PHP 实用代码收集

1. 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. 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. 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 = '<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. 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. 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. 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. 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. 解析 XML 数据

//xml string 
$xml_string="<?xml version='1.0'?> 
<users> 
<user id='398'> 
<name>Foo</name> 
<email>[e-mail]</name> 
</user> 
<user id='867'> 
<name>Foobar</name> 
<email>[e-mail]</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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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 
}