python argparse - 在没有命令行的情况下传递值

Question

我想我不了解 python 的 argparse 的一些基本知识。

我正在尝试将 Google YouTube API 用于 python 脚本，但我不明白如何在不使用命令行的情况下将值传递给脚本。

例如，here是 API 的示例。 github 和其他地方的示例显示此示例是从命令行调用的，在调用脚本时从命令行传递 argparse 值。

我不想使用命令行。我正在构建一个应用程序，它使用装饰器来获取用户的登录凭据，当该用户想要上传到他们的 YouTube 帐户时，他们提交一个表单，然后该表单将调用此脚本并将 argparse 值传递给它。

如何从另一个 python 脚本将值传递给 argparser(请参阅下面的 YouTube 上传 API 脚本中的部分代码)？

if __name__ == '__main__':
    argparser.add_argument("--file", required=True, help="Video file to upload")
    argparser.add_argument("--title", help="Video title", default="Test Title")
    argparser.add_argument("--description", help="Video description",
        default="Test Description")
    argparser.add_argument("--category", default="22",
        help="Numeric video category. " +
            "See https://developers.google.com/youtube/v3/docs/videoCategories/list")
    argparser.add_argument("--keywords", help="Video keywords, comma separated",
        default="")
    argparser.add_argument("--privacyStatus", choices=VALID_PRIVACY_STATUSES,
        default=VALID_PRIVACY_STATUSES[0], help="Video privacy status.")
    args = argparser.parse_args()

    if not os.path.exists(args.file):
        exit("Please specify a valid file using the --file= parameter.")

    youtube = get_authenticated_service(args)
    try:
        initialize_upload(youtube, args)
    except HttpError, e:
        print "An HTTP error %d occurred:\n%s" % (e.resp.status, e.content)

---

编辑:根据请求，这是我使用标准方法初始化字典或使用 argparse 创建字典时遇到的 400 错误的回溯。我以为我得到这个是因为参数格式不正确，但也许不是:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1535, in __call__
    rv = self.handle_exception(request, response, e)
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1529, in __call__
    rv = self.router.dispatch(request, response)
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "C:\Program Files (x86)\Google\google_appengine\lib\webapp2-2.5.2\webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "C:\Users\...\testapp\oauth2client\appengine.py", line 796, in setup_oauth
    resp = method(request_handler, *args, **kwargs)
  File "C:\Users\...\testapp\testapp.py", line 116, in get
    resumable_upload(insert_request)
  File "C:\Users\...\testapp\testapp.py", line 183, in resumable_upload
    status, response = insert_request.next_chunk()
  File "C:\Users\...\testapp\oauth2client\util.py", line 129, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "C:\Users\...\testapp\apiclient\http.py", line 874, in next_chunk
    return self._process_response(resp, content)
  File "C:\Users\...\testapp\apiclient\http.py", line 901, in _process_response
    raise HttpError(resp, content, uri=self.uri)
HttpError: <HttpError 400 when requesting https://www.googleapis.com/upload/youtube/v3/videos?alt=json&part=status%2Csnippet&uploadType=resumable returned "Bad Request">

Answer 1

这是否是最佳方法真的需要您自己判断。但是在没有命令行的情况下使用 argparse 是简单的。我一直这样做，因为我有可以从命令行运行的批处理。或者也可以被其他代码调用——如前所述，这非常适合单元测试。例如，argparse 特别擅长默认参数。

从您的样本开始。

import argparse

argparser = argparse.ArgumentParser()
argparser.add_argument("--file", required=True, help="Video file to upload")
argparser.add_argument("--title", help="Video title", default="Test Title")
argparser.add_argument("--description", help="Video description",
    default="Test Description")
argparser.add_argument("--category", default="22",
    help="Numeric video category. " +
        "See https://developers.google.com/youtube/v3/docs/videoCategories/list")
argparser.add_argument("--keywords", help="Video keywords, comma separated",
    default="")
VALID_PRIVACY_STATUSES = ("private","public")
argparser.add_argument("--privacyStatus", choices=VALID_PRIVACY_STATUSES,
    default=VALID_PRIVACY_STATUSES[0], help="Video privacy status.")

#pass in any positional or required variables.. as strings in a list
#which corresponds to sys.argv[1:].  Not a string => arcane errors.
args = argparser.parse_args(["--file", "myfile.avi"])

#you can populate other optional parameters, not just positionals/required
#args = argparser.parse_args(["--file", "myfile.avi", "--title", "my title"])


print vars(args)

#modify them as you see fit, but no more validation is taking place
#so best to use parse_args.
args.privacyStatus = "some status not in choices - already parsed"
args.category = 42

print vars(args)

#proceed as before, the system doesn't care if it came from the command line or not
# youtube = get_authenticated_service(args)    

输出:

{'category': '22', 'description': 'Test Description', 'title': 'Test Title', 'privacyStatus': 'private', 'file': 'myfile.avi', 'keywords': ''}
{'category': 42, 'description': 'Test Description', 'title': 'Test Title', 'privacyStatus': 'some status not in choices - already parsed', 'file': 'myfile.avi', 'keywords': ''}