使用urllib2发起带头的POST请求

Question

我想要向一个网址发送一个带有特定数据和头信息的POST请求。我通过这两个链接找到了方法，但它并没有成功：
https://stackoverflow.com/questions/5693931/python-post-request
如何在HTTP请求中使用urllib2发送自定义头信息？
这是我的代码：

import urllib
import urllib2

url = 'https://clients6.google.com/rpc'
values = [
    {"method": "pos.plusones.get",
     "id": "p",
     "params": {
                "nolog": True,
                "id": "http://www.newswhip.com",
                "source": "widget",
                "userId": "@viewer",
                "groupId": "@self"
                },
     "jsonrpc": "2.0",
     "key": "p",
     "apiVersion": "v1"
    }]
headers = {"Content-type" : "application/json:"}

data = urllib.urlencode(values)
req = urllib2.Request(url, data, headers)
response = urllib2.urlopen(req)
the_page = response.read()
print the_page

我可以在Postman这个工具中用这些值得到结果。但是执行这段代码后，结果是：

Traceback (most recent call last):
  File "D:/Developer Center/Republishan/republishan2/republishan2/test2.py", line 22, in <module>
    data = urllib.urlencode(values)
  File "C:\Python27\lib\urllib.py", line 1312, in urlencode
    raise TypeError
TypeError: not a valid non-string sequence or mapping object

我还尝试用字典代替列表，像这样：

values = {"method": "pos.plusones.get",
     "id": "p",
     "params": {
                "nolog": True,
                "id": "http://www.newswhip.com",
                "source": "widget",
                "userId": "@viewer",
                "groupId": "@self"
                },
     "jsonrpc": "2.0",
     "key": "p",
     "apiVersion": "v1"
    }

这个脚本可以执行，但结果却出现了错误：

{"error":{"code":-32700,"message":"Unable to parse json","data":[{"domain":"global","reason":"parseError","message":"Unable to parse json"}]}}

正如我所说，我可以在Postman中用列表执行脚本，而不是字典。看看Postman中的结果：

我该怎么办？

Answer 1

看起来 urllib.urlencode 这个工具不太懂嵌套的字典：

     In [38]: urllib.urlencode({"a": "asas", "df": {"sds": 123, "t": "fgfg"}})
     Out[38]: 'a=asas&df=%7B%27t%27%3A+%27fgfg%27%2C+%27sds%27%3A+123%7D'

或者你的例子：

     In [41]: urllib.urlencode(values)
     Out[41]: 'jsonrpc=2.0&apiVersion=v1&id=p&params=%7B%27nolog%27%3A+True%2C+%27source%27%3A+%27widget%27%2C+%27userId%27%3A+%27%40viewer%27%2C+%27id%27%3A+%27http%3A%2F%2Fwww.newswhip.com%27%2C+%27groupId%27%3A+%27%40self%27%7D&key=p&method=pos.plusones.get'

你看，“params”里的大括号搞得乱七八糟的。

我不太确定怎么用 urllib 来解决这个问题。所以我推荐使用 requests 这个库。http://docs.python-requests.org/en/latest/user/quickstart/#custom-headers

简单来说，它看起来会是这样的（你需要先安装 requests 库，比如用 pip：pip install requests）：

     import requests
     import json

     url = 'https://clients6.google.com/rpc'
     values = {
         "method": "pos.plusones.get",
         "id": "p",
         "params": {
                    "nolog": True,
                    "id": "http://www.newswhip.com",
                    "source": "widget",
                    "userId": "@viewer",
                    "groupId": "@self"
                   },
          "jsonrpc": "2.0",
          "key": "p",
          "apiVersion": "v1"
     }
     headers = {"content-type" : "application/json"}

     req = requests.post(url, data=json.dumps(values), headers=headers)
     print req.text

对我来说是有效的。