[ic] mod_interchange and Apache MaxClients

John1 list_subscriber at yahoo.co.uk
Sat Nov 19 20:04:11 EST 2005

On Saturday, November 19, 2005 11:43 PM, kevin at cursor.biz wrote:

> John1 [list_subscriber at yahoo.co.uk] wrote:
>> I mentioned a scenario earlier in this thread that *always* causes my
>> Interchange session to hang:
>> ############
>> If we click the "Take payment" button and the PSP server fails to
>> respond to the POST request due to a fault at their end our page
>> just hangs.  After 60 seconds, the browser page goes blank (i.e.
>> white).  Then, after a further 60 seconds the browser finally times
>> out with the usual "Cannot find server or DNS error" page.  Now, the
>> interesting thing is that once this has occured, my Interchange
>> session is either very slow at best, or completely hung.  To carry
>> on working I must close the browser, clear the cookies and log back
>> on  again (presumably in order for Interchange to allocate me a new
>> session). #############
>> This particular scenario may or may not be related to the main
>> problem we have been discussing in this thread.  However, it must be
>> related to timeouts et al, and it occurs to me that one good way to
>> test the effect
>> of a payment gateway's failure to return a response to a POST request
>> would be to write a dummy payment gateway.
>> The code would need to listen out for a POST request on a particular
>> port, wait for a given length of time, and then respond with a
>> simple status result.  The length of time that the code should wait
>> between accepting
>> the POST request and responding should be made configurable.
>> Indeed, the timeout value could be passed from the client in the
>> POST request.
> You could modify the TestPayment module to recognise a specific magic
> card number and just do nothing for a while, thus forcing a timeout
> elsewhere.
Thanks for idea - I should be able to manage that.

BTW, should a payment gateway's failure to respond cause the session to 
hang - is this a feature or bug?  :-)

i.e. pressing the back button and trying to navigate to a new page doesn't 
work - you have to close the browser and restart the browser (presumably to 
be allocated another session) before you can access the site again.  Do you 
consider it to be Interchange or mod_interchange that causes a session to 
hang in this scenario?

BTW, I am not taking about a properley communicated timeout - if the payment 
gateway sends back a "timed out" error message then there is no problem. 
But if the payment gateway simply fails to respond at all and you sit their 
waiting for 2 minutes until the browser gives up with "Cannot find server or 
DNS error", that's when the session hangs and you have to close the browser 
before you can connect to the site again. 

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