client.py

import requests
from tqdm import tqdm
import filecmp
import argparse

def fetch_in_chunks(url, chunk_size_kib, original_file, output_file):
    chunk_size = chunk_size_kib * 1024  # Convert KiB to bytes

    # Send a HEAD request to get the total size of the file
    response = requests.head(url)
    if response.status_code != 200:
        raise Exception(f"Failed to get file size: {response.status_code}")

    file_size = int(response.headers.get('Content-Length', 0))
    print(f"Total file size: {file_size} bytes")

    # Initialize the progress bar
    progress_bar = tqdm(total=file_size, unit='B', unit_scale=True, desc=output_file)

    # Open the output file in binary write mode
    with open(output_file, 'wb') as f:
        for start in range(0, file_size, chunk_size):
            end = min(start + chunk_size - 1, file_size - 1)

            headers = {
                "Range": f"bytes={start}-{end}"
            }
            
            chunk_response = requests.get(url, headers=headers, stream=True)
            if chunk_response.status_code not in [200, 206]:
                raise Exception(f"Failed to fetch chunk: {chunk_response.status_code}")

            # Write the chunk to the file and update the progress bar
            for chunk in chunk_response.iter_content(chunk_size=8192):
                if chunk:
                    f.write(chunk)
                    progress_bar.update(len(chunk))

    progress_bar.close()
    print(f"File downloaded successfully as {output_file}")

    # Compare the downloaded file with the original file
    if filecmp.cmp(output_file, original_file, shallow=False):
        print("The downloaded file matches the original file.")
    else:
        print("The downloaded file does not match the original file.")

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Download a file in chunks using HTTP Range requests.")
    parser.add_argument("url", help="The URL of the file to download")
    parser.add_argument("original_file", help="The path to the original file for comparison")
    parser.add_argument("output_file", help="The path to save the downloaded file")
    parser.add_argument("chunk_size_kib", type=int, help="The chunk size in KiB, eg: 102400 KiB (100 MiB)")

    args = parser.parse_args()

    fetch_in_chunks(args.url, args.chunk_size_kib, args.original_file, args.output_file)