Response not loading in localhost when using requests.request method in python

Question

import tornado.web
import tornado.ioloop
from apiApplicationModel import userData
from cleanArray import Label_Correction
import json
import requests

colName=['age', 'resting_blood_pressure', 'cholesterol', 'max_heart_rate_achieved', 'st_depression', 'num_major_vessels', 'st_slope_downsloping', 'st_slope_flat', 'st_slope_upsloping', 'sex_male', 'chest_pain_type_atypical angina', 'chest_pain_type_non-anginal pain', 'chest_pain_type_typical angina', 'fasting_blood_sugar_lower than 120mg/ml', 'rest_ecg_left ventricular hypertrophy', 'rest_ecg_normal', 'exercise_induced_angina_yes', 'thalassemia_fixed defect', 'thalassemia_normal',
       'thalassemia_reversable defect']

class processRequestHandler(tornado.web.RequestHandler):
    def post(self):
        data_input_array = []
        for name in colName:
            x = self.get_body_argument(name, default=0)
            data_input_array.append(int(x))
        label = Label_Correction(data_input_array)
        finalResult = int(userData(label))
        output = json.dumps({"Giveput":finalResult})
        self.write(output)

class basicRequestHandler(tornado.web.RequestHandler):

  def get(self):
    self.render('report.html')

class staticRequestHandler(tornado.web.RequestHandler):

  def post(self):
      data_input_array = []
      for name in colName:
          x = self.get_body_argument(name, default=0)
          data_input_array.append(str(x))
      send_data = dict(zip(colName, data_input_array))
      print(send_data)
      print(type(send_data))
      url = "http://localhost:8887/output"
      headers={}
      response = requests.request('POST',url,headers=headers,data=send_data)
      print(response.text.encode('utf8'))
      print("DONE")

if __name__=='__main__':
  app = tornado.web.Application([(r"/",basicRequestHandler),
                                 (r"/result",staticRequestHandler),
                                 (r"/output",processRequestHandler)])
  print("API IS RUNNING.......")
  app.listen(8887)
  tornado.ioloop.IOLoop.current().start()

Actually I am trying to create an API and the result of the API can be used but The page keeps on loading, and no response is shown. Response should be a python dictionary send by post function of class processRequestHandler After using a debugger the lines after response = requests.request('POST',url,headers=headers,data=send_data) are not executed. The class processRequestHandler is working fine when checked with POSTMAN.

Answer 1

requests.request is a blocking method. This blocks the event loop and prevents any other handlers from running. In a Tornado handler, you need to use Tornado's AsyncHTTPClient (or another non-blocking HTTP client such as aiohttp) instead.

async def post(self):
    ...
    response = await AsyncHTTPClient().fetch(url, method='POST', headers=headers, body=send_data)

See the Tornado users's guide for more information.