Error with Facebook messenger bot code

Question

I'm trying to follow the quickstart Facebook Messenger Bot code (found here: https://developers.facebook.com/docs/messenger-platform/quickstart)

And I'm getting this error:

{"error":{"message":"(#100) param recipient must be non-empty.","type":"OAuthException","code":100,"fbtrace_id":"ALtKsX4nJtX"}}

Any ideas? Seems like I'm returning the right response but for some reason Facebook isn't accepting it? Thanks

Code as follows (python/appengine):

import webapp2
import json
import urllib
from google.appengine.api import urlfetch

class MainHandler(webapp2.RequestHandler):
    print "hello"

FB_MESSENGER_ACCESS_TOKEN = ""

def respond_FB(sender_id, text):
    json_data = {
        "recipient": {"id": sender_id},
        "message": {"text": text + " to you!"}
    }
    url = "https://graph.facebook.com/v2.6/me/messages?access_token="+FB_MESSENGER_ACCESS_TOKEN
    print("json_data", json_data)
    data = urllib.urlencode(json_data)
    response = urlfetch.fetch(url = url, payload = data, method = urlfetch.POST, headers = {"Content-Type": "application/json"})
    print(response.content)

class FacebookMessenger(webapp2.RequestHandler):
    def get(self):
        if (self.request.get("hub.verify_token") == 'tomstoken'):
            return self.response.write(self.request.get("hub.challenge"))
        return self.response.write('Error, wrong validation token')


    def post(self):
        body = self.request.body
        messaging_events = json.loads(body.decode("utf-8"))
        sender_id = messaging_events["entry"][0]["messaging"][0]["sender"]["id"]
        message = messaging_events["entry"][0]["messaging"][0]["message"]["text"]
        respond_FB(sender_id, message)
        return self.response.write('Received.')

app = webapp2.WSGIApplication([
    ('/', MainHandler),
    ('/webhook*', FacebookMessenger)
], debug=True)

iownthegame iownthegame · Accepted Answer · 2016-05-26T06:39:29

I just tested with your function respond_FB(sender_id, text) and since I don't have google app engine api so I used requests

response = requests.post(url, json=data)

and everything goes fine if data is replaced with json_data

don't know why you need to have the json_data encoded, it is not url

Error with Facebook messenger bot code

1 Answers