Publish images to io.adafruit.com

Gemfile

source 'https://rubygems.org'

gem 'mqtt'

# mac only!
gem 'av_capture'

# If you have trouble installing, this is what worked for me:
#
#   $ brew install imagemagick@6
#   $ PKG_CONFIG_PATH='/usr/local/opt/imagemagick@6/lib/pkgconfig:$PKG_CONFIG_PATH' gem install rmagick
#
# The PKG_CONFIG_PATH I used came from the output of the brew install command.
#
# https://github.com/Homebrew/homebrew-core/pull/8756
gem 'rmagick'

take.rb

require 'av_capture'
require 'RMagick'
require 'mqtt'
require 'json'

# MQTT Client
AIO_USER=ENV['AIO_USER']
AIO_KEY=ENV['AIO_KEY']
AIO_URL='io.adafruit.com'
AIO_PROTOCOL='mqtts'
AIO_PORT=8883

# connecting to IO
connect_uri = "#{AIO_PROTOCOL}://#{AIO_USER}:#{AIO_KEY}@#{AIO_URL}"

puts "CONNECT #{connect_uri}"
client = MQTT::Client.connect(connect_uri, AIO_PORT, ack_timeout: 10)
IMAGE_TOPIC = "#{AIO_USER}/f/image-stream"
SHUTTER_TOPIC  = "#{AIO_USER}/f/click/json"

def post_image(client)
  # Create a recording session
  session = AVCapture::Session.new

  dev = AVCapture.devices.select(&:video?).last

  image = nil

  # Connect the camera to the recording session
  puts "[post_image] SNAP"
  session.run_with(dev) do |connection|
    # Capture an image and store as image
     image = Magick::Image.from_blob(connection.capture)[0]
  end

  puts "[post_image] PREP"

  # pull center chunk
  image.crop!(Magick::CenterGravity, 700, 700)

  # write to local file, reducing quality to make sure it fits
  image.write('snapshot.jpg') do
    self.format = 'jpeg'
    self.quality = 75
  end

  # encode to base64 from command line
  encoded = `cat snapshot.jpg | base64`.strip
  puts "[post_image]  size: #{ encoded.size } bytes"

  puts "[post_image] PUBLISH"
  client.publish(IMAGE_TOPIC, encoded, true, 0)
rescue => ex
  puts "[post_image] failed to publish image: #{ex.message}"
  puts ex.backtrace[0..5].join("\n")
end

client.get(SHUTTER_TOPIC) do |topic, message|
  value = nil

  begin
    obj = JSON.parse(message)
    value = obj['last_value'].to_i
  rescue => ex
    puts "failed to parse: #{message}"
    puts "error: #{ex.message}"
  end

  if value === 1
    puts 'click received'
    post_image(client)
  end
end