Extract all email address in an .eml file, decoding all UTF-8 encoded names.

extract-eml-addr.py

import re
NAME_PATTERN = re.compile(r'(?P<name>[^ "]+|".*") \<(?P<email>.*@.*)\>')
ENCODED_PATTERN = re.compile(r'=\?(?P<charset>.*)\?(?P<encoding>.*)\?(?P<encodedtext>.*)\?=')
import sys


def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


import base64

heads = {"From", "To", "Cc"}


def decode_email_name(s):
    m = ENCODED_PATTERN.match(s)
    if not m:
        #eprint(f"Not match in {s}")
        return s
    if m.group('charset') != 'UTF-8':
        eprint('Encoding {} not supported'.format(m.group('charset')))
        return s
    if m.group('encoding') != 'B':
        return s
    return base64.b64decode(m.group('encodedtext')).decode('utf-8')


cur_tag = ''
for l in open("XXXX.eml"):
    if l[0] != '\t':
        pos = l.find(':')
        if pos:
            cur_tag = l[:pos]
            l = l[pos+1:]
    if cur_tag in heads:
        m = NAME_PATTERN.search(l)
        if m:
            name, email = m.group('name'), m.group('email')
            name = name.strip().strip('"')
            print(f"{cur_tag:9} {decode_email_name(name)} <{email}>")