二进制文件电子邮件附件问题

问题描述

使用 Python 3.1.2 我在发送二进制附件文件(jpeg、pdf 等)时遇到问题 - MIMEText 附件工作正常.有问题的代码如下...

Using Python 3.1.2 I am having a problem sending binary attachment files (jpeg, pdf, etc.) - MIMEText attachments work fine. The code in question is as follows...

for file in self.attachments:
   part = MIMEBase('application', "octet-stream")
   part.set_payload(open(file,"rb").read())
   encoders.encode_base64(part)
   part.add_header('Content-Disposition', 'attachment; filename="%s"' % file)
   msg.attach(part)   # msg is an instance of MIMEMultipart()

server = smtplib.SMTP(host, port)
server.login(username, password)
server.sendmail(from_addr, all_recipients, msg.as_string())

但是，在调用堆栈的下方(请参阅下面的回溯)，似乎 msg.as_string() 收到了一个附件，该附件创建了一个字节"类型而不是字符串的有效负载.

However, way down in the calling-stack (see traceback below), it looks as though msg.as_string() has received an attachment which creates a payload of 'bytes' type instead of string.

有没有人知道是什么导致了这个问题?任何帮助将不胜感激.

Has anyone any idea what might be causing the problem? Any help would be appreciated.

艾伦

builtins.TypeError: string payload expected: <class 'bytes'>
File "c:DevCommonPYScriptsemail_send.py", line 147, in send
  server.sendmail(self.from_addr, all_recipients, msg.as_string())
File "c:Program FilesPython31Libemailmessage.py", line 136, in as_string
  g.flatten(self, unixfrom=unixfrom)
File "c:Program FilesPython31Libemailgenerator.py", line 76, in flatten
  self._write(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 101, in _write
  self._dispatch(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 127, in _dispatch
  meth(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 181, in _handle_multipart
  g.flatten(part, unixfrom=False)
File "c:Program FilesPython31Libemailgenerator.py", line 76, in flatten
  self._write(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 101, in _write
  self._dispatch(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 127, in _dispatch
  meth(msg)
File "c:Program FilesPython31Libemailgenerator.py", line 155, in _handle_text
  raise TypeError('string payload expected: %s' % type(payload))

推荐答案

好的 - 经过很多挫折和网络搜索，我发现问题是适用于 Python 3.x、encoders.py、函数的已知错误encode_base64，应该是这样的……

Ok - after much frustration and web-searching, I have found that the problem is a known bug that applies to Python 3.x, encoders.py, function encode_base64, which should read as follows...

def encode_base64(msg):
    """Encode the message's payload in Base64.

    Also, add an appropriate Content-Transfer-Encoding header.
    """
    orig = msg.get_payload()
    encdata = _bencode(orig)

    # new line inserted to ensure all bytes characters are converted to ASCII
    encdata = str(encdata, "ASCII")

    msg.set_payload(encdata)
    msg['Content-Transfer-Encoding'] = 'base64'

该错误已作为问题 #4768 提出，并已升级为严重状态在 2010 年 5 月 10 日.希望它会在下一个版本(3.1.3?)中得到修复

The bug has been raised as issue #4768, and was escalated to critical status on 2010-05-10. Hopefully it will be fixed in the next version (3.1.3?)

问候，艾伦

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