常用的函數

　1. PHP可閱讀隨機字符串

　　此代碼將創建一個可閱讀的字符串，使其更接近詞典中的單詞，實用且具有密碼驗證功能。

/**************
*@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生成一個隨機字符串

　　如果不需要可閱讀的字符串，使用此函數替代，即可創建一個隨機字符串，作爲用戶的隨機密碼等。

/*************
*@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編碼電子郵件地址

　　使用此代碼，可以將任何電子郵件地址編碼爲 html 字符實體，以防止被垃圾郵件程序收集。

function encode_email($email='[email protected]', $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驗證郵件地址

　　電子郵件驗證也許是中最常用的網頁表單驗證，此代碼除了驗證電子郵件地址，也可以選擇檢查郵件域所屬 DNS 中的 MX 記錄，使郵件驗證功能更加強大。

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列出目錄內容

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銷燬目錄

　　刪除一個目錄，包括它的內容。

/*****
*@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 數據

　　與大多數流行的 Web 服務如 twitter 通過開放 API 來提供數據一樣，它總是能夠知道如何解析 API 數據的各種傳送格式，包括 JSON，XML 等等。

$json_string='{"id":1,"name":"foo","email":"[email protected]","interest":["wordpress","php"]} ';
$obj=json_decode($json_string);
echo $obj->name; //prints foo
echo $obj->interest[1]; //prints php

 

 

　　8. PHP解析 XML 數據

//xml string
$xml_string="<?xml version='1.0'?>
<users>
<user id='398'>
<name>Foo</name>
<email>[email protected]</name>
</user>
<user id='867'>
<name>Foobar</name>
<email>[email protected]</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創建日誌縮略名

　　創建用戶友好的日誌縮略名。

function create_slug($string){
$slug=preg_replace('/[^A-Za-z0-9-]+/', '-', $string);
return $slug;
}

 

 

　　10. PHP獲取客戶端真實 IP 地址

　　該函數將獲取用戶的真實 IP 地址，即便他使用代理服務器。

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強制性文件下載

　　爲用戶提供強制性的文件下載功能。

/********************
*@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創建標籤雲

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. PHP尋找兩個字符串的相似性

　　PHP 提供了一個極少使用的 similar_text 函數，但此函數非常有用，用於比較兩個字符串並返回相似程度的百分比。

similar_text($string1, $string2, $percent);
//$percent will have the percentage of similarity

 

 

　　14. PHP在應用程序中使用 Gravatar 通用頭像

　　隨着 WordPress 越來越普及，Gravatar 也隨之流行。由於 Gravatar 提供了易於使用的 API，將其納入應用程序也變得十分方便。

/******************
*@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. PHP在字符斷點處截斷文字

　　所謂斷字 (word break)，即一個單詞可在轉行時斷開的地方。這一函數將在斷字處截斷字符串。

// 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 壓縮

/* 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解壓縮 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爲 URL 地址預設 http 字符串

 

　　有時需要接受一些表單中的網址輸入，但用戶很少添加 http:// 字段，此代碼將爲網址添加該字段。

if (!preg_match("/^(http|ftp):/", $_POST['url'])) {
   $_POST['url'] = 'http://'.$_POST['url'];
}

 

 

 

　　19. PHP將網址字符串轉換成超級鏈接

　　該函數將 URL 和 E-mail 地址字符串轉換爲可點擊的超級鏈接。

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調整圖像尺寸

　　創建圖像縮略圖需要許多時間，此代碼將有助於瞭解縮略圖的邏輯。

/**********************
*@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檢測 ajax 請求

　　大多數的 JavaScript 框架如 jquery，Mootools 等，在發出 Ajax 請求時，都會發送額外的 HTTP_X_REQUESTED_WITH 頭部信息，頭當他們一個ajax請求，因此你可以在服務器端偵測到 Ajax 請求。

if(!emptyempty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest'){
    //If AJAX Request Then
}else{
//something else
}