Python-requests之POST Data的json问题

代码如下:

import json
import requests
r = requests.post(url, data = {"a": json.dumps({"b": "c"})}); #url为随意URL

使用Fiddler抓包，虽然在WebForms里面看到格式如下:

但是在Raw中看到结果如下:

即自动执行了urlencode，查看requests/models.py源码发现，如果数据可迭代，即自动加入"application/x-www-form-urlencoded"头，并且执行urlencode:

PreparedRequest类的prepare_body方法中

if data:
    body = self._encode_params(data)
    if isinstance(data, basestring) or hasattr(data, 'read'):
        content_type = None
    else:
        content_type = 'application/x-www-form-urlencoded'

RequestEncodingMixin类中_encode_params(data)方法中

if isinstance(data, (str, bytes)):
    return data
elif hasattr(data, 'read'):
    return data
elif hasattr(data, '__iter__'):
    result = []
    for k, vs in to_key_val_list(data):
        if isinstance(vs, basestring) or not hasattr(vs, '__iter__'):
            vs = [vs]
        for v in vs:
            if v is not None:
                result.append(
                    (k.encode('utf-8') if isinstance(k, str) else k,
                     v.encode('utf-8') if isinstance(v, str) else v))
    return urlencode(result, doseq=True)
else:
    return data

解决办法:

import json
import requests

headers = {"Content-Type": "application/x-www-form-urlencoded"} 
data = "a=%s" %  json.dumps({"b": "c"})
r = requests.post(url, data = data, headers = headers);