Alexa Skill Development using flask-ask and ngrok

Question

I'm trying to begin developing a skill for alexa using flask-ask and ngrok in python. Following is my code:

from flask import Flask
from flask_ask import Ask, statement, question, session
import json
import requests
import time
import unidecode

app = Flask(__name__)
ask = Ask(app, "/reddit_reader")

def get_headlines():

    titles = 'is this working'
    return titles  

@app.route('/')
def homepage():
    return "hi there, how ya doin?"

@ask.launch
def start_skill():
    welcome_message = 'Hello there, would you like the news?'
    return question(welcome_message)

@ask.intent("YesIntent")
def share_headlines():
    headlines = get_headlines()
    headline_msg = 'The current world news headlines are 
{}'.format(headlines)
    return statement(headline_msg)

@ask.intent("NoIntent")
def no_intent():
    bye_text = 'I am not sure why you asked me to run then, but okay... bye'
    return statement(bye_text)

if __name__ == '__main__':
    app.run(debug=True)

The code runs fine on my machine and returns the correct output if I print it out. But the skill gives a HTTP 500 internal error when I deploy it on amazon using ngrok. I get the same 500 internal error both in the text as well as json simulator in the development console.

This is my intent schema:

{
  "intents": [
    {
      "intent": "YesIntent"
    },
    {
      "intent": "NoIntent"
    }
  ]
}

I get the following error in my python prompt: AttributeError: module 'lib' has no attribute 'X509V3_EXT_get

The stacktrace is as follows:

Traceback (most recent call last):
  File "C:\Python36\lib\site-packages\flask\app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Python36\lib\site-packages\flask\app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "C:\Python36\lib\site-packages\flask\app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Python36\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\Python36\lib\site-packages\flask\app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Python36\lib\site-packages\flask\app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\Python36\lib\site-packages\flask\app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Python36\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\Python36\lib\site-packages\flask\app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\Python36\lib\site-packages\flask\app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Python36\lib\site-packages\flask_ask\core.py", line 728, in _flask_view_func
    ask_payload = self._alexa_request(verify=self.ask_verify_requests)
  File "C:\Python36\lib\site-packages\flask_ask\core.py", line 662, in _alexa_request
    cert = verifier.load_certificate(cert_url)
  File "C:\Python36\lib\site-packages\flask_ask\verifier.py", line 21, in load_certificate
    if not _valid_certificate(cert):
  File "C:\Python36\lib\site-packages\flask_ask\verifier.py", line 63, in _valid_certificate
    value = str(extension)
  File "C:\Python36\lib\site-packages\OpenSSL\crypto.py", line 779, in __str__
    return self._subjectAltNameString()
  File "C:\Python36\lib\site-packages\OpenSSL\crypto.py", line 740, in _subjectAltNameString
    method = _lib.X509V3_EXT_get(self._extension)
AttributeError: module 'lib' has no attribute 'X509V3_EXT_get'

Pip freeze output:

aniso8601==1.2.0
asn1crypto==0.24.0
certifi==2018.1.18
cffi==1.11.5
chardet==3.0.4
click==6.7
cryptography==2.2
Flask==0.12.1
Flask-Ask==0.9.8
idna==2.6
itsdangerous==0.24
Jinja2==2.10
MarkupSafe==1.0
pycparser==2.18
pyOpenSSL==17.0.0
python-dateutil==2.7.0
PyYAML==3.12
requests==2.18.4
six==1.11.0
Unidecode==1.0.22
urllib3==1.22
Werkzeug==0.14.1

I've tried running it on both python 2.7 and python 3.6. Any help is appreciated

Answer 1

Ran into the same issue, you can fix it by downgrading cryptography to anything less than 2.2 for me.

pip install 'cryptography<2.2'

rpg711 gets all the credit (see comments the on original post)