为什么我不能使用 Python 的 `requests` 库在 POST 请求中将 `None` 作为数据发送? [英] Why can't I send `None` as data in a POST request using Python's `requests` library?

问题描述

似乎当 data 中的键的值为 None 时，请求中不包含该键.

<预><代码>>>>req = requests.Request('POST', 'http://google.com', data=dict(a=None, b=1))>>>req.prepare().body'b=1'

为什么会这样?我期待一个空字符串，或者类似 json.dumps(d) 的东西，其中 None 被呈现为 null.我相信有一个很好的理由——只是好奇它是什么.(我能想到的一件事是，可能没有可用于 POST 请求的 null 或 None 编码——这是真的吗?)

另外一个好奇——为什么 requests 会默默地忽略这些数据而不是抛出错误?

解决方案

将字典元素设置为 None 是您明确表示不希望将该参数发送到服务器的方式.

我在 requests.Request() 文档中找不到具体提到的这一点，但在 在 URL 中传递参数 它说:

<块引用>

请注意，任何值为 None 的字典键都不会添加到 URL 的查询字符串中.

显然它也对 POST 请求使用一致的逻辑.

如果要发送空字符串，请将字典元素设置为空字符串而不是None.

It seems that when a key in data has a value of None, the key isn't included by requests.

>>> req = requests.Request('POST', 'http://google.com', data=dict(a=None, b=1))
>>> req.prepare().body
'b=1'

Why is this the case? I was expecting an empty string, or something like json.dumps(d) where None is rendered as null. I'm sure there's a good reason -- just curious about what it is. (One thing I can think of is that maybe there just isn't an encoding of null or None available to the POST request -- is that true?)

Additionally curious -- why does requests silently ignore such data instead of throwing an error?

解决方案

Setting a dictionary element to None is how you explicitly say that you don't want that parameter to be sent to the server.

I can't find this mentioned specifically in the requests.Request() documentation, but in Passing Parameters in URLs it says:

Note that any dictionary key whose value is None will not be added to the URL's query string.

Obviously it uses consistent logic for POST requests as well.

If you want to send an empty string, set the dictionary element to an empty string rather than None.

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