REST client library using CodeIgniter

Using REST in applications makes life easier to some extent. And using REST in codeigniter can be easier. There exist some REST libraries in codeigniter but somehow they seem to have lots of code and features which is not required in my case. I'm not degrading existing codeigniter REST libraries, they are excellent codes
developed by experts, but i wanted a simple REST client using Codeigniter, so thought of coding my own.
Following is the code for REST client library in codeIgniter, that suits simple needs.

 
class Rest_Lib {
 
 private $useCurl;
 private $userAgent = "Rest";
 
 /*
  * constructor function
  */
 function Rest_Lib() {
     //check if curl function exists
     if(function_exists('curl_init')) {
  $this->useCurl = TRUE;   
     }
     else {
  $this->useCurl = FALSE;
     }
 }
 
 /*
  * GET method
  * @param string $url : this is the service url
  * @param array $arr: this is the key value
  * @return string : resulting response of GET method
  */
 public function get($url, $arr) {
     $str = '?';
     if(is_array($arr)) {
  foreach($arr as $key => $value) {
   $str .= urlencode($key) . '=' . urlencode($value) . '&';
  }
     }
     else {
  $str .= $arr;
     }
     $url .= $str;
     if($this->useCurl) {
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_HTTPGET, TRUE);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
  $response = curl_exec($ch);
  curl_close($ch);
     } 
     else {
  $options = array(
  'http' => array(
         'method' => 'GET',
  'header' => 'User-Agent:' . $this->userAgent . '\r\n' 
  )
  );
  //create and return stream context with options
  $streamContext = stream_context_create($options);
  $fh = file_open($url, 'r', FALSE, $streamContext);
  $response = fpassthru($fh);
  fclose($fh);
     } 
     return $response;
 }
 
 /*
  * POST method
  * @param string: $url: service url
  * @param string $postData: request data
  * @return response
  */
 public function post($url, $postData) {
  if($this->useCurl) {
   $curlHeaders = array(
    'Content-Type: application/x-www-form-urlencoded'
   );
   $ch = curl_init();
   curl_setopt($ch, CURLOPT_HTTPHEADER, $curlHeaders);
   curl_setopt($ch, CURLOPT_URL, $url);
   curl_setopt($ch, CURLOPT_POST, TRUE);
   curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
   curl_setopt($ch, CURLOPT_USERAGENT, $this->userAgent);
   $response = curl_exec($ch);
   curl_close($ch);
  }
  else {
   $options = array(
    'http' => array(
     'method' => 'POST',
     'header' => 'User-Agent: ' . $this->userAgent . '\r\n',
     'Content-Type: application/x-www-form-urlencoded' . '\r\n',
     'Content-Length: ' . strlen($postData) . '\r\n',
     'Content' => $postData
    )
   );
   $streamContext = stream_context_create($options);
   $fh = file_open($url, 'r', FALSE, $streamContext);
   $response = fpassthru($fh);
   fclose($fh);
  }
  return $response;
 }
 
 /*
  * PUT method
  * 
  */
 public function put($url, $putData) {
  if($this->useCurl) {
   $fh = fopen('php://memory', 'rw');
   fwrite($fh, $putData);
   rewind($fh);
   
   $ch = curl_init();
   curl_setopt($ch, CURLOPT_USERAGENT, $this->userAgent);
   curl_setopt($ch, CURLOPT_INFILE, $fh);
   curl_setopt($ch, CURLOPT_INFILESIZE, strlen($putData));
   curl_setopt($ch, CURLOPT_TIMEOUT, 10);
   curl_setopt($ch, CURLOPT_PUT, TRUE);
   curl_setopt($ch, CURLOPT_URL, $url);
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
   $response = curl_exec($ch);
   curl_close($ch);
   fclose($fh);
  }
  else {
   $options = array(
    'http' => array(
     'method' => 'PUT',
     'header' => 'User-Agent: ' . $this->userAgent . '\r\n',
     'Content-Type: application/x-www-form-urlencoded' . '\r\n',
     'Content-Length: ' . strlen($putData) . '\r\n',
     'Content' => $putData 
    )
   );
   $context = stream_context_create();
   $fh = file_open($url, 'r', FALSE, $context);
   $response = fpassthru($fh);
   fclose($fh);
  }
  return $response;
 }
 
 /*
  * DELETE method
  */
 public function delete($url, $arr) {
  $str = '?';
  if(is_array($arr)) {
   foreach($arr as $key => $value) {
    $str .= urlencode($key) . '=' . urlencode($value) . '&';
   }
  }
  else {
   $str .= $arr;
  }
  $url .= $str;
  if($this->useCurl) {
   $ch = curl_init();
   curl_setopt($ch, CURLOPT_URL, $url);
   curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'delete');
   curl_setopt($ch, CURLOPT_USERAGENT, $this->userAgent);
   $response = curl_exec($ch);
   curl_close($ch);
  }
  else {
   $options = array(
    'http' => array(
     'method' => 'DELETE',
     'header' => 'User-Agent: ' . $this->userAgent . '\r\n'
    )
   );
   $context = stream_context_create($options);
   $fh = file_open($url, 'r', FALSE, $context);
   $response = fpassthru($fh);
   fclose($fh);
  }
  return TRUE;
 }
}
?>