1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
\declaremodule{standard}{email.Generator}
\modulesynopsis{Generate flat text email messages from a message structure.}
One of the most common tasks is to generate the flat text of the email
message represented by a message object structure. You will need to do
this if you want to send your message via the \refmodule{smtplib}
module or the \refmodule{nntplib} module, or print the message on the
console. Taking a message object structure and producing a flat text
document is the job of the \class{Generator} class.
Again, as with the \refmodule{email.Parser} module, you aren't limited
to the functionality of the bundled generator; you could write one
from scratch yourself. However the bundled generator knows how to
generate most email in a standards-compliant way, should handle MIME
and non-MIME email messages just fine, and is designed so that the
transformation from flat text, to a message structure via the
\class{Parser} class, and back to flat text, is idempotent (the input
is identical to the output).
Here are the public methods of the \class{Generator} class:
\begin{classdesc}{Generator}{outfp\optional{, mangle_from_\optional{,
maxheaderlen}}}
The constructor for the \class{Generator} class takes a file-like
object called \var{outfp} for an argument. \var{outfp} must support
the \method{write()} method and be usable as the output file in a
Python extended print statement.
Optional \var{mangle_from_} is a flag that, when \code{True}, puts a
\samp{>} character in front of any line in the body that starts exactly as
\samp{From }, i.e. \code{From} followed by a space at the beginning of the
line. This is the only guaranteed portable way to avoid having such
lines be mistaken for a Unix mailbox format envelope header separator (see
\ulink{WHY THE CONTENT-LENGTH FORMAT IS BAD}
{http://home.netscape.com/eng/mozilla/2.0/relnotes/demo/content-length.html}
for details). \var{mangle_from_} defaults to \code{True}, but you
might want to set this to \code{False} if you are not writing Unix
mailbox format files.
Optional \var{maxheaderlen} specifies the longest length for a
non-continued header. When a header line is longer than
\var{maxheaderlen} (in characters, with tabs expanded to 8 spaces),
the header will be broken on semicolons and continued as per
\rfc{2822}. If no semicolon is found, then the header is left alone.
Set to zero to disable wrapping headers. Default is 78, as
recommended (but not required) by \rfc{2822}.
\end{classdesc}
The other public \class{Generator} methods are:
\begin{methoddesc}[Generator]{flatten}{msg\optional{, unixfrom}}
Print the textual representation of the message object structure rooted at
\var{msg} to the output file specified when the \class{Generator}
instance was created. Subparts are visited depth-first and the
resulting text will be properly MIME encoded.
Optional \var{unixfrom} is a flag that forces the printing of the
envelope header delimiter before the first \rfc{2822} header of the
root message object. If the root object has no envelope header, a
standard one is crafted. By default, this is set to \code{False} to
inhibit the printing of the envelope delimiter.
Note that for subparts, no envelope header is ever printed.
\versionadded{2.2.2}
\end{methoddesc}
\begin{methoddesc}[Generator]{clone}{fp}
Return an independent clone of this \class{Generator} instance with
the exact same options.
\versionadded{2.2.2}
\end{methoddesc}
\begin{methoddesc}[Generator]{write}{s}
Write the string \var{s} to the underlying file object,
i.e. \var{outfp} passed to \class{Generator}'s constructor. This
provides just enough file-like API for \class{Generator} instances to
be used in extended print statements.
\end{methoddesc}
As a convenience, see the methods \method{Message.as_string()} and
\code{str(aMessage)}, a.k.a. \method{Message.__str__()}, which
simplify the generation of a formatted string representation of a
message object. For more detail, see \refmodule{email.Message}.
The \module{email.Generator} module also provides a derived class,
called \class{DecodedGenerator} which is like the \class{Generator}
base class, except that non-\mimetype{text} parts are substituted with
a format string representing the part.
\begin{classdesc}{DecodedGenerator}{outfp\optional{, mangle_from_\optional{,
maxheaderlen\optional{, fmt}}}}
This class, derived from \class{Generator} walks through all the
subparts of a message. If the subpart is of main type
\mimetype{text}, then it prints the decoded payload of the subpart.
Optional \var{_mangle_from_} and \var{maxheaderlen} are as with the
\class{Generator} base class.
If the subpart is not of main type \mimetype{text}, optional \var{fmt}
is a format string that is used instead of the message payload.
\var{fmt} is expanded with the following keywords, \samp{\%(keyword)s}
format:
\begin{itemize}
\item \code{type} -- Full MIME type of the non-\mimetype{text} part
\item \code{maintype} -- Main MIME type of the non-\mimetype{text} part
\item \code{subtype} -- Sub-MIME type of the non-\mimetype{text} part
\item \code{filename} -- Filename of the non-\mimetype{text} part
\item \code{description} -- Description associated with the
non-\mimetype{text} part
\item \code{encoding} -- Content transfer encoding of the
non-\mimetype{text} part
\end{itemize}
The default value for \var{fmt} is \code{None}, meaning
\begin{verbatim}
[Non-text (%(type)s) part of message omitted, filename %(filename)s]
\end{verbatim}
\versionadded{2.2.2}
\end{classdesc}
\subsubsection{Deprecated methods}
The following methods are deprecated in \module{email} version 2.
They are documented here for completeness.
\begin{methoddesc}[Generator]{__call__}{msg\optional{, unixfrom}}
This method is identical to the \method{flatten()} method.
\deprecated{2.2.2}{Use the \method{flatten()} method instead.}
\end{methoddesc}
|
