[OpenLayers-Users] OpenLayers Proxying in IIS

[Jeff Dege]

OpenLayers uses AJAX, and AJAX has a problem with cross-domain http
requests.  So OpenLayers has a mechanism by which a proxy prefix can be
prepended to every request, directing the request to a proxy site on the
host domain.

The issue has always been how to set up such a proxy site.

If your website is hosted by Apache, it's easy.  Apache ships with tools
that make creating such a proxy easy.

If your website is IIS, it has not been.  I, at least, have been unable
to find either public domain code, or understandable instructions, on
how to create a proxying site for IIS.

I've asked on OpenLayers-Users, and had no answers.  I've asked
elsewhere, and had no answers.

Eventually, I found a discussion of the issue:
 
http://blogs.msdn.com/david.wang/archive/2005/08/01/HOWTO_Common_URL_Red
irection_Techniques_for_IIS_Summary.aspx

The relevant quote:

   No one seems to provide modules to do Server-Side Redirection or
Server-Side 
   Forwarding on IIS for free. At least, I am not aware of any
free/open-source
   add-on IIS modules which implement those Server-Side behaviors; I
only know 
   of for-fee modules like ISAPIRewrite.

Which got me looking for ISAPIRewrite.  This I found at:

    http://www.helicontech.com/isapi_rewrite/

This is a commercial, but reasonably priced ($99), ISAPI filter DLL that
implements the functionality of Apache's mod_rewrite and mod_proxy.  And
with it, creating a forwarding proxy for OpenLayers is simple.

ISAPI_Rewrite has a "lite" version that is free, but the lite version
doesn't do proxying.  The commercial version is available for download
on a 45-day free trial.  I downloaded it yesterday morning, and had a
proxy working before lunchtime.

I know there are others who have had the same problem.  This may be of
help.