imapext-2007
view docs/rfc/rfc2088.txt @ 0:ada5e610ab86
imap-2007e
| author | yuuji@gentei.org |
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| date | Mon, 14 Sep 2009 15:17:45 +0900 |
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7 Network Working Group J. Myers
8 Request for Comments: 2088 Carnegie Mellon
9 Cateogry: Standards Track January 1997
12 IMAP4 non-synchronizing literals
14 Status of this Memo
16 This document specifies an Internet standards track protocol for the
17 Internet community, and requests discussion and suggestions for
18 improvements. Please refer to the current edition of the "Internet
19 Official Protocol Standards" (STD 1) for the standardization state
20 and status of this protocol. Distribution of this memo is unlimited.
22 1. Abstract
24 The Internet Message Access Protocol [IMAP4] contains the "literal"
25 syntactic construct for communicating strings. When sending a
26 literal from client to server, IMAP4 requires the client to wait for
27 the server to send a command continuation request between sending the
28 octet count and the string data. This document specifies an
29 alternate form of literal which does not require this network round
30 trip.
32 2. Conventions Used in this Document
34 In examples, "C:" and "S:" indicate lines sent by the client and
35 server respectively.
37 3. Specification
39 The non-synchronizing literal is added an alternate form of literal,
40 and may appear in communication from client to server instead of the
41 IMAP4 form of literal. The IMAP4 form of literal, used in
42 communication from client to server, is referred to as a
43 synchronizing literal.
45 Non-synchronizing literals may be used with any IMAP4 server
46 implementation which returns "LITERAL+" as one of the supported
47 capabilities to the CAPABILITY command. If the server does not
48 advertise the LITERAL+ capability, the client must use synchronizing
49 literals instead.
51 The non-synchronizing literal is distinguished from the original
52 synchronizing literal by having a plus ('+') between the octet count
53 and the closing brace ('}'). The server does not generate a command
54 continuation request in response to a non-synchronizing literal, and
58 Myers Standards Track [Page 1]
60 RFC 2088 LITERAL January 1997
63 clients are not required to wait before sending the octets of a non-
64 synchronizing literal.
66 The protocol receiver of an IMAP4 server must check the end of every
67 received line for an open brace ('{') followed by an octet count, a
68 plus ('+'), and a close brace ('}') immediately preceeding the CRLF.
69 If it finds this sequence, it is the octet count of a non-
70 synchronizing literal and the server MUST treat the specified number
71 of following octets and the following line as part of the same
72 command. A server MAY still process commands and reject errors on a
73 line-by-line basis, as long as it checks for non-synchronizing
74 literals at the end of each line.
76 Example: C: A001 LOGIN {11+}
77 C: FRED FOOBAR {7+}
78 C: fat man
79 S: A001 OK LOGIN completed
81 4. Formal Syntax
83 The following syntax specification uses the augmented Backus-Naur
84 Form (BNF) notation as specified in [RFC-822] as modified by [IMAP4].
85 Non-terminals referenced but not defined below are as defined by
86 [IMAP4].
88 literal ::= "{" number ["+"] "}" CRLF *CHAR8
89 ;; Number represents the number of CHAR8 octets
91 6. References
93 [IMAP4] Crispin, M., "Internet Message Access Protocol - Version 4",
94 draft-crispin-imap-base-XX.txt, University of Washington, April 1996.
96 [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text
97 Messages", STD 11, RFC 822.
99 7. Security Considerations
101 There are no known security issues with this extension.
103 8. Author's Address
105 John G. Myers
106 Carnegie-Mellon University
107 5000 Forbes Ave.
108 Pittsburgh PA, 15213-3890
110 Email: jgm+@cmu.edu
114 Myers Standards Track [Page 2]