1:mod:`email.iterators`: Iterators
2---------------------------------
3
4.. module:: email.iterators
5   :synopsis: Iterate over a  message object tree.
6
7
8Iterating over a message object tree is fairly easy with the
9:meth:`Message.walk <email.message.Message.walk>` method.  The
10:mod:`email.iterators` module provides some useful higher level iterations over
11message object trees.
12
13
14.. function:: body_line_iterator(msg[, decode])
15
16   This iterates over all the payloads in all the subparts of *msg*, returning the
17   string payloads line-by-line.  It skips over all the subpart headers, and it
18   skips over any subpart with a payload that isn't a Python string.  This is
19   somewhat equivalent to reading the flat text representation of the message from
20   a file using :meth:`~io.TextIOBase.readline`, skipping over all the
21   intervening headers.
22
23   Optional *decode* is passed through to :meth:`Message.get_payload
24   <email.message.Message.get_payload>`.
25
26
27.. function:: typed_subpart_iterator(msg[, maintype[, subtype]])
28
29   This iterates over all the subparts of *msg*, returning only those subparts that
30   match the MIME type specified by *maintype* and *subtype*.
31
32   Note that *subtype* is optional; if omitted, then subpart MIME type matching is
33   done only with the main type.  *maintype* is optional too; it defaults to
34   :mimetype:`text`.
35
36   Thus, by default :func:`typed_subpart_iterator` returns each subpart that has a
37   MIME type of :mimetype:`text/\*`.
38
39The following function has been added as a useful debugging tool.  It should
40*not* be considered part of the supported public interface for the package.
41
42
43.. function:: _structure(msg[, fp[, level]])
44
45   Prints an indented representation of the content types of the message object
46   structure.  For example::
47
48      >>> msg = email.message_from_file(somefile)
49      >>> _structure(msg)
50      multipart/mixed
51          text/plain
52          text/plain
53          multipart/digest
54              message/rfc822
55                  text/plain
56              message/rfc822
57                  text/plain
58              message/rfc822
59                  text/plain
60              message/rfc822
61                  text/plain
62              message/rfc822
63                  text/plain
64          text/plain
65
66   Optional *fp* is a file-like object to print the output to.  It must be suitable
67   for Python's extended print statement.  *level* is used internally.
68
69