19.1.1. email.message
: 電子メールメッセージの表現¶
ソースコード: Lib/email/message.py
バージョン 3.6 で追加: 1
The central class in the email
package is the EmailMessage
class, imported from the email.message
module. It is the base class for
the email
object model. EmailMessage
provides the core
functionality for setting and querying header fields, for accessing message
bodies, and for creating or modifying structured messages.
An email message consists of headers and a payload (which is also referred to as the content). Headers are RFC 5322 or RFC 6532 style field names and values, where the field name and value are separated by a colon. The colon is not part of either the field name or the field value. The payload may be a simple text message, or a binary object, or a structured sequence of sub-messages each with their own set of headers and their own payload. The latter type of payload is indicated by the message having a MIME type such as multipart/* or message/rfc822.
The conceptual model provided by an EmailMessage
object is that of an
ordered dictionary of headers coupled with a payload that represents the
RFC 5322 body of the message, which might be a list of sub-EmailMessage
objects. In addition to the normal dictionary methods for accessing the header
names and values, there are methods for accessing specialized information from
the headers (for example the MIME content type), for operating on the payload,
for generating a serialized version of the message, and for recursively walking
over the object tree.
The EmailMessage
dictionary-like interface is indexed by the header
names, which must be ASCII values. The values of the dictionary are strings
with some extra methods. Headers are stored and returned in case-preserving
form, but field names are matched case-insensitively. Unlike a real dict,
there is an ordering to the keys, and there can be duplicate keys. Additional
methods are provided for working with headers that have duplicate keys.
The payload is either a string or bytes object, in the case of simple message
objects, or a list of EmailMessage
objects, for MIME container
documents such as multipart/* and message/rfc822
message objects.
-
class
email.message.
EmailMessage
(policy=default)¶ If policy is specified use the rules it specifies to update and serialize the representation of the message. If policy is not set, use the
default
policy, which follows the rules of the email RFCs except for line endings (instead of the RFC mandated\r\n
, it uses the Python standard\n
line endings). For more information see thepolicy
documentation.-
as_string
(unixfrom=False, maxheaderlen=None, policy=None)¶ Return the entire message flattened as a string. When optional unixfrom is true, the envelope header is included in the returned string. unixfrom defaults to
False
. For backward compatibility with the baseMessage
class maxheaderlen is accepted, but defaults toNone
, which means that by default the line length is controlled by themax_line_length
of the policy. The policy argument may be used to override the default policy obtained from the message instance. This can be used to control some of the formatting produced by the method, since the specified policy will be passed to theGenerator
.もし、文字列への変換を完全に行うためにデフォルト値を埋める必要がある場合、メッセージのフラット化は
EmailMessage
の変更を引き起こす可能性があります (例えば、MIME の境界が生成される、変更される等)。Note that this method is provided as a convenience and may not be the most useful way to serialize messages in your application, especially if you are dealing with multiple messages. See
email.generator.Generator
for a more flexible API for serializing messages. Note also that this method is restricted to producing messages serialized as "7 bit clean" whenutf8
isFalse
, which is the default.バージョン 3.6 で変更: the default behavior when maxheaderlen is not specified was changed from defaulting to 0 to defaulting to the value of max_line_length from the policy.
-
__str__
()¶ Equivalent to
as_string(policy=self.policy.clone(utf8=True))
. Allowsstr(msg)
to produce a string containing the serialized message in a readable format.バージョン 3.4 で変更: the method was changed to use
utf8=True
, thus producing an RFC 6531-like message representation, instead of being a direct alias foras_string()
.
-
as_bytes
(unixfrom=False, policy=None)¶ Return the entire message flattened as a bytes object. When optional unixfrom is true, the envelope header is included in the returned string. unixfrom defaults to
False
. The policy argument may be used to override the default policy obtained from the message instance. This can be used to control some of the formatting produced by the method, since the specified policy will be passed to theBytesGenerator
.もし、文字列への変換を完全に行うためにデフォルト値を埋める必要がある場合、メッセージのフラット化は
EmailMessage
の変更を引き起こす可能性があります (例えば、MIME の境界が生成される、変更される等)。Note that this method is provided as a convenience and may not be the most useful way to serialize messages in your application, especially if you are dealing with multiple messages. See
email.generator.BytesGenerator
for a more flexible API for serializing messages.
-
__bytes__
()¶ Equivalent to
as_bytes()
. Allowsbytes(msg)
to produce a bytes object containing the serialized message.
-
is_multipart
()¶ Return
True
if the message's payload is a list of sub-EmailMessage
objects, otherwise returnFalse
. Whenis_multipart()
returnsFalse
, the payload should be a string object (which might be a CTE encoded binary payload). Note thatis_multipart()
returningTrue
does not necessarily mean that "msg.get_content_maintype() == 'multipart'" will return theTrue
. For example,is_multipart
will returnTrue
when theEmailMessage
is of typemessage/rfc822
.
-
set_unixfrom
(unixfrom)¶ Set the message's envelope header to unixfrom, which should be a string. (See
mboxMessage
for a brief description of this header.)
-
get_unixfrom
()¶ メッセージのエンベロープヘッダを返します。エンベロープヘッダが設定されていない場合は
None
が返されます。
The following methods implement the mapping-like interface for accessing the message's headers. Note that there are some semantic differences between these methods and a normal mapping (i.e. dictionary) interface. For example, in a dictionary there are no duplicate keys, but here there may be duplicate message headers. Also, in dictionaries there is no guaranteed order to the keys returned by
keys()
, but in anEmailMessage
object, headers are always returned in the order they appeared in the original message, or in which they were added to the message later. Any header deleted and then re-added is always appended to the end of the header list.These semantic differences are intentional and are biased toward convenience in the most common use cases.
注意: どんな場合も、メッセージ中のエンベロープヘッダはこのマップ形式のインタフェイスには含まれません。
-
__len__
()¶ 複製されたものもふくめてヘッダ数の合計を返します。
-
__contains__
(name)¶ Return true if the message object has a field named name. Matching is done without regard to case and name does not include the trailing colon. Used for the
in
operator. For example:if 'message-id' in myMessage: print('Message-ID:', myMessage['message-id'])
-
__getitem__
(name)¶ Return the value of the named header field. name does not include the colon field separator. If the header is missing,
None
is returned; aKeyError
is never raised.Note that if the named field appears more than once in the message's headers, exactly which of those field values will be returned is undefined. Use the
get_all()
method to get the values of all the extant headers named name.Using the standard (non-
compat32
) policies, the returned value is an instance of a subclass ofemail.headerregistry.BaseHeader
.
-
__setitem__
(name, val)¶ メッセージヘッダに name という名前の val という値をもつフィールドをあらたに追加します。このフィールドは現在メッセージに存在するヘッダーのいちばん後に追加されます。
注意: このメソッドでは、すでに同一の名前で存在するフィールドは上書き されません。もしメッセージが名前 name をもつフィールドをひとつしか持たないようにしたければ、最初にそれを除去してください。たとえば:
del msg['subject'] msg['subject'] = 'Python roolz!'
If the
policy
defines certain headers to be unique (as the standard policies do), this method may raise aValueError
when an attempt is made to assign a value to such a header when one already exists. This behavior is intentional for consistency's sake, but do not depend on it as we may choose to make such assignments do an automatic deletion of the existing header in the future.
-
__delitem__
(name)¶ メッセージのヘッダから、name という名前をもつフィールドをすべて除去します。たとえこの名前をもつヘッダが存在していなくても例外は発生しません。
-
keys
()¶ メッセージ中にあるすべてのヘッダのフィールド名のリストを返します。
-
values
()¶ メッセージ中にあるすべてのフィールドの値のリストを返します。
-
items
()¶ メッセージ中にあるすべてのヘッダのフィールド名とその値を 2-タプルのリストとして返します。
-
get
(name, failobj=None)¶ 指定された名前をもつフィールドの値を返します。これは指定された名前がないときにオプション引数の failobj (failobj のデフォルトは
None
) を返すことをのぞけば、__getitem__()
と同じです。
Here are some additional useful header related methods:
-
get_all
(name, failobj=None)¶ name の名前をもつフィールドのすべての値からなるリストを返します。該当する名前のヘッダがメッセージ中に含まれていない場合は failobj (デフォルトでは
None
) が返されます。
-
add_header
(_name, _value, **_params)¶ 拡張ヘッダ設定。このメソッドは
__setitem__()
と似ていますが、追加のヘッダ・パラメータをキーワード引数で指定できるところが違っています。 _name に追加するヘッダフィールドを、 _value にそのヘッダの 最初の 値を渡します。For each item in the keyword argument dictionary _params, the key is taken as the parameter name, with underscores converted to dashes (since dashes are illegal in Python identifiers). Normally, the parameter will be added as
key="value"
unless the value isNone
, in which case only the key will be added.If the value contains non-ASCII characters, the charset and language may be explicitly controlled by specifying the value as a three tuple in the format
(CHARSET, LANGUAGE, VALUE)
, whereCHARSET
is a string naming the charset to be used to encode the value,LANGUAGE
can usually be set toNone
or the empty string (see RFC 2231 for other possibilities), andVALUE
is the string value containing non-ASCII code points. If a three tuple is not passed and the value contains non-ASCII characters, it is automatically encoded in RFC 2231 format using aCHARSET
ofutf-8
and aLANGUAGE
ofNone
.以下に例を示します。:
msg.add_header('Content-Disposition', 'attachment', filename='bud.gif')
こうするとヘッダには以下のように追加されます
Content-Disposition: attachment; filename="bud.gif"
An example of the extended interface with non-ASCII characters:
msg.add_header('Content-Disposition', 'attachment', filename=('iso-8859-1', '', 'Fußballer.ppt'))
-
replace_header
(_name, _value)¶ Replace a header. Replace the first header found in the message that matches _name, retaining header order and field name case of the original header. If no matching header is found, raise a
KeyError
.
-
get_content_type
()¶ Return the message's content type, coerced to lower case of the form maintype/subtype. If there is no Content-Type header in the message return the value returned by
get_default_type()
. If the Content-Type header is invalid, returntext/plain
.(According to RFC 2045, messages always have a default type,
get_content_type()
will always return a value. RFC 2045 defines a message's default type to be text/plain unless it appears inside a multipart/digest container, in which case it would be message/rfc822. If the Content-Type header has an invalid type specification, RFC 2045 mandates that the default type be text/plain.)
-
get_content_maintype
()¶ そのメッセージの主 content-type を返します。これは
get_content_type()
によって返される文字列の maintype 部分です。
-
get_content_subtype
()¶ そのメッセージの副 content-type (sub content-type、subtype) を返します。これは
get_content_type()
によって返される文字列の subtype 部分です。
-
get_default_type
()¶ デフォルトの content-type を返します。ほどんどのメッセージではデフォルトの content-type は text/plain ですが、メッセージが multipart/digest コンテナに含まれているときだけ例外的に message/rfc822 になります。
-
set_default_type
(ctype)¶ Set the default content type. ctype should either be text/plain or message/rfc822, although this is not enforced. The default content type is not stored in the Content-Type header, so it only affects the return value of the
get_content_type
methods when no Content-Type header is present in the message.
-
set_param
(param, value, header='Content-Type', requote=True, charset=None, language='', replace=False)¶ Set a parameter in the Content-Type header. If the parameter already exists in the header, replace its value with value. When header is
Content-Type
(the default) and the header does not yet exist in the message, add it, set its value to text/plain, and append the new parameter value. Optional header specifies an alternative header to Content-Type.If the value contains non-ASCII characters, the charset and language may be explicitly specified using the optional charset and language parameters. Optional language specifies the RFC 2231 language, defaulting to the empty string. Both charset and language should be strings. The default is to use the
utf8
charset andNone
for the language.If replace is
False
(the default) the header is moved to the end of the list of headers. If replace isTrue
, the header will be updated in place.Use of the requote parameter with
EmailMessage
objects is deprecated.Note that existing parameter values of headers may be accessed through the
params
attribute of the header value (for example,msg['Content-Type'].params['charset']
).バージョン 3.4 で変更:
replace
キーワードが追加されました。
-
del_param
(param, header='content-type', requote=True)¶ 指定されたパラメータを Content-Type ヘッダ中から完全にとりのぞきます。ヘッダはそのパラメータと値がない状態に書き換えられます。オプション変数 header が与えられた場合、 Content-Type のかわりにそのヘッダが使用されます。
Use of the requote parameter with
EmailMessage
objects is deprecated.
-
get_filename
(failobj=None)¶ そのメッセージ中の Content-Disposition ヘッダにある、
filename
パラメータの値を返します。目的のヘッダにfilename
パラメータがない場合には Content-Type ヘッダにあるname
パラメータを探します。それも無い場合またはヘッダが無い場合には failobj が返されます。返される文字列はつねにemail.utils.unquote()
によって unquote されます。
-
get_boundary
(failobj=None)¶ そのメッセージ中の Content-Type ヘッダにある、
boundary
パラメータの値を返します。目的のヘッダが欠けていたり、boundary
パラメータがない場合には failobj が返されます。返される文字列はつねにemail.utils.unquote()
によって unquote されます。
-
set_boundary
(boundary)¶ メッセージ中の Content-Type ヘッダにある、
boundary
パラメータに値を設定します。set_boundary()
は必要に応じて boundary を quote します。そのメッセージが Content-Type ヘッダを含んでいない場合、HeaderParseError
が発生します。Note that using this method is subtly different from deleting the old Content-Type header and adding a new one with the new boundary via
add_header()
, becauseset_boundary()
preserves the order of the Content-Type header in the list of headers.
-
get_content_charset
(failobj=None)¶ そのメッセージ中の Content-Type ヘッダにある、
charset
パラメータの値を返します。値はすべて小文字に変換されます。メッセージ中に Content-Type がなかったり、このヘッダ中にcharaset
パラメータがない場合には failobj が返されます。
-
get_charsets
(failobj=None)¶ メッセージ中に含まれる文字セットの名前をすべてリストにして返します。そのメッセージが multipart である場合、返されるリストの各要素がそれぞれの subpart のペイロードに対応します。それ以外の場合、これは長さ 1 のリストを返します。
リスト中の各要素は文字列であり、これは対応する subpart 中のそれぞれの Content-Type ヘッダにある
charset
の値です。その subpart が Content-Type をもってないか、charset
がないか、あるいは MIME maintype が text でないいずれかの場合には、リストの要素として failobj が返されます。
-
is_attachment
()¶ Content-Disposition ヘッダが存在し、その (大文字小文字を区別しない) 値が
attachment
の場合、True
を返します。 それ以外の場合はFalse
を返します。バージョン 3.4.2 で変更:
is_multipart()
との一貫性のために、is_attachment が属性からメソッドになりました。
-
get_content_disposition
()¶ Return the lowercased value (without parameters) of the message's Content-Disposition header if it has one, or
None
. The possible values for this method are inline, attachment orNone
if the message follows RFC 2183.バージョン 3.5 で追加.
The following methods relate to interrogating and manipulating the content (payload) of the message.
-
walk
()¶ walk()
メソッドは多目的のジェネレータで、これはあるメッセージオブジェクトツリー中のすべての part および subpart をわたり歩くのに使えます。順序は深さ優先です。おそらく典型的な用法は、walk()
をfor
ループ中でのイテレータとして使うことでしょう。ループを一回まわるごとに、次の subpart が返されるのです。以下の例は、 multipart メッセージのすべての part において、その MIME タイプを表示していくものです。 :
>>> for part in msg.walk(): ... print(part.get_content_type()) multipart/report text/plain message/delivery-status text/plain text/plain message/rfc822 text/plain
walk
iterates over the subparts of any part whereis_multipart()
returnsTrue
, even thoughmsg.get_content_maintype() == 'multipart'
may returnFalse
. We can see this in our example by making use of the_structure
debug helper function:>>> for part in msg.walk(): ... print(part.get_content_maintype() == 'multipart', ... part.is_multipart()) True True False False False True False False False False False True False False >>> _structure(msg) multipart/report text/plain message/delivery-status text/plain text/plain message/rfc822 text/plain
Here the
message
parts are notmultiparts
, but they do contain subparts.is_multipart()
returnsTrue
andwalk
descends into the subparts.
-
get_body
(preferencelist=('related', 'html', 'plain'))¶ メッセージの "本体" の最有力候補となる MIME 部を返します。
preferencelist must be a sequence of strings from the set
related
,html
, andplain
, and indicates the order of preference for the content type of the part returned.Start looking for candidate matches with the object on which the
get_body
method is called.If
related
is not included in preferencelist, consider the root part (or subpart of the root part) of any related encountered as a candidate if the (sub-)part matches a preference.When encountering a
multipart/related
, check thestart
parameter and if a part with a matching Content-ID is found, consider only it when looking for candidate matches. Otherwise consider only the first (default root) part of themultipart/related
.If a part has a Content-Disposition header, only consider the part a candidate match if the value of the header is
inline
.If none of the candidates matches any of the preferences in preferencelist, return
None
.Notes: (1) For most applications the only preferencelist combinations that really make sense are
('plain',)
,('html', 'plain')
, and the default('related', 'html', 'plain')
. (2) Because matching starts with the object on whichget_body
is called, callingget_body
on amultipart/related
will return the object itself unless preferencelist has a non-default value. (3) Messages (or message parts) that do not specify a Content-Type or whose Content-Type header is invalid will be treated as if they are of typetext/plain
, which may occasionally causeget_body
to return unexpected results.
-
iter_attachments
()¶ Return an iterator over all of the immediate sub-parts of the message that are not candidate "body" parts. That is, skip the first occurrence of each of
text/plain
,text/html
,multipart/related
, ormultipart/alternative
(unless they are explicitly marked as attachments via Content-Disposition: attachment), and return all remaining parts. When applied directly to amultipart/related
, return an iterator over the all the related parts except the root part (ie: the part pointed to by thestart
parameter, or the first part if there is nostart
parameter or thestart
parameter doesn't match the Content-ID of any of the parts). When applied directly to amultipart/alternative
or a non-multipart
, return an empty iterator.
-
iter_parts
()¶ Return an iterator over all of the immediate sub-parts of the message, which will be empty for a non-
multipart
. (See alsowalk()
.)
-
get_content
(*args, content_manager=None, **kw)¶ Call the
get_content()
method of the content_manager, passing self as the message object, and passing along any other arguments or keywords as additional arguments. If content_manager is not specified, use thecontent_manager
specified by the currentpolicy
.
-
set_content
(*args, content_manager=None, **kw)¶ Call the
set_content()
method of the content_manager, passing self as the message object, and passing along any other arguments or keywords as additional arguments. If content_manager is not specified, use thecontent_manager
specified by the currentpolicy
.
Convert a non-
multipart
message into amultipart/related
message, moving any existing Content- headers and payload into a (new) first part of themultipart
. If boundary is specified, use it as the boundary string in the multipart, otherwise leave the boundary to be automatically created when it is needed (for example, when the message is serialized).
-
make_alternative
(boundary=None)¶ Convert a non-
multipart
or amultipart/related
into amultipart/alternative
, moving any existing Content- headers and payload into a (new) first part of themultipart
. If boundary is specified, use it as the boundary string in the multipart, otherwise leave the boundary to be automatically created when it is needed (for example, when the message is serialized).
-
make_mixed
(boundary=None)¶ Convert a non-
multipart
, amultipart/related
, or amultipart-alternative
into amultipart/mixed
, moving any existing Content- headers and payload into a (new) first part of themultipart
. If boundary is specified, use it as the boundary string in the multipart, otherwise leave the boundary to be automatically created when it is needed (for example, when the message is serialized).
If the message is a
multipart/related
, create a new message object, pass all of the arguments to itsset_content()
method, andattach()
it to themultipart
. If the message is a non-multipart
, callmake_related()
and then proceed as above. If the message is any other type ofmultipart
, raise aTypeError
. If content_manager is not specified, use thecontent_manager
specified by the currentpolicy
. If the added part has no Content-Disposition header, add one with the valueinline
.
-
add_alternative
(*args, content_manager=None, **kw)¶ If the message is a
multipart/alternative
, create a new message object, pass all of the arguments to itsset_content()
method, andattach()
it to themultipart
. If the message is a non-multipart
ormultipart/related
, callmake_alternative()
and then proceed as above. If the message is any other type ofmultipart
, raise aTypeError
. If content_manager is not specified, use thecontent_manager
specified by the currentpolicy
.
-
add_attachment
(*args, content_manager=None, **kw)¶ If the message is a
multipart/mixed
, create a new message object, pass all of the arguments to itsset_content()
method, andattach()
it to themultipart
. If the message is a non-multipart
,multipart/related
, ormultipart/alternative
, callmake_mixed()
and then proceed as above. If content_manager is not specified, use thecontent_manager
specified by the currentpolicy
. If the added part has no Content-Disposition header, add one with the valueattachment
. This method can be used both for explicit attachments (Content-Disposition: attachment) andinline
attachments (Content-Disposition: inline), by passing appropriate options to thecontent_manager
.
-
clear
()¶ ペイロードとヘッダの全てを削除します。
-
clear_content
()¶ Remove the payload and all of the
Content-
headers, leaving all other headers intact and in their original order.
EmailMessage
オブジェクトは次のようなインスタンス属性を持ちます:-
preamble
¶ MIME ドキュメントの形式では、ヘッダ直後にくる空行と最初の multipart 境界をあらわす文字列のあいだにいくらかのテキスト (訳注: preamble, 序文) を埋めこむことを許しています。このテキストは標準的な MIME の範疇からはみ出しているので、MIME 形式を認識するメールソフトからこれらは通常まったく見えません。しかしメッセージのテキストを生で見る場合、あるいはメッセージを MIME 対応していないメールソフトで見る場合、このテキストは目に見えることになります。
preamble 属性は MIME ドキュメントに加えるこの最初の MIME 範囲外テキストを含んでいます。
Parser
があるテキストをヘッダ以降に発見したが、それはまだ最初の MIME 境界文字列が現れる前だった場合、パーザはそのテキストをメッセージの preamble 属性に格納します。Generator
がある MIME メッセージからプレーンテキスト形式を生成するときメッセージが preamble 属性を持つことが発見されれば、これはそのテキストをヘッダと最初の MIME 境界の間に挿入します。詳細はemail.parser
およびemail.generator
を参照してください。注意: そのメッセージに preamble がない場合、preamble 属性には
None
が格納されます。
-
epilogue
¶ The epilogue attribute acts the same way as the preamble attribute, except that it contains text that appears between the last boundary and the end of the message. As with the
preamble
, if there is no epilog text this attribute will beNone
.
-
defects
¶ defects 属性はメッセージを解析する途中で検出されたすべての問題点 (defect、障害) のリストを保持しています。解析中に発見されうる障害についてのより詳細な説明は
email.errors
を参照してください。
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class
email.message.
MIMEPart
(policy=default)¶ This class represents a subpart of a MIME message. It is identical to
EmailMessage
, except that no MIME-Version headers are added whenset_content()
is called, since sub-parts do not need their own MIME-Version headers.
脚注
- 1
Originally added in 3.4 as a provisional module. Docs for legacy message class moved to email.message.Message: compat32 API を使用した電子メールメッセージの表現.