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

}