That time I reimplemented/replaced the raw_input builtin so I could log stdin.

gistfile1.py

PY3K = sys.version_info[:2] >= (3, 0)
# The global_logging system replaces the raw_input builtin (input on Python 3)
# for two reasons:
#
#  1) It's the easiest way to capture the raw_input prompt and subsequent user
#     input to the log.
#
#  2) On Python 2.x raw_input() does not play nicely with GUI toolkits if
#     sys.stdout has been replaced by a non-file object (as global_logging
#     does).  The default raw_input() implementation first checks that
#     sys.stdout and sys.stdin are connected to a terminal.  If so it uses the
#     PyOS_Readline() implementation, which allows a GUI's event loop to run
#     while waiting for user input via PyOS_InputHook().  However, if
#     sys.stdout is not attached to a terminal, raw_input() uses
#     PyFile_GetLine(), which blocks until a line is entered on sys.stdin,
#     thus preventing the GUI from updating.  It doesn't matter if sys.stdin is
#     still attached to the terminal even if sys.stdout isn't, nor does it
#     automatically fall back on sys.__stdout__ and sys.__stdin__.
#
#     This replacement raw_input() reimplements most of the built in
#     raw_input(), but is aware that sys.stdout may have been replaced and
#     knows how to find the real stdout if so.
#
#     Note that this is a non-issue in Python 3 which has a new implementation
#     in which it doesn't matter what sys.stdout points to--only that it has a
#     fileno() method that returns the correct file descriptor for the
#     console's stdout.
if not PY3K:
    import os
    import __builtin__ as builtins
    from ctypes import pythonapi, py_object, c_void_p, c_char_p, c_int
    # PyFile_AsFile returns a FILE * from a python file object.
    # This is used later with pythonapi.PyOS_Readline to perform
    # the readline.
    pythonapi.PyFile_AsFile.argtypes = (py_object,)
    pythonapi.PyFile_AsFile.restype = c_void_p
    pythonapi.PyOS_Readline.argtypes = (c_void_p, c_void_p, c_char_p)
    pythonapi.PyOS_Readline.restype = c_char_p
    def global_logging_raw_input(prompt):
        def get_stream(name):
            if hasattr(sys, name):
                stream = getattr(sys, name)
                if isinstance(stream, file):
                    return stream
                elif isinstance(stream, StreamTeeLogger):
                    return stream.stream
            if hasattr(sys, '__%s__' % name):
                stream = getattr(sys, '__%s__' % name)
                if isinstance(stream, file):
                    return stream
            return None
        def check_interactive(stream, name):
            try:
                fd = stream.fileno()
            except:
                # Could be an AttributeError, an OSError, and IOError, or who
                # knows what else...
                return False
            realfd = {'stdin': 0, 'stdout': 1, 'stderr': 2}[name]
            return fd == realfd and os.isatty(fd)
        stdout = get_stream('stdout')
        stdin = get_stream('stdin')
        stderr = get_stream('stderr')
        if stdout is None:
            raise RuntimeError('raw_input(): lost sys.stdout')
        if stdin is None:
            raise RuntimeError('raw_input(): lost sys.stdin')
        if stderr is None:
            raise RuntimeError('raw_input(): lost sys.stderr')
        if (not check_interactive(stdin, 'stdin') or
            not check_interactive(stdout, 'stdout')):
            # Use the built-in raw_input(); this will repeat some of the checks
            # we just did, but will save us from having to reimplement
            # raw_input() in its entirety
            retval = builtins._original_raw_input(prompt)
        else:
            stdout.flush()
            infd = pythonapi.PyFile_AsFile(stdin)
            outfd = pythonapi.PyFile_AsFile(stdout)
            retval = pythonapi.PyOS_Readline(infd, outfd, str(prompt))
            retval = retval.rstrip('\n')
        if isinstance(sys.stdout, StreamTeeLogger):
            sys.stdout.log_orig(str(prompt) + retval, echo=False)
        return retval
else:
    import builtins
    def global_logging_raw_input(prompt):
        retval = builtins._original_raw_input(prompt)
        if isinstance(sys.stdout, StreamTeeLogger):
            sys.stdout.log_orig(str(prompt) + retval, echo=False)
        return retval