21个实用便利的PHP代码

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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. 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:';      $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 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='.$rating.'" width="'.$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  }

来源：python脚本自动迁移