cpython/Doc/library/email.iterators.rst

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:mod:`!email.iterators`: Iterators
----------------------------------
.. module:: email.iterators
:synopsis: Iterate over a message object tree.
**Source code:** :source:`Lib/email/iterators.py`
--------------
Iterating over a message object tree is fairly easy with the
:meth:`Message.walk <email.message.Message.walk>` method. The
:mod:`email.iterators` module provides some useful higher level iterations over
message object trees.
.. function:: body_line_iterator(msg, decode=False)
This iterates over all the payloads in all the subparts of *msg*, returning the
string payloads line-by-line. It skips over all the subpart headers, and it
skips over any subpart with a payload that isn't a Python string. This is
somewhat equivalent to reading the flat text representation of the message from
a file using :meth:`~io.TextIOBase.readline`, skipping over all the
intervening headers.
Optional *decode* is passed through to :meth:`Message.get_payload
<email.message.Message.get_payload>`.
.. function:: typed_subpart_iterator(msg, maintype='text', subtype=None)
This iterates over all the subparts of *msg*, returning only those subparts that
match the MIME type specified by *maintype* and *subtype*.
Note that *subtype* is optional; if omitted, then subpart MIME type matching is
done only with the main type. *maintype* is optional too; it defaults to
:mimetype:`text`.
Thus, by default :func:`typed_subpart_iterator` returns each subpart that has a
MIME type of :mimetype:`text/\*`.
The following function has been added as a useful debugging tool. It should
*not* be considered part of the supported public interface for the package.
.. function:: _structure(msg, fp=None, level=0, include_default=False)
Prints an indented representation of the content types of the message object
structure. For example:
.. testsetup::
import email
from email.iterators import _structure
somefile = open('../Lib/test/test_email/data/msg_02.txt')
.. doctest::
>>> msg = email.message_from_file(somefile)
>>> _structure(msg)
multipart/mixed
text/plain
text/plain
multipart/digest
message/rfc822
text/plain
message/rfc822
text/plain
message/rfc822
text/plain
message/rfc822
text/plain
message/rfc822
text/plain
text/plain
.. testcleanup::
somefile.close()
Optional *fp* is a file-like object to print the output to. It must be
suitable for Python's :func:`print` function. *level* is used internally.
*include_default*, if true, prints the default type as well.