ISAPI Filter - share memory?

Question

User-202510524 posted

Hi,

I've written a custom ISAPI filter that redirects a request to another port if it asked for a special URL. There's a config-file that defines some ports on the server:

[TargetUrlDef]
http://localhost:8080
http://localhost:8084
http://localhost:8089

And each user that requests http://localhost:80/redir.html should get redirected to one of these url definitions. That is no problem at all and it is working already. However, I want to redirect the users cyclically:

First request -> Target-URL 1
Second request -> Target-URL 2
Third request -> Target-URL 3
Fourth request -> Target-URL 1
Fifth request -> Target-URL 2
(and so on)

Now I run into problems because each running instance of the ISAPI filter needs to know the last Target-URL the user has been redirected to.
Thus, I need some shared memory each filter instance may access. File access will be too slow I guess and might cause problems with many requests.

Could anybody tell me the direction to go?

Regards
Marco Buerckel

Answer 1

User1356161706 posted

If you can't ensure that your ISAPI filter runs in the same AppPool Shared Memory is probably the way you have to go.

 

Answer 2

User742541801 posted

Some existing Url Rewriting filters may allow you to code this in rules, rather than depending on writing your own filter.