pytabs.py

#!/usr/bin/env python
""" pytabs
Replace tabs with spaces on python files.
Author: Eduard S. Markelov <markeloveduard@gmail.com>

Command line arguments:

-r, --recursive
    Search Python files in the specified directory.
-n, --spaces
    Number of spaces to replace one tab (default: 4).
-s, --start-only
    Replace only at the beginning of the line.
-t, --spaces-to-tabs
    Conversely, replace spaces with tabs.

"""
# -*- coding: utf-8 -*-
import argparse
import os
import hashlib
from datetime import datetime

# command line arguments
paramspace = None
# symbol replacement settings
replace_what = None
replace_than = None


def createArgumentParser():
    ''' prepare command line parser '''
    parser = argparse.ArgumentParser(description="Replace tabs with spaces on python files.")

    parser.add_argument(
        "-r", "--recursive",
        action="store_true",
        help="Operate on python (*.py) files on subdirectories recursively.")
    parser.add_argument(
        "-n", "--spaces",
        default=4,
        type=int,
        help="Number of spaces to replace one tab (default: 4).")
    parser.add_argument(
        "-s", "--start-only",
        action="store_true",
        help="Replace only at the beginning of the line.")
    parser.add_argument(
        "-t", "--spaces-to-tabs",
        action="store_true",
        help="Replace spaces with tabs.")
    parser.add_argument("-e", "--extension",
        type=str,
        help="Change default extension (.py) to... (without dot!)",
        default="py")
    parser.add_argument("filename", type=str)

    return parser


def temporaryFileName(filename):
    ''' generate temporary file name '''
    tmpname = filename + '.new'
    # if the file already exists, generate a new name
    while os.path.isfile(tmpname):
        tmpname = filename + '.' + hashlib.md5(str(datetime.now()).encode()).hexdigest()[:4]

    return tmpname


def parseFile(filename):
    ''' replace spaces on file '''
    # check file rights
    if not os.access(filename, os.W_OK):
        print("No rights for write to '%s'" % filename)

    # generate temporary file name
    tmpfile = temporaryFileName(filename)

    try:
        # replace and store result into temporary file
        with open(tmpfile, "w") as file_out:
            with open(filename, "r") as file_in:
                for line in file_in:
                    if paramspace.start_only:
                        for i, c in enumerate(line):
                            if c not in (' ', '\t'):
                                line = line[:i+1].replace(replace_what, replace_than) + line[i+1:]
                                break
                    else:
                        line = line.replace(replace_what, replace_than)
                    file_out.write(line)
    except Exception as e:
        print(e)
        return False

    # remove original file and move temporary file with original's name
    try:
        os.remove(filename)
        os.rename(tmpfile, filename)
    except Exception as e:
        print(e)
        return False

    return True


def parseDir(dirname, extension):
    ''' replace spaces on files in directory '''
    for root, _, files in os.walk(dirname):
        # check parent directory for write rights
        if not os.access(root, os.W_OK):
            print("No rights for write on '%s'" % root)
        else:
            # filter files by *.py extension
            for filename in [file for file in files if file.endswith('.%s' % extension)]:
                ''' parse file '''
                if not parseFile(os.path.abspath('%s/%s' % (root, filename))):
                    return False
    return True


if __name__ == "__main__":
    paramspace = createArgumentParser().parse_args()

    # replacement characters setup
    replace_what = '\t'
    replace_than = ' ' * paramspace.spaces

    if paramspace.spaces_to_tabs:
        replace_what, replace_than = replace_than, replace_what

    # check if file exists
    if not os.path.exists(paramspace.filename):
        print("File '%s' does not exists." % paramspace.filename)
        exit(1)

    # check if path is a directory or file
    if paramspace.recursive:
        if not os.path.isdir(paramspace.filename):
            print("'%s' not a directory." % paramspace.filename)
        else:
            exit(not parseDir(paramspace.filename, paramspace.extension))
    else:
        if not os.path.isfile(paramspace.filename):
            print("'%s' not a regular file." % paramspace.filename)
        else:
            dirname = os.path.dirname(os.path.abspath(paramspace.filename))
            # check parent directory for write rights.
            # Because we will create temporary files.
            if os.access(dirname, os.W_OK):
                exit(not parseFile(paramspace.filename))
            else:
                print("No rights for write on '%s'" % dirname)

    exit(1)