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MQTT in your browser

MQTT is probably best known as a lightweight messaging protocol implemented for small sensors, but there is actually a JavaScript implementation called MQTT.js. It's a JavaScript implementation, so of course it works in a browser. I think it's a great option for front-end engineers who are working with MQTT/IoT-related projects (for example, creating a dashboard to visualize MQTT data). In this article, I'd like to write about what I did when I tried to connect MQTT.js to the test server (broker) of Mosquitto™.

Connecting Svelte to Apollo

Query to Search for an Item with Apollo

Last time was to get list of todo from Apollo. This time I am going to add task search functionality by id.

Code

const { ApolloServer, gql } = require('apollo-server');

Update Tasks with Mutations

last time was search by id form the task list. This time, I am going to update the liset. It's called Mutation, which is a cool name in the GraphQL community :D

Code

Simple list view with Apollo

I've been playing around with GraphQL lately and that's fun. After playing with GraphQL for a while, I thought I'd write about it in a series of articles.

The best way to get started with GraphQL now is to start with these two great sites to grasp the concept.

Introduction to GraphQL

How much is a data center

I will start with the cost of the power to run servers.

Number of servers

I wanted to know how much servers IT giants have. There is no official data on it off cource but some estimates.

As of today (dez/2015) both microsoft and google are leading - MS is 1,020,00 machines and google 750,000. Facebook 2015 is 'undisclosed' but their operation is quite small compared to those million-machine business.

	require "readline"
	require "yaml"
	require "json"

	class CLI
	attr_accessor :command_tree

	def initialize(swagger_json)
	# TODO: json might be broken
	if swagger_json.nil?

	require "readline"
	require "yaml"

	command_tree = {"pet"=>
	{"buy"=>{"dog"=>nil, "cat"=>nil},
	"sell"=>{"bird"=>nil, "fox"=>nil},
	"sellGroup"=>{"pig"=>nil, "kingfisher"=>nil},
	"list"=>{"all"=>nil, "filter_by"=>nil}},
	"store"=>
	{"find"=>{"by_name"=>nil, "by_tag"=>nil, "by_address"=>nil}, "list"=>nil},

	require "readline"

	pet_store = [ "pet", "store", "user"]

	Readline.completion_proc = proc do \|input\|
	pet_store.select { \|name\| name.start_with?(input) }
	end

	while input = Readline.readline("$ ", false)
	if input

	let ary = [
	'0:00',
	'0:30',
	'1:00',
	'1:30',
	'2:00',
	'2:30',
	'3:00',
	'3:30',
	'4:00',