imap4 - imap client-side tcl implementation of imap protocol

Bugs, Ideas, Feedback

       This  document,  and  the package it describes, will undoubtedly contain bugs and other problems.  Please
       report such in the category imap4 of the TcllibTrackers [http://core.tcl.tk/tcllib/reportlist].   Please
       also report any ideas for enhancements you may have for either package and/or documentation.

       When proposing code changes, please provide unifieddiffs, i.e the output of diff-u.

       Note  further  that  attachments  are strongly preferred over inlined patches. Attachments can be made by
       going to the Edit form of the ticket immediately after its creation, and then using the left-most  button
       in the secondary navigation bar.  Only a small part of rfc3501 implemented.

Description

       The  imap4  library package provides the client side of the InternetMessageAccessProtocol (IMAP) using
       standard sockets or secure connection via TLS/SSL.  The package is fully implemented in Tcl.

       This document describes the procedures and explains their usage.

Examples

                  set user myusername
                  set pass xtremescrt
                  set server imap.test.tld
                  set FOLDER INBOX
                  # Connect to server
                  set imap [::imap4::open $server]
                  ::imap4::login $imap $user $pass
                  ::imap4::select $imap $FOLDER
                  # Output all the information about that mailbox
                  foreach info [::imap4::mboxinfo $imap] {
                      puts "$info -> [::imap4::mboxinfo $imap $info]"
                  }
                  # fetch 3 records inline
                  set fields {from: to: subject: size}
                  foreach rec [::imap4::fetch $imap :3 -inline {*}$fields] {
                      puts -nonewline "#[incr idx])"
                      for {set j 0} {$j<[llength $fields]} {incr j} {
                          puts "\t[lindex $fields $j] [lindex $rec $j]"
                      }
                  }

                  # Show all the information available about the message ID 1
                  puts "Available info about message 1: [::imap4::msginfo $imap 1]"

                  # Use the capability stuff
                  puts "Capabilities: [::imap4::isableto $imap]"
                  puts "Is able to imap4rev1? [::imap4::isableto $imap imap4rev1]"

                  # Cleanup
                  ::imap4::cleanup $imap

Keywords

       email, imap, internet, mail, net, rfc3501, ssl, tls

Name

       imap4 - imap client-side tcl implementation of imap protocol

Procedures

This package defines the following public procedures:

::imap4::openhostname ?port?

Open a new IMAP connection and initalize the handler, the imap communication channel (handler) is
returned.

hostname - mail server

port - connection port, defaults to 143

The namespace variable ::imap4::use_ssl can be used to establish to a secure connection via
TSL/SSL if set to true. In this case default connection port defaults to 993.

Note: For connecting via SSL the Tcl module tls must be already loaded otherwise an error is
raised.

package require tls ; # must be loaded for TLS/SSL
set ::imap4::use_ssl 1 ; # request a secure connection
set chan [::imap4::open $server] ; # default port is now 993

::imap4::starttlschan
Use this when tasked with connecting to an unsecure port which must be changed to a secure port
prior to user login. This feature is known as STARTTLS.

::imap4::loginchanuserpass

chan - imap channel

user - username

pass - password

::imap4::folderschan ?-inline? ?mboxref? ?mboxname?

Get list of matching folders, 0 is returned on success.

Wildcards '*' as '%' are allowed for mboxref and mboxname, command ::imap4::folderinfo can be used
to retrieve folder information.

chan - imap channel

mboxref - mailbox reference, defaults to ""

mboxname - mailbox name, defaults to "*"

If -inline is specified a compact folderlist is returned instead of the result code. All flags are
converted to lowercase and leading special characters are removed.

{{Arc08 noselect} {Arc08/Private {noinferiors unmarked}} {INBOX noinferiors}}

::imap4::selectchan ?mailbox?

Select a mailbox, 0 is returned on success.

chan - imap channel

mailbox - Path of the mailbox, defaults to INBOX

Prior to examine/select an open mailbox must be closed - see: ::imap4::close.

::imap4::examinechan ?mailbox?

"Examines" a mailbox, read-only equivalent of ::imap4::select.

chan - imap channel

mailbox - mailbox name or path to mailbox, defaults to INBOX

Prior to examine/select an open mailbox must be closed - see: ::imap4::close.

::imap4::fetchchanrange ?-inline? ?attr...?

Fetch attributes from messages.

The attributes are fetched and stored in the internal state which can be retrieved with command
::imap4::msginfo, 0 is returned on success. If -inline is specified, alle records are returned as
list in order as defined in the attr argument.

chan - imap channel

range - message index in format FROM:TOattr - imap attributes to fetch

Note: If FROM is omitted, the 1st message is assumed, if TO is ommitted the last message is
assumed. All message index ranges are 1-based.

::imap4::noopchan
Send NOOP command to server. May get information as untagged data.

chan - imap channel

::imap4::checkchan
Send CHECK command to server. Flush to disk.

chan - imap channel

::imap4::folderinfochan ?info?

Get information on the recently selected folderlist. If the info argument is omitted or a null
string, the full list of information available for the mailbox is returned.

If the required information name is suffixed with a ? character, the command returns true if the
information is available, or false if it is not.

chan - imap channel

info - folderlist options to retrieve

Currently supported options: delim - hierarchy delimiter only, match - ref and mbox search
patterns (see ::imap4::folders), names - list of folder names only, flags - list of folder names
with flags in format {{name{flags}}...} (see also compact format in function
::imap4::folders).

{{Arc08 {{\NoSelect}}} {Arc08/Private {{\NoInferiors} {\UnMarked}}} {INBOX {\NoInferiors}}}

::imap4::msginfochanmsgid ?info? ?defval?

Get information (from previously collected using fetch) from a given msgid. If the 'info' argument
is omitted or a null string, the list of available information options for the given message is
returned.

If the required information name is suffixed with a ? character, the command returns true if the
information is available, or false if it is not.

chan - imap channel

msgid - message number

info - imap keyword to retrieve

defval - default value, returned if info is empty

Note: All message index ranges are 1-based.

::imap4::mboxinfochan ?info?

Get information on the currently selected mailbox. If the info argument is omitted or a null
string, the list of available information options for the mailbox is returned.

If the required information name is suffixed with a ? character, the command returns true if the
information is available, or false if it is not.

chan - imap channel

opt - mailbox option to retrieve

Currently supported options: EXISTS (noof msgs), RECENT (noof 'recent' flagged msgs), FLAGS

In conjunction with OK: PERMFLAGS, UIDNEXT, UIDVAL, UNSEEN

Div. states: CURRENT, FOUND, PERM.

::imap4::select $chan INBOX
puts "[::imap4::mboxinfo $chan exists] mails in INBOX"

::imap4::isabletochan ?capability?

Test for capability. It returns 1 if requested capability is supported, 0 otherwise. If
capability is omitted all capability imap codes are retured as list.

chan - imap channel

info - imap keyword to retrieve

Note: Use the capability command to ask the server if not already done by the user.

::imap4::createchanmailbox

Create a new mailbox.

chan - imap channel

mailbox - mailbox name

::imap4::deletechanmailbox

Delete a new mailbox.

chan - imap channel

mailbox - mailbox name

::imap4::renamechanoldnamenewname

Rename a new mailbox.

chan - imap channel

mailbox - old mailbox name

mailbox - new mailbox name

::imap4::subscribechanmailbox

Subscribe a new mailbox.

chan - imap channel

mailbox - mailbox name

::imap4::unsubscribechanmailbox

Unsubscribe a new mailbox.

chan - imap channel

mailbox - mailbox name

::imap4::searchchanexpr ?...?

Search for mails matching search criterions, 0 is returned on success.

chan - imap channel

expr - imap search expression

Notes: Currently the following search expressions are handled:

Mailheaderflags: all mail header entries (ending with a colon ":"), like "From:", "Bcc:", ...

Imapmessagesearchflags: ANSWERED, DELETED, DRAFT, FLAGGED, RECENT, SEEN, NEW, OLD, UNANSWERED,
UNDELETED, UNDRAFT, UNFLAGGED, UNSEEN, ALL

Imapheadersearchflags: BODY, CC, FROM, SUBJECT, TEXT, KEYWORD, BCC

Imapconditionalsearchflags: SMALLER, LARGER, ON, SENTBEFORE, SENTON, SENTSINCE, SINCE, BEFORE
(not implemented), UID (not implemented)

Logicalsearchconditions: OR, NOT

::imap4::search $chan larger 4000 seen
puts "Found messages: [::imap4::mboxinfo $chan found]"
Found messages: 1 3 6 7 8 9 13 14 15 19 20

::imap4::closechan

Close the mailbox. Permanently removes \Deleted messages and return to the AUTH state.

chan - imap channel

::imap4::cleanupchan

Destroy an IMAP connection and free the used space. Close the mailbox. Permanently removes
\Deleted messages and return to the AUTH state.

chan - imap channel

::imap4::debugmodechan ?errormsg?
Switch client into command line debug mode.

This is a developers mode only that pass the control to the programmer. Every line entered is sent
verbatim to the server (after the addition of the request identifier). The ::imap4::debug
variable is automatically set to '1' on enter.

It's possible to execute Tcl commands starting the line with a slash.

chan - imap channel

errormsg - optional error message to display

::imap4::storechanrangedataflaglist

Alters data associated with a message in the selected mailbox.

chan - imap channel

range - message index in format FROM:TOflaglist - Flags the data operates on.

data - The currently defined data items that can be stored are shown below. Note that all of these
data types may also be suffixed with ".SILENT" to suppress the untagged FETCH response.

FLAGS Replace the flags for the message (other than \Recent) with the flaglist.

+FLAGS Add the flags in flaglist to the existing flags for the message.

-FLAGS Remove the flags in flaglist to the existing flags for the message.

For example:

::imap4::store $chan $start_msgid:$end_msgid +FLAGS "Deleted"

::imap4::expungechan

Permanently removes all messages that have the \Deleted flag set from the currently selected
mailbox, without the need to close the connection.

chan - imap channel

::imap4::copychanmsgidmailbox

Copies the specified message (identified by its message number) to the named mailbox, i.e. imap
folder.

chan - imap channel

msgid - message number

mailbox - mailbox name

::imap4::logoutchan

Informs the server that the client is done with the connection and closes the network connection.
Permanently removes \Deleted messages.

A new connection will need to be established to login once more.

chan - imap channel

References

       Mark  R.  Crispin,  "INTERNET  MESSAGE  ACCESS  PROTOCOL  -  VERSION  4rev1",  RFC  3501,   March   2003,
       http://www.rfc-editor.org/rfc/rfc3501.txt

       OpenSSL, http://www.openssl.org/

Synopsis

       package require Tcl8.59

       package require imap4?0.5.5?::imap4::openhostname ?port?

       ::imap4::starttlschan::imap4::loginchanuserpass::imap4::folderschan ?-inline? ?mboxref? ?mboxname?

       ::imap4::selectchan ?mailbox?

       ::imap4::examinechan ?mailbox?

       ::imap4::fetchchanrange ?-inline? ?attr...?

       ::imap4::noopchan::imap4::checkchan::imap4::folderinfochan ?info?

       ::imap4::msginfochanmsgid ?info? ?defval?

       ::imap4::mboxinfochan ?info?

       ::imap4::isabletochan ?capability?

       ::imap4::createchanmailbox::imap4::deletechanmailbox::imap4::renamechanoldnamenewname::imap4::subscribechanmailbox::imap4::unsubscribechanmailbox::imap4::searchchanexpr ?...?

       ::imap4::closechan::imap4::cleanupchan::imap4::debugmodechan ?errormsg?

       ::imap4::storechanrangedataflaglist::imap4::expungechan::imap4::copychanmsgidmailbox::imap4::logoutchan

________________________________________________________________________________________________________________

Tls Security Considerations

       This package uses the TLS package to handle the security for https urls and other socket connections.

       Policy  decisions like the set of protocols to support and what ciphers to use are not the responsibility
       of TLS, nor of this  package  itself  however.   Such  decisions  are  the  responsibility  of  whichever
       application  is  using  the package, and are likely influenced by the set of servers the application will
       talk to as well.

       For        example,        in        light        of        the        recent        POODLEattack
       [http://googleonlinesecurity.blogspot.co.uk/2014/10/this-poodle-bites-exploiting-ssl-30.html]  discovered
       by Google many servers will  disable  support  for  the  SSLv3  protocol.   To  handle  this  change  the
       applications  using  TLS  must  be patched, and not this package, nor TLS itself.  Such a patch may be as
       simple as generally activating tls1 support, as shown in the example below.

                  package require tls
                  tls::init -tls1 1 ;# forcibly activate support for the TLS1 protocol

                  ... your own application code ...