Character Encoding: Why my email receiving code cannot run in PyQt4? - python-2.7

Question

I am recently finishing a spam classification application as my final project and now I meet a problem.
The problem came from a module to receive emails. I wrote the test code in a single .py file and it worked really well. Here is the code:
#!/usr/bin/env python
# coding=utf-8
import poplib
from email import parser
host = 'pop.qq.com'
username = 'xxxxx#qq.com'
password = 'xxxxxxxxxxxxx'
pop_conn = poplib.POP3_SSL(host)
pop_conn.user(username)
pop_conn.pass_(password)
messages = [pop_conn.retr(i) for i in range(1, len(pop_conn.list()[1]) + 1)]
# Concat message pieces:
messages = ["\n".join(mssg[1]) for mssg in messages]
#print messages
messages = [parser.Parser().parsestr(mssg) for mssg in messages]
i = 0
for message in messages:
i = i + 1
mailName = "mail"+str(i)
f = open(mailName + '.log', 'w');
print >> f, "Date: ", message["Date"]
print >> f, "From: ", message["From"]
print >> f, "To: ", message["To"]
print >> f, "Subject: ", message["Subject"]
print >> f, "Data: "
for part in message.walk():
contentType = part.get_content_type()
if contentType == 'text/plain' :
data = part.get_payload(decode=True)
print >> f, data
f.close()
pop_conn.quit()
But when I tried to transplant exactly the same code to my PyQt4 application, the problem came out in this line:
messages = ["\n".join(mssg[1]) for mssg in messages]
and this is the problem:
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe5 in position 4:ordinal not in range(128)
mssg[1] is a list that contains every line of the mail. I guess this is because the text from the mail was encoded by "utf-8" or "gbk" which can't be decoded by the default "ascii". So I tried to write the code like this:
messages = ["\n".join([m.decode("utf-8") for m in mssg[1]]) for mssg in messages]
The problem became like this:
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xcc in position 7
I used Python chardet module to detect the encoding of the text of the email, and it turned out to be "ascii". Now I am really confused. Why the same code can't run on my small application? What is the real problem, and how I can fix it? I will be very appreciated for your help.

Answer 1

I finally solved this problem by receiving the email in a .py file and using my application to import that file. This may not be useful in other situations because I actually didn't solve the character encoding problem. When I was implementing my application, I met lots of encoding problems, and it's quite annoying. For this, I guess it is caused by some irregular text from my mail(maybe some pictures) which is shown in the following picture:
This was shown when I tried to print some of my email data on the screen. However, I still don't know why this cannot run in my application, though it worked well in a simple file. The character encoding problem is very annoying, and maybe I still have a long way to go.:-D