replace_stuff.py

def split_header_footer(filetext, header_re, footer_re):
    import re
    import os
    text = filetext
    header_start = None
    for h in header_re:
        s = h.search(text)
        if s is not None:
            header_start = s.start()
            break
    if header_start is None:
        print('Header not found')
        header = []
        header_start = 0
    else:
        header_start = text.rfind(os.linesep, 0, header_start)
        header = text[:header_start].split(os.linesep)
    footer_start = None
    for f in footer_re:
        s = f.search(text[header_start:])
        if s is not None:
            footer_start = s.start()
            break
    if footer_start is None:
        print('Footer not found')
        body = text[header_start:].split(os.linesep)
    else:
        footer_start = text.rfind(os.linesep, 0, footer_start)
        body = text[header_start:footer_start].split(os.linesep)
    footer = text[footer_start:].split(os.linesep) if footer_start is not None else []
    all_lines = []
    for content, repl in [(header, 'HEADER'), (body, 'CONTENT'), (footer, 'FOOTER')]:
        content = [x.replace('LINE', repl) for x in content]
        all_lines.extend(content)
    return os.linesep.join(all_lines)