Issue 4768: email.generator.Generator object bytes/str crash - b64encode() bug? (original) (raw)
Created on 2008-12-29 17:21 by beazley, last changed 2022-04-11 14:56 by admin. This issue is now closed.
Messages (10)
Author: David M. Beazley (beazley)
Date: 2008-12-29 17:21
The email.generator.Generator class does not work correctly message objects created with binary data (MIMEImage, MIMEAudio, MIMEApplication, etc.). For example:
from email.mime.image import MIMEImage data = open("IMG.jpg","rb").read() m = MIMEImage(data,'jpeg') s = m.as_string() Traceback (most recent call last): File "", line 1, in File "/tmp/lib/python3.0/email/message.py", line 136, in as_string g.flatten(self, unixfrom=unixfrom) File "/tmp/lib/python3.0/email/generator.py", line 76, in flatten self._write(msg) File "/tmp/lib/python3.0/email/generator.py", line 101, in _write self._dispatch(msg) File "/tmp/lib/python3.0/email/generator.py", line 127, in _dispatch meth(msg) File "/tmp/lib/python3.0/email/generator.py", line 155, in _handle_text raise TypeError('string payload expected: %s' % type(payload)) TypeError: string payload expected: <class 'bytes'>
The source of the problem is rather complicated, but here is the gist of it.
Classes such as MIMEAudio and MIMEImage accept raw binary data as input. This data is going to be in the form of bytes.
These classes immediately encode the data using a base64 encoder. This encoder uses the library function base64.b64encode().
base64.b64encode() takes a byte string as input and returns a byte string as output. So, even after encoding, the payload of the message is of type 'bytes'
When messages are generated, the method Generator._dispatch() is used. It looks at the MIME main type and subtype and tries to dispatch message processing to a handler method of the form '_handle_type_subtype'. If it can't find such a handler, it defaults to a method _writeBody(). For image and audio types, this is what happens.
_writeBody() is an alias for _handle_text().
_handle_text() crashes because it's not expecting a payload of type 'bytes'.
Suggested fix:
I think the library function base64.b64encode() should return a string, not bytes. The whole point of base64 encoding is to take binary data and encode it into characters safe for inclusion in text strings.
Other fixes:
Modify the Generator class in email.generator to properly detect bytes and use a different _handle function for it. For instance, maybe add a _handle_binary() method.
Author: STINNER Victor (vstinner) * 
Date: 2009-01-02 01:21
I think the library function base64.b64encode() should return a string, not bytes.
Yes, in the email module, the payload is an unicode string, not a bytes string. We have to be able to concatenate headers (eg. "Content-Type: image/fish\nMIME-Version: 1.0\nContent-Transfer-Encoding: base64\n") and encoded data (eg. "R0lGO").
Attached patch implements this fix: encode_base64() returns str (and not bytes). The patchs fixes the unit tests and adds a new regression test for MIMEImage.as_string().
Author: Stac (stac)
Date: 2010-04-19 13:59
Hello,
This patch has never been commited. I tested today with the 3.1 branch (and checked in the lib code). Is there a better way to attach images in an email ?
Thanks in advance for your help,
Regards, Stac
Author: (garazi111)
Date: 2010-05-09 11:54
Hi,
I think the bug is also present in the function encode_quopri which should look like this :
def encode_quopri(msg): """Encode the message's payload in quoted-printable.
Also, add an appropriate Content-Transfer-Encoding header.
"""
orig = msg.get_payload()
encdata = _qencode(orig)
data = str(encdata, "ASCII")
msg.set_payload(data)
msg['Content-Transfer-Encoding'] = 'quoted-printable'Author: STINNER Victor (vstinner) *
Date: 2010-05-26 17:09
I wrote a patch for base64.b64encode() to accept str (str is encoded to utf-8): patch attached to #4768. It should fix this issue, but we can add the tests of email_base64_bytes.patch.
Author: Forest Bond (forest_atq) *
Date: 2010-06-04 15:01
Attaching patch from reported duplicate .
Author: Forest Bond (forest_atq) *
Date: 2010-06-04 15:03
Note that my patch is roughly the same as the original posted by haypo.
Author: R. David Murray (r.david.murray) *
Date: 2010-06-04 16:17
Yes, but yours was better formatted, so I used it :) Thanks for the patch. Applied in r81685 to py3k, and r81686.
Author: R. David Murray (r.david.murray) *
Date: 2010-06-04 16:45
@garazi111: if you have an example where quopri fails, please open a new issue for it. I suspect you are right that there is a problem there.
Author: R. David Murray (r.david.murray) *
Date: 2013-06-28 19:05
For the record, encode_quopri was fixed in #14360.
History
Date
User
Action
Args
2022-04-11 14:56:43
admin
set
github: 49018
2013-06-28 19:05:06
r.david.murray
set
messages: +
2011-07-06 04:59:21
anacrolix
set
nosy: + anacrolix
2010-06-26 02:10:51
r.david.murray
link
2010-06-04 16:45:30
r.david.murray
set
messages: +
2010-06-04 16:17:20
r.david.murray
set
status: open -> closed
resolution: accepted -> fixed
messages: +
stage: patch review -> resolved
2010-06-04 15:03:23
forest_atq
set
messages: +
2010-06-04 15:01:47
forest_atq
set
files: + python-email-encoders-base64-str.patch
nosy: + forest_atq
messages: +
2010-06-04 14:57:37
r.david.murray
link
2010-05-26 17:09:16
vstinner
set
messages: +
2010-05-10 19:06:51
r.david.murray
set
priority: high -> critical
2010-05-09 11:54:44
garazi111
set
nosy: + garazi111
messages: +
2010-04-23 01:55:23
r.david.murray
set
type: crash -> behavior
resolution: accepted
assignee: barry -> r.david.murray
2010-04-22 22:44:53
pitrou
set
priority: high
stage: patch review
versions: + Python 3.1, Python 3.2, - Python 3.0
2010-04-22 22:25:14
eric.araujo
set
nosy: + eric.araujo
2010-04-19 19:19:02
l0nwlf
set
nosy: + l0nwlf
2010-04-19 19:01:14
l0nwlf
set
nosy: + r.david.murray
2010-04-19 13:59:19
stac
set
nosy: + stac
messages: +
2009-01-02 01:22:12
vstinner
set
files: + email_base64_bytes.patch
keywords: + patch
2009-01-02 01:21:59
vstinner
set
nosy: + vstinner
messages: +
2009-01-01 08:38:25
brotchie
set
nosy: + brotchie
2008-12-29 17:28:30
benjamin.peterson
set
2008-12-29 17:21:40
beazley
create