Paypal's IPN, PDT and how it all comes together....

[tlflow]

I've been reading some of the other posts on this subject, and I can tell already that this project is going to be FUN.  We want to do something like this, but I'm just trying to wrap my mind around how to do it. 

 

Question 1) For all the other posts I think the flow has been like this:

• Step1- customer enters info
  
• Step 2- info is written to database
  
• Step 3- paypal processes request
  
• Step 4- sends thank you
  

 

but, I was wondering...what happens if the order doesnt go through?  So, shouldnt it be like this:

 

• Step1- customer enters info
  
• Step 2- paypal processes request
  
• Step 3- info is written to database
  
• Step 4- sends thank you
  

 

This is really just a matter of what's best - by theory...like I said, I'm trying to figure this out before I really get going.

 

Question 2) I tried just using Paypal's code, putting my token in, but I'm not getting any variables posted back after the transaction goes through (except for the merchant_return_link).  At least I get that, so I'm optimistic...but I'm missing all the other variables (first_name, last_name, etc...).

 

<?php

                // Check to see if variables are at least coming over
                var_dump($_POST,$_GET);
                
                // read the post from PayPal system and add 'cmd'
                $req = 'cmd=_notify-synch';
                
                $tx_token = $_GET['tx'];
                $auth_token = "***my live token - should I have a test token since Im using sandbox?****";
                $req .= "&tx=$tx_token&at=$auth_token";
                
                // post back to PayPal system to validate
                $header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
                $header .= "Content-Type: application/x-www-form-urlencoded\r\n";
                $header .= "Content-Length: " . strlen($req) . "\r\n\r\n";
                $fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30);
                // If possible, securely post back to paypal using HTTPS
                // Your PHP server will need to be SSL enabled
                // $fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);

							if (!$fp) {
                // HTTP ERROR
                } else {
                fputs ($fp, $header . $req);
                // read the body data 
                $res = '';
                $headerdone = false;
                while (!feof($fp)) {
                $line = fgets ($fp, 1024);
                if (strcmp($line, "\r\n") == 0) {
                // read the header
                $headerdone = true;
                }
                else if ($headerdone)
                {
                // header has been read. now read the contents
                $res .= $line;
                }
                }
                
                // parse the data
                $lines = explode("\n", $res);
                $keyarray = array();
                if (strcmp ($lines[0], "SUCCESS") == 0) {
                for ($i=1; $i<count($lines);$i++){
                list($key,$val) = explode("=", $lines[$i]);
                $keyarray[urldecode($key)] = urldecode($val);
                }
                // check the payment_status is Completed
                // check that txn_id has not been previously processed
                // check that receiver_email is your Primary PayPal email
                // check that payment_amount/payment_currency are correct
                // process payment
                $firstname = $keyarray['first_name'];
                $lastname = $keyarray['last_name'];
                $itemname = $keyarray['item_name'];
                $amount = $keyarray['payment_gross'];
                
                echo ("<p><h3>Thank you for your purchase!</h3></p>");
                
                echo ("<b>Payment Details</b><br>\n");
                echo ("<li>Name: $firstname $lastname</li>\n");
                echo ("<li>Item: $itemname</li>\n");
                echo ("<li>Amount: $amount</li>\n");
                echo ("");
                }
                else if (strcmp ($lines[0], "FAIL") == 0) {
                // log for manual investigation
                }
                
                }
                
                fclose ($fp);
                
                ?>