chardetect.py

#!/usr/bin/env python
"""
Script which takes one or more file paths and reports on their detected
encodings

Example::

    % chardetect somefile someotherfile
    somefile: windows-1252 with confidence 0.5
    someotherfile: ascii with confidence 1.0

If no paths are provided, it takes its input from stdin.

"""

from __future__ import absolute_import, print_function, unicode_literals

import argparse
import sys

from chardet import __version__
from chardet.compat import PY2
from chardet.universaldetector import UniversalDetector


def description_of(lines, name='stdin'):
    """
    Return a string describing the probable encoding of a file or
    list of strings.

    :param lines: The lines to get the encoding of.
    :type lines: Iterable of bytes
    :param name: Name of file or collection of lines
    :type name: str
    """
    u = UniversalDetector()
    for line in lines:
        line = bytearray(line)
        u.feed(line)
        # shortcut out of the loop to save reading further - particularly useful if we read a BOM.
        if u.done:
            break
    u.close()
    result = u.result
    if PY2:
        name = name.decode(sys.getfilesystemencoding(), 'ignore')
    if result['encoding']:
        return '{}: {} with confidence {}'.format(name, result['encoding'],
                                                     result['confidence'])
    else:
        return '{}: no result'.format(name)


def main(argv=None):
    """
    Handles command line arguments and gets things started.

    :param argv: List of arguments, as if specified on the command-line.
                 If None, ``sys.argv[1:]`` is used instead.
    :type argv: list of str
    """
    # Get command line arguments
    parser = argparse.ArgumentParser(
        description="Takes one or more file paths and reports their detected \
                     encodings")
    parser.add_argument('input',
                        help='File whose encoding we would like to determine. \
                              (default: stdin)',
                        type=argparse.FileType('rb'), nargs='*',
                        default=[sys.stdin if PY2 else sys.stdin.buffer])
    parser.add_argument('--version', action='version',
                        version='%(prog)s {}'.format(__version__))
    args = parser.parse_args(argv)

    for f in args.input:
        if f.isatty():
            print("You are running chardetect interactively. Press " +
                  "CTRL-D twice at the start of a blank line to signal the " +
                  "end of your input. If you want help, run chardetect " +
                  "--help\n", file=sys.stderr)
        print(description_of(f, f.name))


if __name__ == '__main__':
    main()