Foundations of Python Network Programming 978-1-4302-3004-5

CHAPTER 12 ■ E-MAIL COMPOSITION AND DECODING
» mimetype, mimeencoding = mimetypes.guess_type(filename)
» if mimeencoding or (mimetype is None):
» » mimetype = 'application/octet-stream'
» maintype, subtype = mimetype.split('/')
» if maintype == 'text':
» » retval = MIMEText(fd.read(), _subtype=subtype)
» else:
» » retval = MIMEBase(maintype, subtype)
» » retval.set_payload(fd.read())
» » encoders.encode_base64(retval)
» retval.add_header('Content-Disposition', 'attachment',
» » » filename = filename)
» fd.close()
» return retval
message = """Hello,
This is a test message from Chapter 12. I hope you enjoy it!
-- Anonymous"""
msg = MIMEMultipart()
msg['To'] = 'recipient@example.com'
msg['From'] = 'Test Sender '
msg['Subject'] = 'Test Message, Chapter 12'
msg['Date'] = utils.formatdate(localtime = 1)
msg['Message-ID'] = utils.make_msgid()
body = MIMEText(message, _subtype='plain')
msg.attach(body)
for filename in sys.argv[1:]:
» msg.attach(attachment(filename))
print msg.as_string()
The attachment() function does the work of creating a message attachment object. First, it determines
the MIME type of each file by using Python’s built-in mimetypes module. If the type can’t be determined, or
it will need a special kind of encoding, then a type is declared that promises only that the data is made of a
“stream of octets” (sequence of bytes) but without any further promise about what they mean.
If the file is a text document whose MIME type starts with text/, a MIMEText object is created to handle
it; otherwise, a MIMEBase generic object is created. In the latter case, the contents are assumed to be binary,
so they are encoded with base-64. Finally, an appropriate Content-Disposition header is added to that
section of the MIME file so that mail readers will know that they are dealing with an attachment.
The result of running this program is shown in Listing 12–9.
Listing 12–9. Running the Program in Listing 12–8
$ echo "This is a test" > test.txt
$ gzip < test.txt > test.txt.gz
$ ./mime_gen_basic.py test.txt test.txt.gz
Content-Type: multipart/mixed; boundary="===============1623374356=="
MIME-Version: 1.0
To: recipient@example.com
From: Test Sender
Subject: Test Message, Chapter 12
Date: Thu, 11 Dec 2003 16:00:55 -0600
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