mailbox
— 操纵各种格式的邮箱
¶
源代码： Lib/mailbox.py
此模块定义 2 类，
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.
另请参阅
email
Mailbox
对象
¶
mailbox.
Mailbox
¶
A mailbox, which may be inspected and modified.
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.
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
实例。
默认
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.
警告
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
实例具有下列方法：
add
(
message
)
¶
添加 message to the mailbox and return the key that has been assigned to it.
Parameter
message
可以是
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.
3.2 版改变： 添加支持二进制输入。
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
可以是
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.
注意
行为在
__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()
和
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.
3.2 版新增。
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.
3.2 版改变：
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.
注意
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
)
¶
返回
True
if
key
corresponds to a message,
False
否则。
__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
被设为
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
实例。
注意
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
)
¶
子类化的
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
，和
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”.
注意
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 = '!'
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
)
¶
返回
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
)
¶
警告
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.
另请参阅
mbox
¶
mailbox.
mbox
(
path
,
factory=None
,
create=True
)
¶
子类化的
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:
另请参阅
MH
¶
mailbox.
MH
(
path
,
factory=None
,
create=True
)
¶
子类化的
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.
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
)
¶
返回
MH
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 an
MH
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.
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.
注意
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.
另请参阅
Babyl
¶
mailbox.
Babyl
(
path
,
factory=None
,
create=True
)
¶
子类化的
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.
注意
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.
另请参阅
MMDF
¶
mailbox.
MMDF
(
path
,
factory=None
,
create=True
)
¶
子类化的
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:
另请参阅
Message
对象
¶
mailbox.
Message
(
message=None
)
¶
A subclass of the
email.message
module’s
Message
. Subclasses of
mailbox.Message
add mailbox-format-specific state and behavior.
若
message
is omitted, the new instance is created in a default, empty state. If
message
是
email.message.Message
instance, its contents are copied; furthermore, any format-specific information is converted insofar as possible if
message
是
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
构造函数。
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 | 含义 | 解释 |
|---|---|---|
| D | 草案 | 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).
注意
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'
，和
'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.
当
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 |
当
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 |
当
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
构造函数。
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 | 含义 | 解释 |
|---|---|---|
| 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_
。若
time_
is specified, it should be a
time.struct_time
instance, a tuple suitable for passing to
time.strftime()
，或
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'
，和
'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'
，和
'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.
当
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 |
当
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 |
当
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 |
当
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
构造函数。
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 | 解释 |
|---|---|
| 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
)
¶
添加 sequence to the list of sequences that include this message.
remove_sequence
(
sequence
)
¶
移除 sequence from the list of sequences that include this message.
当
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 |
当
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 |
当
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
构造函数。
Certain message labels, called attributes , are defined by convention to have special meanings. The attributes are as follows:
| Label | 解释 |
|---|---|
| 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
)
¶
添加 label to the list of labels on the message.
remove_label
(
label
)
¶
移除 label from the list of labels on the message.
get_visible
(
)
¶
返回
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
(
)
¶
当
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
，和
Subject
that are present in the original headers but not the visible headers are added to the visible headers.
当
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 |
当
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 |
当
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
构造函数。
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 | 含义 | 解释 |
|---|---|---|
| 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_
。若
time_
is specified, it should be a
time.struct_time
instance, a tuple suitable for passing to
time.strftime()
，或
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'
，和
'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'
，和
'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.
当
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 |
当
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 |
当
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 |
当
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
模块：
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()