Re: [EAI] AD review of draft-ietf-eai-pop-06

[Barry Leiba <[e-mail]>]

>>   The octet count (size) of a message reported in a response to the
>>   LIST command SHOULD match the actual number of octets sent in a RETR
>>   response.  Sizes reported elsewhere, such as in STAT responses and
>>   non-standardized free-form text in positive status indicators
>>   (following "+OK") need not be accurate, but it is preferable if they
>>   are.
>
> I would like to hear some justification for returning inaccurate sizes (and
> for the SHOULD instead of a MUST).

It may be that a conversion has to be made in order to get an accurate
size.  Perhaps an implementation would be well advised to go ahead and
do the conversion as soon as the size is needed, and then cache the
converted document until the RETR is done, but that might not be
practical (suppose a LIST is listing 5000 messages; the server can't
really convert all 5000 for the list command, and it'd likely then
have to re-convert the ones that are actually retrieved).

The SHOULD (and the permission to be inaccurate in other responses)
gives an "out" to the server, allowing it to reserve the expensive
processing for when the message is actually retrieved.

Because clients have to be changed to ask for this anyway, those
clients can also understand that they have to deal with a retrieval
that might be larger than they were led to expect, and they can code
for it.

Barry