## 13 使用例

ここでは `email` パッケージを使って電子メールメッセージを 読む・書く・送信するいくつかの例を紹介します。より複雑な MIME メッセージについても扱います。

最初に、テキスト形式の単純なメッセージを作成・送信する方法です:

    # Import smtplib for the actual sending function
    import smtplib

    # Import the email modules we'll need
    from email.MIMEText import MIMEText

    # Open a plain text file for reading.  For this example, assume that
    # the text file contains only ASCII characters.
    fp = open(textfile, 'rb')
    # Create a text/plain message
    msg = MIMEText(fp.read())
    fp.close()

    # me == the sender's email address
    # you == the recipient's email address
    msg['Subject'] = 'The contents of %s' % textfile
    msg['From'] = me
    msg['To'] = you

    # Send the message via our own SMTP server, but don't include the
    # envelope header.
    s = smtplib.SMTP()
    s.connect()
    s.sendmail(me, [you], msg.as_string())
    s.close()

つぎに、あるディレクトリ内にある何枚かの家族写真をひとつの MIME メッセージに 収めて送信する例です:

    # Import smtplib for the actual sending function
    import smtplib

    # Here are the email pacakge modules we'll need
    from email.MIMEImage import MIMEImage
    from email.MIMEMultipart import MIMEMultipart

    COMMASPACE = ', '

    # Create the container (outer) email message.
    msg = MIMEMultipart()
    msg['Subject'] = 'Our family reunion'
    # me == the sender's email address
    # family = the list of all recipients' email addresses
    msg['From'] = me
    msg['To'] = COMMASPACE.join(family)
    msg.preamble = 'Our family reunion'
    # Guarantees the message ends in a newline
    msg.epilogue = ''

    # Assume we know that the image files are all in PNG format
    for file in pngfiles:
        # Open the files in binary mode.  Let the MIMEImage class automatically
        # guess the specific image type.
        fp = open(file, 'rb')
        img = MIMEImage(fp.read())
        fp.close()
        msg.attach(img)

    # Send the email via our own SMTP server.
    s = smtplib.SMTP()
    s.connect()
    s.sendmail(me, family, msg.as_string())
    s.close()

つぎはあるディレクトリに含まれている内容全体を ひとつの電子メールメッセージとして送信するやり方です 45:

    #!/usr/bin/env python

    """Send the contents of a directory as a MIME message.

    Usage: dirmail [options] from to [to ...]*

    Options:
        -h / --help
            Print this message and exit.

        -d directory
        --directory=directory
            Mail the contents of the specified directory, otherwise use the
            current directory.  Only the regular files in the directory are sent,
            and we don't recurse to subdirectories.

    `from' is the email address of the sender of the message.

    `to' is the email address of the recipient of the message, and multiple
    recipients may be given.

    The email is sent by forwarding to your local SMTP server, which then does the
    normal delivery process.  Your local machine must be running an SMTP server.
    """

    import sys
    import os
    import getopt
    import smtplib
    # For guessing MIME type based on file name extension
    import mimetypes

    from email import Encoders
    from email.Message import Message
    from email.MIMEAudio import MIMEAudio
    from email.MIMEBase import MIMEBase
    from email.MIMEMultipart import MIMEMultipart
    from email.MIMEImage import MIMEImage
    from email.MIMEText import MIMEText

    COMMASPACE = ', '

    def usage(code, msg=''):
        print >> sys.stderr, __doc__
        if msg:
            print >> sys.stderr, msg
        sys.exit(code)

    def main():
        try:
            opts, args = getopt.getopt(sys.argv[1:], 'hd:', ['help', 'directory='])
        except getopt.error, msg:
            usage(1, msg)

        dir = os.curdir
        for opt, arg in opts:
            if opt in ('-h', '--help'):
                usage(0)
            elif opt in ('-d', '--directory'):
                dir = arg

        if len(args) < 2:
            usage(1)

        sender = args[0]
        recips = args[1:]

        # Create the enclosing (outer) message
        outer = MIMEMultipart()
        outer['Subject'] = 'Contents of directory %s' % os.path.abspath(dir)
        outer['To'] = COMMASPACE.join(recips)
        outer['From'] = sender
        outer.preamble = 'You will not see this in a MIME-aware mail reader.\n'
        # To guarantee the message ends with a newline
        outer.epilogue = ''

        for filename in os.listdir(dir):
            path = os.path.join(dir, filename)
            if not os.path.isfile(path):
                continue
            # Guess the content type based on the file's extension.  Encoding
            # will be ignored, although we should check for simple things like
            # gzip'd or compressed files.
            ctype, encoding = mimetypes.guess_type(path)
            if ctype is None or encoding is not None:
                # No guess could be made, or the file is encoded (compressed), so
                # use a generic bag-of-bits type.
                ctype = 'application/octet-stream'
            maintype, subtype = ctype.split('/', 1)
            if maintype == 'text':
                fp = open(path)
                # Note: we should handle calculating the charset
                msg = MIMEText(fp.read(), _subtype=subtype)
                fp.close()
            elif maintype == 'image':
                fp = open(path, 'rb')
                msg = MIMEImage(fp.read(), _subtype=subtype)
                fp.close()
            elif maintype == 'audio':
                fp = open(path, 'rb')
                msg = MIMEAudio(fp.read(), _subtype=subtype)
                fp.close()
            else:
                fp = open(path, 'rb')
                msg = MIMEBase(maintype, subtype)
                msg.set_payload(fp.read())
                fp.close()
                # Encode the payload using Base64
                Encoders.encode_base64(msg)
            # Set the filename parameter
            msg.add_header('Content-Disposition', 'attachment', filename=filename)
            outer.attach(msg)

        # Now send the message
        s = smtplib.SMTP()
        s.connect()
        s.sendmail(sender, recips, outer.as_string())
        s.close()

    if __name__ == '__main__':
        main()

そして最後に、上のような MIME メッセージをどうやって 展開してひとつのディレクトリ上の複数ファイルにするかを示します:

    #!/usr/bin/env python

    """Unpack a MIME message into a directory of files.

    Usage: unpackmail [options] msgfile

    Options:
        -h / --help
            Print this message and exit.

        -d directory
        --directory=directory
            Unpack the MIME message into the named directory, which will be
            created if it doesn't already exist.

    msgfile is the path to the file containing the MIME message.
    """

    import sys
    import os
    import getopt
    import errno
    import mimetypes
    import email

    def usage(code, msg=''):
        print >> sys.stderr, __doc__
        if msg:
            print >> sys.stderr, msg
        sys.exit(code)

    def main():
        try:
            opts, args = getopt.getopt(sys.argv[1:], 'hd:', ['help', 'directory='])
        except getopt.error, msg:
            usage(1, msg)

        dir = os.curdir
        for opt, arg in opts:
            if opt in ('-h', '--help'):
                usage(0)
            elif opt in ('-d', '--directory'):
                dir = arg

        try:
            msgfile = args[0]
        except IndexError:
            usage(1)

        try:
            os.mkdir(dir)
        except OSError, e:
            # Ignore directory exists error
            if e.errno <> errno.EEXIST: raise

        fp = open(msgfile)
        msg = email.message_from_file(fp)
        fp.close()

        counter = 1
        for part in msg.walk():
            # multipart/* are just containers
            if part.get_content_maintype() == 'multipart':
                continue
            # Applications should really sanitize the given filename so that an
            # email message can't be used to overwrite important files
            filename = part.get_filename()
            if not filename:
                ext = mimetypes.guess_extension(part.get_type())
                if not ext:
                    # Use a generic bag-of-bits extension
                    ext = '.bin'
                filename = 'part-%03d%s' % (counter, ext)
            counter += 1
            fp = open(os.path.join(dir, filename), 'wb')
            fp.write(part.get_payload(decode=1))
            fp.close()

    if __name__ == '__main__':
        main()

#### Footnotes

... ひとつの電子メールメッセージとして送信するやり方です 45
  最初の思いつきと用例は Matthew Dixon Cowles のおかげです。