mirror of
https://github.com/python/cpython.git
synced 2024-12-01 05:45:40 +08:00
182 lines
6.2 KiB
Python
182 lines
6.2 KiB
Python
"""Generic MIME writer.
|
|
|
|
This module defines the class MimeWriter. The MimeWriter class implements
|
|
a basic formatter for creating MIME multi-part files. It doesn't seek around
|
|
the output file nor does it use large amounts of buffer space. You must write
|
|
the parts out in the order that they should occur in the final file.
|
|
MimeWriter does buffer the headers you add, allowing you to rearrange their
|
|
order.
|
|
|
|
"""
|
|
|
|
|
|
import mimetools
|
|
|
|
__all__ = ["MimeWriter"]
|
|
|
|
class MimeWriter:
|
|
|
|
"""Generic MIME writer.
|
|
|
|
Methods:
|
|
|
|
__init__()
|
|
addheader()
|
|
flushheaders()
|
|
startbody()
|
|
startmultipartbody()
|
|
nextpart()
|
|
lastpart()
|
|
|
|
A MIME writer is much more primitive than a MIME parser. It
|
|
doesn't seek around on the output file, and it doesn't use large
|
|
amounts of buffer space, so you have to write the parts in the
|
|
order they should occur on the output file. It does buffer the
|
|
headers you add, allowing you to rearrange their order.
|
|
|
|
General usage is:
|
|
|
|
f = <open the output file>
|
|
w = MimeWriter(f)
|
|
...call w.addheader(key, value) 0 or more times...
|
|
|
|
followed by either:
|
|
|
|
f = w.startbody(content_type)
|
|
...call f.write(data) for body data...
|
|
|
|
or:
|
|
|
|
w.startmultipartbody(subtype)
|
|
for each part:
|
|
subwriter = w.nextpart()
|
|
...use the subwriter's methods to create the subpart...
|
|
w.lastpart()
|
|
|
|
The subwriter is another MimeWriter instance, and should be
|
|
treated in the same way as the toplevel MimeWriter. This way,
|
|
writing recursive body parts is easy.
|
|
|
|
Warning: don't forget to call lastpart()!
|
|
|
|
XXX There should be more state so calls made in the wrong order
|
|
are detected.
|
|
|
|
Some special cases:
|
|
|
|
- startbody() just returns the file passed to the constructor;
|
|
but don't use this knowledge, as it may be changed.
|
|
|
|
- startmultipartbody() actually returns a file as well;
|
|
this can be used to write the initial 'if you can read this your
|
|
mailer is not MIME-aware' message.
|
|
|
|
- If you call flushheaders(), the headers accumulated so far are
|
|
written out (and forgotten); this is useful if you don't need a
|
|
body part at all, e.g. for a subpart of type message/rfc822
|
|
that's (mis)used to store some header-like information.
|
|
|
|
- Passing a keyword argument 'prefix=<flag>' to addheader(),
|
|
start*body() affects where the header is inserted; 0 means
|
|
append at the end, 1 means insert at the start; default is
|
|
append for addheader(), but insert for start*body(), which use
|
|
it to determine where the Content-Type header goes.
|
|
|
|
"""
|
|
|
|
def __init__(self, fp):
|
|
self._fp = fp
|
|
self._headers = []
|
|
|
|
def addheader(self, key, value, prefix=0):
|
|
"""Add a header line to the MIME message.
|
|
|
|
The key is the name of the header, where the value obviously provides
|
|
the value of the header. The optional argument prefix determines
|
|
where the header is inserted; 0 means append at the end, 1 means
|
|
insert at the start. The default is to append.
|
|
|
|
"""
|
|
lines = value.split("\n")
|
|
while lines and not lines[-1]: del lines[-1]
|
|
while lines and not lines[0]: del lines[0]
|
|
for i in range(1, len(lines)):
|
|
lines[i] = " " + lines[i].strip()
|
|
value = "\n".join(lines) + "\n"
|
|
line = key + ": " + value
|
|
if prefix:
|
|
self._headers.insert(0, line)
|
|
else:
|
|
self._headers.append(line)
|
|
|
|
def flushheaders(self):
|
|
"""Writes out and forgets all headers accumulated so far.
|
|
|
|
This is useful if you don't need a body part at all; for example,
|
|
for a subpart of type message/rfc822 that's (mis)used to store some
|
|
header-like information.
|
|
|
|
"""
|
|
self._fp.writelines(self._headers)
|
|
self._headers = []
|
|
|
|
def startbody(self, ctype, plist=[], prefix=1):
|
|
"""Returns a file-like object for writing the body of the message.
|
|
|
|
The content-type is set to the provided ctype, and the optional
|
|
parameter, plist, provides additional parameters for the
|
|
content-type declaration. The optional argument prefix determines
|
|
where the header is inserted; 0 means append at the end, 1 means
|
|
insert at the start. The default is to insert at the start.
|
|
|
|
"""
|
|
for name, value in plist:
|
|
ctype = ctype + ';\n %s=\"%s\"' % (name, value)
|
|
self.addheader("Content-Type", ctype, prefix=prefix)
|
|
self.flushheaders()
|
|
self._fp.write("\n")
|
|
return self._fp
|
|
|
|
def startmultipartbody(self, subtype, boundary=None, plist=[], prefix=1):
|
|
"""Returns a file-like object for writing the body of the message.
|
|
|
|
Additionally, this method initializes the multi-part code, where the
|
|
subtype parameter provides the multipart subtype, the boundary
|
|
parameter may provide a user-defined boundary specification, and the
|
|
plist parameter provides optional parameters for the subtype. The
|
|
optional argument, prefix, determines where the header is inserted;
|
|
0 means append at the end, 1 means insert at the start. The default
|
|
is to insert at the start. Subparts should be created using the
|
|
nextpart() method.
|
|
|
|
"""
|
|
self._boundary = boundary or mimetools.choose_boundary()
|
|
return self.startbody("multipart/" + subtype,
|
|
[("boundary", self._boundary)] + plist,
|
|
prefix=prefix)
|
|
|
|
def nextpart(self):
|
|
"""Returns a new instance of MimeWriter which represents an
|
|
individual part in a multipart message.
|
|
|
|
This may be used to write the part as well as used for creating
|
|
recursively complex multipart messages. The message must first be
|
|
initialized with the startmultipartbody() method before using the
|
|
nextpart() method.
|
|
|
|
"""
|
|
self._fp.write("\n--" + self._boundary + "\n")
|
|
return self.__class__(self._fp)
|
|
|
|
def lastpart(self):
|
|
"""This is used to designate the last part of a multipart message.
|
|
|
|
It should always be used when writing multipart messages.
|
|
|
|
"""
|
|
self._fp.write("\n--" + self._boundary + "--\n")
|
|
|
|
|
|
if __name__ == '__main__':
|
|
import test.test_MimeWriter
|