HC3 Lua scenes part 5: How to do a simple HTTP request

In this blog I explain how you write a simple HTTP request in a Lua scene.

Sometimes you want to do a simple HTTP request from a Lua scene on your Home Center 3 to interact with a local device (like an Raspberry or Arduino project) or a cloud service like Voice Monkey.

How to do a Lua HTTP request on the HC3

A basic HTTP request in a Lua scene looks like below:

local url = "http://192.168.1.10"

net.HTTPClient():request(url, {
    options={
        method = 'GET',
        headers = {
            ["Content-Type"] = "application/json"
        },
        timeout = 5000
    },
    success = function(response)
        hub.debug("Scene26", response.data)
    end,
    error = function(errorMessage)
        hub.debug("Scene26", "HTTPClient error" .. errorMessage)
    end
})

This code returns the data in the property response.data and shows it in the HC3 logging.

The HTTP request is setup with the following parameters:

Add Alexa voice capabilities to your HC3

As an example, I’ll show you how a Lua scene to have Alexa speak a text using the Voice Monkey Alex skill looks like. This can be controlled with an HTTP POST request in an HC3 scene:

-- SAMPLE VOICEMONKEY SCENE ---------------------------------------------------
-- Version 1.0 (April 2023)
-- Copyright (c)2023 Joep Verhaeg <info@joepverhaeg.nl>
-- https://docs.joepverhaeg.nl

net.HTTPClient():request("https://api.voicemonkey.io/trigger", {
    options = {
        method = 'POST',
        timeout = 5000,
        headers= {['Content-Type'] = 'application/json'},
        data = '{"access_token":"INSERT HERE","secret_token":"INSERT HERE","monkey":"monkey1","announcement":"Hello%20FIBARO%20User"}'
    },
    success = function(response)
        hub.debug ("Scene1", response.status .. " " .. response.data)
    end,
    error = function(message)
        hub.debug("Scene1", "HTTPClient error: " .. message)
    end
})

You have to set up Voice Monkey first for this scene to work. You need an access token and secret_token to communicate with their servers. This is out of scope of this blog.

If you set a condition (trigger) so that the scene starts when the door sensor is breached when arriving at home, you can let Alexs greet you with a nice warm welcome home message! How neat is that!

This is the basis for making an HTTP request from a Lua scene on the HC3. I explain in depth how HTTP requests and APIs work in my How do I send an HTTP request from a Lua scene with the Home Center 3 article.

Writing Lua scene’s on the Home Center 3

This was the last blog in my series where I learned you to master Lua scenes with the HC3. The whole series of training material consists of the following modules:

1. HC3 Lua conditions explained with real world examples;
2. Different types of variables you can use in scenes explained;
3. How you can use the sourceTrigger variable?
4. What is the difference between hub.setTimeout() and hub.sleep()?
5. How to do a simple HTTP call from a scene?