Re: [htdig] update digging

Geoff Hutchison (
Tue, 2 Mar 1999 15:01:01 -0500 (EST)

On Tue, 2 Mar 1999, Frank Guangxin Liu wrote:

> hmm. Maybe my apache 1.2.x server doesn't support If-Modified-Since header?

Possibly. I guess the Apache people would be the ones to ask. ;-)

> That is much better, though lots of network bandwidth is still wasted.
> Is it safer to use two connections for each document (in case of update dig)?
> HEAD and GET. Does the reply from HEAD provide more reliable information
> and always give the last modification date?

HEAD does supply the last modification date, but there's no benefit as far
as reliability. Not all servers implement HEAD... Further,
If-Modified-Since is nice since it does everything we want. If it isn't
modified, it doesn't send it. If it is, it performs the usual GET. Using
HEAD would *require* two connections, which increases network usage.
(In other words, it's a big tradeoff. For any server that implements
If-Modified-Since, that's the best solution.)

However, this is something that I hope to test for the 3.2 series. I'm
hoping to put in full HTTP/1.1 support, including Keep-Alives and
persistent connections. This will *really* help network bandwidth.

> hm.. I am running the latest version.
> Both the initial db and the update db are created using htdig-3.1.1.
> I had to re-create the initial db because the pdf_parser screwed up
> in htdig-3.1.0.

If you could send me info on how you're calling htdig and htmerge, I'd
appreciate it. This should not be happening at all.

-Geoff Hutchison
Williams Students Online

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This archive was generated by hypermail 2.0b3 on Thu Mar 04 1999 - 09:09:18 PST