RE: Message Threads

From: Mark Moore <>
Date: Fri, 16 Jul 2004 20:16:31 -0700
Message-ID: <PXb6CD.A.dOB.w3J-AB_at_vesta>


Thanks for the snappy response! See my comments below.


> -----Original Message-----
> From: Martin Duerst []
> Sent: Friday, July 16, 2004 7:19 PM
> To: Mark Moore;
> Subject: Re: Message Threads
> Implementing such changes in hypermail would probably not be too
> difficult,
> although scanning the body for message-ids could reduce performance.

If you require the message ID to be in the subject, or at the beginning of a line in the body, the load on the CPU should be minimal (equivalent to scanning the headers for In-Reply-To:).

For ridiculously loaded list servers, the scan could be limited to the first N lines, or M characters of the body.

> The real problem with this proposal is to get users to include message-
> ids.
> My guess is that it just won't be possible to force users to not forget
> to do that.

The point isn't to force them to do anything. ;o) On the other hand, for users that care, there currently is no mechanism to reliably send a response to a particular message short of massaging the outgoing headers.

> The In-Reply-To header is already included in the URI behind the
> 'Respond' link on the html version of the page, at least in the
> setup for W3C lists (

I hadn't noticed that. You are absolutely right, and that is mighty cool! But...

> The question may be whether
> this header is included by the mail software then the user
> clicks on that link. The answer may differ for different mailers.

The latest version of Microsoft Outlook definitely *doesn't* include the References: and In-Reply-To: headers (even though they are in the URI).

Worse, section 4 of RFC2368, "Unsafe headers," specifically recommends that mail software should not include "unsafe" headers from mailto URL's, and that "Only the Subject, Keywords, and Body headers are believed to be both safe and useful." [1]

RFC2368 goes on to say that creators of mailto URL's "cannot expect the resolver of a URL to understand more than the 'subject' and 'body' headers."

The converse of this is that creators of mailto URL's SHOULD expect resolvers to understand subject and body headers. Incidentally, Outlook does.

Maybe there's a synthesis to be had here. If Hypermail adds a "?Body=In-Reply-To:%20<message-ID>%0A" clause to response reply URI's, the In-Reply-To: line will be automatically inserted on the first line of the response.

A similar strategy could insert the message ID into the subject line which may be a little better. It limits the amount of text the list server has to scan, and it may be more transparent to existing users.

> Regards, Martin.

[1] Received on Sat 17 Jul 2004 10:33:04 AM GMT

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