slack event api

events.py

@app.route('/slack/slack-reactions', methods=['POST'])
def slack_reactions():
    logger.info(request)

    slack_payload = request.get_json()
    
    # slack event subscription verification
    slack_request_timestamp = request.headers["X-Slack-Request-Timestamp"]
    request_body = request.get_data().decode()
    slack_signature = request.headers["X-Slack-Signature"]

    if (int(time.time()) - int(slack_request_timestamp)) > 60:
        print("Verification failed. Request is out of date.")
        return Response(), 400

    sig_basestring = 'v0:' + slack_request_timestamp + ':' + request_body
    sig_basestring = sig_basestring.encode('utf-8')
    signing_secret = bytes(SLACK_SIGNING_SECRET, 'utf-8')

    my_signature = 'v0=' + hmac.new(signing_secret, sig_basestring, hashlib.sha256).hexdigest()

    if hmac.compare_digest(my_signature, slack_signature):
        return Response(slack_payload['challenge']), 200
    else:
        return Response(), 500