``Applies this URL to our current server?''

["Ralf S. Engelschall" <rs...@engelschall.com>]

Some people with virtual servers out there have the following problem on
redirects between virtual servers, which seems complicated to solve. The
problem for mod_rewrie is the question:
     ``Applies this URL to our current server?''
In other words:
     ``How could a module determine if the URL http://host:port/url/ really
       applies to the current (virtual) server instance?''

The problem comes from the three situations:
     o server is a non-virtual server (i.e. the main server)
     o server is a ip-based virtual server (ifconfig alias)
     o server is a non-ip-based virtual server (HTTP/1.1 Host: || ServerPath /url)

For the first situation there are a lot of good working solutions, for
instance I could do 

    ourhost = gethostbyname(r->server->server_hostname)
    testhost = gethostbyname(host)
    for all ip-adresses of ourhost
        for all ip-adresses of testhost
            if match then this is our server

BUT: Do anyone know a correct check for the other two situations?
     The above approach will not work because in situation two not all
     ip-addresses could used and in situation three the Host: header,
     ServerAlias and ServerPath have to keep in mind. For virtual servers
     there are a lot of special context things which the check has to know
     about.

Any pseudo-code solutions for situation two and three?
         
                                        Ralf S. Engelschall    
                                        rse@engelschall.com
                                        http://www.engelschall.com/~rse

Re: ``Applies this URL to our current server?''

[Dean Gaudet <dg...@hotwired.com>]

In article <ho...@en.muc.de>,
Ralf S. Engelschall <ne...@hyperreal.com> wrote:
>     ``How could a module determine if the URL http://host:port/url/ really
>       applies to the current (virtual) server instance?''

Isn't that gear already in read_request and its children?

I'm biased against the webserver going about trying to guess what
the adminstrator wants.  If we borrow from sendmail we'll notice that
the w class needs to be configured by the administrator -- it doesn't
go about looking at MX records to find out if it should be handling
the request.

read_request and its children use ServerAlias, ServerPath and <VirtualHost>
as hints to figure out what vhost to use.  If that functionality was
modularized you'd be able to use it in mod_rewrite.

Dean