#!/usr/bin/env python3
# Download unseen files from a folder in Google Drive

import sys
if sys.version_info < (3, 3):
    sys.stderr.write("Sorry, requires at least Python 3.3\n")
    sys.exit(1)

import argparse
import collections
import os
import pickle
import shlex
from pydrive.auth import GoogleAuth
from pydrive.drive import GoogleDrive


def read_seen():
    global seen
    try:
        with open(os.path.expanduser('~/.local/share/drive-download/seen.pickle'), 'rb') as f:
            seen = pickle.load(f)
    except FileNotFoundError:
        seen = set()


def save_seen():
    global seen
    with open(os.path.expanduser('~/.local/share/drive-download/seen.pickle'), 'wb') as f:
        pickle.dump(seen, f)


def folder_id(folder_name):
    query = "title = '%s'" % folder_name
    file1 = drive.ListFile({'q': query}).GetList()[0]
    assert file1['mimeType'] == 'application/vnd.google-apps.folder'
    return file1['id']


def main():
    global seen, drive

    parser = argparse.ArgumentParser(
        description='Download unseen files from a folder in Google Drive')
    parser.add_argument('folder', type=str, help='folder to download from')
    args = parser.parse_args()

    read_seen()

    gauth = GoogleAuth(settings_file=os.path.expanduser('~/.config/drive-download/settings.yaml'))
    gauth.CommandLineAuth()
    drive = GoogleDrive(gauth)

    file_query = "'%s' in parents and trashed=false" % folder_id(args.folder)
    file_list = drive.ListFile({'q': file_query}).GetList()

    file_names = [f['title'] for f in file_list]
    file_names_dupes = [f for f, count in collections.Counter(file_names).items() if count > 1]
    if len(file_names_dupes) > 0:
        print('Duplicate filenames on Drive!')
        for fn in sorted(file_names_dupes):
            print(shlex.quote(fn))
        sys.exit(1)

    for file1 in file_list:
        if file1['mimeType'] == 'application/vnd.google-apps.folder':
            continue
        if file1['id'] in seen:  # XXX could update the file if it needs updating
            continue

        local_filename = file1['title']
        print(shlex.quote(local_filename))
        if not os.path.exists(local_filename):
            file1.GetContentFile(local_filename)
            seen.add(file1['id'])
            save_seen()
        else:
            print("{} exists locally!".format(shlex.quote(local_filename)))
            sys.exit(2)


main()

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