Using a http proxy without manually configuring the browser to use proxy server

From your comment on my previous answer I gather that you are using Apache as a forwarding proxy (ProxyRequests On). You can use mod_rewrite to proxy pass through specific URL's.

You probably got something like this in your Apache config:

ProxyRequests On
ProxyVia On
<Proxy *>
   Order deny,allow
   Allow from xx.xx.xx.xx
</Proxy>

Then you have to add the following in order to proxy-pass all requests from www.olddomain.com/foo to www.newdomain.com/bar:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.olddomain\.com$
RewriteRule /foo(.*)$ http://www.newdomain.com/bar/$1 [P,L]

What this does is:

• When a request is made to the host www.olddomain.com, the RewriteRule will fire.
• This rule substitutes /foo to http://www.newdomain.com/bar/.
• The substitution is handed over to mod_proxy (P).
• Stop rewriting (L).

Example result:

• Browser is configured to use your Apache as proxy server.
• It requests www.olddomain.com/foo/test.html.
• Your Apache will rewrite this to www.newdomain.com/bar/test.html.
• It will request this page from the responsible web server.
• Return the result to the browser as www.olddomain.com/foo/test.html.

Basic Authentication normally is a Base64 Encoded String of "username:password" and a HTTP-Header "Authorization".

By adding the following to a Apache2 vHost you should be fine:

<Location /path>
    RequestHeader set Authorization "Basic <base64string>"
</Location>

ProxyPass /path http://backend/path
ProxyPassReverse /path http://backend/path

You can base64 encode the "username:password" part at http://www.motobit.com/util/base64-decoder-encoder.asp (for example). The example above needs mod_headers and mod_proxy (should be available for both - Linux and Windows - with Apache2.