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

Written by Joep on
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 = ""

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

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:

Property Description
url The URL you want to connect to.
method The request method as described in this article.
headers The HTTP headers as described in this article.
timeout The request timeout. When to stop trying to connect to the server described in the url.
success The function to run when data is retrieved.
error The function to run when an error occured.


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)
    error = function(message)
        hub.debug("Scene1", "HTTPClient error: " .. message)

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?


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