python requests post多层字典的方法

pyhton requests模块post方法传参为多层字典时，转换错误，

如，表单传参

{ 
“a”:1, 
“b”:{ 
“A”:2, 
“B”:3 
} 
}

post请求后看到form data是：

a:1 
b:A 
b:B

查看官方文档：

More complicated POST requests
Typically, you want to send some form-encoded data ― much like an HTML form. To do this, simply pass a dictionary to the data argument. Your dictionary of data will automatically be form-encoded when the request is made:

payload = {‘key1': ‘value1', ‘key2': ‘value2'}

r = requests.post(“http://httpbin.org/post“, data=payload) 
print(r.text) 
{ 
… 
“form”: { 
“key2”: “value2”, 
“key1”: “value1” 
}, 
… 
}

这里说post传入的dict类型参数会被自动转化为form-encoded，查看请求后，这里的demo是一个一层的字典。多层字典传输的时候，确实会异常。

解决办法：

将第二层字典转化为json，json.dumps({“A”:2,”B”:3})，然后赋给b。