如何将字符串数据转换为Python中的JSON对象？

Question

这是我从一个网络服务收到的示例字符串，

body=%7B%22type%22%3A%22change%22%2C%22url%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ftriggers%2F4100%22%2C%22environment%22%3A%7B%22feed%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ffeeds%2F36133%22%2C%22title%22%3A%22Current+Cost+Bridge%22%2C%22description%22%3Anull%2C%22id%22%3A36133%7D%2C%22threshold_value%22%3Anull%2C%22timestamp%22%3A%222012-01-05T09%3A27%3A01Z%22%2C%22triggering_datastream%22%3A%7B%22url%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ffeeds%2F36133%2Fdatastreams%2F1%22%2C%22value%22%3A%7B%22value%22%3A%22523%22%2C%22max_value%22%3A1269.0%2C%22min_value%22%3A0.0%7D%2C%22id%22%3A%221%22%2C%22units%22%3A%7B%22symbol%22%3A%22W%22%2C%22type%22%3A%22derivedUnits%22%2C%22label%22%3A%22watts%22%7D%7D%2C%22id%22%3A4100%7D

这是代码，

class Feeds():
    def GET(self):
        print "Get request is accepted."
        return render.index(None)

    def POST(self):
        print "Post request is accepted."
        print (web.data())

现在，当这个网络服务发送上面提到的数据时，我该如何将其转换为可读的格式呢？接着，我需要把它转换成JSON对象，以便后续使用。那么，我该怎么做呢？

当我尝试这段代码时，

        json_data = json.loads(web.data())
        print json_data['body']
        return render.index(json_data['body'])

它给了我一个错误，

enter code Traceback (most recent call last):
File "/usr/local/lib/python2.6/dist-packages/web/application.py", line 237, in process
return self.handle()
File "/usr/local/lib/python2.6/dist-packages/web/application.py", line 228, in handle
return self._delegate(fn, self.fvars, args)
File "/usr/local/lib/python2.6/dist-packages/web/application.py", line 409, in _delegate
return handle_class(cls)
File "/usr/local/lib/python2.6/dist-packages/web/application.py", line 385, in      handle_class
return tocall(*args)
File "/home/ubuntu/pachubeConsumer/src/controllers/feeds.py", line 17, in POST
json_data = json.loads(web.data())
File "/usr/lib/python2.6/json/__init__.py", line 307, in loads
return _default_decoder.decode(s)
File "/usr/lib/python2.6/json/decoder.py", line 319, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib/python2.6/json/decoder.py", line 338, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded here

我哪里出错了呢？？

提前谢谢你。

Answer 1

Python 3 中的 urllib unquote 功能已经移到了解析模块里：

from urllib import parse
parse.unquote(web.data())

Answer 2

你需要先用 urllib.unquote() 来处理一下查询字符串，让它变得正常可读。

import urllib

unescaped = urllib.unquote(web.data())

然后你可以使用 json.loads 把它转换成 JSON 格式。

json_data = json.loads(unescaped)

Answer 3

首先，你需要去掉正文中的引号。

import urllib
body="%7B%22type%22%3A%22change%22%2C%22url%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ftriggers%2F4100%22%2C%22environment%22%3A%7B%22feed%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ffeeds%2F36133%22%2C%22title%22%3A%22Current+Cost+Bridge%22%2C%22description%22%3Anull%2C%22id%22%3A36133%7D%2C%22threshold_value%22%3Anull%2C%22timestamp%22%3A%222012-01-05T09%3A27%3A01Z%22%2C%22triggering_datastream%22%3A%7B%22url%22%3A%22http%3A%2F%2Fapi.pachube.com%2Fv2%2Ffeeds%2F36133%2Fdatastreams%2F1%22%2C%22value%22%3A%7B%22value%22%3A%22523%22%2C%22max_value%22%3A1269.0%2C%22min_value%22%3A0.0%7D%2C%22id%22%3A%221%22%2C%22units%22%3A%7B%22symbol%22%3A%22W%22%2C%22type%22%3A%22derivedUnits%22%2C%22label%22%3A%22watts%22%7D%7D%2C%22id%22%3A4100%7D"
unquoted = urllib.unquote(body)

然后就像平常一样加载JSON数据。

import json
pythonDict = json.loads(unquoted)