Welcome, guest | Sign In | My Account | Store | Cart

Zero (Batch) Programs (Python recipe) by Stephen Chappell
ActiveState Code (http://code.activestate.com/recipes/578205/)

Having written many programs that work with groups of files, the zero programs were written based on a simple batch engine in the zero utility. All of the other programs import the first program to take advantage of its batch processor while supplementing there own functionality in place of zeroing out file data. This is committed for archival to be run under Python 2.5 or later versions.

Python, 185 lines
Download
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
# ==============================================================================
# zero.py
# ==============================================================================

import os
import sys

ERROR = False

def main(function):
    try:
        arguments = sys.argv[1:]
        assert arguments
        for path in arguments:
            assert os.path.isdir(path)
        for path in arguments:
            engine(path, function)
    except:
        sys.stdout.write('Usage: %s <directory>' % os.path.basename(sys.argv[0]))

def engine(path, function):
    global ERROR
    for root, dirs, files in os.walk(path):
        for name in files:
            path = os.path.join(root, name)
            try:
                function(path)
            except:
                sys.stderr.write('%sError: %s' % (ERROR and '\n' or '', path))
                ERROR = True

def zero(path):
    size = os.path.getsize(path)
    if size:
        data = open(path, 'wb')
        todo = size
        if todo >= 2 ** 20:
            buff = '\x00' * 2 ** 20
            while todo >= 2 ** 20:
                data.write(buff)
                todo = size - data.tell()
        data.write('\x00' * todo)
        data.close()

if __name__ == '__main__':
    main(zero)

# ==============================================================================
# upper.py
# ==============================================================================

import zero

def upper(path):
    root, ext = zero.os.path.splitext(path)
    upper = ext.upper()
    if ext != upper:
        zero.os.rename(path, root + upper)

if __name__ == '__main__':
    zero.main(upper)

# ==============================================================================
# untar.py
# ==============================================================================

import zero
import tarfile

if __name__ == '__main__':
    zero.main(lambda path: tarfile.open(path).extractall(
        zero.os.path.dirname(path)))

# ==============================================================================
# remove.py
# ==============================================================================

import zero

if __name__ == '__main__':
    zero.main(zero.os.remove)

# ==============================================================================
# one.py
# ==============================================================================

import zero

def one(path):
    size = zero.os.path.getsize(path)
    if size:
        data = open(path, 'wb')
        todo = size
        if todo >= 2 ** 20:
            buff = '\xFF' * 2 ** 20
            while todo >= 2 ** 20:
                data.write(buff)
                todo = size - data.tell()
        data.write('\xFF' * todo)
        data.close()

if __name__ == '__main__':
    zero.main(one)

# ==============================================================================
# lower.py
# ==============================================================================

import zero

def lower(path):
    root, ext = zero.os.path.splitext(path)
    lower = ext.lower()
    if ext != lower:
        zero.os.rename(path, root + lower)

if __name__ == '__main__':
    zero.main(lower)

# ==============================================================================
# random.py
# ==============================================================================

import zero

def kaos(path):
    size = zero.os.path.getsize(path)
    if size:
        data = open(path, 'wb')
        todo = size
        while todo:
            data.write(zero.os.urandom(min(todo, 2 ** 20)))
            todo = size - data.tell()
        data.close()

if __name__ == '__main__':
    zero.main(kaos)

# ==============================================================================
# name.py
# ==============================================================================

import zero
import random

STRING = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'

def ident(path):
    d, b = zero.os.path.split(path)
    zero.os.rename(path, zero.os.path.join(d, ''.join(random.sample(
        STRING, len(STRING))) + zero.os.path.splitext(b)[1]))

if __name__ == '__main__':
    zero.main(ident)

# ==============================================================================
# newlines.py
# ==============================================================================

import zero

TABLE = ''.join(map(chr, range(256)))
DELETECHARS = ''.join(c for c in TABLE if len(repr(c)) != 6)

def convert(path):
    if not file(path, 'rb').read(2 ** 20).translate(TABLE, DELETECHARS):
        data = file(path, 'r').read()
        file(path, 'w').write(data)

if __name__ == '__main__':
    zero.main(convert)

# ==============================================================================
# extension.py
# ==============================================================================

import zero

def bias(path):
    root, ext = zero.os.path.splitext(path)
    if not ext[1:]:
        zero.os.rename(path, root + '.txt')

if __name__ == '__main__':
    zero.main(bias)

Please ensure that you understand a program before running it. There utilities work on groups of files and can cause quite a mess if not used responsibly.

Tags: archive, batch, old, processing, utility

1 comment

Martin Miller 11 years, 8 months ago  # | flag

Interesting approach -- sort of like plug-ins in reverse. Seems like it would make equal (or perhaps more) sense to make each file a module that zero would import and run one of them based on a command-line argument. In fact one could establish a whole plug-in API that would effectively make each utility an object that could be asked to perform additional tasks, such as provide instructions for usage or post-processing statistics -- all with the same generic front-end.

Implementation-wise, I don't care for each utility accessing modules imported by the zero module because it's longer, slower, and creates undesirable dependencies between each and how the latter is implemented. It's also an unnecessary optimization because sys.modules effectively keeps a cache of the modules that have been imported already and avoids doing so a second time.