发送 JSON 字符串到 cherrypy

Question

我正在尝试通过 Javascript 从单个 HTML（此文件不由 cherrypy 提供服务）文件发送 JSON 字符串到 cherrpy 服务器。

这是我的最小 cherrypy 示例 (followed the "dealing with json" part)

import cherrypy

class HelloJson(object):
    @cherrypy.expose
    @cherrypy.tools.json_in()
    def default(self):
        data = cherrypy.request.json
        print(data)
        return "Hello world!"

if __name__ == '__main__':
    cherrypy.config.update({'server.socket_port':1234})
    cherrypy.quickstart(HelloJson())

通过 python 发送 JSON 字符串工作正常

>>> requests.post('http://localhost:1234', json=json.dumps({'Hello': 'Json'}))
<Response [200]>
>>>

cherrypy 输出也打印 json 字符串

20:59 $ ./HelloJson.py 
[24/Aug/2015:20:59:34] ENGINE Listening for SIGTERM.
[24/Aug/2015:20:59:34] ENGINE Listening for SIGUSR1.
[24/Aug/2015:20:59:34] ENGINE Listening for SIGHUP.
[24/Aug/2015:20:59:34] ENGINE Bus STARTING
CherryPy Checker:
The Application mounted at '' has an empty config.

[24/Aug/2015:20:59:34] ENGINE Started monitor thread '_TimeoutMonitor'.
[24/Aug/2015:20:59:34] ENGINE Started monitor thread 'Autoreloader'.
[24/Aug/2015:20:59:34] ENGINE Serving on http://127.0.0.1:1234
[24/Aug/2015:20:59:34] ENGINE Bus STARTED
{"Hello": "Json"}
127.0.0.1 - - [24/Aug/2015:21:00:17] "POST / HTTP/1.1" 200 12 "" "python-requests/2.7.0 CPython/3.4.3 Linux/4.1.5-1-ARCH"

所以我的单个 HTML 文件看起来像这样

<html>
<head>
<script>
function makeRequest()
{
    var insertJSON = { "my_key": "my_value" };

    var xmlhttp = new XMLHttpRequest();   // new HttpRequest instance 
    xmlhttp.open("POST", "http://localhost:1234");
    xmlhttp.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
    xmlhttp.send(JSON.stringify(insertJSON));

}
</script>
</head>
<body>
<form name="frm1" id="yourTextBox" onsubmit="makeRequest()">
<input type="submit" value="Submit">
</form>
</body>
</html>

但这会导致错误AttributeError: 'Request' object has no attribute 'json'

[24/Aug/2015:21:10:36] HTTP 
Request Headers:
  CONNECTION: keep-alive
  ACCEPT-LANGUAGE: en-US,en;q=0.5
  ACCESS-CONTROL-REQUEST-HEADERS: content-type
  ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
  USER-AGENT: Mozilla/5.0 (X11; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0
  ACCESS-CONTROL-REQUEST-METHOD: POST
  ACCEPT-ENCODING: gzip, deflate
  PRAGMA: no-cache
  CACHE-CONTROL: no-cache
  HOST: localhost:1234
  Remote-Addr: 127.0.0.1
  ORIGIN: null
[24/Aug/2015:21:10:36] HTTP Traceback (most recent call last):
  File "/usr/lib/python3.4/site-packages/cherrypy/_cprequest.py", line 670, in respond
    response.body = self.handler()
  File "/usr/lib/python3.4/site-packages/cherrypy/lib/encoding.py", line 217, in __call__
    self.body = self.oldhandler(*args, **kwargs)
  File "/usr/lib/python3.4/site-packages/cherrypy/_cpdispatch.py", line 61, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "./HelloJson.py", line 15, in default
    data = cherrypy.request.json
  File "/usr/lib/python3.4/site-packages/cherrypy/__init__.py", line 224, in __getattr__
    return getattr(child, name)
AttributeError: 'Request' object has no attribute 'json'

127.0.0.1 - - [24/Aug/2015:21:10:36] "OPTIONS / HTTP/1.1" 500 1515 "" "Mozilla/5.0 (X11; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0"

我不知道我做错了什么。

Answer 1

您看到的 OPTIONS 请求是 CORS preflight request, which obviously isn't a JSON request and you see the error. Because you open your file from file:// protocol (or another host), and CherryPy is serving on http://127.0.0.1:1234 you do a cross-domain request, which is subject to Same-Origin Policy。

解决此问题的最简单方法是同时通过 CherryPy (Static content serving). The hard way is to provide proper CORS headers to allow cross domain requests (see )

提供 HTML 文件

Answer 2

我同意 saaj 的回应，即浏览器发送 CORS 预检请求，可以按以下方式处理：

import cherrypy

class HelloJson(object):
    @cherrypy.expose
    @cherrypy.tools.json_in()
    def POST(self):
        data = cherrypy.request.json
        print(data)
        return "Hello world!"

    def OPTIONS(self):
        cherrypy.response.headers["Access-Control-Allow-Methods"] = "POST, OPTIONS"
        cherrypy.response.headers["Access-Control-Allow-Credentials"] = "true"
        cherrypy.response.headers["Access-Control-Max-Age"] = "86400"
        cherrypy.response.headers[
            "Access-Control-Allow-Headers"] = "X-Mobile, Authorization, Origin, X-Requested-With, Content-Type, Accept"
        cherrypy.response.headers["Content-Type"] = "application/json; charset=utf-8"
        return ''


if __name__ == '__main__':
    cherrypy.config.update({
            'server.socket_port':1234, 
            'request.dispatch': cherrypy.dispatch.MethodDispatcher()
    })
    cherrypy.quickstart(HelloJson(), '/')

这会起作用，因为现在您已启用 API 后端来侦听浏览器的 OPTIONS 调用，该调用告诉浏览器允许的方法和来源是什么。 cherrypy.dispatch.MethodDispatcher() 使您能够将 class 视为方法调度程序，因此您可以使用 class 服务 RESTFUL API.

发送 JSON 字符串到 cherrypy

Sending JSON string to cherrypy

html

javascript

python

json

cherrypy