View source for ReverseProxy for IIS 6.0 in CS using ASP.NET

== Problem to solve ==
We want to embed content from an internal webserver e.g. <code><nowiki>http://foo</nowiki></code> to our public webserver
<code><nowiki>http://sar.informatik.hu-berlin.de</nowiki></code>. In particular the frontend request 
<code><nowiki>http://sar.informatik.hu-berlin.de/test/bla.html</nowiki></code> should get the response for <code><nowiki>http://foo/dir/bla.html</nowiki></code>.
Thus the mapping is:
* <code><nowiki>http://sar.informatik.hu-berlin.de/test -> http://foo/dir</nowiki></code>.
From outside this should be look like a local web directory.

== Used Software ==
[http://www.saltypickle.com/Home/16 IIS Reverse Proxy] in particular [http://www.saltypickle.com/Home/uploads/16/ReverseProxy(v1.5).zip v1.5].
In that release of software redirections of the backend server are not forwarded transparently to the frontend. Therfore we patched the C-Sharpe code to take care of that. We disabled the internal handling <code>MaximumRedirections = 0;</code> of redirections and send them instead through the frontend to the browser.
The differences are:
<pre><nowiki>
38c38
<   	const int MaximumRedirections = 50;
---
> 		const int MaximumRedirections = 0;
357a358,370
> 			switch((int) backEndResponse.StatusCode) {
> 				case 301:
> 				case 302:
> 				case 303:
> 				case 307:
> 					frontEndResponse.StatusCode = (int) backEndResponse.StatusCode;
> 					string newLocation = backEndResponse.Headers["Location"];
> 					newLocation = Regex.Replace(newLocation, backEndSite, 
> 						frontEndRequest.Url.GetLeftPart(UriPartial.Authority) + frontEndRequest.ApplicationPath, 
> 						RegexOptions.IgnoreCase);
> 					frontEndResponse.RedirectLocation = newLocation;
> 					break;
> 			}</nowiki>
</pre>
Complete [[ReverseProxy.cs]].

Then redirections which usally occur if you enter e.g. <code><nowiki>http://foo/dir -> http://foo/dir/</nowiki></code> are forwarded to the browser as <code><nowiki>http://sar.informatik.hu-berlin.de/test -> http://sar.informatik.hu-berlin.de/test/</nowiki></code>

== Installation ==
Based on [http://www.saltypickle.com/Home/20 W2k/XP], [http://www.saltypickle.com/Home/19 Win2003]
=== Walk through ===
# Create directory where software lives e.g. <code>C:\Inetpub\test_virtual</code> and extract archive <code>"\\dc\pub\2006\2006 Software\ReverseProxy_15_SAR.zip"</code> to that directory. [[Image:rproxy_1.png]]
# Create in the IIS MMC a virtual directory [[Image:rproxy_2.png]]
# Give the alias name under which the resource should be reachable by the frontend <code>test</code> [[Image:rproxy_3.png]]
# Select the Web Site Content Directory <code>C:\Inetpub\test_virtual</code> [[Image:rproxy_4.png]]
# OK. [[Image:rproxy_5.png]]
# Check the Properties of the virtual dir. [[Image:rproxy_6.png]]
# Press Create. [[Image:rproxy_7.png]]
# Press Configuration [[Image:rproxy_8.png]]
# Insert [[Image:rproxy_9.png]]
# Enter: Executable <code>C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\aspnet_isapi.dll</code> and uncheck "Verify that file exists" [[Image:rproxy_10.png]]
# If you select <code>.asax</code> and then press Edit it should look like that: [[Image:rproxy_11.png]]
# Open cmd-prompt and to register <code>ICSharpCode.SharpZipLib.dll</code> and run <pre><nowiki>cd C:\Inetpub\test_virtual
C:\Inetpub\test_virtual>C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\gacutil.exe /i ICSharpCode.SharpZipLib.dll</nowiki></pre> [[Image:rproxy_12.png]]
# Finally you have to configure the proxy by editing <code>C:\Inetpub\test_virtual\Web.config</code><pre><nowiki><?xml version="1.0" encoding="utf-8" ?>
<configuration>

	<appSettings>
	   <add key="BackEndSite" value="http://foo/dir" />
	</appSettings>

  <system.web>
...
</nowiki></pre>

== Uninstalling ==
* Unregister the  gzip-dll by running <code>gacutil /u ICSharpCode.SharpZipLib.dll</code>.
* Remove the virtual directory <code>test</code> in the IIS-MMC.
* Remove the directory <code>C:\Inetpub\test_virtual</code>.
--[[User:Wolfm|WM]] 12:54, 13 December 2006 (CET)