How to differentiate ASP page Refresh versus Requested by other pa

[adam]

Hi ASP Expert,

I encounter a page reload situation in ASP.
It is I need a way to differentiate whether the current page -
"Application_Result.asp" got reloaded itself when user click on the browser
Refresh button or is requested by the previous page "Application_Form.asp".

I tried using
<%if Request.ServerVariables("REQUEST_METHOD") = "POST" then%>
<!--it is requested from "Application_Form.asp, do something-->
<%else%>
<!--Application_Result.asp refreshed itself(such as user clicks on the
browser Refresh button, do something else-->
<%end if%>

However, in both cases, the IF statement above all evaluated as true.
Any idea about how to differentiate this two different behavior (Page
Refresh versus Page requested by another Page) ?

Thanks for your help!

-adam

[Anthony Jones]

"adam" <adam@discussions.microsoft.com> wrote in message
news:BFA43B05-8897-4931-85F6-F223614DADFD@microsoft.com...

> Hi ASP Expert,
>
> I encounter a page reload situation in ASP.
> It is I need a way to differentiate whether the current page -
> "Application_Result.asp" got reloaded itself when user click on the

browser

> Refresh button or is requested by the previous page

"Application_Form.asp".

>
> I tried using
> <%if Request.ServerVariables("REQUEST_METHOD") = "POST" then%>
> <!--it is requested from "Application_Form.asp, do something-->
> <%else%>
> <!--Application_Result.asp refreshed itself(such as user clicks on the
> browser Refresh button, do something else-->
> <%end if%>
>
> However, in both cases, the IF statement above all evaluated as true.
> Any idea about how to differentiate this two different behavior (Page
> Refresh versus Page requested by another Page) ?
>
> Thanks for your help!
>
> -adam

A referesh will use the same method to request the resource. If the page is
navigated to by means of a POST then the browser will use a POST to refresh
(it keeps a copy of the original request body in order to do that). So
REQUEST_METHOD doesn't help. Even the Referrer header remains the same.
The only difference in the request generated by a refresh is the inclusion
of a Pragma: nocache header and a Cache-Control: max-age=0 which will force
any cache/proxy between the browser and the origin server to forward the
request to the server. Unfortunately these headers are not exposed in the
ServerVariables property.

I'm gonna guess you are trying to prevent a Form post duplicating activities
when the user refreshes the resulting page.
Add a hidden field to the original form to hold a unique transaction ID ( a
GUID or sequential number). When you have processed the posted data, mark
the transaction ID as processed. In your processing page before doing
anything else check that the transaction ID hasn't already been processed.
If it has just do the output part of the page.

Anthony.