Extract Email Subject Line, Single line only support.

email-parse-subject.py

import email.parser
from email import policy

def openFromFile(fp) -> email.message.EmailMessage:
    """
    Read in the open file pointer

    :param fp: file pointer to open file.
    :type fp: file pointer
    :returns: msg which is an email.message.EmailMessage
    :rtype: email.message.EmailMessage
    """

    msg = email.parser.Parser(policy=policy.default)
    return msg.parse(fp)

def openFromStr(string) -> email.message.EmailMessage:
    """
    Read in the email from string.

    :param string:
    :type string: str
    :returns: msg which is an email.message.EmailMessage
    :rtype: email.message.EmailMessage
    """

    msg = email.parser.Parser(policy=policy.default)
    return msg.parsestr(string)