CODEWITHSUNDEEP
python-2.7email
PurpleVermont
PurpleVermont

Reputation: 1241

how can I determine whether an email header is base64 encoded

Using the email.header package, I can do

the_text,the_charset = decode_header(inputText)

to get the character set of the email header, where the inputText was retrieved by a command like

inputText = msg.get('From')

to use the From: header as an example.

in order to extract the header encoding for that header, do I have to do something like this?:

the_header_encoding = email.charset.Charset(the_charset).header_encoding

That is, do I have to create an instance of the Charset class based on the name of the charset (and would that even work?), or is there a way to extract the header encoding more directly from the header itself?

Upvotes: 0

Views: 244

Answers (1)

Martijn Pieters
Martijn Pieters

Reputation: 1122152

Encoded-Message header can consist of 1 or more lines, and each line can use a different encoding, or no encoding at all.

You'll have to parse the type of encoding out yourself, one per line. Using a regular expression:

import re

quopri_entry = re.compile(r'=\?[\w-]+\?(?P<encoding>[QB])\?[^?]+?\?=', flags=re.I)
encodings = {'Q': 'quoted-printable', 'B': 'base64'}

def encoded_message_codecs(header):
    used = []
    for line in header.splitlines():
        entry = quopri_entry.search(line)
        if not entry:
            used.append(None)
            continue
        used.append(encodings.get(entry.group('encoding').upper(), 'unknown'))
    return used

This returns a list of strings drawn from quoted-printable, base64, unknown or None if no Encoded-Message was used for that line.

Upvotes: 1

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