20.13. imaplib — IMAP4 protocol client
This module defines three classes, IMAP4, IMAP4_SSL and
IMAP4_stream, which encapsulate a connection to an IMAP4 server and
implement a large subset of the IMAP4rev1 client protocol as defined in
RFC 2060. It is backward compatible with IMAP4 (RFC 1730) servers, but
note that the STATUS command is not supported in IMAP4.
Three classes are provided by the imaplib module, IMAP4 is the
class imaplib.IMAP4(host='', port=IMAP4_PORT)
- This class implements the actual IMAP4 protocol. The connection is created and
protocol version (IMAP4 or IMAP4rev1) is determined when the instance is
initialized. If host is not specified, '' (the local host) is used. If
port is omitted, the standard IMAP4 port (143) is used.
Three exceptions are defined as attributes of the IMAP4 class:
- Exception raised on any errors. The reason for the exception is passed to the
constructor as a string.
- IMAP4 server errors cause this exception to be raised. This is a sub-class of
IMAP4.error. Note that closing the instance and instantiating a new one
will usually allow recovery from this exception.
- This exception is raised when a writable mailbox has its status changed by the
server. This is a sub-class of IMAP4.error. Some other client now has
write permission, and the mailbox will need to be re-opened to re-obtain write
There’s also a subclass for secure connections:
class imaplib.IMAP4_SSL(host='', port=IMAP4_SSL_PORT, keyfile=None, certfile=None)
- This is a subclass derived from IMAP4 that connects over an SSL
encrypted socket (to use this class you need a socket module that was compiled
with SSL support). If host is not specified, '' (the local host) is used.
If port is omitted, the standard IMAP4-over-SSL port (993) is used. keyfile
and certfile are also optional - they can contain a PEM formatted private key
and certificate chain file for the SSL connection.
The second subclass allows for connections created by a child process:
- This is a subclass derived from IMAP4 that connects to the
stdin/stdout file descriptors created by passing command to
The following utility functions are defined:
- Converts an IMAP4 INTERNALDATE string to Coordinated Universal Time. Returns a
time module tuple.
- Converts an integer into a string representation using characters from the set
[A .. P].
- Converts an IMAP4 FLAGS response to a tuple of individual flags.
- Converts a time module tuple to an IMAP4 INTERNALDATE representation.
Returns a string in the form: "DD-Mmm-YYYY HH:MM:SS +HHMM" (including
Note that IMAP4 message numbers change as the mailbox changes; in particular,
after an EXPUNGE command performs deletions the remaining messages are
renumbered. So it is highly advisable to use UIDs instead, with the UID command.
At the end of the module, there is a test section that contains a more extensive
example of usage.
Documents describing the protocol, and sources and binaries for servers
implementing it, can all be found at the University of Washington’s IMAP
Information Center (http://www.washington.edu/imap/).
20.13.1. IMAP4 Objects
All IMAP4rev1 commands are represented by methods of the same name, either
upper-case or lower-case.
All arguments to commands are converted to strings, except for AUTHENTICATE,
and the last argument to APPEND which is passed as an IMAP4 literal. If
necessary (the string contains IMAP4 protocol-sensitive characters and isn’t
enclosed with either parentheses or double quotes) each string is quoted.
However, the password argument to the LOGIN command is always quoted. If
you want to avoid having an argument string quoted (eg: the flags argument to
STORE) then enclose the string in parentheses (eg: r'(\Deleted)').
Each command returns a tuple: (type, [data, ...]) where type is usually
'OK' or 'NO', and data is either the text from the command response,
or mandated results from the command. Each data is either a string, or a
tuple. If a tuple, then the first part is the header of the response, and the
second part contains the data (ie: ‘literal’ value).
The message_set options to commands below is a string specifying one or more
messages to be acted upon. It may be a simple message number ('1'), a range
of message numbers ('2:4'), or a group of non-contiguous ranges separated by
commas ('1:3,6:9'). A range can contain an asterisk to indicate an infinite
upper bound ('3:*').
An IMAP4 instance has the following methods:
IMAP4.append(mailbox, flags, date_time, message)
- Append message to named mailbox.
Authenticate command — requires response processing.
mechanism specifies which authentication mechanism is to be used - it should
appear in the instance variable capabilities in the form AUTH=mechanism.
authobject must be a callable object:
data = authobject(response)
It will be called to process server continuation responses. It should return
data that will be encoded and sent to server. It should return None if
the client abort response * should be sent instead.
- Checkpoint mailbox on server.
- Close currently selected mailbox. Deleted messages are removed from writable
mailbox. This is the recommended command before LOGOUT.
- Copy message_set messages onto end of new_mailbox.
- Create new mailbox named mailbox.
- Delete old mailbox named mailbox.
- Delete the ACLs (remove any rights) set for who on mailbox.
- Permanently remove deleted items from selected mailbox. Generates an EXPUNGE
response for each deleted message. Returned data contains a list of EXPUNGE
message numbers in order received.
- Fetch (parts of) messages. message_parts should be a string of message part
names enclosed within parentheses, eg: "(UID BODY[TEXT])". Returned data
are tuples of message part envelope and data.
- Get the ACLs for mailbox. The method is non-standard, but is supported
by the Cyrus server.
IMAP4.getannotation(mailbox, entry, attribute)
- Retrieve the specified ANNOTATIONs for mailbox. The method is
non-standard, but is supported by the Cyrus server.
- Get the quota root‘s resource usage and limits. This method is part of the
IMAP4 QUOTA extension defined in rfc2087.
- Get the list of quota roots for the named mailbox. This method is part
of the IMAP4 QUOTA extension defined in rfc2087.
- List mailbox names in directory matching pattern. directory defaults to
the top-level mail folder, and pattern defaults to match anything. Returned
data contains a list of LIST responses.
- Identify the client using a plaintext password. The password will be quoted.
- Force use of CRAM-MD5 authentication when identifying the client to protect
the password. Will only work if the server CAPABILITY response includes the
- Shutdown connection to server. Returns server BYE response.
- List subscribed mailbox names in directory matching pattern. directory
defaults to the top level directory and pattern defaults to match any mailbox.
Returned data are tuples of message part envelope and data.
- Show my ACLs for a mailbox (i.e. the rights that I have on mailbox).
- Returns IMAP namespaces as defined in RFC2342.
- Send NOOP to server.
- Opens socket to port at host. This method is implicitly called by
the IMAP4 constructor. The connection objects established by this
method will be used in the read, readline, send, and shutdown
methods. You may override this method.
IMAP4.partial(message_num, message_part, start, length)
- Fetch truncated part of a message. Returned data is a tuple of message part
envelope and data.
- Assume authentication as user. Allows an authorised administrator to proxy
into any user’s mailbox.
- Reads size bytes from the remote server. You may override this method.
- Reads one line from the remote server. You may override this method.
- Prompt server for an update. Returned data is None if no new messages, else
value of RECENT response.
- Rename mailbox named oldmailbox to newmailbox.
- Return data for response code if received, or None. Returns the given
code, instead of the usual type.
IMAP4.search(charset, criterion[, ...])
Search mailbox for matching messages. charset may be None, in which case
no CHARSET will be specified in the request to the server. The IMAP
protocol requires that at least one criterion be specified; an exception will be
raised when the server returns an error.
# M is a connected IMAP4 instance...
typ, msgnums = M.search(None, 'FROM', '"LDJ"')
typ, msgnums = M.search(None, '(FROM "LDJ")')
- Select a mailbox. Returned data is the count of messages in mailbox
(EXISTS response). The default mailbox is 'INBOX'. If the readonly
flag is set, modifications to the mailbox are not allowed.
- Sends data to the remote server. You may override this method.
IMAP4.setacl(mailbox, who, what)
- Set an ACL for mailbox. The method is non-standard, but is supported by
the Cyrus server.
IMAP4.setannotation(mailbox, entry, attribute[, ...])
- Set ANNOTATIONs for mailbox. The method is non-standard, but is
supported by the Cyrus server.
- Set the quota root‘s resource limits. This method is part of the IMAP4
QUOTA extension defined in rfc2087.
- Close connection established in open. This method is implicitly
called by IMAP4.logout(). You may override this method.
- Returns socket instance used to connect to server.
IMAP4.sort(sort_criteria, charset, search_criterion[, ...])
The sort command is a variant of search with sorting semantics for the
results. Returned data contains a space separated list of matching message
Sort has two arguments before the search_criterion argument(s); a
parenthesized list of sort_criteria, and the searching charset. Note that
unlike search, the searching charset argument is mandatory. There is also
a uid sort command which corresponds to sort the way that uid search
corresponds to search. The sort command first searches the mailbox for
messages that match the given searching criteria using the charset argument for
the interpretation of strings in the searching criteria. It then returns the
numbers of matching messages.
This is an IMAP4rev1 extension command.
- Request named status conditions for mailbox.
IMAP4.store(message_set, command, flag_list)
Alters flag dispositions for messages in mailbox. command is specified by
section 6.4.6 of RFC 2060 as being one of “FLAGS”, “+FLAGS”, or “-FLAGS”,
optionally with a suffix of “.SILENT”.
For example, to set the delete flag on all messages:
typ, data = M.search(None, 'ALL')
for num in data.split():
M.store(num, '+FLAGS', '\\Deleted')
- Subscribe to new mailbox.
IMAP4.thread(threading_algorithm, charset, search_criterion[, ...])
The thread command is a variant of search with threading semantics for
the results. Returned data contains a space separated list of thread members.
Thread members consist of zero or more messages numbers, delimited by spaces,
indicating successive parent and child.
Thread has two arguments before the search_criterion argument(s); a
threading_algorithm, and the searching charset. Note that unlike
search, the searching charset argument is mandatory. There is also a
uid thread command which corresponds to thread the way that uid
search corresponds to search. The thread command first searches the
mailbox for messages that match the given searching criteria using the charset
argument for the interpretation of strings in the searching criteria. It then
returns the matching messages threaded according to the specified threading
This is an IMAP4rev1 extension command.
IMAP4.uid(command, arg[, ...])
- Execute command args with messages identified by UID, rather than message
number. Returns response appropriate to command. At least one argument must be
supplied; if none are provided, the server will return an error and an exception
will be raised.
- Unsubscribe from old mailbox.
- Allow simple extension commands notified by server in CAPABILITY response.
The following attributes are defined on instances of IMAP4:
- The most recent supported protocol in the CAPABILITY response from the
- Integer value to control debugging output. The initialize value is taken from
the module variable Debug. Values greater than three trace each command.
20.13.2. IMAP4 Example
Here is a minimal example (without error checking) that opens a mailbox and
retrieves and prints all messages:
import getpass, imaplib
M = imaplib.IMAP4()
typ, data = M.search(None, 'ALL')
for num in data.split():
typ, data = M.fetch(num, '(RFC822)')
print('Message %s\n%s\n' % (num, data))