21个常用的PHP函数代码段

PHP开源脚本语言

PHP(外文名: Hypertext Preprocessor，中文名：“超文本预处理器”)是一种通用开源脚本语言。语法吸收了C语言、Java和Perl的特点，入门门槛较低，易于学习，使用广泛，主要适用于Web开发领域。PHP的文件后缀名为php。

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=’[e-mail]’, $linkText=’Contact Us’,$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); $part1 = ‘$part2 = ‘ilto:’; $part3 = ‘” ‘. $attrs .’ >’; $part4 = ‘’; $encoded = ‘’; 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 != “..” && $file != “Thumbs.db”) { echo ‘’.$file.’ ’.”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”:”[e-mail]”,”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=” Foo [e-mail] Foobar [e-mail] ”; //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 $user->email, ‘ ’; } 9. PHP创建日志缩略名 创建用户友好的日志缩略名。 function create_slug($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[] = ‘. ‘” href=”#” title=”” . $tag . ‘’ returned a count of ‘ . $count . ‘”>’ . htmlspecialchars( stripslashes( $tag ) ) . ‘’; } return join( “n”, $cloudTags ) . “n”; }/************************** **** Sample usage ***/ $arr = Array(‘Actionscript’ => 35, ‘Adobe’ => 22, ‘Array’ => 44, ‘Background’ => 43, ‘Blur’ => 18, ‘Canvas’ => 33, ‘Class’ => 15, ‘Color Palette’ => 11, ‘Crop’ => 42, ‘Delimiter’ => 13, ‘Depth’ => 34, ‘Design’ => 8, ‘Encode’ => 12, ‘Encryption’ => 30, ‘Extract’ => 28, ‘Filters’ => 42); echogetCloud($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, $rating) { echo‘‘&default=’.$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. functionmyTruncate($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 = ”,$overwrite = false) { //if the zip file already exists and overwrite is false, return falseif(file_exists($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) { returnfalse; } //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! $zip->close(); //check to make sure the file exists returnfile_exists($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@:%_+.~#?&//=]+)’, ‘1’, $text); $text = eregi_replace(‘([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_+.~#?&//=]+)’, ‘12’, $text); $text = eregi_replace(‘([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})’, ‘1’, $text); return $text; } 20. PHP调整图像尺寸 创建图像缩略图需要许多时间，此代码将有助于了解缩略图的逻辑。 /********************** *@filename – path to the image *@tmpname – temporary path to thumbnail *@xmax – max width *@ymax – max height */ functionresize_image($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 }