New feature: Skip existed files when downloading folders

[GeekDream-x]

Background

Due to some accidents, some users encounter the problems that the download tasks break up unexpectedly. When downloading just a single file, it is acceptable to re-download it from the beginning. However, when downloading a folder, it is a waste of time to re-download the files downloaded before the break.

Update:

• Add a new parameter skip_existed to the function download_folder().
• Print the skipped files if quite is set to False.

Example Python Snippet:

import gdown
import os

output_dir = "./xxx/your_target_dir"
if not os.path.exists(output_dir):
    os.makedirs(output_dir)
url = "https://drive.google.com/drive/folders/xxxxxxxxxxxxxxxxxxxxx=sharing"
gdown.download_folder(url, output=output_dir, remaining_ok=True, quite=False, skip_existed=True)

[genghisun]

Thanks! This feature is very useful.
But why not set skip_existed default to True?

[GeekDream-x]

Thanks! This feature is very useful. But why not set skip_existed default to True?

@genghisun Thanks! You are right and I have changed the default value to True in the new commit.

[genghisun]

Hi~ Sorry to bother you again.
Today I realized that single file download also needs the skip_existed parameter, especially when downloading a list with multiple files, just like example below. Because in case the middle file in the list download fails, running the code again will re-download all the previous files, which is unnecessary.

import gdown

url_list = [
    'https://drive.google.com/file/d/xxxx',
    'https://drive.google.com/file/d/xxxx',
    'https://drive.google.com/file/d/xxxx',
]

for url in url_list:
    gdown.download(url, fuzzy=True, skip_existed=True)

Also, it is more uniform to have this parameter for both download and download_folder.
The implementation can be done by checking if the output file exists at https://github.com/wkentaro/gdown/blob/main/gdown/download.py#L280.

[GeekDream-x]

Hi~ Sorry to bother you again. Today I realized that single file download also needs the skip_existed parameter, especially when downloading a list with multiple files, just like example below. Because in case the middle file in the list download fails, running the code again will re-download all the previous files, which is unnecessary.

import gdown

url_list = [
    'https://drive.google.com/file/d/xxxx',
    'https://drive.google.com/file/d/xxxx',
    'https://drive.google.com/file/d/xxxx',
]

for url in url_list:
    gdown.download(url, fuzzy=True, skip_existed=True)

Also, it is more uniform to have this parameter for both download and download_folder. The implementation can be done by checking if the output file exists at https://github.com/wkentaro/gdown/blob/main/gdown/download.py#L280.

@genghisun Sounds useful. I have updated download.py and please help to check whether it is reliable.

[wkentaro]

Use resume=True introduced by #288, and it will skip downloading files if they already exist.