mailbox
— Manipulate mailboxes in various formats¶Source code: Lib/mailbox.py
This module defines two classes, Mailbox
and Message
, for
accessing and manipulating on-disk mailboxes and the messages they contain.
Mailbox
offers a dictionary-like mapping from keys to messages.
Message
extends the email.message
module’s
Message
class with format-specific state and behavior.
Supported mailbox formats are Maildir, mbox, MH, Babyl, and MMDF.
See also
email
Mailbox
objects¶mailbox.
Mailbox
¶A mailbox, which may be inspected and modified.
The Mailbox
class defines an interface and is not intended to be
instantiated. Instead, format-specific subclasses should inherit from
Mailbox
and your code should instantiate a particular subclass.
The Mailbox
interface is dictionary-like, with small keys
corresponding to messages. Keys are issued by the Mailbox
instance
with which they will be used and are only meaningful to that Mailbox
instance. A key continues to identify a message even if the corresponding
message is modified, such as by replacing it with another message.
Messages may be added to a Mailbox
instance using the set-like
method add()
and removed using a del
statement or the set-like
methods remove()
and discard()
.
Mailbox
interface semantics differ from dictionary semantics in some
noteworthy ways. Each time a message is requested, a new representation
(typically a Message
instance) is generated based upon the current
state of the mailbox. Similarly, when a message is added to a
Mailbox
instance, the provided message representation’s contents are
copied. In neither case is a reference to the message representation kept by
the Mailbox
instance.
The default Mailbox
iterator iterates over message representations,
not keys as the default dictionary iterator does. Moreover, modification of a
mailbox during iteration is safe and well-defined. Messages added to the
mailbox after an iterator is created will not be seen by the
iterator. Messages removed from the mailbox before the iterator yields them
will be silently skipped, though using a key from an iterator may result in a
KeyError
exception if the corresponding message is subsequently
removed.
Warning
Be very cautious when modifying mailboxes that might be simultaneously
changed by some other process. The safest mailbox format to use for such
tasks is Maildir; try to avoid using single-file formats such as mbox for
concurrent writing. If you’re modifying a mailbox, you must lock it by
calling the lock()
and unlock()
methods before reading any
messages in the file or making any changes by adding or deleting a
message. Failing to lock the mailbox runs the risk of losing messages or
corrupting the entire mailbox.
Mailbox
instances have the following methods:
add
(message)¶Add message to the mailbox and return the key that has been assigned to it.
Parameter message may be a Message
instance, an
email.message.Message
instance, a string, a byte string, or a
file-like object (which should be open in binary mode). If message is
an instance of the
appropriate format-specific Message
subclass (e.g., if it’s an
mboxMessage
instance and this is an mbox
instance), its
format-specific information is used. Otherwise, reasonable defaults for
format-specific information are used.
Changed in version 3.2: Support for binary input was added.
remove
(key)¶__delitem__
(key)¶discard
(key)¶Delete the message corresponding to key from the mailbox.
If no such message exists, a KeyError
exception is raised if the
method was called as remove()
or __delitem__()
but no
exception is raised if the method was called as discard()
. The
behavior of discard()
may be preferred if the underlying mailbox
format supports concurrent modification by other processes.
__setitem__
(key, message)¶Replace the message corresponding to key with message. Raise a
KeyError
exception if no message already corresponds to key.
As with add()
, parameter message may be a Message
instance, an email.message.Message
instance, a string, a byte
string, or a file-like object (which should be open in binary mode). If
message is an
instance of the appropriate format-specific Message
subclass
(e.g., if it’s an mboxMessage
instance and this is an
mbox
instance), its format-specific information is
used. Otherwise, the format-specific information of the message that
currently corresponds to key is left unchanged.
iterkeys
()¶keys
()¶Return an iterator over all keys if called as iterkeys()
or return a
list of keys if called as keys()
.
itervalues
()¶__iter__
()¶values
()¶Return an iterator over representations of all messages if called as
itervalues()
or __iter__()
or return a list of such
representations if called as values()
. The messages are represented
as instances of the appropriate format-specific Message
subclass
unless a custom message factory was specified when the Mailbox
instance was initialized.
Note
The behavior of __iter__()
is unlike that of dictionaries, which
iterate over keys.
iteritems
()¶items
()¶Return an iterator over (key, message) pairs, where key is a key and
message is a message representation, if called as iteritems()
or
return a list of such pairs if called as items()
. The messages are
represented as instances of the appropriate format-specific
Message
subclass unless a custom message factory was specified
when the Mailbox
instance was initialized.
get
(key, default=None)¶__getitem__
(key)¶Return a representation of the message corresponding to key. If no such
message exists, default is returned if the method was called as
get()
and a KeyError
exception is raised if the method was
called as __getitem__()
. The message is represented as an instance
of the appropriate format-specific Message
subclass unless a
custom message factory was specified when the Mailbox
instance
was initialized.
get_message
(key)¶Return a representation of the message corresponding to key as an
instance of the appropriate format-specific Message
subclass, or
raise a KeyError
exception if no such message exists.
get_bytes
(key)¶Return a byte representation of the message corresponding to key, or
raise a KeyError
exception if no such message exists.
New in version 3.2.
get_string
(key)¶Return a string representation of the message corresponding to key, or
raise a KeyError
exception if no such message exists. The
message is processed through email.message.Message
to
convert it to a 7bit clean representation.
get_file
(key)¶Return a file-like representation of the message corresponding to key,
or raise a KeyError
exception if no such message exists. The
file-like object behaves as if open in binary mode. This file should be
closed once it is no longer needed.
Changed in version 3.2: The file object really is a binary file; previously it was incorrectly
returned in text mode. Also, the file-like object now supports the
context management protocol: you can use a with
statement to
automatically close it.
Note
Unlike other representations of messages, file-like representations are
not necessarily independent of the Mailbox
instance that
created them or of the underlying mailbox. More specific documentation
is provided by each subclass.
__contains__
(key)¶Return True
if key corresponds to a message, False
otherwise.
__len__
()¶Return a count of messages in the mailbox.
clear
()¶Delete all messages from the mailbox.
pop
(key, default=None)¶Return a representation of the message corresponding to key and delete
the message. If no such message exists, return default. The message is
represented as an instance of the appropriate format-specific
Message
subclass unless a custom message factory was specified
when the Mailbox
instance was initialized.
popitem
()¶Return an arbitrary (key, message) pair, where key is a key and
message is a message representation, and delete the corresponding
message. If the mailbox is empty, raise a KeyError
exception. The
message is represented as an instance of the appropriate format-specific
Message
subclass unless a custom message factory was specified
when the Mailbox
instance was initialized.
update
(arg)¶Parameter arg should be a key-to-message mapping or an iterable of
(key, message) pairs. Updates the mailbox so that, for each given
key and message, the message corresponding to key is set to
message as if by using __setitem__()
. As with __setitem__()
,
each key must already correspond to a message in the mailbox or else a
KeyError
exception will be raised, so in general it is incorrect
for arg to be a Mailbox
instance.
Note
Unlike with dictionaries, keyword arguments are not supported.
flush
()¶Write any pending changes to the filesystem. For some Mailbox
subclasses, changes are always written immediately and flush()
does
nothing, but you should still make a habit of calling this method.
lock
()¶Acquire an exclusive advisory lock on the mailbox so that other processes
know not to modify it. An ExternalClashError
is raised if the lock
is not available. The particular locking mechanisms used depend upon the
mailbox format. You should always lock the mailbox before making any
modifications to its contents.
unlock
()¶Release the lock on the mailbox, if any.
Maildir
¶mailbox.
Maildir
(dirname, factory=None, create=True)¶A subclass of Mailbox
for mailboxes in Maildir format. Parameter
factory is a callable object that accepts a file-like message representation
(which behaves as if opened in binary mode) and returns a custom representation.
If factory is None
, MaildirMessage
is used as the default message
representation. If create is True
, the mailbox is created if it does not
exist.
It is for historical reasons that dirname is named as such rather than path.
Maildir is a directory-based mailbox format invented for the qmail mail transfer agent and now widely supported by other programs. Messages in a Maildir mailbox are stored in separate files within a common directory structure. This design allows Maildir mailboxes to be accessed and modified by multiple unrelated programs without data corruption, so file locking is unnecessary.
Maildir mailboxes contain three subdirectories, namely: tmp
,
new
, and cur
. Messages are created momentarily in the
tmp
subdirectory and then moved to the new
subdirectory to
finalize delivery. A mail user agent may subsequently move the message to the
cur
subdirectory and store information about the state of the message
in a special “info” section appended to its file name.
Folders of the style introduced by the Courier mail transfer agent are also
supported. Any subdirectory of the main mailbox is considered a folder if
'.'
is the first character in its name. Folder names are represented by
Maildir
without the leading '.'
. Each folder is itself a Maildir
mailbox but should not contain other folders. Instead, a logical nesting is
indicated using '.'
to delimit levels, e.g., “Archived.2005.07”.
Note
The Maildir specification requires the use of a colon (':'
) in certain
message file names. However, some operating systems do not permit this
character in file names, If you wish to use a Maildir-like format on such
an operating system, you should specify another character to use
instead. The exclamation point ('!'
) is a popular choice. For
example:
import mailbox
mailbox.Maildir.colon = '!'
The colon
attribute may also be set on a per-instance basis.
Maildir
instances have all of the methods of Mailbox
in
addition to the following:
list_folders
()¶Return a list of the names of all folders.
get_folder
(folder)¶Return a Maildir
instance representing the folder whose name is
folder. A NoSuchMailboxError
exception is raised if the folder
does not exist.
add_folder
(folder)¶Create a folder whose name is folder and return a Maildir
instance representing it.
remove_folder
(folder)¶Delete the folder whose name is folder. If the folder contains any
messages, a NotEmptyError
exception will be raised and the folder
will not be deleted.
clean
()¶Delete temporary files from the mailbox that have not been accessed in the last 36 hours. The Maildir specification says that mail-reading programs should do this occasionally.
Some Mailbox
methods implemented by Maildir
deserve special
remarks:
add
(message)¶__setitem__
(key, message)¶update
(arg)¶Warning
These methods generate unique file names based upon the current process ID. When using multiple threads, undetected name clashes may occur and cause corruption of the mailbox unless threads are coordinated to avoid using these methods to manipulate the same mailbox simultaneously.
flush
()¶All changes to Maildir mailboxes are immediately applied, so this method does nothing.
lock
()¶unlock
()¶Maildir mailboxes do not support (or require) locking, so these methods do nothing.
close
()¶Maildir
instances do not keep any open files and the underlying
mailboxes do not support locking, so this method does nothing.
get_file
(key)¶Depending upon the host platform, it may not be possible to modify or remove the underlying message while the returned file remains open.
See also
mbox
¶mailbox.
mbox
(path, factory=None, create=True)¶A subclass of Mailbox
for mailboxes in mbox format. Parameter factory
is a callable object that accepts a file-like message representation (which
behaves as if opened in binary mode) and returns a custom representation. If
factory is None
, mboxMessage
is used as the default message
representation. If create is True
, the mailbox is created if it does not
exist.
The mbox format is the classic format for storing mail on Unix systems. All messages in an mbox mailbox are stored in a single file with the beginning of each message indicated by a line whose first five characters are “From ”.
Several variations of the mbox format exist to address perceived shortcomings in
the original. In the interest of compatibility, mbox
implements the
original format, which is sometimes referred to as mboxo. This means that
the Content-Length header, if present, is ignored and that any
occurrences of “From ” at the beginning of a line in a message body are
transformed to “>From ” when storing the message, although occurrences of “>From
” are not transformed to “From ” when reading the message.
Some Mailbox
methods implemented by mbox
deserve special
remarks:
See also
MH
¶mailbox.
MH
(path, factory=None, create=True)¶A subclass of Mailbox
for mailboxes in MH format. Parameter factory
is a callable object that accepts a file-like message representation (which
behaves as if opened in binary mode) and returns a custom representation. If
factory is None
, MHMessage
is used as the default message
representation. If create is True
, the mailbox is created if it does not
exist.
MH is a directory-based mailbox format invented for the MH Message Handling
System, a mail user agent. Each message in an MH mailbox resides in its own
file. An MH mailbox may contain other MH mailboxes (called folders) in
addition to messages. Folders may be nested indefinitely. MH mailboxes also
support sequences, which are named lists used to logically group
messages without moving them to sub-folders. Sequences are defined in a file
called .mh_sequences
in each folder.
The MH
class manipulates MH mailboxes, but it does not attempt to
emulate all of mh‘s behaviors. In particular, it does not modify
and is not affected by the context
or .mh_profile
files that
are used by mh to store its state and configuration.
MH
instances have all of the methods of Mailbox
in addition
to the following:
list_folders
()¶Return a list of the names of all folders.
get_folder
(folder)¶Return an MH
instance representing the folder whose name is
folder. A NoSuchMailboxError
exception is raised if the folder
does not exist.
remove_folder
(folder)¶Delete the folder whose name is folder. If the folder contains any
messages, a NotEmptyError
exception will be raised and the folder
will not be deleted.
get_sequences
()¶Return a dictionary of sequence names mapped to key lists. If there are no sequences, the empty dictionary is returned.
set_sequences
(sequences)¶Re-define the sequences that exist in the mailbox based upon sequences,
a dictionary of names mapped to key lists, like returned by
get_sequences()
.
pack
()¶Rename messages in the mailbox as necessary to eliminate gaps in numbering. Entries in the sequences list are updated correspondingly.
Note
Already-issued keys are invalidated by this operation and should not be subsequently used.
Some Mailbox
methods implemented by MH
deserve special
remarks:
remove
(key)¶__delitem__
(key)¶discard
(key)¶These methods immediately delete the message. The MH convention of marking a message for deletion by prepending a comma to its name is not used.
lock
()¶unlock
()¶Three locking mechanisms are used—dot locking and, if available, the
flock()
and lockf()
system calls. For MH mailboxes, locking
the mailbox means locking the .mh_sequences
file and, only for the
duration of any operations that affect them, locking individual message
files.
get_file
(key)¶Depending upon the host platform, it may not be possible to remove the underlying message while the returned file remains open.
flush
()¶All changes to MH mailboxes are immediately applied, so this method does nothing.
See also
Babyl
¶mailbox.
Babyl
(path, factory=None, create=True)¶A subclass of Mailbox
for mailboxes in Babyl format. Parameter
factory is a callable object that accepts a file-like message representation
(which behaves as if opened in binary mode) and returns a custom representation.
If factory is None
, BabylMessage
is used as the default message
representation. If create is True
, the mailbox is created if it does not
exist.
Babyl is a single-file mailbox format used by the Rmail mail user agent
included with Emacs. The beginning of a message is indicated by a line
containing the two characters Control-Underscore ('\037'
) and Control-L
('\014'
). The end of a message is indicated by the start of the next
message or, in the case of the last message, a line containing a
Control-Underscore ('\037'
) character.
Messages in a Babyl mailbox have two sets of headers, original headers and so-called visible headers. Visible headers are typically a subset of the original headers that have been reformatted or abridged to be more attractive. Each message in a Babyl mailbox also has an accompanying list of labels, or short strings that record extra information about the message, and a list of all user-defined labels found in the mailbox is kept in the Babyl options section.
Babyl
instances have all of the methods of Mailbox
in
addition to the following:
get_labels
()¶Return a list of the names of all user-defined labels used in the mailbox.
Note
The actual messages are inspected to determine which labels exist in the mailbox rather than consulting the list of labels in the Babyl options section, but the Babyl section is updated whenever the mailbox is modified.
Some Mailbox
methods implemented by Babyl
deserve special
remarks:
get_file
(key)¶In Babyl mailboxes, the headers of a message are not stored contiguously
with the body of the message. To generate a file-like representation, the
headers and body are copied together into an io.BytesIO
instance,
which has an API identical to that of a
file. As a result, the file-like object is truly independent of the
underlying mailbox but does not save memory compared to a string
representation.
See also
MMDF
¶mailbox.
MMDF
(path, factory=None, create=True)¶A subclass of Mailbox
for mailboxes in MMDF format. Parameter factory
is a callable object that accepts a file-like message representation (which
behaves as if opened in binary mode) and returns a custom representation. If
factory is None
, MMDFMessage
is used as the default message
representation. If create is True
, the mailbox is created if it does not
exist.
MMDF is a single-file mailbox format invented for the Multichannel Memorandum
Distribution Facility, a mail transfer agent. Each message is in the same
form as an mbox message but is bracketed before and after by lines containing
four Control-A ('\001'
) characters. As with the mbox format, the
beginning of each message is indicated by a line whose first five characters
are “From ”, but additional occurrences of “From ” are not transformed to
“>From ” when storing messages because the extra message separator lines
prevent mistaking such occurrences for the starts of subsequent messages.
Some Mailbox
methods implemented by MMDF
deserve special
remarks:
See also
Message
objects¶mailbox.
Message
(message=None)¶A subclass of the email.message
module’s
Message
. Subclasses of mailbox.Message
add
mailbox-format-specific state and behavior.
If message is omitted, the new instance is created in a default, empty state.
If message is an email.message.Message
instance, its contents are
copied; furthermore, any format-specific information is converted insofar as
possible if message is a Message
instance. If message is a string,
a byte string,
or a file, it should contain an RFC 2822-compliant message, which is read
and parsed. Files should be open in binary mode, but text mode files
are accepted for backward compatibility.
The format-specific state and behaviors offered by subclasses vary, but in general it is only the properties that are not specific to a particular mailbox that are supported (although presumably the properties are specific to a particular mailbox format). For example, file offsets for single-file mailbox formats and file names for directory-based mailbox formats are not retained, because they are only applicable to the original mailbox. But state such as whether a message has been read by the user or marked as important is retained, because it applies to the message itself.
There is no requirement that Message
instances be used to represent
messages retrieved using Mailbox
instances. In some situations, the
time and memory required to generate Message
representations might
not be acceptable. For such situations, Mailbox
instances also
offer string and file-like representations, and a custom message factory may
be specified when a Mailbox
instance is initialized.
MaildirMessage
¶mailbox.
MaildirMessage
(message=None)¶A message with Maildir-specific behaviors. Parameter message has the same
meaning as with the Message
constructor.
Typically, a mail user agent application moves all of the messages in the
new
subdirectory to the cur
subdirectory after the first time
the user opens and closes the mailbox, recording that the messages are old
whether or not they’ve actually been read. Each message in cur
has an
“info” section added to its file name to store information about its state.
(Some mail readers may also add an “info” section to messages in
new
.) The “info” section may take one of two forms: it may contain
“2,” followed by a list of standardized flags (e.g., “2,FR”) or it may
contain “1,” followed by so-called experimental information. Standard flags
for Maildir messages are as follows:
Flag | Meaning | Explanation |
---|---|---|
D | Draft | Under composition |
F | Flagged | Marked as important |
P | Passed | Forwarded, resent, or bounced |
R | Replied | Replied to |
S | Seen | Read |
T | Trashed | Marked for subsequent deletion |
MaildirMessage
instances offer the following methods:
get_subdir
()¶Return either “new” (if the message should be stored in the new
subdirectory) or “cur” (if the message should be stored in the cur
subdirectory).
Note
A message is typically moved from new
to cur
after its
mailbox has been accessed, whether or not the message is has been
read. A message msg
has been read if "S" in msg.get_flags()
is
True
.
set_subdir
(subdir)¶Set the subdirectory the message should be stored in. Parameter subdir must be either “new” or “cur”.
get_flags
()¶Return a string specifying the flags that are currently set. If the
message complies with the standard Maildir format, the result is the
concatenation in alphabetical order of zero or one occurrence of each of
'D'
, 'F'
, 'P'
, 'R'
, 'S'
, and 'T'
. The empty string
is returned if no flags are set or if “info” contains experimental
semantics.
set_flags
(flags)¶Set the flags specified by flags and unset all others.
add_flag
(flag)¶Set the flag(s) specified by flag without changing other flags. To add more than one flag at a time, flag may be a string of more than one character. The current “info” is overwritten whether or not it contains experimental information rather than flags.
remove_flag
(flag)¶Unset the flag(s) specified by flag without changing other flags. To remove more than one flag at a time, flag maybe a string of more than one character. If “info” contains experimental information rather than flags, the current “info” is not modified.
get_date
()¶Return the delivery date of the message as a floating-point number representing seconds since the epoch.
set_date
(date)¶Set the delivery date of the message to date, a floating-point number representing seconds since the epoch.
get_info
()¶Return a string containing the “info” for a message. This is useful for accessing and modifying “info” that is experimental (i.e., not a list of flags).
set_info
(info)¶Set “info” to info, which should be a string.
When a MaildirMessage
instance is created based upon an
mboxMessage
or MMDFMessage
instance, the Status
and X-Status headers are omitted and the following conversions
take place:
Resulting state | mboxMessage or MMDFMessage
state |
---|---|
“cur” subdirectory | O flag |
F flag | F flag |
R flag | A flag |
S flag | R flag |
T flag | D flag |
When a MaildirMessage
instance is created based upon an
MHMessage
instance, the following conversions take place:
Resulting state | MHMessage state |
---|---|
“cur” subdirectory | “unseen” sequence |
“cur” subdirectory and S flag | no “unseen” sequence |
F flag | “flagged” sequence |
R flag | “replied” sequence |
When a MaildirMessage
instance is created based upon a
BabylMessage
instance, the following conversions take place:
Resulting state | BabylMessage state |
---|---|
“cur” subdirectory | “unseen” label |
“cur” subdirectory and S flag | no “unseen” label |
P flag | “forwarded” or “resent” label |
R flag | “answered” label |
T flag | “deleted” label |
mboxMessage
¶mailbox.
mboxMessage
(message=None)¶A message with mbox-specific behaviors. Parameter message has the same meaning
as with the Message
constructor.
Messages in an mbox mailbox are stored together in a single file. The sender’s envelope address and the time of delivery are typically stored in a line beginning with “From ” that is used to indicate the start of a message, though there is considerable variation in the exact format of this data among mbox implementations. Flags that indicate the state of the message, such as whether it has been read or marked as important, are typically stored in Status and X-Status headers.
Conventional flags for mbox messages are as follows:
Flag | Meaning | Explanation |
---|---|---|
R | Read | Read |
O | Old | Previously detected by MUA |
D | Deleted | Marked for subsequent deletion |
F | Flagged | Marked as important |
A | Answered | Replied to |
The “R” and “O” flags are stored in the Status header, and the “D”, “F”, and “A” flags are stored in the X-Status header. The flags and headers typically appear in the order mentioned.
mboxMessage
instances offer the following methods:
get_from
()¶Return a string representing the “From ” line that marks the start of the message in an mbox mailbox. The leading “From ” and the trailing newline are excluded.
set_from
(from_, time_=None)¶Set the “From ” line to from_, which should be specified without a
leading “From ” or trailing newline. For convenience, time_ may be
specified and will be formatted appropriately and appended to from_. If
time_ is specified, it should be a time.struct_time
instance, a
tuple suitable for passing to time.strftime()
, or True
(to use
time.gmtime()
).
get_flags
()¶Return a string specifying the flags that are currently set. If the
message complies with the conventional format, the result is the
concatenation in the following order of zero or one occurrence of each of
'R'
, 'O'
, 'D'
, 'F'
, and 'A'
.
set_flags
(flags)¶Set the flags specified by flags and unset all others. Parameter flags
should be the concatenation in any order of zero or more occurrences of
each of 'R'
, 'O'
, 'D'
, 'F'
, and 'A'
.
add_flag
(flag)¶Set the flag(s) specified by flag without changing other flags. To add more than one flag at a time, flag may be a string of more than one character.
remove_flag
(flag)¶Unset the flag(s) specified by flag without changing other flags. To remove more than one flag at a time, flag maybe a string of more than one character.
When an mboxMessage
instance is created based upon a
MaildirMessage
instance, a “From ” line is generated based upon the
MaildirMessage
instance’s delivery date, and the following conversions
take place:
Resulting state | MaildirMessage state |
---|---|
R flag | S flag |
O flag | “cur” subdirectory |
D flag | T flag |
F flag | F flag |
A flag | R flag |
When an mboxMessage
instance is created based upon an
MHMessage
instance, the following conversions take place:
Resulting state | MHMessage state |
---|---|
R flag and O flag | no “unseen” sequence |
O flag | “unseen” sequence |
F flag | “flagged” sequence |
A flag | “replied” sequence |
When an mboxMessage
instance is created based upon a
BabylMessage
instance, the following conversions take place:
Resulting state | BabylMessage state |
---|---|
R flag and O flag | no “unseen” label |
O flag | “unseen” label |
D flag | “deleted” label |
A flag | “answered” label |
When a Message
instance is created based upon an MMDFMessage
instance, the “From ” line is copied and all flags directly correspond:
Resulting state | MMDFMessage state |
---|---|
R flag | R flag |
O flag | O flag |
D flag | D flag |
F flag | F flag |
A flag | A flag |
MHMessage
¶mailbox.
MHMessage
(message=None)¶A message with MH-specific behaviors. Parameter message has the same meaning
as with the Message
constructor.
MH messages do not support marks or flags in the traditional sense, but they do support sequences, which are logical groupings of arbitrary messages. Some mail reading programs (although not the standard mh and nmh) use sequences in much the same way flags are used with other formats, as follows:
Sequence | Explanation |
---|---|
unseen | Not read, but previously detected by MUA |
replied | Replied to |
flagged | Marked as important |
MHMessage
instances offer the following methods:
get_sequences
()¶Return a list of the names of sequences that include this message.
set_sequences
(sequences)¶Set the list of sequences that include this message.
add_sequence
(sequence)¶Add sequence to the list of sequences that include this message.
remove_sequence
(sequence)¶Remove sequence from the list of sequences that include this message.
When an MHMessage
instance is created based upon a
MaildirMessage
instance, the following conversions take place:
Resulting state | MaildirMessage state |
---|---|
“unseen” sequence | no S flag |
“replied” sequence | R flag |
“flagged” sequence | F flag |
When an MHMessage
instance is created based upon an
mboxMessage
or MMDFMessage
instance, the Status
and X-Status headers are omitted and the following conversions
take place:
Resulting state | mboxMessage or MMDFMessage
state |
---|---|
“unseen” sequence | no R flag |
“replied” sequence | A flag |
“flagged” sequence | F flag |
When an MHMessage
instance is created based upon a
BabylMessage
instance, the following conversions take place:
Resulting state | BabylMessage state |
---|---|
“unseen” sequence | “unseen” label |
“replied” sequence | “answered” label |
BabylMessage
¶mailbox.
BabylMessage
(message=None)¶A message with Babyl-specific behaviors. Parameter message has the same
meaning as with the Message
constructor.
Certain message labels, called attributes, are defined by convention to have special meanings. The attributes are as follows:
Label | Explanation |
---|---|
unseen | Not read, but previously detected by MUA |
deleted | Marked for subsequent deletion |
filed | Copied to another file or mailbox |
answered | Replied to |
forwarded | Forwarded |
edited | Modified by the user |
resent | Resent |
By default, Rmail displays only visible headers. The BabylMessage
class, though, uses the original headers because they are more
complete. Visible headers may be accessed explicitly if desired.
BabylMessage
instances offer the following methods:
get_labels
()¶Return a list of labels on the message.
set_labels
(labels)¶Set the list of labels on the message to labels.
add_label
(label)¶Add label to the list of labels on the message.
remove_label
(label)¶Remove label from the list of labels on the message.
get_visible
()¶Return an Message
instance whose headers are the message’s
visible headers and whose body is empty.
set_visible
(visible)¶Set the message’s visible headers to be the same as the headers in
message. Parameter visible should be a Message
instance, an
email.message.Message
instance, a string, or a file-like object
(which should be open in text mode).
update_visible
()¶When a BabylMessage
instance’s original headers are modified, the
visible headers are not automatically modified to correspond. This method
updates the visible headers as follows: each visible header with a
corresponding original header is set to the value of the original header,
each visible header without a corresponding original header is removed,
and any of Date, From, Reply-To,
To, CC, and Subject that are
present in the original headers but not the visible headers are added to
the visible headers.
When a BabylMessage
instance is created based upon a
MaildirMessage
instance, the following conversions take place:
Resulting state | MaildirMessage state |
---|---|
“unseen” label | no S flag |
“deleted” label | T flag |
“answered” label | R flag |
“forwarded” label | P flag |
When a BabylMessage
instance is created based upon an
mboxMessage
or MMDFMessage
instance, the Status
and X-Status headers are omitted and the following conversions
take place:
Resulting state | mboxMessage or MMDFMessage
state |
---|---|
“unseen” label | no R flag |
“deleted” label | D flag |
“answered” label | A flag |
When a BabylMessage
instance is created based upon an
MHMessage
instance, the following conversions take place:
Resulting state | MHMessage state |
---|---|
“unseen” label | “unseen” sequence |
“answered” label | “replied” sequence |
MMDFMessage
¶mailbox.
MMDFMessage
(message=None)¶A message with MMDF-specific behaviors. Parameter message has the same meaning
as with the Message
constructor.
As with message in an mbox mailbox, MMDF messages are stored with the sender’s address and the delivery date in an initial line beginning with “From ”. Likewise, flags that indicate the state of the message are typically stored in Status and X-Status headers.
Conventional flags for MMDF messages are identical to those of mbox message and are as follows:
Flag | Meaning | Explanation |
---|---|---|
R | Read | Read |
O | Old | Previously detected by MUA |
D | Deleted | Marked for subsequent deletion |
F | Flagged | Marked as important |
A | Answered | Replied to |
The “R” and “O” flags are stored in the Status header, and the “D”, “F”, and “A” flags are stored in the X-Status header. The flags and headers typically appear in the order mentioned.
MMDFMessage
instances offer the following methods, which are
identical to those offered by mboxMessage
:
get_from
()¶Return a string representing the “From ” line that marks the start of the message in an mbox mailbox. The leading “From ” and the trailing newline are excluded.
set_from
(from_, time_=None)¶Set the “From ” line to from_, which should be specified without a
leading “From ” or trailing newline. For convenience, time_ may be
specified and will be formatted appropriately and appended to from_. If
time_ is specified, it should be a time.struct_time
instance, a
tuple suitable for passing to time.strftime()
, or True
(to use
time.gmtime()
).
get_flags
()¶Return a string specifying the flags that are currently set. If the
message complies with the conventional format, the result is the
concatenation in the following order of zero or one occurrence of each of
'R'
, 'O'
, 'D'
, 'F'
, and 'A'
.
set_flags
(flags)¶Set the flags specified by flags and unset all others. Parameter flags
should be the concatenation in any order of zero or more occurrences of
each of 'R'
, 'O'
, 'D'
, 'F'
, and 'A'
.
add_flag
(flag)¶Set the flag(s) specified by flag without changing other flags. To add more than one flag at a time, flag may be a string of more than one character.
remove_flag
(flag)¶Unset the flag(s) specified by flag without changing other flags. To remove more than one flag at a time, flag maybe a string of more than one character.
When an MMDFMessage
instance is created based upon a
MaildirMessage
instance, a “From ” line is generated based upon the
MaildirMessage
instance’s delivery date, and the following conversions
take place:
Resulting state | MaildirMessage state |
---|---|
R flag | S flag |
O flag | “cur” subdirectory |
D flag | T flag |
F flag | F flag |
A flag | R flag |
When an MMDFMessage
instance is created based upon an
MHMessage
instance, the following conversions take place:
Resulting state | MHMessage state |
---|---|
R flag and O flag | no “unseen” sequence |
O flag | “unseen” sequence |
F flag | “flagged” sequence |
A flag | “replied” sequence |
When an MMDFMessage
instance is created based upon a
BabylMessage
instance, the following conversions take place:
Resulting state | BabylMessage state |
---|---|
R flag and O flag | no “unseen” label |
O flag | “unseen” label |
D flag | “deleted” label |
A flag | “answered” label |
When an MMDFMessage
instance is created based upon an
mboxMessage
instance, the “From ” line is copied and all flags directly
correspond:
Resulting state | mboxMessage state |
---|---|
R flag | R flag |
O flag | O flag |
D flag | D flag |
F flag | F flag |
A flag | A flag |
The following exception classes are defined in the mailbox
module:
mailbox.
Error
¶The based class for all other module-specific exceptions.
mailbox.
NoSuchMailboxError
¶Raised when a mailbox is expected but is not found, such as when instantiating a
Mailbox
subclass with a path that does not exist (and with the create
parameter set to False
), or when opening a folder that does not exist.
mailbox.
NotEmptyError
¶Raised when a mailbox is not empty but is expected to be, such as when deleting a folder that contains messages.
mailbox.
ExternalClashError
¶Raised when some mailbox-related condition beyond the control of the program causes it to be unable to proceed, such as when failing to acquire a lock that another program already holds a lock, or when a uniquely-generated file name already exists.
A simple example of printing the subjects of all messages in a mailbox that seem interesting:
import mailbox
for message in mailbox.mbox('~/mbox'):
subject = message['subject'] # Could possibly be None.
if subject and 'python' in subject.lower():
print(subject)
To copy all mail from a Babyl mailbox to an MH mailbox, converting all of the format-specific information that can be converted:
import mailbox
destination = mailbox.MH('~/Mail')
destination.lock()
for message in mailbox.Babyl('~/RMAIL'):
destination.add(mailbox.MHMessage(message))
destination.flush()
destination.unlock()
This example sorts mail from several mailing lists into different mailboxes, being careful to avoid mail corruption due to concurrent modification by other programs, mail loss due to interruption of the program, or premature termination due to malformed messages in the mailbox:
import mailbox
import email.errors
list_names = ('python-list', 'python-dev', 'python-bugs')
boxes = {name: mailbox.mbox('~/email/%s' % name) for name in list_names}
inbox = mailbox.Maildir('~/Maildir', factory=None)
for key in inbox.iterkeys():
try:
message = inbox[key]
except email.errors.MessageParseError:
continue # The message is malformed. Just leave it.
for name in list_names:
list_id = message['list-id']
if list_id and name in list_id:
# Get mailbox to use
box = boxes[name]
# Write copy to disk before removing original.
# If there's a crash, you might duplicate a message, but
# that's better than losing a message completely.
box.lock()
box.add(message)
box.flush()
box.unlock()
# Remove original message
inbox.lock()
inbox.discard(key)
inbox.flush()
inbox.unlock()
break # Found destination, so stop looking.
for box in boxes.itervalues():
box.close()