Add filetimelapse.py

filetimelapse.py

@@ -0,0 +1,76 @@
+'''
+Copy your file every few minutes while you work on it, so that you can have snapshots of its history.
+Not a replacement for real version control but could be applicable in very simple situations or in
+cases where e.g. git is not.
+'''
+import argparse
+import glob
+import hashlib
+import os
+import shutil
+import sys
+import time
+
+from voussoirkit import bytestring
+from voussoirkit import pathclass
+
+def hash_file(filepath, hasher):
+    bytestream = read_filebytes(filepath)
+    for chunk in bytestream:
+        hasher.update(chunk)
+    return hasher.hexdigest()
+
+def hash_file_md5(filepath):
+    return hash_file(filepath, hasher=hashlib.md5())
+
+def read_filebytes(filepath, chunk_size=bytestring.MIBIBYTE):
+    '''
+    Yield chunks of bytes from the file between the endpoints.
+    '''
+    filepath = pathclass.Path(filepath)
+    if not filepath.is_file:
+        raise FileNotFoundError(filepath)
+
+    f = open(filepath.absolute_path, 'rb')
+    with f:
+        while True:
+            chunk = f.read(chunk_size)
+            if len(chunk) == 0:
+                break
+
+            yield chunk
+
+def filetimelapse(filepath, rate):
+    (noext, extension) = os.path.splitext(filepath)
+
+    last_hash = None
+    existing_timelapses = glob.glob(f'{noext}-*.filetimelapse{extension}')
+    if existing_timelapses:
+        last_hash = hash_file_md5(existing_timelapses[-1])
+        print(f'Starting with previous {existing_timelapses[-1]} {last_hash}')
+
+    while True:
+        new_hash = hash_file_md5(filepath)
+        if new_hash != last_hash:
+            timestamp = time.strftime('%Y%m%d%H%M%S')
+            copy_name = f'{noext}-{timestamp}.filetimelapse{extension}'
+            shutil.copy(filepath, copy_name)
+            last_hash = new_hash
+            print(copy_name, new_hash)
+        time.sleep(rate)
+
+def filetimelapse_argparse(args):
+    return filetimelapse(args.filepath, args.rate)
+
+def main(argv):
+    parser = argparse.ArgumentParser(description=__doc__)
+
+    parser.add_argument('filepath')
+    parser.add_argument('--rate', dest='rate', default=None, required=True, type=int)
+    parser.set_defaults(func=filetimelapse_argparse)
+
+    args = parser.parse_args(argv)
+    args.func(args)
+
+if __name__ == '__main__':
+    raise SystemExit(main(sys.argv[1:]))