再来二十一段救命的PHP代码_PHP教程
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
{
$password.=$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
$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 = '';
$part4 = '';
$encoded = '
$encoded .= "document.write('$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 .= '';
return $encoded;
}
4. PHP验证邮件地址 www.2cto.com
电子邮件验证也许是中最常用的网页表单验证，此代码除了验证电子邮件地址，也可以选择检查邮件域所属DNS 中的MX 记录，使邮件验证功能更加强大。
function is_valid_email($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":"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="
";
//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[] = ''
. htmlspecialchars( stripslashes( $tag ) ) . '';
}
return join( "\n", $cloudTags ) . "\n";
}
/**************************
**** Sample usage ***/
$arr = Array('Actionscript' => 35, 'Adobe' => 22, 'Array' => 44, 'Background' => 43,
'Blur' => 18, 'Canvas' => 33, 'Class' => 15, 'Color Palette' => 11, 'Crop' => 42,
'Delimiter' => 13, 'Depth' => 34, 'Design' => 8, 'Encode' => 12, 'Encryption' => 30,
'Extract' => 28, 'Filters' => 42);
echo getCloud($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, $rating)
{
echo '
height="'.$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。
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@:%_+.~#?&//=]+)',
'\1', $text);
$text = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_+.~#?&//=]+)',
'\1\2', $text);
$text = eregi_replace('([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})',
'\1', $text);
return $text;
} 20. PHP调整图像尺寸
创建图像缩略图需要许多时间，此代码将有助于了解缩略图的逻辑。
/**********************
*@filename - path to the image
*@tmpname - temporary path to thumbnail
*@xmax - max width
*@ymax - max height
*/
function resize_image($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
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
}
摘自 周飞甫的博客