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email.contentmanager: Managing MIME Content
Source code: Lib/email/contentmanager.py
New in version 3.6: 1
- class
email.contentmanager.
ContentManager
-
Base class for content managers. Provides the standard registry mechanisms to register converters between MIME content and other representations, as well as the
get_content
andset_content
dispatch methods.get_content
( msg, *args, **kw )-
Look up a handler function based on the
mimetype
of msg (see next paragraph), call it, passing through all arguments, and return the result of the call. The expectation is that the handler will extract the payload from msg and return an object that encodes information about the extracted data.To find the handler, look for the following keys in the registry, stopping with the first one found:
the string representing the full MIME type (
maintype/subtype
)the string representing the
maintype
the empty string
If none of these keys produce a handler, raise a
KeyError
for the full MIME type.
set_content
( msg, obj, *args, **kw )-
If the
maintype
ismultipart
, raise aTypeError
; otherwise look up a handler function based on the type of obj (see next paragraph), callclear_content()
on the msg, and call the handler function, passing through all arguments. The expectation is that the handler will transform and store obj into msg, possibly making other changes to msg as well, such as adding various MIME headers to encode information needed to interpret the stored data.To find the handler, obtain the type of obj (
typ = type(obj)
), and look for the following keys in the registry, stopping with the first one found:the type itself (
typ
)the type’s fully qualified name (
typ.__module__ + '.' + typ.__qualname__
).the type’s qualname (
typ.__qualname__
)the type’s name (
typ.__name__
).
If none of the above match, repeat all of the checks above for each of the types in the MRO (
typ.__mro__
). Finally, if no other key yields a handler, check for a handler for the keyNone
. If there is no handler forNone
, raise aKeyError
for the fully qualified name of the type.Also add a MIME-Version header if one is not present (see also
MIMEPart
).
add_get_handler
( key, handler )-
Record the function handler as the handler for key. For the possible values of key, see
get_content()
.
add_set_handler
( typekey, handler )-
Record handler as the function to call when an object of a type matching typekey is passed to
set_content()
. For the possible values of typekey, seeset_content()
.
Content Manager Instances
Currently the email package provides only one concrete content manager, raw_data_manager
, although more may be added in the future. raw_data_manager
is the content_manager
provided by EmailPolicy
and its derivatives.
email.contentmanager.
raw_data_manager
-
This content manager provides only a minimum interface beyond that provided by
Message
itself: it deals only with text, raw byte strings, andMessage
objects. Nevertheless, it provides significant advantages compared to the base API:get_content
on a text part will return a unicode string without the application needing to manually decode it,set_content
provides a rich set of options for controlling the headers added to a part and controlling the content transfer encoding, and it enables the use of the variousadd_
methods, thereby simplifying the creation of multipart messages.email.contentmanager.
get_content
( msg, errors='replace' )-
Return the payload of the part as either a string (for
text
parts), anEmailMessage
object (formessage/rfc822
parts), or abytes
object (for all other non-multipart types). Raise aKeyError
if called on amultipart
. If the part is atext
part and errors is specified, use it as the error handler when decoding the payload to unicode. The default error handler isreplace
.
email.contentmanager.
set_content
( msg, <'str'>, subtype="plain", charset='utf-8' cte=None, disposition=None, filename=None, cid=None, params=None, headers=None )email.contentmanager.
set_content
( msg, <'bytes'>, maintype, subtype, cte="base64", disposition=None, filename=None, cid=None, params=None, headers=None )email.contentmanager.
set_content
( msg, <'EmailMessage'>, cte=None, disposition=None, filename=None, cid=None, params=None, headers=None )-
Add headers and payload to msg:
Add a Content-Type header with a
maintype/subtype
value.For
str
, set the MIMEmaintype
totext
, and set the subtype to subtype if it is specified, orplain
if it is not.For
bytes
, use the specified maintype and subtype, or raise aTypeError
if they are not specified.For
EmailMessage
objects, set the maintype tomessage
, and set the subtype to subtype if it is specified orrfc822
if it is not. If subtype ispartial
, raise an error (bytes
objects must be used to constructmessage/partial
parts).
If charset is provided (which is valid only for
str
), encode the string to bytes using the specified character set. The default isutf-8
. If the specified charset is a known alias for a standard MIME charset name, use the standard charset instead.If cte is set, encode the payload using the specified content transfer encoding, and set the Content-Transfer-Encoding header to that value. Possible values for cte are
quoted-printable
,base64
,7bit
,8bit
, andbinary
. If the input cannot be encoded in the specified encoding (for example, specifying a cte of7bit
for an input that contains non-ASCII values), raise aValueError
.For
str
objects, if cte is not set use heuristics to determine the most compact encoding.For
EmailMessage
, per RFC 2046 , raise an error if a cte ofquoted-printable
orbase64
is requested for subtyperfc822
, and for any cte other than7bit
for subtypeexternal-body
. Formessage/rfc822
, use8bit
if cte is not specified. For all other values of subtype, use7bit
.
Note
A cte of
binary
does not actually work correctly yet. TheEmailMessage
object as modified byset_content
is correct, butBytesGenerator
does not serialize it correctly.If disposition is set, use it as the value of the Content-Disposition header. If not specified, and filename is specified, add the header with the value
attachment
. If disposition is not specified and filename is also not specified, do not add the header. The only valid values for disposition areattachment
andinline
.If filename is specified, use it as the value of the
filename
parameter of the Content-Disposition header.If cid is specified, add a Content-ID header with cid as its value.
If params is specified, iterate its
items
method and use the resulting(key, value)
pairs to set additional parameters on the Content-Type header.If headers is specified and is a list of strings of the form
headername: headervalue
or a list ofheader
objects (distinguished from strings by having aname
attribute), add the headers to msg.
Footnotes
- 1
-
Originally added in 3.4 as a provisional module