BUG! Modifying the order process to accept external payments.

[Jarno Niemela <jargon@iki.fi>]

This is very curious, my only about an half of my mail got sent ?????


Well heres the whole thing


Hello.

I'm implementing a minivend based WEB shop in Finland,
and the local customers don't like to use credit card in
making orders (we have online back cards and online accounts).

So instead of credit card we use following system:

when the user clicks accept order (which would normally result in 
email to the shop owner and receipt to customer), he gets a new page
containing following form 

<FORM METHOD="POST"
ACTION="https://verkkomaksu.leonia.fi/vema.nd/Verkkomaksu/pgTunnistus">
<INPUT NAME="KNRO" TYPE="HIDDEN" VALUE="000000000000">
KNRO = 000000000000
etc
etc
<INPUT NAME="OKURL" TYPE="HIDDEN" SIZE=40
VALUE="http://www.asiakas.fi/cgi/ok?"> 
OK-URL: http://www.asiakas.fi/cgi/ok?<BR>
<INPUT NAME="ERRORURL" TYPE="HIDDEN" SIZE=40
VALUE="http://www.asiakas.fi/cgi/error?"> Virhe-URL:
http://www.asiakas.fi/cgi/virhe? <BR>
<INPUT NAME="CHECKSUM" TYPE="HIDDEN"
VALUE="b93fd1146a0e06ba59461ae8baa1fcf0"> MD5-Tarkiste =
b93fd1146a0e06ba59461ae8baa1fcf0 <BR>
<INPUT TYPE="IMAGE" NAME="Leonia"
SRC="https://verkkomaksu.leonia.fi/logoverkkomaksu.gif" ALT="Leonia"
BORDER=0></FORM></TD>
</FORM>

This form is sent to processing on to the bank WWW server which will 
then forward the browser to the OKURL or ERRORURL page, depending 
on was the payment successful or not. 

Diagram of the general idea

------
checkout.html
------
  |
  |
------
payment form (still in minivend server)
------
  |
  |
------
bank server (out of my control)
------
  |
  |
------
OKURL (back to minivend)
------
  |
  |
------
process order
------



So what I need to do, is to redirect the user to the payment form page after
he has accepted the order, and to return back to the minivend is the payment
transaction was successful.

Does anyone have any hint how I can redirect the minivend to the payment
page, and
still return to minivend after the payment is done, so that I can still
retain the 
information in the shopping cart. Because the email to the shopowner is
supposed to be
sent only if the payment was successful.

I understand that I can retain the session, just by putting the session ID
into the
OKURL, but how I can keep the shopping cart data.


Jarno Niemela