Python 3.x script to backup and restore RPGMaker projects without all the boilerplate files

rpgmaker-backup.py

import argparse
import hashlib
import os
import shutil
import sys
import zipfile
import zlib

if __name__ == "__main__":
  parser = argparse.ArgumentParser(
    description="Backup and restore RPGMaker projects without wasting space on default files",
    epilog="")
  parser.add_argument("mode", choices=["backup", "restore"])
  parser.add_argument("-t", "--template", required=True, help="An empty/default project for the appropriate RPGMaker version.")
  parser.add_argument("-p", "--project", required=True, help="The location of the project to backup or restore. In 'restore' mode, this directory is the output, and will be overwritten. In 'backup' mode, this directory is the input.")
  parser.add_argument("-z", "--zip", required=True, help="The location of the backed-up project, as a ZIP file. In 'restore' mode, this file is the input. In 'backup' mode, this file is the output, and will be overwritten.")
  parser.add_argument("-f", dest="overwrite", action="store_true", help="Overwrite existing output file/directory, if it already exists.")
  args = parser.parse_args()
  
  # validation
  if not os.path.isdir(args.template):
    sys.exit(f"ERROR: template project not found at {args.template}")
  if args.mode == "backup":
    if not os.path.isdir(args.project):
      sys.exit(f"ERROR: can't back up non-existent project {args.project}")
    if os.path.isfile(args.zip) and not args.overwrite:
      sys.exit(f"ERROR: output file {args.zip} already exists; use -f to automatically overwrite it.")
  elif args.mode == "restore":
    if not os.path.isfile(args.zip):
      sys.exit(f"ERROR: can't restore non-existent project {args.zip}")
    if os.path.isdir(args.project) and not args.overwrite:
      sys.exit(f"ERROR: output project {args.project} already exists; use -f to automatically overwrite it.")

  if args.mode == "backup":
    # Compute hashes of all files in the template project
    template_path_hashes = {}
    for root, dirs, files in os.walk(args.template):
      for filename in files:
        abspath = os.path.abspath(os.path.join(root,filename))
        relpath = os.path.relpath(abspath,args.template)
        with open(abspath, "rb") as f:
          template_path_hashes[relpath] = hashlib.sha256(f.read()).hexdigest()

    # Iterate over files in the project directory.
    # If they don't exist in the template, or if they exist but their hash value is different, add them to the output zip.
    with zipfile.ZipFile(args.zip, "w", compression=zipfile.ZIP_DEFLATED) as z:
      for root, dirs, files in os.walk(args.project, topdown=True):
        # Filter .git, it's full of noise and is basically already its own backup.
        if ".git" in dirs:
          del dirs[dirs.index(".git")]
        for filename in files:
          add_to_zip = False
          abspath = os.path.abspath(os.path.join(root,filename))
          relpath = os.path.relpath(abspath,args.project)
          expected_hash = template_path_hashes.get(relpath, None)
          if expected_hash is None:
            # files not in the template always get added; no need to compute a hash.
            #print(f"  {relpath} not found in template")
            add_to_zip = True
          else:
            # files in the template are only added if their hash is different.
            with open(abspath, "rb") as f:
              if hashlib.sha256(f.read()).hexdigest() != expected_hash:
                #print(f"  {relpath} has different hash")
                add_to_zip = True
          if add_to_zip:
            print(f"  {relpath} ({os.path.getsize(abspath)})")
            z.write(abspath, arcname=relpath)
    print(f"Wrote {args.zip} (size={os.path.getsize(args.zip)})")
  elif args.mode == "restore":
    # Copy the template files to the output project dir
    print(f"Copying template {args.template} to project {args.template}")
    shutil.copytree(args.template, args.project, dirs_exist_ok=True)
    # unzip the zipfile into the project dir, overwriting anything already there.
    with zipfile.ZipFile(args.zip, "r") as z:
      for member_info in z.infolist():
        print(f"  {member_info.filename} ({member_info.compress_size} -> {member_info.file_size})")
        z.extract(member_info, path=args.project)