Connect to API and send back a message with Flask app - python-3.x

Question

I have a flask app deployed to Heroku and would like to receive text from Chatfuel (bot building platform) and send back texts in return.
Now, what I did is to use my heroku app as a web-hook, so that Chatfuel can make a simple GET or POST query to my API. The problem is that I have no experience with Flask or APIs, so I am not sure about how my app can receive information (in json format) and send it back to chatfuel.
This is what I wrote so far:
import os
import sys
import json
import requests
from flask import Flask, jsonify, render_template, request
app = Flask(__name__)
#app.route('/', methods=['GET'])
def verify():
# when the endpoint is registered as a webhook, it must echo back
# the 'hub.challenge' value it receives in the query arguments
if request.args.get("hub.mode") == "subscribe" and request.args.get("hub.challenge"):
if not request.args.get("hub.verify_token") == os.environ["VERIFY_TOKEN"]:
return "Verification token mismatch", 403
return request.args["hub.challenge"], 200
return "Hello world", 200
#app.route("/json", methods=['GET','POST'])
def json():
url = "chatfuel_api"
data = json.load(urllib2.urlopen(url))
if request.json:
mydata = request.json
return "Thanks",200
else:
return "no json received"
#app.route('/hello', methods = ['GET','POST'])
def api_echo():
if request.method == 'GET':
return "ECHO: GET\n",200
if __name__ == '__main__':
app.run(debug=True)
The verify() function works, as I see an 'Hello world' message if I run the app locally. However, both json() and api_echo() don't work, and when my server receives a get or post request from chatfuel, it returns a 404 error.
As you can see, I really have a lot of confusion, and your help would be really invaluable.
Thanks

Answer 1

You need to make sure you have registered the proper webhook url with Chatfuel. For the code you currently have, to hit the json endpoint the url would be https://www.your_server.com/json
The verify route looks like the hub challenge FB sends, so you would have to register the root of your site (that is, with your current code) with FB to hit the verify function. That url would look like this https://www.your_site.com/