实用PHP代码二十一个实例

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='[email protected]', $linkText='Contact Us', $attrs ='class="emailencoder"' ) {     // remplazar aroba y puntos     $email = str_replace('@', '&#64;', $email);     $email = str_replace('.', '&#46;', $email);     $email = str_split($email, 5);      $linkText = str_replace('@', '&#64;', $linkText);     $linkText = str_replace('.', '&#46;', $linkText);     $linkText = str_split($linkText, 5);      $part1 = '<a href="ma';     $part2 = 'ilto&#58;';     $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":"[email protected]","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>[email protected]</name> </user> <user id='867'> <name>Foobar</name> <email>[email protected]</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, $rating) { echo '<img src=\'#\'" //www.gravatar.com/avatar.php?gravatar_id='.md5($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 }

英文原稿：21 Really Useful & Handy PHP Code Snippets | Web Developer Plus

翻译整理：21+ 实用便捷的 PHP 代码摘录 | 芒果