total'=>$sub_total);
24 }

原文：http://css.dzone.com/news/10-super-useful-php-snippets

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原文地址：https://www.cnblogs.com/chenqianpeng/p/2425723.html