[New-bugs-announce] [issue40359] email.parse part.get_filename() fails to unwrap long attachment file names

[Matthew Davis]

New submission from Matthew Davis <ubuntu.one at mdavis.xyz>:

# Summary

When parsing emails with long attachment file names, part.get_filename() often returns \n or \r\n.
It should strip those characters out.

# Steps to reproduce

I have attached a minimal working example.

The relevant part of the raw email is:

--_004_D6CEDE1EBD6645898F5643C0C6878005examplecom_
Content-Type: text/plain;
	name="an attachment with a very very very long super long file name which has
 many words and just keeps on going and going.txt"

# Expected output:

attachments = ["an attachment with a very very very long super long file name which has many words and just keeps on going and going.txt"]

Maybe I'm reading the email RFC spec wrong. My interpretation is that the parser should do something like:

raw = raw.replace('\r\n ', ' ').replace('\n ', ' ')

# Actual output

attachments = ["an attachment with a very very very long super long file name which\n has many words and just keeps on going and going.txt"]

Note that I have seen other examples where the output includes \r\n not just \n

# Impact

I'm trying to write an email bot which saves attachments to a database, and also forwards on the emails.
My both thinks that the filename includes a line break. This inevitably causes failures in my subsequent code.

# Relevant links:

The RFC for email spec is here: https://tools.ietf.org/html/rfc2822.html#section-2.2.3

This Stack Overflow answer seems relevant: https://stackoverflow.com/questions/3050298/parsing-email-with-python/3050374#3050374

Issue 3601 may be relevant, but doesn't seem exactly the same. It seems to be the reverse, *constructing* emails with long headers. My issue is *parsing* emails with long headers.

----------
components: email
files: mwe.py
messages: 366963
nosy: barry, matt-davis, r.david.murray
priority: normal
severity: normal
status: open
title: email.parse part.get_filename() fails to unwrap long attachment file names
versions: Python 3.6
Added file: https://bugs.python.org/file49083/mwe.py

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40359>
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