On Tue, May 30, 2006 at 05:00:02PM +0100, Chris Lightfoot wrote: > I am looking at deploying squid as an HTTP accelerator in > front of a site which uses an IP-to-country lookup to vary > certain elements of the site's content. Obviously I can't > specify this information in the Vary: header; I could have > the site emit `Vary: *' but that would guarantee that no > useful cacheing is done. > > Is there a suggested solution to this? One which occurs to > me is to modify squid to do the IP-to-country lookup > itself, and to add an additional header to the client's > request containing the results of the lookup; the > application behind the accelerator could then name this > header in the Vary: header it returns. I think that would > work, but it's a bit ugly; is there a better (or, better > still, standard) approach? for those who are interested, this is the approach I adopted in the end. The patch for squid-2.5.9 (as in Debian stable, which is the platform we're using) is below, in case this is of use to others. There are also binary and source packages on http://debian.mysociety.org/ with this modification. So far it's working well. --- squid-2.5.9-orig/configure.in 2005-02-23 23:54:54.000000000 +0000 +++ squid-2.5.9/configure.in 2006-06-02 19:00:59.000000000 +0100 @@ -775,6 +775,20 @@ fi ]) +AC_ARG_ENABLE(geoip-lookups, +[ --enable-geoip-lookups + This adds code which does GeoIP lookups on each + incoming connection, and synthesises an + X-GeoIP-Country: header on each client connection.], +[ if test "$enableval" = "yes" ; then + echo "Enabling GeoIP Lookups" + AC_DEFINE(USE_GEOIP, 1) + USE_GEOIP="yes" + else + AC_DEFINE(USE_GEOIP, 0) + fi +]) + AM_CONDITIONAL(USE_DNSSERVER, false) use_dnsserver= AC_ARG_ENABLE(internal-dns, @@ -1893,6 +1907,19 @@ sleep 10 fi +dnl If we're configured to use GeoIP then we need to find the appropriate +dnl header files and library +if test "$USE_GEOIP" ; then + AC_CHECK_LIB(GeoIP, GeoIP_new) + AC_CHECK_HEADERS(GeoIP.h) + if test "$ac_cv_header_GeoIP_h" = "yes" ; then + echo "using GeoIP" + else + echo "ERROR: GeoIP not found" + exit 1 + fi +fi + if test -z "$USE_GNUREGEX" ; then case "$host" in *-sun-solaris2.[[0-4]]) --- squid-2.5.9-orig/src/client_side.c 2005-02-20 19:07:45.000000000 +0000 +++ squid-2.5.9/src/client_side.c 2006-06-02 19:51:24.000000000 +0100 @@ -3104,6 +3104,12 @@ safe_free(prefix); break; } +#if USE_GEOIP + /* Cull any existing country header and add a new one. */ + httpHeaderDelByName(&request->header, "X-GeoIP-Country"); + httpHeaderPutExt(&request->header, "X-GeoIP-Country", + *conn->country ? conn->country : "none"); +#endif request->flags.accelerated = http->flags.accel; if (!http->flags.internal) { if (internalCheck(strBuf(request->urlpath))) { --- squid-2.5.9-orig/src/structs.h 2005-02-23 00:06:35.000000000 +0000 +++ squid-2.5.9/src/structs.h 2006-06-02 15:28:30.000000000 +0100 @@ -1138,6 +1138,9 @@ int n; time_t until; } defer; + + /* country inferred from peer IP address */ + char country[3]; }; struct _ipcache_addrs { -- Television is a medium, so called because it is neither rare nor well done.
