Argthtjtr

I have a method that invokes asynchronous calls using twisted and returns a value. My requirement is to return only when all the callbacks are done.

from twisted.web import client

from twisted.internet import reactor, ssl

from OpenSSL import SSL

from twisted.web.http_headers import Headers

from twisted.internet import reactor

from twisted.web.client import Agent, readBody

import traceback



class sslPolicyForAgent(client.BrowserLikePolicyForHTTPS):

    def creatorForNetloc(self, hostname, port):

        return ssl.optionsForClientTLS(

            hostname.decode("ascii"),

            trustRoot=self._trustRoot

        )



class ReadData(object):

    def __init__(self, cred_data, security_resource_list):

        try:

            self.creds = cred_data

            self.securitycenter_list = security_resource_list

            self.callbackstack = list()

        except Exception as e:

            traceback.print_exc()



    def deferred_rest_api_call(self, url, num):

        try:

            agent = Agent(reactor, contextFactory=sslPolicyForAgent())

            deferred = agent.request(b'GET',url)

            return deferred

        except Exception as e:

            traceback.print_exc()



    def successCallback(self, result, num):

        print('Processing callback')

        print(result)



    def errorCallback(self, err):

        print('Error')



    def getDiscoveryResultListData(self):

        for num in range(0,2):

            self.url = 'https://www.google.com/'

            deferred = self.deferred_rest_api_call(self.url, num)

            deferred.addCallback(self.successCallback, num)

            deferred.addErrback(self.errorCallback)

        return 'Finished processing'



if __name__ == '__main__':

    data = dict()

    data['url'] = 'DemoLB'

    readDataObj = ReadData(data, list())

    value_ret = readDataObj.getDiscoveryResultListData()

    print(value_ret)

    reactor.run()

but as expected, since the call is asynchronous the callbacks are done post returning from the method. What would be the way to have the results/block until the callbacks are done.

I am working with python 2.7.

-Bala