Re: What about including virus filter to squid ?

Hello Evgeny,

> And what about to write some doc's on how is works, Not only on what
> to write in it's config ?

Yes, as Henrik points out, the ICAP Forum and the OPES forum
(http://www.ietf-opes.org) are good places to find more details. The
protocol spec, a white paper on ICAP are all out there.

In short, ICAP is a protocol to encapsulate (currently) HTTP messages
from a proxy server to an ICAP server. ICAP has 2 different modes,
request modification mode and response modification mode. In reqmod, the
proxy sends every HTTP request that it receives to the ICAP server - the
server then modifies the request appropriately and sends back the
modifies request. The proxy fetches the modified request instead of
original one and serves it. In respmod, the proxy fetches the response
for a request (original or modified - depending upon whether reqmod was
on or not), encapsulates it and sends it to the ICAP server - this
response is modified by the ICAP server and sent back - which is then
delivered to the client.

We have enhanced squid proxy to include an simple ICAP client
capability. Which means, squid now, based on the config parameters and
acls, sends requests and responses to the specified ICAP server.

If you are asking for design doc - hmmmmmm may be we should write it
sometime.

>
> I have looked at sources of icap-server squid client and can't
> understood,

It is basically modifed squid source code ;-)
To look for ICAP specific changes, pl search for code under the define
HS_FEAT_ICAP

> then I have looked at sources of icap server but was frustrated - it
> is something for http and non-C/C++ source

It is in Python language (http://www.python.org) ! We chose this
language as it is extremely easy to write small filters - called
proxylets - and hook them up into the content adaptation framework.
There are several other ICAP servers available commercially. For the
virus check, we used the Symantec Virus scanner that supported ICAP
protocol with squid client. We did not use the Python ICAP server.

Hope this helps,
regards
Geetha
>
> SY,
> Evgeny Kotsuba
Received on Wed Nov 13 2002 - 22:54:39 MST