问题
Note: Our site is built in PHP and uses MySQL databases. I already manage another site with shopping cart in its entirety using Authorize.net so please dont respond with suggestions to use another provider. A new product/service we are releasing is classified as "High Risk" to the merchant providers and they want to charge us out the a**. In response, I figured setting up a Website Payments Standard account on Paypal.com was the best alternative for the following reasons:
1) no monthly charges, only pay for what is used
2) trust brand and people are comfortable with Paypal
The rates are quite a bit higher than we are used to but any High Risk Merchant account is so that is irrelevant. The issue I am running into is this:
1) throughout the registration process on our site, we collect quite a bit of user information and pass it from page to page using SESSION variables. When you use Website Payments Standard, you are forced to pass the consumer off to a Paypal owned webpage to submit their payment information. Upon successful completion, they are able to direct them back to a 'confirmation' page on our site but it is my understanding there is NO way to keep the old SESSION variables in tact. This is very important to us because the overall concept is to store the SESSION variables ONLY after successful payment has been made.
2) Using Website Payments Standard, I am unable to find a way to send a Pay-Amount variable (everything must be dictated up front, i.e. T-shirt is $2.99). Our site allows the consumer to enrollee multiple persons and have several 'add-ons' for each person so there are literally over 100 end check out amount possibilities. I am not sure if it is possible to override this.
Has ANYBODY had luck using Website Payments Standard on Paypal acknowledging the information above?
回答1:
1) Assuming the Session is cookie based, it should still be there when they come back to your site (as long as they havn't closed the browser window in the mean time which is unlikely).
If you really wan't to be sure, store the session in the database in a temp table associated with the order_id you're generating. I belive it's possible that this (order_id) is passed back after the transaction is completed. Read the docs on PDT.
2) I belive this is not the case. Check the docs page 250 onwards.
回答2:
I'm months too late for my answer... but I also had the same problem...losing sessions and cookies after redirection to the return url.
For those who will be encountering the same problem, here is the solution I came up with,
In the paypal form you add
<input type='hidden' name='return' value='".http_dir."shop/return.php'>
<input type='hidden' name='custom' value='$session_id'>
where $session_id = session_id( );
and in shop/return.php, I tested if it works with
echo '<pre>';
print_r($_SESSION);
echo '</pre>';
echo '<pre>';
print_r($_COOKIE);
echo '</pre>';
echo '<pre>';
print_r($_GET);
echo '</pre>';
When you do not include 'custom' parameter in the form, it will return an empty array. It's crazy how just two lines change everything. I thought I was gonna repeat the whole shopping cart logic, oh boy.
Hope this would help someone in the future... Cheers^^
Source: WPS HTML Variables
回答3:
1.)I agree with Pete above in that your probably looking for the PDT functionality. It sounds like your best bet would be do digest the request sent to your return page for the PDT variables and build your session variables then.
2.) You can send any amount you want using the "amount" parameter. Here's the info on PayPal's HTML parameters
回答4:
Question 2 should be responded, regarding Question 1, I'd like to add that you can simply use the builtin Session functionality of PHP as usual (whichever Storing mechanism you have in place then, may it be memcached, file (default), mysql database or whatever), and pass the session id to paypal.
When paypal calls back to you, you can access your Session Variables by using session_id($backpassed_sessionid_from_paypal), which simply loads the session data associated with the sessionid you pass into the function, which is probably what you meant.
来源：https://stackoverflow.com/questions/3208283/anybody-ever-used-paypal-website-payments-standard-with-session-variables