imaplib —- IMAP4 protocol client

Source code:Lib/imaplib.py

This module defines three classes, IMAP4, IMAP4_SSL andIMAP4_stream, which encapsulate a connection to an IMAP4 server andimplement a large subset of the IMAP4rev1 client protocol as defined inRFC 2060. It is backward compatible with IMAP4 (RFC 1730) servers, butnote that the STATUS command is not supported in IMAP4.

Three classes are provided by the imaplib module, IMAP4 is thebase class:

  • class imaplib.IMAP4(host='', port=IMAP4_PORT)
  • This class implements the actual IMAP4 protocol. The connection is created andprotocol version (IMAP4 or IMAP4rev1) is determined when the instance isinitialized. If host is not specified, '' (the local host) is used. Ifport is omitted, the standard IMAP4 port (143) is used.

The IMAP4 class supports the with statement. When usedlike this, the IMAP4 LOGOUT command is issued automatically when thewith statement exits. E.g.:

  1. >>> from imaplib import IMAP4
  2. >>> with IMAP4("domain.org") as M:
  3. ...     M.noop()
  4. ...
  5. ('OK', [b'Nothing Accomplished. d25if65hy903weo.87'])

在 3.5 版更改: 支持了 with 语句。

Three exceptions are defined as attributes of the IMAP4 class:

  • exception IMAP4.error
  • Exception raised on any errors. The reason for the exception is passed to theconstructor as a string.
  • exception IMAP4.abort
  • IMAP4 server errors cause this exception to be raised. This is a sub-class ofIMAP4.error. Note that closing the instance and instantiating a new onewill usually allow recovery from this exception.
  • exception IMAP4.readonly
  • This exception is raised when a writable mailbox has its status changed by theserver. This is a sub-class of IMAP4.error. Some other client now haswrite permission, and the mailbox will need to be re-opened to re-obtain writepermission.

There's also a subclass for secure connections:

  • class imaplib.IMAP4SSL(_host='', port=IMAP4_SSL_PORT, keyfile=None, certfile=None, ssl_context=None)
  • This is a subclass derived from IMAP4 that connects over an SSLencrypted socket (to use this class you need a socket module that was compiledwith 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.ssl_context is a ssl.SSLContext object which allows bundlingSSL configuration options, certificates and private keys into a single(potentially long-lived) structure. Please read Security considerations forbest practices.

keyfile and certfile are a legacy alternative to ssl_context - theycan point to PEM-formatted private key and certificate chain files forthe SSL connection. Note that the keyfile/certfile parameters aremutually exclusive with ssl_context, a ValueError is raisedif keyfile/certfile is provided along with ssl_context.

在 3.3 版更改: ssl_context parameter added.

在 3.4 版更改: The class now supports hostname check withssl.SSLContext.check_hostname and Server Name Indication (seessl.HAS_SNI).

3.6 版后已移除: keyfile and certfile are deprecated in favor of ssl_context.Please use ssl.SSLContext.load_cert_chain() instead, or letssl.create_default_context() select the system's trusted CAcertificates for you.

The second subclass allows for connections created by a child process:

  • class imaplib.IMAP4stream(_command)
  • This is a subclass derived from IMAP4 that connects to thestdin/stdout file descriptors created by passing command tosubprocess.Popen().

The following utility functions are defined:

  • imaplib.Internaldate2tuple(datestr)
  • Parse an IMAP4 INTERNALDATE string and return corresponding localtime. The return value is a time.struct_time tuple orNone if the string has wrong format.
  • imaplib.Int2AP(num)
  • Converts an integer into a string representation using characters from the set[A .. P].
  • imaplib.ParseFlags(flagstr)
  • Converts an IMAP4 FLAGS response to a tuple of individual flags.
  • imaplib.Time2Internaldate(date_time)
  • Convert date_time to an IMAP4 INTERNALDATE representation.The return value is a string in the form: "DD-Mmm-YYYY HH:MM:SS+HHMM" (including double-quotes). The date_time argument canbe a number (int or float) representing seconds since epoch (asreturned by time.time()), a 9-tuple representing local timean instance of time.struct_time (as returned bytime.localtime()), an aware instance ofdatetime.datetime, or a double-quoted string. In the lastcase, it is assumed to already be in the correct format.

Note that IMAP4 message numbers change as the mailbox changes; in particular,after an EXPUNGE command performs deletions the remaining messages arerenumbered. 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 extensiveexample of usage.

参见

Documents describing the protocol, and sources and binaries for serversimplementing it, can all be found at the University of Washington's IMAPInformation Center (https://www.washington.edu/imap/).

IMAP4 Objects

All IMAP4rev1 commands are represented by methods of the same name, eitherupper-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. Ifnecessary (the string contains IMAP4 protocol-sensitive characters and isn'tenclosed with either parentheses or double quotes) each string is quoted.However, the password argument to the LOGIN command is always quoted. Ifyou want to avoid having an argument string quoted (eg: the flags argument toSTORE) 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 atuple. If a tuple, then the first part is the header of the response, and thesecond part contains the data (ie: 'literal' value).

The message_set options to commands below is a string specifying one or moremessages to be acted upon. It may be a simple message number ('1'), a rangeof message numbers ('2:4'), or a group of non-contiguous ranges separated bycommas ('1:3,6:9'). A range can contain an asterisk to indicate an infiniteupper bound ('3:*').

An IMAP4 instance has the following methods:

  • IMAP4.append(mailbox, flags, date_time, message)
  • Append message to named mailbox.
  • IMAP4.authenticate(mechanism, authobject)
  • Authenticate command —- requires response processing.

mechanism specifies which authentication mechanism is to be used - it shouldappear in the instance variable capabilities in the form AUTH=mechanism.

authobject must be a callable object:

  1. data = authobject(response)

It will be called to process server continuation responses; the _response_argument it is passed will be bytes. It should return bytes _data_that will be base64 encoded and sent to the server. It should returnNone if the client abort response * should be sent instead.

在 3.5 版更改: string usernames and passwords are now encoded to utf-8 instead ofbeing limited to ASCII.

  • IMAP4.check()
  • Checkpoint mailbox on server.
  • IMAP4.close()
  • Close currently selected mailbox. Deleted messages are removed from writablemailbox. This is the recommended command before LOGOUT.
  • IMAP4.copy(message_set, new_mailbox)
  • Copy message_set messages onto end of new_mailbox.
  • IMAP4.create(mailbox)
  • Create new mailbox named mailbox.
  • IMAP4.delete(mailbox)
  • Delete old mailbox named mailbox.
  • IMAP4.deleteacl(mailbox, who)
  • Delete the ACLs (remove any rights) set for who on mailbox.
  • IMAP4.enable(capability)
  • Enable capability (see RFC 5161). Most capabilities do not need to beenabled. Currently only the UTF8=ACCEPT capability is supported(see RFC 6855).

3.5 新版功能: The enable() method itself, and RFC 6855 support.

  • IMAP4.expunge()
  • Permanently remove deleted items from selected mailbox. Generates an EXPUNGEresponse for each deleted message. Returned data contains a list of EXPUNGEmessage numbers in order received.
  • IMAP4.fetch(message_set, message_parts)
  • Fetch (parts of) messages. message_parts should be a string of message partnames enclosed within parentheses, eg: "(UID BODY[TEXT])". Returned dataare tuples of message part envelope and data.
  • IMAP4.getacl(mailbox)
  • Get the ACLs for mailbox. The method is non-standard, but is supportedby the Cyrus server.
  • IMAP4.getannotation(mailbox, entry, attribute)
  • Retrieve the specified ANNOTATIONs for mailbox. The method isnon-standard, but is supported by the Cyrus server.
  • IMAP4.getquota(root)
  • Get the quota root's resource usage and limits. This method is part of theIMAP4 QUOTA extension defined in rfc2087.
  • IMAP4.getquotaroot(mailbox)
  • Get the list of quota roots for the named mailbox. This method is partof the IMAP4 QUOTA extension defined in rfc2087.
  • IMAP4.list([directory[, pattern]])
  • List mailbox names in directory matching pattern. directory defaults tothe top-level mail folder, and pattern defaults to match anything. Returneddata contains a list of LIST responses.
  • IMAP4.login(user, password)
  • Identify the client using a plaintext password. The password will be quoted.
  • IMAP4.logincram_md5(_user, password)
  • Force use of CRAM-MD5 authentication when identifying the client to protectthe password. Will only work if the server CAPABILITY response includes thephrase AUTH=CRAM-MD5.
  • IMAP4.logout()
  • Shutdown connection to server. Returns server BYE response.
  • IMAP4.lsub(directory='""', pattern='*')
  • 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.
  • IMAP4.myrights(mailbox)
  • Show my ACLs for a mailbox (i.e. the rights that I have on mailbox).
  • IMAP4.namespace()
  • Returns IMAP namespaces as defined in RFC 2342.
  • IMAP4.noop()
  • Send NOOP to server.
  • IMAP4.partial(message_num, message_part, start, length)
  • Fetch truncated part of a message. Returned data is a tuple of message partenvelope and data.
  • IMAP4.proxyauth(user)
  • Assume authentication as user. Allows an authorised administrator to proxyinto any user's mailbox.
  • IMAP4.read(size)
  • Reads size bytes from the remote server. You may override this method.
  • IMAP4.readline()
  • Reads one line from the remote server. You may override this method.
  • IMAP4.recent()
  • Prompt server for an update. Returned data is None if no new messages, elsevalue of RECENT response.
  • IMAP4.rename(oldmailbox, newmailbox)
  • Rename mailbox named oldmailbox to newmailbox.
  • IMAP4.response(code)
  • Return data for response code if received, or None. Returns the givencode, instead of the usual type.
  • IMAP4.search(charset, criterion[, …])
  • Search mailbox for matching messages. charset may be None, in which caseno CHARSET will be specified in the request to the server. The IMAPprotocol requires that at least one criterion be specified; an exception will beraised when the server returns an error. charset must be None ifthe UTF8=ACCEPT capability was enabled using the enable()command.

示例:

  1. # M is a connected IMAP4 instance...
  2. typ, msgnums = M.search(None, 'FROM', '"LDJ"')
  3.  
  4. # or:
  5. typ, msgnums = M.search(None, '(FROM "LDJ")')
  • IMAP4.select(mailbox='INBOX', readonly=False)
  • 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.
  • IMAP4.send(data)
  • 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 bythe Cyrus server.
  • IMAP4.setannotation(mailbox, entry, attribute[, …])
  • Set ANNOTATIONs for mailbox. The method is non-standard, but issupported by the Cyrus server.
  • IMAP4.setquota(root, limits)
  • Set the quota root's resource limits. This method is part of the IMAP4QUOTA extension defined in rfc2087.
  • IMAP4.shutdown()
  • Close connection established in open. This method is implicitlycalled by IMAP4.logout(). You may override this method.
  • IMAP4.socket()
  • 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 theresults. Returned data contains a space separated list of matching messagenumbers.

Sort has two arguments before the search_criterion argument(s); aparenthesized list of sort_criteria, and the searching charset. Note thatunlike search, the searching charset argument is mandatory. There is alsoa uid sort command which corresponds to sort the way that uid searchcorresponds to search. The sort command first searches the mailbox formessages that match the given searching criteria using the charset argument forthe interpretation of strings in the searching criteria. It then returns thenumbers of matching messages.

This is an IMAP4rev1 extension command.

  • IMAP4.starttls(ssl_context=None)
  • Send a STARTTLS command. The ssl_context argument is optionaland should be a ssl.SSLContext object. This will enableencryption on the IMAP connection. Please read Security considerations forbest practices.

3.2 新版功能.

在 3.4 版更改: The method now supports hostname check withssl.SSLContext.check_hostname and Server Name Indication (seessl.HAS_SNI).

  • IMAP4.status(mailbox, names)
  • Request named status conditions for mailbox.
  • IMAP4.store(message_set, command, flag_list)
  • Alters flag dispositions for messages in mailbox. command is specified bysection 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:

  1. typ, data = M.search(None, 'ALL')
  2. for num in data[0].split():
  3.    M.store(num, '+FLAGS', '\\Deleted')
  4. M.expunge()

注解

Creating flags containing ']' (for example: "[test]") violatesRFC 3501 (the IMAP protocol). However, imaplib has historicallyallowed creation of such tags, and popular IMAP servers, such as Gmail,accept and produce such flags. There are non-Python programs which alsocreate such tags. Although it is an RFC violation and IMAP clients andservers are supposed to be strict, imaplib nonetheless continues to allowsuch tags to be created for backward compatibility reasons, and as ofPython 3.6, handles them if they are sent from the server, since thisimproves real-world compatibility.

  • IMAP4.subscribe(mailbox)
  • Subscribe to new mailbox.
  • IMAP4.thread(threading_algorithm, charset, search_criterion[, …])
  • The thread command is a variant of search with threading semantics forthe 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); athreading_algorithm, and the searching charset. Note that unlikesearch, the searching charset argument is mandatory. There is also auid thread command which corresponds to thread the way that uidsearch corresponds to search. The thread command first searches themailbox for messages that match the given searching criteria using the charsetargument for the interpretation of strings in the searching criteria. It thenreturns the matching messages threaded according to the specified threadingalgorithm.

This is an IMAP4rev1 extension command.

  • IMAP4.uid(command, arg[, …])
  • Execute command args with messages identified by UID, rather than messagenumber. Returns response appropriate to command. At least one argument must besupplied; if none are provided, the server will return an error and an exceptionwill be raised.
  • IMAP4.unsubscribe(mailbox)
  • Unsubscribe from old mailbox.
  • IMAP4.xatom(name[, …])
  • Allow simple extension commands notified by server in CAPABILITY response.

The following attributes are defined on instances of IMAP4:

  • IMAP4.PROTOCOL_VERSION
  • The most recent supported protocol in the CAPABILITY response from theserver.
  • IMAP4.debug
  • Integer value to control debugging output. The initialize value is taken fromthe module variable Debug. Values greater than three trace each command.
  • IMAP4.utf8_enabled
  • Boolean value that is normally False, but is set to True if anenable() command is successfully issued for the UTF8=ACCEPTcapability.

3.5 新版功能.

IMAP4 Example

Here is a minimal example (without error checking) that opens a mailbox andretrieves and prints all messages:

  1. import getpass, imaplib
  2.  
  3. M = imaplib.IMAP4()
  4. M.login(getpass.getuser(), getpass.getpass())
  5. M.select()
  6. typ, data = M.search(None, 'ALL')
  7. for num in data[0].split():
  8.     typ, data = M.fetch(num, '(RFC822)')
  9.     print('Message %s\n%s\n' % (num, data[0][1]))
  10. M.close()
  11. M.logout()