Caching in PHP

The term Caching refers to storing of data for later usage. Commonly used data can be cached it can be accessed faster and caching in PHP can be easier task as well, if you know what you are doing. Following code snippet demonstrates File Caching in php in which data is written to the file by caching process.

 class CacheFile {
  protected $fPointer;
  protected $fileName;
  protected $expirationTime;
  protected $tempFileName;
  
  //constructor function
  //pass in the filename along with optional expiration
  public function __construct($fileName, $expiration = false) {
   $this->fileName = $fileName;
   $this->expirationTime = $expiration;
   $this->tempFileName = "$filename.".getmypid();
  }
  
  public function get() {
   //check for expiration  and return contents of cache file
   if($this->expirationTime) {
    //get the file status
    $status = @stat($this->fileName);
    if($status[9]) {
     //check the filetime
     if(($modified + $this->expirationTime) < time()) {
      @unlink($this->fileName);
      return false;
     }
    }
   }
   return file_get_contents($this->fileName);
  }
  
  public function put($fileBuffer) {
   if(($this->fPointer == fopen($this->tempFileName, 'w')) == false) {
    return false;
   }
   fwrite($this->fPointer, $fileBuffer);
   fclose($this->fPointer);
   rename($this->tempFileName, $this->fileName);
   return true;
  }
  
  //remove the cache file
  public function remove() {
   @unlink($this->fileName);
  }
  
  //start the caching process
  public function startOutputBuffer() {
   if(($this->fPointer = fopen($this->tempFileName, 'w')) == false) {
    return false;
   }
   ob_start();
  }
  
  //end the caching process
  public function endOutputBuffer() {
   //get the output bufer contents
   $bufferContents = ob_get_contents();
   ob_end_flush();
   if(strlen($bufferContents)) {
    fwrite($this->fPointer, $bufferContents);
    fclose($this->fPointer);
    rename($this->tempFileName, $this->fileName);
    return true;
   }
   else {
    fclose($this->fPointer);
    @unlink($this->tempFileName);
    return false;
   }
  }
 }
?>

And the File Cache class cane be used as follows:

   require_once('CacheFile.php');
  $cacheData = CacheFile($pathToCacheFile);
  //check if the string exists in cache
  if($string = $cacheData->get()) {
   var_dump($string);
  }
  else {
   //start caching process
   $cacheData->startOutputBuffer();
 ?>
   //your page data included here
    $cacheData->endOutputBuffer();
  }
 ?>

In this way we can implement Caching in php.

Get all files inside a directory using php

Listing of files inside a directory can be done simply using php.
Following function can be used to list all the files inside a directory.

function list_directory($dirpath) {
 $files = array(); //files array
 $dirs = array(); //directories array
 $file_num = 0;  //set number of files to 0
 $dir_num = 0;  //set number of directories to 0
 //check if the path is a directory
 if (is_dir($dirpath)) { 
  //create a handle for opening directory
  $hndl = opendir($dirpath);
  //start the loop
  do {
   //read the directory
   $fle = readdir($hndl);
   if ($fle !== FALSE && $fle != "." && $fle != "..") {
    //check if its a directory or a file
    if (is_dir("$dirpath/$fle")) $dirs[$dir_num++] = $fle;
    else $files[$file_num++] = $fle;
   }
  } while($fle !== FALSE);
  closedir($hndl);
 }
 return array($dir_num, $file_num, $dirs, $files);
}

Get path of a file in PHP

Once i have to get location of a file using a single line of code in php. Here's how i did it.

$filePath = substr($_SERVER["SCRIPT_FILENAME"], 0, strrpos($_SERVER["SCRIPT_FILENAME"], "/"));
    echo $filePath;  // this gives the full file path

Hope it helps someone.

Get only the path for a file

Sometimes it is required the get only the path that a file exists. In such cases following function could be of some help. I
hope this function helps someone like me

     function getPath($path) {
         if(substr($path, -1, 1) == '/') {
             return $path;
         }
         else {
             $pathArr = explode('/', $path);
             $total = count($pathArr);
             $end = $pathArr[$total - 1];
             if(substr_count($end, '.') > 0) {
                 array_pop($pathArr);
             }
             $finalPath = implode('/', $pathArr);
             return $finalPath;
         }
     }
?>

Access folder inside nested folders in PHP

//Access nested folders contents using PHP
<?php
function getDir($id=0,$maxLvl=20){
  $id1=$id;
  $id=str_pad($id,$maxLvl,0,STR_PAD_LEFT);
  $dir=NULL;
  for($i=0;$i<$maxLvl-2;$i=$i+2){
  $dir.=substr($id,$i,2)."/";
  $dir1=substr($id,$i,2);
  if(!file_exists($dir1))
     mkdir($dir1);
  chdir($dir1);
  }
if(!file_exists($id1))

mkdir($id1);

return $dir.$id1; 
}
?>

Create nested folders using PHP

Create maximum levels of nested folders using PHP
<?php
   function getWDir($id=0,$maxLvl=20){
       $id1=$id;
       //add 0 to the left
       $id=str_pad($id,$maxLvl,0,STR_PAD_LEFT);
       $dir=NULL;
       for($i=0;$i<$maxLvl-2;$i=$i+2){
           //get the sub-strings for generating multiple folders
           $dir.=substr($id,$i,2)."/";
           $dir1=substr($id,$i,2);
       }
   return $dir;
   }
?>

File extension in PHP

For getting file extension, simply this can be done:
$fileName = "SampleOne.jpg";
$fileExtension = array_pop(explode(".", $fileName));