draft-karp-morg-sortdisplay-00

1
draft-karp-morg-sortdisplay-00

• Display-based Address Sorting for the IMAP4 SORT
  Extension

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Background

• SORT extension (RFC 5256) defines a standard set
  of sort criteria ARRIVAL, CC, DATE, FROM, SIZE,
  SUBJECT, and TO
• Address-based sort criteria evaluate to the
  addr-mailbox of the headers first address
• Examples
• Waverly Bindle ltbindle_at_example.comgt sorts as
  bindle
• Pat Walton ltbpw_at_example.comgt sorts as bpw
• bobby.avertain_at_example.com sorts as
  bobby.avertain

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Problems

• Unfortunately, clients do not display the strings
  by which the SORT criteria is ordering messages
• Instead, clients display the display name from
  the address in question
• As a result, when messages are displayed as a
  result of a SORT ordering, they often appear to
  be out of order
• Under SORT ordering Under expected ordering
• Waverly Bindle bobby.avertain_at_example.com
• bobby.avertain_at_example.com Pat Walton
• Pat Walton Waverly Bindle

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Proposal

• Introduce a new SORT ordering that mirrors the
  way real-world clients sort addresses
• Algorithm
• If the header is absent or if the header contains
  no mailboxes, the message's sort value is the
  empty string.
• If the mailbox contains an RFC2822
  display-name, replace each instance of RFC2822
  CFWS in the display-name with a single space,
  trim all leading and trailing whitespace, and
  decode any RFC2047 encoded-words. If the
  resulting string is not the empty string, use it
  as the sort value for the message.
• Otherwise, completely remove all RFC2822 CFWS
  from the mailbox's RFC2822 addr-spec and use
  the resulting string as the message's sort value.

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Issues

• Locale- and/or language-dependent ordering
  delegated to the active comparator
• Draft defines new DISPLAYFROM criteria for From
  header is it worthwhile to also define similar
  criteria for CC and To?
• pro mirrors set of address-based criteria from
  SORT draft
• con extra server overhead for headers that are
  very rarely sorted on
• Should algorithm consider RFC2822 comments?
• Example bdobbs_at_example.com (Bob Dobbs)
• Other issues?