Friday, January 25, 2013

21 Really Useful & Handy PHP Code Snippets

PHP Code Snippets

Contents

  1. Human Readable Random String
  2. Generate a Random String
  3. Encode Email Address
  4. Validate email Address
  5. List Directory Contents
  6. Destroy Directory
  7. Parse JSON Data
  8. Parse XML Data
  9. Create Post Slugs
  10. Get Real IP Address of Client
  11. Force file Download
  12. Creating a Tag Cloud
  13. Find Similarity Between Two Strings
  14. Use Gravatars in Your Application
  15. Truncate Text at Word Break
  16. Zip Files on the Fly
  17. Unzip Zip File
  18. Prepend http to a URL
  19. Convert URLs within String into hyperlinks
  20. Resize Images on the fly
  21. Detect AJAX Request

Human Readable Random String

This code will create a human readable string that will look more close to dictionary words, useful for captchas.

/**************
*@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;
}

Generate a Random String

If you don't need human readable string, then use this function instead, which will create a random string you can use for user id's etc.

/*************
*@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;
 }

Encode Email Address

With this snippet, you can encode any email address into HTML entities so that spam bots do not find it.

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 = '';

    $encoded = '';

    return $encoded;
}

Validate email Address

E-mail validation is perhaps the most used validation in web forms, this code will validate email address and also optionally check the MX records of the domain provided in email address to make email validation more robust.

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;
}

List Directory Contents

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); } } }

Destroy Directory

Delete a directory including its contents.

/*****
*@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;
    }
}

Parse JSON Data

With most of the popular web services like Twitter providing their data through APIs, it is always helpful to know how to parse API data which is sent in various formats including JSON, XML etc.

$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


Parse XML Data

//xml string
$xml_string="

   
      Foo
      foo@bar.com
   
   
      Foobar
      foobar@foo.com
   
";

//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, '
'; }

Create Post Slugs

Create user friendly post slugs from title string to use within URLs.

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


Get Real IP Address of Client

This function will fetch the real IP address of the user even if he is behind a proxy server.

function getRealIpAddr()
{
    if (!empty($_SERVER['HTTP_CLIENT_IP']))
    {
        $ip=$_SERVER['HTTP_CLIENT_IP'];
    }
    elseif (!empty($_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;
}

Force file Download

Provide files to the user by forcing them to download.

/********************
*@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";
    }
}

Creating a Tag Cloud

function getCloud( $data = array(), $minFontSize = 12, $maxFontSize = 30 )
{
    $minimumCount = min($data);
    $maximumCount = max($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' 
        . '" class="tag_cloud" 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);

Find Similarity Between Two Strings

PHP includes a function similar_text very rarely used but quite useful that compares two strings and returns the percentage of similarity between two.

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

Use Gravatars in Your Application

With ever increasing popularity of WordPress, Gravatars have become quite popular. It is very easy to integrate them into your application as they provide a very easy to use API.

/******************
*@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" />';
}

Truncate Text at Word Break

This function will truncate strings only at word breaks which can be used to show a teaser for complete article without breaking words.

// 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, ' ');

Zip Files on the Fly

/* 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);

Source: David Walsh

Unzip Zip File

/**********************
*@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 (Ć¢€™Could not open archiveĆ¢€™);
    }
    // extract contents to destination directory
    $zip->extractTo($destination);
    // close archive
    $zip->close();
    echo 'Archive extracted to directory';
}

Prepend http to a URL

Some times you need to accept some url as input but users seldom add http:// to it, this code will add http:// to the URL if it’s not there.

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

Convert URLs within String into hyperlinks

This function converts URLs and e-mail addresses within a string into clickable hyperlinks.

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;
}

Resize Images on the fly

Creating thumbnails of the images is required many a times, this code will be useful to know about the logic of thumbnail generation.

/**********************
*@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; 
}

Detect AJAX Request

Most of the JavaScript frameworks like jQuery, mootools send and additional HTTP_X_REQUESTED_WITH header when they make an AJAX request, so that you can detect AJAX request on server side (source).

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