flask_ask_ros

A locally hosted web service + ROS node for custom Alexa skills based on Flask-Ask.

Table of Contents

• Description
• Requirements
• Maintainers
• Installation
• Usage
• TO DO

Description

This package combines a Flask server and ROS node into a script that serves as an endpoint for a custom Alexa Skill. This enables information sent by voice to the Amazon Alexa to be processed by other ROS nodes and services.

In this package we provide a simple Alexa skill that parses a single slot (word/argument) from an utterance (spoken function call) and publishes it to a ROS topic.

Requirements

• Ubuntu 16.04

• ROS Kinetic

• Flask-ask (Python): follow installation from source here.

Maintainers

• Lucas Porto lucasporto@outlook.com

• Sina Radmard s.radmard85@gmail.com

Installation

• Navigate to source directory of your ROS catkin workspace (e.g. catkin_ws):

      cd catkin_ws/src
      git clone https://github.com/3SpheresRoboticsProject/flask_ask_ros

• Build catkin workspace:

      cd catkin_ws
      catkin_make

• If necessary, set script file permissions to executable:

      chmod +x catkin_ws/src/flask_ask_ros/src/*

• Source workspace:

      source catkin_ws/devel/setup.bash

Usage

Endpoint configuration

In order for the Alexa requests to reach the local skill server, the local network must be configured to tunnel HTTPS traffic to a specific port on the local machine.

We have tested two ways to accomplish this:

• Using ngrok as a tunnel

• Static IP/Dynamic DNS + self-signed SSL certificate

ngrok tunnel configuration

1. Set the ROS_IP environment variable to be the local machine IP

2. Download ngrok for Linux and unzip

3. Start an ngrok server:

   ./ngrok http $ROS_IP:5000

4. Open the Amazon Developer Console and navigate to your custom skill:

   • Under Configuration, select HTTPS and paste the URL shown on the ngrok terminal (see below).

     

   • Under SSL Certificate select My development endpoint is a sub-domain of a domain that has a wildcard certificate from a certificate authority.

5. Run the skill server with the ngrok argument set to true:

   roslaunch flask_ask_ros start_skill_server.launch ngrok:=true

Static IP/Dynamic DNS + self-signed SSL certificate

1. Set the ROS_IP environment variable to be the local machine IP

2. Configure the router to forward HTTPS requests (port 443) from the local network's public IP to a local IP and port 5000

   This setting is usually located under 'Virtual Server', or 'Port triggering'. See an example below on the D-Link DIR-655 router.

   

3. Include the static IP and/or Dynamic DNS hostname in a SSL configuration file /config/ssl_keys/configuration.cnf (sample provided)

   Under [subject_alternate_names] add the line IP.1 = <your ip> and/or DNS.1 = <your hostname>

4. Run the script generate_ssl_cert.sh to generate the certificate in /config/ssl_keys/certificate.pem

5. Open the Amazon Developer Console and navigate to your custom skill:

   • Under Configuration, select HTTPS and type in https://<your hostname> or https://<your ip>

   • Under SSL Certificate, select I will upload a self-signed certificate... and paste the contents of /config/ssl_keys/certificate.pem

6. Run the skill server

   roslaunch flask_ask_ros start_skill_server.launch

Testing

In order to test the provided skill server, open your Amazon Developer Console, create a custom skill, and follow the steps above to configure your endpoint.

Inside the skill builder, navigate to the JSON Editor and paste the contents of src/test_skill.json. Save and build the model.

Run the skill server to test your skill.

TODO

• Sample code for ROS services

This app was not created or endorsed by Amazon.