Replace corrupted images that were imported into Lightroom, with originals from a memory stick.

replace_files.py

#!/usr/bin/env python
#
# Damien Ayers 2014
#
# Replace corrupted images that were imported into Lightroom, with originals from a memory stick.
#
# Walk through a target directory structure of possibly corrupted files, and replace them
# with files from a source directory. Files in the source may be at completely different
# relative paths, but will have the same file name.
#
# Usage:
#  replace_files  <source_dir>   <target_dir>
#
#

import sys
import os
import os.path
import hashlib
import shutil


source_dir = sys.argv[1]
target_dir = sys.argv[2]



BLOCKSIZE = 65536

def checksum_file(path):
    hasher = hashlib.sha1()
    with open(path, 'rb') as afile:
        buf = afile.read(BLOCKSIZE)
        while len(buf) > 0:
            hasher.update(buf)
            buf = afile.read(BLOCKSIZE)
    return hasher.hexdigest()

def find(name, path):
    for root, dirs, files in os.walk(path):
        if name in files:
            return os.path.join(root, name)

def compare_sizes(source, target):
    source_size = os.path.getsize(source)
    target_size = os.path.getsize(target)

    if source_size != target_size:
        print "files don't match %s %s" % (source, target)

def checksums_match(source, target):
    source_hash = checksum_file(source)
    target_hash = checksum_file(target)

    if source_hash != target_hash:
        print "files don't match %s %s" % (source, target)
        return False

    return True


def fake_copy(source, target):
    print "Copy %s onto %s" % (source, target)

def real_copy(source, target):
    shutil.copy(source, target)
    print "File replaced: %s" % target

def process_path(path):
    checked = 0
    replaced = 0
    for root, dirs, files in os.walk(path):
        for name in files:
            if name in ('Thumbs.db', '.DS_Store'):
                continue
            target = os.path.join(root, name)
            source = find(name, source_dir)

            if not source:
                print "ERROR: could not find source file for target: %s" % target

            if not checksums_match(source, target):
                replaced += 1
                real_copy(source, target)

            checked += 1
    print "Checked %s files" % checked
    print "Replaced %s files" % replaced






process_path(target_dir)