[SOLVED] Code Explanation

[coop]

Hi all,

 

Still new to PHP, but with a ActionScript background - I'm trying to run through this class which is for IPN with Paypal. I sort of get the idea but I'm trying to get a better understanding, could anyone explain this code. I know it's a big ask but any help would br greatly appreciated.

 

<?php
class paypal_ipn{
var $paypal_post_vars;
var $paypal_response;
var $timeout;
var $error_email;
function paypal_ipn($paypal_post_vars) {
	$this->paypal_post_vars = $paypal_post_vars;
	$this->timeout = 120;
}
function send_response(){
	$fp = @fsockopen( "www.paypal.com", 80, &$errno, &$errstr, 120 ); 
	if (!$fp) { 
		$this->error_out("PHP fsockopen() error: " . $errstr , "");
	} else {
		foreach($this->paypal_post_vars AS $key => $value) {
			if (@get_magic_quotes_gpc()) {
				$value = stripslashes($value);
			}
			$values[] = "$key" . "=" . urlencode($value);
		}
		$response = @implode("&", $values);
		$response .= "&cmd=_notify-validate";
		fputs( $fp, "POST /cgi-bin/webscr HTTP/1.0\r\n" ); 
		fputs( $fp, "Content-type: application/x-www-form-urlencoded\r\n" ); 
		fputs( $fp, "Content-length: " . strlen($response) . "\r\n\n" ); 
		fputs( $fp, "$response\n\r" ); 
		fputs( $fp, "\r\n" );
		$this->send_time = time();
		$this->paypal_response = ""; 
		// get response from paypal
		while (!feof($fp)) { 
			$this->paypal_response .= fgets( $fp, 1024 ); 
			if ($this->send_time < time() - $this->timeout) {
				$this->error_out("Timed out waiting for a response from PayPal. ($this->timeout seconds)" , "");
			}
		}
		fclose( $fp );
	}
}
function is_verified() {
	if( ereg("VERIFIED", $this->paypal_response) )
		return true;
	else
		return false;
} 
function get_payment_status() {
	return $this->paypal_post_vars['payment_status'];
}
function error_out($message, $em_headers){
	$date = date("D M j G:i:s T Y", time());
	$message .= "\n\nThe following data was received from PayPal:\n\n";
	@reset($this->paypal_post_vars);
	while( @list($key,$value) = @each($this->paypal_post_vars)) {
		$message .= $key . ':' . " \t$value\n";
	}
	mail($this->error_email, "[$date] paypay_ipn notification", $message, $em_headers);
}
} 
?>

[obsidian]

OK, I'll try to make this clear. I'll comment each section and/or function for you:

<?php
class paypal_ipn{
var $paypal_post_vars;
var $paypal_response;
var $timeout;
var $error_email;

// This is your constructor, when it runs, you pass in the values that you have
// received from paypal as an array.
function paypal_ipn($paypal_post_vars) {
	// Assign the array passed in to the member variable
	$this->paypal_post_vars = $paypal_post_vars;

	// Set the execution timeout
	$this->timeout = 120;
}

// Function that sends a response to alert paypal as to whether or not you
// received a successful data transmission
function send_response(){
	// Open a connection to paypal
	$fp = @fsockopen( "www.paypal.com", 80, &$errno, &$errstr, 120 ); 

	if (!$fp) { 
		// Connection to paypal failed
		$this->error_out("PHP fsockopen() error: " . $errstr , "");
	} else {
	  // Connection successful, loop through all your paypal variables and create
		// a query string to pass as a response
		foreach($this->paypal_post_vars AS $key => $value) {
			if (@get_magic_quotes_gpc()) {
				// Clean the values
				$value = stripslashes($value);
			}
			$values[] = "$key" . "=" . urlencode($value);
		}
		// Create a URL readable string
		$response = @implode("&", $values);

		// Add the command "_notify-validate" to pass to paypal
		$response .= "&cmd=_notify-validate";

		// POST the result string you have created to the paypal page
		fputs( $fp, "POST /cgi-bin/webscr HTTP/1.0\r\n" ); 
		fputs( $fp, "Content-type: application/x-www-form-urlencoded\r\n" ); 
		fputs( $fp, "Content-length: " . strlen($response) . "\r\n\n" ); 
		fputs( $fp, "$response\n\r" ); 
		fputs( $fp, "\r\n" );

		// Record the time of your transmission
		$this->send_time = time();

		// Clear the paypal response variable in preparation for receiving an answer
		$this->paypal_response = ""; 

		// get response from paypal
		while (!feof($fp)) { 
			$this->paypal_response .= fgets( $fp, 1024 ); 
			if ($this->send_time < time() - $this->timeout) {
				// If you have been waiting for more than your timeout time, throw an error
				$this->error_out("Timed out waiting for a response from PayPal. ($this->timeout seconds)" , "");
			}
		}

		// Close your file connection to paypal
		fclose( $fp );
	}
}

// Function simply returns a boolean value TRUE if the paypal response was
// successful, FALSE otherwise
function is_verified() {
	if( ereg("VERIFIED", $this->paypal_response) )
		return true;
	else
		return false;
} 

// Returns the payment status that was in the initial POST vars
function get_payment_status() {
	return $this->paypal_post_vars['payment_status'];
}

// This function handles all the errors for you
function error_out($message, $em_headers){
	// Current date
	$date = date("D M j G:i:s T Y", time());
	$message .= "\n\nThe following data was received from PayPal:\n\n";
	// Reset member variables since you had an error
	@reset($this->paypal_post_vars);
	// Display all the values that were in the POST vars
	while( @list($key,$value) = @each($this->paypal_post_vars)) {
		$message .= $key . ':' . " \t$value\n";
	}
	// Email the error to the provided error email
	mail($this->error_email, "[$date] paypay_ipn notification", $message, $em_headers);
}
} 
?>

 

Does this help?

[coop]

Thanks obsidian, thats a great help