这里有一个更接近原始代码的答案，包括使用最小内存的分块，它只是将open（）放在下载代码之前：

import sys
import requests
from requests.auth import HTTPBasicAuth

def get_artifact(url, save_artifact_name, username, password, chunk_size=128):
    try:

        with open(save_artifact_name, 'wb') as artifact:

            get_method = requests.get(url,
                        auth = HTTPBasicAuth(username, password), stream=True)
            for chunk in get_method.iter_content(chunk_size=chunk_size):
                artifact.write(chunk)

    except requests.exceptions.RequestException as error:
        sys.exit(str(error))

if __name__ == '__main__':

    username_and_password = sys.argv[1].split(':')
    username = username_and_password[0]
    password = username_and_password[1]

    url = sys.argv[2]
    save_artifact_name = url.split("/")[-1]

    print(f'Retrieving artifact {save_artifact_name}...')
    get_artifact(url, save_artifact_name, username, password)
    print("Finished successfully!")

你一次只传输几个字节，然后把每个块都写入文件，但每次都是新的，所以我怀疑你看到的只是文件中的最后一个块。除非文件非常大，否则你应该可以简单地把整个文件加载到内存中，然后再把它写出来。下面是修改后的版本：

import sys
import requests
from requests.auth import HTTPBasicAuth

def get_artifact(url, save_artifact_name, username, password):
    try:
        get_method = requests.get(url,
            auth = HTTPBasicAuth(username, password))

        with open(save_artifact_name, 'wb') as artifact:
            artifact.write(get_method.content)

    except requests.exceptions.RequestException as error:
        sys.exit(str(error))

if __name__ == '__main__':

    username_and_password = sys.argv[1].split(':')
    username = username_and_password[0]
    password = username_and_password[1]

    url = sys.argv[2]
    save_artifact_name = url.split("/")[-1]

    print(f'Retrieving artifact {save_artifact_name}...')
    get_artifact(url, save_artifact_name, username, password)
    print("Finished successfully!")

这样就可以一次获取整个文件并将其写入输出。我刚刚用一个5MB的测试文件测试了一下，我在网上找到了这个测试文件，它下载得很好。
不再需要块大小，因为您不是在块中下载。：）