我正在尝试使用龙卷风做一个简单的获取和发布方法。龙卷风框架相当新。对于我想以json作为输入的帖子，请使用该输入输入另一个必须执行另一部分代码的函数。但是，即使使用简单的self.write（），我也无法使龙卷风过帐方法起作用。
对于我的get方法，我正在从SQL数据库读取以获取传感器的状态并将其以json格式写入。 get方法完美地工作！当我转到localhost：port＃时，它会读出我的get json文件。对于我的post方法，我想只接受一个key：value的简单json，它是一个浮点数。我想获取用户在json中指定的浮点数，并将其用在我的flowMKS.set（）函数中，该函数将更改传感器的设定值参数。我不确定如何将json输入到post方法中并将其读取到变量中。我在下面尝试了一些#commented代码，但没有成功。但是我回到了基础知识，只是做了一个self.write（“ Hello World”）来看看帖子是否正常工作。我也无法使self.write正常工作。当我转到localhost：port＃/ flow_post时，不断收到500条错误消息。我的get方法中使用了flow_status变量。
预期结果是将json {“ setpoint”：45.5}放入post方法。使用该数字并将其插入我的flowMKS方法中以更改传感器上的参数。
您如何将json放入post方法中，并从json输入中获取数字并将其存储在变量中？
class Current(tornado.web.RequestHandler):
def get(self):
global flow_status
time = flow_status[0]
ip = flow_status[1]
rate = flow_status[2]
setp = flow_status[3]
tempc = flow_status[4]
status = {"flow_controller":{
"time":time,
"ip":ip,
"rate_sccm":rate,
"setpoint":setp,
"temperature_c":tempc,
}
}
self.write(status)
class Update(tornado.web.RequestHandler):
# def prepare(self):
# if self.request.haders["Content-Type"].startswith("application/json"):
# self.json_args = json.loads(self.request.body)
# else:
# self.json_args = None
def post(self):
# #expecting body data to contain JSON so we use json.loads to decrypt the JSON into a dict
# data = json.loads(self.request.body)
#
# #Getting what the setpoint should be
# setpoint = self.json_args["setpoint"]
#
# #making the input a float
# setpoint = float(setpoint)
#
# #setting up connection with sensor
# flowMKS = FlowController(flow_status[1])
#
# #sending setpoint to sensor
# flowMKS.set(setpoint)
self.write("Hello World")
if __name__ == '__main__':
# global flow_status
#Below is creating the Tornado based API for get and post methods
tornado.options.parse_command_line()
app = tornado.web.Application(
handlers=[(r'/',Current), (r'/flow_post', Update)])
http_server = tornado.httpserver.HTTPServer(app)
http_server.listen(options.port)
#using PeriodicCallback to get info from the SQL database every 500 ms
PeriodicCallback(get_sql_status,500).start()
#starting the entire Tornado IOLoop
tornado.ioloop.IOLoop.current().start()
答案 0 :(得分：0)
要使用Tornado上载文件，可以使用此功能tornado.httputil.parse_body_arguments，该功能将在file_dict中的字典数据args_dict和FormData中的其他参数中拆分上载的文件内容。
示例代码：
import tornado.httputil
import tornado.web
import tornado.escape
import json
import os
import sys
import traceback
class FileHandler(tornado.web.RequestHandler):
def _return_response(self, request, message_to_be_returned: dict, status_code):
"""
Returns formatted response back to client
"""
try:
request.set_header("Content-Type", "application/json; charset=UTF-8")
request.set_status(status_code)
#If dictionary is not empty then write the dictionary directly into
if(bool(message_to_be_returned)):
request.write(message_to_be_returned)
request.finish()
except Exception:
raise
def set_default_headers(self, *args, **kwargs):
self.set_header('Content-Type','text/csv')
self.set_header("Access-Control-Allow-Origin", "*")
self.set_header("Access-Control-Allow-Headers", "x-requested-with")
self.set_header("Access-Control-Allow-Methods", "*")
def post(self):
"""
This function reads an uploaded file
"""
try:
arg_dict = {}
file_dict = {}
tornado.httputil.parse_body_arguments(self.request.headers["Content-Type"], self.request.body, arg_dict, file_dict)
uploaded_file = file_dict['TestFile'][0]
if not uploaded_file:
return self._return_response(self, { 'message': 'No test file uploaded, please upload a test file' }, 400)
# File contents here
file_contents = str(uploaded_file['body'], "utf-8")
self.set_status(200)
self.finish()
except Exception as ex:
return self._return_response(self, { "message": 'Could not complete the request because of some error at the server!', "cause": ex.args[0], "stack_trace": traceback.format_exc(sys.exc_info()) }, 500)
您也可以使用tornado.escape.json_decode将请求主体反序列化为字典并对其进行处理。
示例代码：
import tornado.gen
import tornado.web
import tornado.escape
import json
import os
import sys
import traceback
class JSONHandler(tornado.web.RequestHandler):
def _return_response(self, request, message_to_be_returned: dict, status_code):
"""
Returns formatted response back to client
"""
try:
request.set_header("Content-Type", "application/json; charset=UTF-8")
request.set_status(status_code)
#If dictionary is not empty then write the dictionary directly into
if(bool(message_to_be_returned)):
request.write(message_to_be_returned)
request.finish()
except Exception:
raise
def set_default_headers(self, *args, **kwargs):
self.set_header("Content-Type", "application/json")
self.set_header("Access-Control-Allow-Origin", "*")
self.set_header("Access-Control-Allow-Headers", "x-requested-with")
self.set_header("Access-Control-Allow-Methods", "*")
def post(self):
"""
This function parses the request body and does something
"""
try:
# Do something with request body
request_payload = tornado.escape.json_decode(self.request.body)
return self._return_response(self, request_payload, 200)
except json.decoder.JSONDecodeError:
return self._return_response(self, { "message": 'Cannot decode request body!' }, 400)
except Exception as ex:
return self._return_response(self, { "message": 'Could not complete the request because of some error at the server!', "cause": ex.args[0], "stack_trace": traceback.format_exc(sys.exc_info()) }, 500)