21个常用的 PHP 代码汇总

PHP 是目前使用最广泛的基于 Web 的编程语言,驱动着数以百万计的网站,其中也包括如 Facebook 等一些大型站点。这里收集了 21个日常开发中实用便捷的 PHP 代码,希望可以对一些 PHP 开发者都会有所帮助。

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='info@domain.com', $linkText='Contact Us', $attrs ='class="emailencoder"' )
{
    // remplazar aroba y puntos
    $email = str_replace('@', '&#64;', $email);
    $email = str_replace('.', '&#46;', $email);
    $email = str_split($email, 5);  

    $linkText = str_replace('@', '&#64;', $linkText);
    $linkText = str_replace('.', '&#46;', $linkText);
    $linkText = str_split($linkText, 5);  

    $part1 = '[';
    $part4 = '](ma)';  

    $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 != ".." && $file != "Thumbs.db")
                {
                    echo '['.$file.']()
'."\n";
                }
            }
            closedir($handle);
        }
    }
}

6. 删除目录

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":"foo@foobar.com","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>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, '
';
}

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[] = '['
        . 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. 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 '![](http://www.gravatar.com/avatar.php?gravatar_id=)';
}

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@:%_+.~#?&//=]+)',
 '[\1](\1)', $text);
 $text = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_+.~#?&//=]+)',
 '\1[\2](http://\2)', $text);
 $text = eregi_replace('([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})',
 '[\1](mailto:\1)', $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
}

英文原稿:21 Really Useful & Handy PHP Code Snippets
翻译整理:21个常用的 PHP 代码汇总 | 断桥残雪部落格