虽然PHP自带的函数库很强大,但是在日常很多情况下,我们也还得自己写自定义的函数去实现某些功能与需求。下面收集了一些比较实用的、解决一些常见需求的自定义函数,比如将网址字符串转换成超级链接、列出目录内容、验证邮件地址等等,如果你觉得好,可以收藏本页,方便以后翻阅~

1. PHP可阅读随机字符串
此代码将创建一个可阅读的字符串,使其更接近词典中的单词,实用且具有密码验证功能。
	/**************
	*@length - length of random string (must be a multiple of 2)
	**************/
	function readable_random_string($length = 6){
	    $conso=array("b","c","d","f","g","h","j","k","l",
	    "m","n","p","r","s","t","v","w","x","y","z");
	    $vocal=array("a","e","i","o","u");
	    $password="";
	    srand ((double)microtime()*1000000);
	    $max = $length/2;
	    for($i=1; $i<=$max; $i++)
	    {
	    $password.=$conso[rand(0,19)];
	    $password.=$vocal[rand(0,4)];
	    }
	    return $password;
	}
	
2. PHP生成一个随机字符串
如果不需要可阅读的字符串,使用此函数替代,即可创建一个随机字符串,作为用户的随机密码等。

	/*************
	*@l - length of random string
	*/
	function generate_rand($l){
	  $c= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
	  srand((double)microtime()*1000000);
	  for($i=0; $i < $l; $i++) {
	      $rand.= $c[rand()%strlen($c)];
	  }
	  return $rand;
	}
	
3. PHP编码电子邮件地址
使用此代码,可以将任何电子邮件地址编码为 html 字符实体,以防止被垃圾邮件程序收集。

	function encode_email($email='info@domain.com', $linkText='Contact Us', $attrs ='class="emailencoder"' )
	{
	    // remplazar aroba y puntos
	    $email = str_replace('@', '@', $email);
	    $email = str_replace('.', '.', $email);
	    $email = str_split($email, 5);  
	  
	    $linkText = str_replace('@', '@', $linkText);
	    $linkText = str_replace('.', '.', $linkText);
	    $linkText = str_split($linkText, 5);  
	  
	    $part1 = '<a href="ma';
	    $part2 = 'ilto:';
	    $part3 = '" '. $attrs .' >';
	    $part4 = '</a>';  
	  
	    $encoded = '<script type="text/javascript">';
	    $encoded .= "document.write('$part1');";
	    $encoded .= "document.write('$part2');";
	    foreach($email as $e)
	    {
	            $encoded .= "document.write('$e');";
	    }
	    $encoded .= "document.write('$part3');";
	    foreach($linkText as $l)
	    {
	            $encoded .= "document.write('$l');";
	    }
	    $encoded .= "document.write('$part4');";
	    $encoded .= '</script>';  
	  
	    return $encoded;
	}
	
4. PHP验证邮件地址
电子邮件验证也许是中最常用的网页表单验证,此代码除了验证电子邮件地址,也可以选择检查邮件域所属 DNS 中的 MX 记录,使邮件验证功能更加强大。

	function is_valid_email($email, $test_mx = false)
	{
	    if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $email))
	        if($test_mx)
	        {
	            list($username, $domain) = split("@", $email);
	            return getmxrr($domain, $mxrecords);
	        }
	        else
	            return true;
	    else
	        return false;
	}
	
5. PHP列出目录内容
	function list_files($dir)
	{
	    if(is_dir($dir))
	    {
	        if($handle = opendir($dir))
	        {
	            while(($file = readdir($handle)) !== false)
	            {
	                if($file != "." && $file != ".." && $file != "Thumbs.db")
	                {
	                    echo '<a target="_blank" href="'.$dir.$file.'">'.$file.'</a><br>'."\n";
	                }
	            }
	            closedir($handle);
	        }
	    }
	}
	
6. PHP销毁目录
删除一个目录,包括它的内容。

	/*****
	*@dir - Directory to destroy
	*@virtual[optional]- whether a virtual directory
	*/
	function destroyDir($dir, $virtual = false)
	{
	    $ds = DIRECTORY_SEPARATOR;
	    $dir = $virtual ? realpath($dir) : $dir;
	    $dir = substr($dir, -1) == $ds ? substr($dir, 0, -1) : $dir;
	    if (is_dir($dir) && $handle = opendir($dir))
	    {
	        while ($file = readdir($handle))
	        {
	            if ($file == '.' || $file == '..')
	            {
	                continue;
	            }
	            elseif (is_dir($dir.$ds.$file))
	            {
	                destroyDir($dir.$ds.$file);
	            }
	            else
	            {
	                unlink($dir.$ds.$file);
	            }
	        }
	        closedir($handle);
	        rmdir($dir);
	        return true;
	    }
	    else
	    {
	        return false;
	    }
	}
7. PHP解析 JSON 数据
与大多数流行的 Web 服务如 twitter 通过开放 API 来提供数据一样,它总是能够知道如何解析 API 数据的各种传送格式,包括 JSON,XML 等等。

	$json_string='{"id":1,"name":"foo","email":"foo@foobar.com","interest":["wordpress","php"]} ';
	$obj=json_decode($json_string);
	echo $obj->name; //prints foo
	echo $obj->interest[1]; //prints php
	
8. PHP解析 XML 数据
	//xml string
	$xml_string="<?xml version='1.0'?>
	<users>
	<user id='398'>
	<name>Foo</name>
	<email>foo@bar.com</name>
	</user>
	<user id='867'>
	<name>Foobar</name>
	<email>foobar@foo.com</name>
	</user>
	</users>"; 
	  
	//load the xml string using simplexml
	$xml = simplexml_load_string($xml_string); 
	  
	//loop through the each node of user
	foreach ($xml->user as $user)
	{
	    //access attribute
	    echo $user['id'], ' ';
	    //subnodes are accessed by -> operator
	    echo $user->name, ' ';
	    echo $user->email, '<br />';
	}
	
9. PHP创建日志缩略名
创建用户友好的日志缩略名。

	function create_slug($string){
	    $slug=preg_replace('/[^A-Za-z0-9-]+/', '-', $string);
	    return $slug;
	}
	
10. PHP获取客户端真实 IP 地址
该函数将获取用户的真实 IP 地址,即便他使用代理服务器。

	function getRealIpAddr()
	{
	    if (!emptyempty($_SERVER['HTTP_CLIENT_IP']))
	    {
	        $ip=$_SERVER['HTTP_CLIENT_IP'];
	    }
	    elseif (!emptyempty($_SERVER['HTTP_X_FORWARDED_FOR']))
	    //to check ip is pass from proxy
	    {
	        $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
	    }
	    else
	    {
	        $ip=$_SERVER['REMOTE_ADDR'];
	    }
	    return $ip;
	}
	
11. PHP强制性文件下载
为用户提供强制性的文件下载功能。

	/********************
	*@file - path to file
	*/
	function force_download($file)
	{
	    if ((isset($file))&&(file_exists($file))) {
	        header("Content-length: ".filesize($file));
	        header('Content-Type: application/octet-stream');
	        header('Content-Disposition: attachment; filename="' . $file . '"');
	        readfile("$file");
	    }
	    else {
	        echo "No file selected";
	    }
	}
	
12. PHP创建标签云
	function getCloud( $data = array(), $minFontSize = 12, $maxFontSize = 30 )
	{
	    $minimumCount = min( array_values( $data ) );
	    $maximumCount = max( array_values( $data ) );
	    $spread = $maximumCount - $minimumCount;
	    $cloudHTML = '';
	    $cloudTags = array(); 
	      
	    $spread == 0 && $spread = 1; 
	      
	    foreach( $data as $tag => $count )
	    {
	        $size = $minFontSize + ( $count - $minimumCount )
	        * ( $maxFontSize - $minFontSize ) / $spread;
	        $cloudTags[] = '<a style="font-size: ' . floor( $size ) . 'px'
	        . '" href="#" title="\'' . $tag .
	        '\' returned a count of ' . $count . '">'
	        . htmlspecialchars( stripslashes( $tag ) ) . '</a>';
	    } 
	  
	    return join( "\n", $cloudTags ) . "\n";
	}
	/**************************
	**** Sample usage ***/
	$arr = Array('Actionscript' => 35, 'Adobe' => 22, 'Array' => 44, 'Background' => 43,
	'Blur' => 18, 'Canvas' => 33, 'Class' => 15, 'Color Palette' => 11, 'Crop' => 42,
	'Delimiter' => 13, 'Depth' => 34, 'Design' => 8, 'Encode' => 12, 'Encryption' => 30,
	'Extract' => 28, 'Filters' => 42);
	echo getCloud($arr, 12, 36);
	
13. PHP寻找两个字符串的相似性
PHP 提供了一个极少使用的 similar_text 函数,但此函数非常有用,用于比较两个字符串并返回相似程度的百分比。

	similar_text($string1, $string2, $percent);
	//$percent will have the percentage of similarity

14. PHP在应用程序中使用 Gravatar 通用头像
随着 WordPress 越来越普及,Gravatar 也随之流行。由于 Gravatar 提供了易于使用的 API,将其纳入应用程序也变得十分方便。

	/******************
	*@email - Email address to show gravatar for
	*@size - size of gravatar
	*@default - URL of default gravatar to use
	*@rating - rating of Gravatar(G, PG, R, X)
	*/
	function show_gravatar($email, $size, $default, $rating)
	{
	    echo '<img src="http://www.gravatar.com/avatar.php?gravatar_id='.md5($email).
	    '&default='.$default.'&size='.$size.'&rating='.$rating.'" width="'.$size.'px"
	    height="'.$size.'px" />';
	}

	
15. PHP在字符断点处截断文字
所谓断字 (word break),即一个单词可在转行时断开的地方。这一函数将在断字处截断字符串。

	// Original PHP code by Chirp Internet: www.chirp.com.au
	// Please acknowledge use of this code by including this header.
	function myTruncate($string, $limit, $break=".", $pad="...") {
	    // return with no change if string is shorter than $limit
	    if(strlen($string) <= $limit)
	    return $string; 
	      
	    // is $break present between $limit and the end of the string?
	    if(false !== ($breakpoint = strpos($string, $break, $limit))) {
	        if($breakpoint < strlen($string) - 1) {
	            $string = substr($string, 0, $breakpoint) . $pad;
	        }
	    }
	    return $string;
	}
	/***** Example ****/
	$short_string=myTruncate($long_string, 100, ' ');
	
	
16. PHP文件 Zip 压缩
	/* creates a compressed zip file */
	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;
	    }
	}
	/***** Example Usage ***/
	$files=array('file1.jpg', 'file2.jpg', 'file3.gif');
	create_zip($files, 'myzipfile.zip', true);
	
17. PHP解压缩 Zip 文件
	/**********************
	*@file - path to zip file
	*@destination - destination directory for unzipped files
	*/
	function unzip_file($file, $destination){
	    // create object
	    $zip = new ZipArchive() ;
	    // open archive
	    if ($zip->open($file) !== TRUE) {
	        die (’Could not open archive’);
	    }
	    // extract contents to destination directory
	    $zip->extractTo($destination);
	    // close archive
	    $zip->close();
	    echo 'Archive extracted to directory';
	}
	
18. PHP为 URL 地址预设 http 字符串
有时需要接受一些表单中的网址输入,但用户很少添加 http:// 字段,此代码将为网址添加该字段。

	if (!preg_match("/^(http|ftp):/", $_POST['url'])) {
	   $_POST['url'] = 'http://'.$_POST['url'];
	}
	
19. PHP将网址字符串转换成超级链接
该函数将 URL 和 E-mail 地址字符串转换为可点击的超级链接。

	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;
	}
	
	
20. PHP调整图像尺寸
创建图像缩略图需要许多时间,此代码将有助于了解缩略图的逻辑。

	/**********************
	*@filename - path to the image
	*@tmpname - temporary path to thumbnail
	*@xmax - max width
	*@ymax - max height
	*/
	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;
	}

21. PHP检测 ajax 请求
大多数的 JavaScript 框架如 jquery,Mootools 等,在发出 Ajax 请求时,都会发送额外的 HTTP_X_REQUESTED_WITH 头部信息,头当他们一个ajax请求,因此你可以在服务器端侦测到 Ajax 请求。

	if(!emptyempty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest'){
	    //If AJAX Request Then
	}else{
	//something else

	
22. 关键词高亮
	function highlight($sString, $aWords) {
	    if (!is_array ($aWords) || emptyempty ($aWords) || !is_string ($sString)) {
	        return false;
	    }
	  
	    $sWords = implode ('|', $aWords);
	    return preg_replace ('@\b('.$sWords.')\b@si', '<strong style="background-color:yellow">$1</strong>', $sString);
	}

23. 获取你的Feedburner的用户
	function get_average_readers($feed_id,$interval = 7){
	    $today = date('Y-m-d', strtotime("now"));
	    $ago = date('Y-m-d', strtotime("-".$interval." days"));
	    $feed_url="https://feedburner.google.com/api/awareness/1.0/GetFeedData?uri=".$feed_id."&dates=".$ago.",".$today;
	    $ch = curl_init();
	    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	    curl_setopt($ch, CURLOPT_URL, $feed_url);
	    $data = curl_exec($ch);
	    curl_close($ch);
	    $xml = new SimpleXMLElement($data);
	    $fb = $xml->feed->entry['circulation'];
	  
	    $nb = 0;
	    foreach($xml->feed->children() as $circ){
	        $nb += $circ['circulation'];
	    }
	  
	    return round($nb/$interval);
	}

24. 自动生成密码
	function generatePassword($length=9, $strength=0) {
	    $vowels = 'aeuy';
	    $consonants = 'bdghjmnpqrstvz';
	    if ($strength >= 1) {
	        $consonants .= 'BDGHJLMNPQRSTVWXZ';
	    }
	    if ($strength >= 2) {
	        $vowels .= "AEUY";
	    }
	    if ($strength >= 4) {
	        $consonants .= '23456789';
	    }
	    if ($strength >= 8 ) {
	        $vowels .= '@#$%';
	    }
	  
	    $password = '';
	    $alt = time() % 2;
	    for ($i = 0; $i < $length; $i++) {
	        if ($alt == 1) {
	            $password .= $consonants[(rand() % strlen($consonants))];
	            $alt = 0;
	        } else {
	            $password .= $vowels[(rand() % strlen($vowels))];
	            $alt = 1;
	        }
	    }
	    return $password;
	}

25. 压缩多个CSS文件
	header('Content-type: text/css');
	ob_start("compress");
	function compress($buffer) {
	  /* remove comments */
	  $buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);
	  /* remove tabs, spaces, newlines, etc. */
	  $buffer = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $buffer);
	  return $buffer;
	}
	  
	/* your css files */
	include('master.css');
	include('typography.css');
	include('grid.css');
	include('print.css');
	include('handheld.css');
	  
	ob_end_flush();

26. 获取短网址
	function getTinyUrl($url) {
	    return file_get_contents("http://tinyurl.com/api-create.php?url=".$url);
	}

27. 根据生日计算年龄
	function age($date){
	    $year_diff = '';
	    $time = strtotime($date);
	    if(FALSE === $time){
	        return '';
	    }
	  
	    $date = date('Y-m-d', $time);
	    list($year,$month,$day) = explode("-",$date);
	    $year_diff = date("Y") – $year;
	    $month_diff = date("m") – $month;
	    $day_diff = date("d") – $day;
	    if ($day_diff < 0 || $month_diff < 0) $year_diff–;
	  
	    return $year_diff;
	}

28. 计算执行时间
	//Create a variable for start time
	$time_start = microtime(true);
	  
	// Place your PHP/HTML/JavaScript/CSS/Etc. Here
	  
	//Create a variable for end time
	$time_end = microtime(true);
	//Subtract the two times to get seconds
	$time = $time_end - $time_start;
	  
	echo 'Script took '.$time.' seconds to execute';

29. PHP的维护模式
	function maintenance($mode = FALSE){
	    if($mode){
	        if(basename($_SERVER['SCRIPT_FILENAME']) != 'maintenance.php'){
	            header("Location: http://example.com/maintenance.php");
	            exit;
	        }
	    }else{
	        if(basename($_SERVER['SCRIPT_FILENAME']) == 'maintenance.php'){
	            header("Location: http://example.com/");
	            exit;
	        }
	    }
	}

30. 阻止CSS样式被缓存
<link href="/stylesheet.css?<?php echo time(); ?>" rel="stylesheet" type="text/css" /&glt;

31. 为数字增加 st\nd\rd 等
	function make_ranked($rank) {
	    $last = substr( $rank, -1 );
	    $seclast = substr( $rank, -2, -1 );
	    if( $last > 3 || $last == 0 ) $ext = 'th';
	    else if( $last == 3 ) $ext = 'rd';
	    else if( $last == 2 ) $ext = 'nd';
	    else $ext = 'st'; 
	  
	    if( $last == 1 && $seclast == 1) $ext = 'th';
	    if( $last == 2 && $seclast == 1) $ext = 'th';
	    if( $last == 3 && $seclast == 1) $ext = 'th'; 
	  
	    return $rank.$ext;
	}

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