python 構建和解析郵件

用python寫傳統的郵件

from email.mime.text import MIMEText
message = ''' hello jason
it is a test mail
please accept it'''

msg = MIMEText(message)
msg['To'] = '[email protected]'
msg['From'] = 'jason <[email protected]>'
msg['Subject'] = 'test mail'

print msg.as_string()

結果：

Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
To: [email protected]
From: jason <[email protected]>
Subject: test mail

 hello jason
it is a test mail
please accept it

默認添加了3個頭部Content-Type，MIME-Version，Content-Transfer-Encoding，而且也已經排好了版，這樣的郵件，如果理解發送是可以的。如果想延遲發送的話，最好還是要加上Date和Message-ID頭部，可以通過下面的方式來添加。

from email.mime.text import MIMEText
from email import Utils
message = ''' hello jason
it is a test mail
please accept it'''

msg = MIMEText(message)
msg['To'] = '[email protected]'
msg['From'] = 'jason <[email protected]>'
msg['Subject'] = 'test mail'
msg['Date'] = Utils.formatdate(localtime=1)
msg['Message-ID'] = Utils.make_msgid()  

print msg.as_string()

結果：

Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
To: [email protected]
From: jason <[email protected]>
Subject: test mail
Date: Wed, 27 Mar 2013 11:48:59 +0800
Message-ID: <20130327034859.14284.670@ZGC-20121219ZKJ>

 hello jason
it is a test mail
please accept it

這樣的郵件就可以正確的被髮送了

解析郵件

import sys,email

msg = email.message_from_file(sys.stdin)
print "*** Headers in message: "
for header,value in msg.items():
    print header+":"
    print " "+value
if msg.is_multipart():
    print "mail is MIME type, can't resolve it."
    sys.exit(1)
else:
    print "-" * 78
    if 'subject' in msg:
        print "Subject: ",msg['subject']
        print "-" * 78
    print "Message body:"
    print
    print msg.get_payload()

把郵件顯示結果寫入到一個mail.txt文件中。

from email.mime.text import MIMEText
from email import Utils

message = ''' hello jason
it is a test mail
please accept it'''

msg = MIMEText(message)
msg['To'] = '[email protected]'
msg['From'] = 'jason <[email protected]>'
msg['Subject'] = 'test mail'
msg['Date'] = Utils.formatdate(localtime=1)
msg['Message-ID'] = Utils.make_msgid()  
fd = open('mail.txt','w')
fd.write(msg.as_string()) 
fd.close()

通過這個把剛剛顯示出來的郵件，以一種更可讀的方式顯示出來，如下圖：

構造MIME郵件

上面說的都是些純文本郵件，那麼如何才能讓郵件發送非純文本郵件呢，這個就設計到了MIME，大家可以跟着到google查一下。

提幾個重點步驟吧！

1. 建立一個MIMEMultipart()對象，設置郵件的header。

2.爲郵件部分內容建立一個MIMEText()對象，把它放到MIMEMultipart()對象中。

3.爲每一個附件，建立一個合適的MIME對象，也把他放到MIMEMultipart()對象中。

4.調用MIMEMultipart()對象中的as_string()函數來得到作爲結果的郵件。

下面我們就用python來構造MIME格式的郵件，這個是可以添加附件的郵件格式。

email_mime.py

from email import Utils,Encoders
import mimetypes,sys
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase

def attachment(filename):
    fd = open(filename,'rb')
    mimetype,mimeencoding = mimetypes.guess_type(filename)
    if mimetype or (mimeencoding 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 jason
it is a test mail
please accept it'''

msg = MIMEMultipart()
msg['To'] = '[email protected]'
msg['From'] = 'jason <[email protected]>'
msg['Subject'] = 'test mail'
msg['Date'] = Utils.formatdate(localtime=1)
msg['Message-ID'] = Utils.make_msgid()

body = MIMEText(message)
msg.attach(body)
for filename in sys.argv[1:]:
    msg.attach(attachment(filename))
print msg.as_string()

運行腳本（這裏添加了mail.txt和Loadrunner.rar作爲附件）：

python email_mime.py mail.txt Loadrunner.rar > results.txt

Content-Type: multipart/mixed; boundary="===============1228986135=="
MIME-Version: 1.0
To: [email protected]
From: jason <[email protected]>
Subject: test mail
Date: Wed, 27 Mar 2013 14:31:02 +0800
Message-ID: <20130327063102.12588.91954@ZGC-20121219ZKJ>

--===============1228986135==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit

 hello jason
it is a test mail
please accept it
--===============1228986135==
Content-Type: application/octet-stream
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="mail.txt"

Q29udGVudC1UeXBlOiB0ZXh0L3BsYWluOyBjaGFyc2V0PSJ1cy1hc2NpaSINCk1JTUUtVmVyc2lv
bjogMS4wDQpDb250ZW50LVRyYW5zZmVyLUVuY29kaW5nOiA3Yml0DQpUbzogeHh4eHhAcXEuY29t
DQpGcm9tOiBqYXNvbiA8bWp6aGVuZ0B4eHh4eC5jb20+DQpTdWJqZWN0OiB0ZXN0IG1haWwNCkRh
dGU6IFdlZCwgMjcgTWFyIDIwMTMgMTI6NTU6MTMgKzA4MDANCk1lc3NhZ2UtSUQ6IDwyMDEzMDMy
NzA0NTUxMy4xMzc1Mi4xNTU1NkBaR0MtMjAxMjEyMTlaS0o+DQoNCiBoZWxsbyBqYXNvbg0KaXQg
aXMgYSB0ZXN0IG1haWwNCnBsZWFzZSBhY2NlcHQgaXQ=
--===============1228986135==
Content-Type: application/octet-stream
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="Loadrunner.rar"

UmFyIRoHAM+QcwAADQAAAAAAAAADJXRAgiwAa0EBAADwAwACkyympH2W+TAdMwwAIAAAAGxtNzAu
ZGxsAAHABhgl1VUMiNXgGmIzJMkmAYExbBsVistY2naRtlsg0LA7YVMAVMTI4OYRSBFoFxyi0UzG
lUgwcmNmHDGnWjaPaFpbR7Ttp37TvaFuWojBDpIVlCVSpGkaxtlt5LmVYqdGNYGfn3esnqzMmtb3
zmeiQG1759/X+NpM5zfN+rWtb1vW9a1vXOfxLX/CefP98+b1vet89MzOYeeL+j/7TGYAFAACay42
...

構造成功。

注意這裏的Content-Type(內容類型)和Content-Transfer-Encoding(內容傳輸編碼格式)的變化

但是呢，有個問題就是爲什麼mail.txt文件爲什麼識別不了呢，應該識別成功text/plian的內容格式啊。

查了一下，發現mimetypes模塊是通過調用mimetypes.pyc文件的，查看一下mimetypes.py文件

可以看到

knownfiles = [
    "/etc/mime.types",
    "/etc/httpd/mime.types",                    # Mac OS X
    "/etc/httpd/conf/mime.types",               # Apache
    "/etc/apache/mime.types",                   # Apache 1
    "/etc/apache2/mime.types",                  # Apache 2
    "/usr/local/etc/httpd/conf/mime.types",
    "/usr/local/lib/netscape/mime.types",
    "/usr/local/etc/httpd/conf/mime.types",     # Apache 1.2
    "/usr/local/etc/mime.types",                # Apache 1.3
    ]

因爲我是在windows環境下運行的，所以當然找不到所識別的mime類型啦