常用PHP代码小结

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

/************* 

*@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&#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":"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 func">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='.$rating.'"  style="max-width:90%".$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 

}