On 13 Nov 2002 at 14:25, Mark Crispin wrote: > > What is the proper action to take when a client issues a SUBSCRIBE > > command with a parameter that already appears in the subscription list? > > Should a duplicate be created, or should the existing entry be removed > > from the subscription list? > > The IMAP protocol takes no position on whether or not duplicate entries are > permitted in the subscription list. I don't think that it should. > > There is a wide range of behaviors in IMAP that are permitted (by > virtue of not being explicitly prohibited), but are "silly" for one > reason or another. Duplicate subscription seems to me to be such a > "silly" behavior; it is generally avoidable, and can not be reliably > used to accomplish anything.
For your interest... I asked this question because I have a situation with my IMAP server at present; the Endymion "Sake" webmail server routinely issues a SUBSCRIBE command every time it selects a folder - according to the author of the product, he does that to satisfy the needs of a specific, very large legacy customer. Mercury *allows* duplicate subscriptions - specifically, according to a comment I've made in the source... I don't remember the incident, but it seems that there was a particular client that was using the subscription list to store preference settings, not folder names, and that it would occasionally duplicate some entries. For the life of me, I can't remember what the client was. I don't have any particular position on this - I'll happily modify Mercury's handling of SUBSCRIBE to match the most common behaviour - I guess the issue is just what that might be... Opinions? Cheers! -- David -- ------------------ David Harris -+- Pegasus Mail ---------------------- Box 5451, Dunedin, New Zealand | e-mail: [EMAIL PROTECTED] Phone: +64 3 453-6880 | Fax: +64 3 453-6612 Advertisement in the Manchester Evening News: ELSAN CHEMICAL TOILET, with 1 gill sanitary fluid, used once, slightly damaged.