LifxDash

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Amazon LIFX Dash Button

lifx_dash is a simple command-line tool to monitor your network for Amazon Dash button presses and toggle LIFX lights ON and OFF. The tool provides two commands, monitor and snoop.

Use snoop to listen for Dash presses on your network, and identify the button's MAC address.

Use monitor (with a MAC address and LIFX HTTP API token) to respond to presses, and toggle your lights ON and OFF. You can optionally pass a bulb selector, or choose to daemonize the monitor process.

A config command also exists, allowing you to set default options for monitor and snoop.

Requirements

lifx_dash requires at least one LIFX bulb, and any Amazon Dash button. You will also need a wifi network and root access to sniff packets on your network adaptor.

This gem uses packet_fu which in turn requires the libpcap library. This is probably already available on your machine, if not download the latest release or install with your package manager e.g.:

sudo apt-get install libpcap0.8-dev  # UNIX
brew install libpcap                 # homebrew on OSX

lifx_dash is distributed via RubyGems and requires Ruby >= 2.0.0.

Installation

gem install lifx_dash

The lifx_dash command will now be available in your PATH.

Dash Button Setup

Follow Amazon's Dash button setup steps, but stop before choosing a product to purchase. Pressing the button should pulse white while connecting to wi-fi, then flash orange. If necessary, you can factory reset your button and start the setup from scratch.

Next use the snoop command to determine the button's MAC address:

$ sudo lifx_dash snoop -i en0

This will listen on network interface 'en0' for Dash button packets. Take a note of the MAC address that's logged when you press. To list network interfaces on your machine use:

$ ifconfig -l

LIFX Bulb Setup

Create a personal token for the LIFX HTTP API.

By default lifx_dash will toggle ALL bulbs. To toggle a specific light you will need to find the LIFX Bulb ID.

Visit the LIFX API list lights doc and use the 'Try It Out' form with your token. Details for all bulbs on your network will be shown along with their IDs (in JSON format).

Or call the API directly with this curl command:

$ curl "https://api.lifx.com/v1/lights/all" -H "Authorization: Bearer LIFX_API_TOKEN"

Usage

To start the lifx_dash monitor:

$ sudo lifx_dash monitor --token=LIFX_API_TOKEN --mac-address=DASH_MAC_ADDRESS --selector='all' --iface=en0
Starting lifx_dash monitor ...

This starts a long-running process listening on 'en0', for button presses (from the given MAC address). When a press occurs, the monitor will toggle all LIFX bulbs.

Only the --mac-address and --token options are required, by default --selector=all and --iface=en0. You can also use short-form flag options like so:

$ sudo lifx_dash monitor -t LIFX_API_TOKEN -m DASH_MAC_ADDRESS -s 'all' -i en0

Running as a Daemon

Use the -d switch (or --daemonize) to run monitor as a daemon:

$ sudo lifx_dash monitor -t LIFX_API_TOKEN -m DASH_MAC_ADDRESS -s 'all' -i en0 -d
[17099] Starting lifx_dash ... (daemon logging to /tmp/lifx_dash.log)

The command will log to /tmp/lifx_dash.log by default (creating the file and folder if it does not exist). Use -l or --log-file to override this location.

Configuration

You can save option defaults using the config command:

$ lifx_dash config
Configuring lifx_dash ...

You will be prompted for values for each option and your choices will be stored at ~/.lifx_dash.rc.yml.

An empty answer will mean no value is set, and the option reverts to it's default. Passing options on the command-line always takes precedence over your saved configuration.

You can inspect the current configuration file options with:

$ lifx_dash config --show

Help

You can get help in number of ways, for example:

$ lifx_dash help
$ lifx_dash help monitor
$ lifx_dash snoop -h
$ lifx_dash config --help

The gem also comes packaged with its own man page. You'll need gem-man to view this from your command line.

Troubles?

If you think something is broken or missing, do raise a new issue. Please remember to take a moment and check it hasn't already been raised (and possibly closed).

What does the code do?

This gem uses the PacketFu gem (and libpcap under the hood) to monitor data packets on your network. This packet stream filters for DHCP packets (sent from 0.0.0.0). See below for more details on packet detection.

When a valid packet is detected with a known source MAC address, the LIFX HTTP API toggle-power endpoint is requested, with a selector and authorization header.

The GLI command line framework is used to define the commands and options. MiniTest and Aruba are used for testing.

Packet detection

Using WireShark to monitor the network it appears that;

  • older buttons send an ARP packet followed by one or more DHCP packets
  • newer buttons send one or more DHCP packets

To detect packets on both devices it should only be necessary to look for DHCP packets; this can be done with the following filter:

udp and src port 68 and dst port 67 and udp[247:4] == 0x63350103 and src host 0.0.0.0

However since DHCP packets appear to arrive in bursts of 2, the Capturer only acts on packets that have an even IP ID field.

Contributing

Bug reports and pull requests are welcome on GitHub.

When submitting pull requests, please remember to add tests covering the new behaviour, and ensure all tests are passing on Travis CI. Read the contributing guidelines for more details.

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct. See here for more details.

Development

After checking out the repo, run bin/setup, this will install dependencies, and re-generate the man page and docs. Then, run bundle exec rake to run all tests (and generate a coverage report). You can run unit or feature tests separately with:

bundle exec rake test
bundle exec rake features

You can also run bin/console for an interactive prompt that will allow you to experiment with the gem code.

Future Work

Work in progress is usually mentioned at the top of the CHANGELOG. If you'd like to get involved in contributing, here are some ideas:

  • Validation of all command line flag values, iface/mac/token etc.
  • More unit test coverage
  • Aruba features covering the happy paths for all commands
  • Smarter config, auto-snoop, list bulbs with names and choose id
  • Show existing values in config, when configuring, allowing edits (with readline)
  • More Rdoc documentation on command classes
  • New optional flag for the configuration file location
  • Handle CTRL-C and kill signals with better exit/cleanup messages
  • Use LIFX LAN API (with a command switch to choose LAN/HTTP)

License

The gem is available as open source under the terms of the MIT License.

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