[Zope-dev] ProxyPass and SiteAccess getting REMOTE_ADDR

[William Noon]

Last week I was setting up an Apache VirtualHost to point to a Zope
object tree using the ProxyPass directive and SiteAccess to get all the
urls right (great stuff!).

However, I noticed that the REMOTE_ADDR was always set to the 
proxy host.  This makes sense because Zope just gets the host/port from
the socket connection.  But I needed the real remote_addr for logging
and user admin.  Adding 'Header's wouldn't pass the info to Zope.

The Zope mail archives mentioned the problem a couple of times without
a configuration fix.

A simple fix to the proxy module (in proxy_http.c) will create a new
header called 'Original-Addr' to contain the client's ip address.

Here is a context diff against Apache 1.3.14 that should work even 
in the new 2.0 servers:

***************
*** 397,402 ****
--- 397,404 ----
        ap_bvputs(f, reqhdrs[i].key, ": ", reqhdrs[i].val, CRLF, NULL);
      }
  
+       ap_bvputs(f, "Original-Addr: ", r->connection->remote_ip, CRLF, NULL);
+ 
      ap_bputs(CRLF, f);
  /* send the request data, if any. */


When the request was proxied, the Zope REQUEST will now have a key
'HTTP_ORIGINAL_ADDR' containing the client address.

This key is also now a good indication that the http request went to 
the VirtualHost address.  

I then made a small change to SiteRoot.py to turn off the url mapping if
HTTP_ORIGINAL_ADDR is present.  This is a context diff against the
SiteRoot.py file shipped with Zope 2.3.0:

***************
*** 108,113 ****
--- 108,116 ----
          if '_SUPPRESS_SITEROOT' in _swallow(request):
              request.setVirtualRoot(request.steps)
              return
+         # only run if passed through ProxyPass
+         t = request.environ.get('HTTP_ORIGINAL_ADDR',None)
+         if t == None : return
          srd = [None, None]
          for i in (0, 1):
              srp = ('SiteRootBASE', 'SiteRootPATH')[i]


These two patches have worked well and solved several problems.  I hope
others will find them useful.

--Bill Noon
Northeast Regional Climate Center
Cornell University