网络实战(二)：应用层 Part IV：Building and Parsing E-mail

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
import email.message, email.policy, email.utils

text = '''Hello,
This is a basic message from Chapter 12 - Anonymouse'''

def main():
    message = email.message.EmailMessage(email.policy.SMTP)
    message['To'] = 'shunmian@gmail.com'
    message['From'] = 'Test Sender<sender@example.com>'
    message['Subject'] = 'Text Message, Chapter 12'
    message['Date'] = email.utils.formatdate(localtime=True)
    message['Message-ID'] = email.utils.make_msgid()
    message.set_content(text)
    print(message.as_string())

if __name__=='__main__':
    main()

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
import email.message, email.policy, email.utils, mimetypes, argparse, sys

plain = """Hello,
This is a MiME Message from Chapter 12.
= Anonymous """

html = """<p>Hello,</p>
<p>This is a <b> test message</b> from Chapter 12.</p>
<p>- <i>Anonymous</i></p>"""

img = """<p> This is the smallest possible blue GIF:</p>
<img src ="cid:{}" height = "80" width = "80">"""

blue_dot = (b'GIF89a1010\x900000\xff000,000010100\x02\x02\x0410;'
            .replace(b'0', b'\x00').replace(b'1', b'\x01'))

def main(args):
    message = email.message.EmailMessage(email.policy.SMTP)
    message['To'] = 'Test Recipient <recipient@example.com>'
    message['From'] = 'Test Sender <sender@example.com>'
    message['Subject'] = 'Foundations of Python Network Programming'
    message['Date'] =  email.utils.formatdate(localtime=True)
    message['Message-ID'] = email.utils.make_msgid()

    if not args.i:
        message.set_content(html,subtype='html')
        message.add_alternative(plain)
    else:
        cid = email.utils.make_msgid()
        message.set_content(html + img.format(cid.strip('<>')), subtype='html')
        message.add_related(blue_dot,'image','gif',cid=cid,filename='blue-dot.gif')
        message.add_alternative(plain)

    for filename in args.filename:
        mime_type, encoding = mimetypes.guess_type(filename)
        if encoding or (mime_type is None):
            mime_type = 'application/octet-stream'
        main, sub = mime_type.split('/')
        if main == 'text':
            with open(filename, encoding = 'utf-8') as f:
                text = f.read()
            message.add_attachment(text,sub,filename=filename)

        else:
            with open(filename,'rb') as f:
                data = f.read()
            message.add_attachment(data,main,sub,filename=filename)

    sys.stdout.buffer.write(message.as_bytes())

if __name__=='__main__':
    parser = argparse.ArgumentParser(description='Build, print a MIME email')
    parser.add_argument('-i', action = 'store_true', help='Include GIF image')
    parser.add_argument('filename', nargs='*',help='Attachment filename')
    main(parser.parse_args())

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
import argparse, email.policy, sys

def main(binary_file):
    policy = email.policy.SMTP
    message = email.message_from_binary_file(binary_file,policy=policy)
    for header in ['From', 'To', 'Date', 'Subject']:                    #header
        print(header + ':', message.get(header,'(none)'))
    print()

    try:                                                                #body
        body = message.get_body(preferencelist=('plain','html'))
    except KeyError:
        print('<This message lacks a printable text or HTML body>')
    else:
        print(body.get_content())


    for part in message.walk():                                         #attachment
        cd = part['Content-Disposition']
        is_attachment = cd and cd.split(';')[0].lower() == 'attachment'
        if not is_attachment:
            continue

        content = part.get_content()
        print('* {} attachment named {!r}: {} object of length {}'.format(part.get_contetn_type().part.get_filename(),type(content).__name__,len(content)))


if __name__=='__main__':
    parser = argparse.ArgumentParser(description='Build, print a MIME email')
    parser.add_argument('filename', nargs='?', help='File containing an email')
    args = parser.parse_args()

    if args.filename is None:
        main(sys.sydin.buffer)
    else:
        with open(args.filename,'rb') as f:
            main(f)

1
2
$ python3 build_basic_email.py > email.txt   #stdout输出到email.txt而不是默认的print。
$ python3 display_email.py email.txt