Ruby - IP Connection – Tinkerforge

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# Ruby - IP Connection

This is the description of the Ruby API bindings for the IP Connection. The IP Connection manages the communication between the API bindings and the Brick Daemon or a WIFI/Ethernet Extension. Before Bricks and Bricklets can be controlled using their API an IP Connection has to be created and its TCP/IP connection has to be established.

An installation guide for the Ruby API bindings is part of their general description.

## Examples

The example code below is Public Domain (CC0 1.0).

### Enumerate

Download (example_enumerate.rb)

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    #!/usr/bin/env ruby
    # -*- ruby encoding: utf-8 -*-

    require 'tinkerforge/ip_connection'

    include Tinkerforge

    HOST = 'localhost'
    PORT = 4223

    # Create IP connection to brickd
    ipcon = IPConnection.new
    ipcon.connect HOST, PORT

    # Enumerate Bricks and Bricklets
    ipcon.register_callback(IPConnection::CALLBACK_ENUMERATE) do |uid, connected_uid, position,
                                                                  hardware_version, firmware_version,
                                                                  device_identifier, enumeration_type|
      puts "UID:               #{uid}"
      puts "Enumeration Type:  #{enumeration_type}"

      if enumeration_type != IPConnection::ENUMERATION_TYPE_DISCONNECTED
        puts "Connected UID:     #{connected_uid}"
        puts "Position:          #{position}"
        puts "Hardware Version:  #{hardware_version}"
        puts "Firmware Version:  #{firmware_version}"
        puts "Device Identifier: #{device_identifier}"
      end

      puts ''
    end

    ipcon.enumerate

    puts 'Press key to exit'
    $stdin.gets
    ipcon.disconnect

### Authenticate

Download (example_authenticate.rb)

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    #!/usr/bin/env ruby
    # -*- ruby encoding: utf-8 -*-

    require 'tinkerforge/ip_connection'

    include Tinkerforge

    HOST = 'localhost'
    PORT = 4223
    SECRET = 'My Authentication Secret!'

    # Create IP connection
    ipcon = IPConnection.new

    # Authenticate each time the connection got (re-)established
    ipcon.register_callback(IPConnection::CALLBACK_CONNECTED) do |connect_reason|
      case connect_reason
        when IPConnection::CONNECT_REASON_REQUEST
          puts 'Connected by request'
        when IPConnection::CONNECT_REASON_AUTO_RECONNECT
          puts 'Auto-Reconnect'
      end

      # Authenticate first...
      begin
        ipcon.authenticate SECRET
        puts 'Authentication succeeded'

        # ...then trigger enumerate
        ipcon.enumerate
      rescue
        puts 'Could not authenticate'
      end
    end

    # Print incoming enumeration
    ipcon.register_callback(IPConnection::CALLBACK_ENUMERATE) do |uid, connected_uid, position,
                                                                  hardware_version, firmware_version,
                                                                  device_identifier, enumeration_type|
      puts "UID: #{uid}, Enumeration Type: #{enumeration_type}"
    end

    # Connecte to brickd
    ipcon.connect HOST, PORT

    puts 'Press key to exit'
    $stdin.gets
    ipcon.disconnect

## API

### Basic Functions

`IPConnection``::``new` → ipcon

  Creates an IP Connection object that can be used to enumerate the available devices. It is also required for the constructor of Bricks and Bricklets.

`IPConnection``#``connect`(host, port) → nil

  Parameters:

  - host -- str
  - port -- int

  Creates a TCP/IP connection to the given `host` and `port`. The host and port can refer to a Brick Daemon or to a WIFI/Ethernet Extension.

  Devices can only be controlled when the connection was established successfully.

  Blocks until the connection is established and throws an exception if there is no Brick Daemon or WIFI/Ethernet Extension listening at the given host and port.

`IPConnection``#``disconnect` → nil

  Disconnects the TCP/IP connection from the Brick Daemon or the WIFI/Ethernet Extension.

`IPConnection``#``authenticate`(secret) → nil

  Parameters: | secret -- str

  Performs an authentication handshake with the connected Brick Daemon or WIFI/Ethernet Extension. If the handshake succeeds the connection switches from non-authenticated to authenticated state and communication can continue as normal. If the handshake fails then the connection gets closed. Authentication can fail if the wrong secret was used or if authentication is not enabled at all on the Brick Daemon or the WIFI/Ethernet Extension.

  See the authentication tutorial for more information.

  New in version 2.1.0.

`IPConnection``#``get_connection_state` → int

  Can return the following states:

  - IPConnection::CONNECTION_STATE_DISCONNECTED (0): No connection is established.
  - IPConnection::CONNECTION_STATE_CONNECTED (1): A connection to the Brick Daemon or the WIFI/Ethernet Extension is established.
  - IPConnection::CONNECTION_STATE_PENDING (2): IP Connection is currently trying to connect.

`IPConnection``#``set_auto_reconnect`(auto_reconnect) → nil

  Parameters: | auto_reconnect -- bool

  Enables or disables auto-reconnect. If auto-reconnect is enabled, the IP Connection will try to reconnect to the previously given host and port, if the connection is lost.

  Default value is true.

`IPConnection``#``get_auto_reconnect` → bool

  Returns true if auto-reconnect is enabled, false otherwise.

`IPConnection``#``set_timeout`(timeout) → nil

  Parameters: | timeout -- float

  Sets the timeout in seconds for getters and for setters for which the response expected flag is activated.

  Default timeout is 2.5.

`IPConnection``#``get_timeout` → float

  Returns the timeout as set by `#set_timeout`.

`IPConnection``#``enumerate` → nil

  Broadcasts an enumerate request. All devices will respond with an enumerate callback.

`IPConnection``#``wait` → nil

  Stops the current thread until `#unwait` is called.

  This is useful if you rely solely on callbacks for events, if you want to wait for a specific callback or if the IP Connection was created in a thread.

  `wait` and `unwait` act in the same way as `acquire` and `release` of a semaphore.

`IPConnection``#``unwait` → nil

  Unwaits the thread previously stopped by `#wait`

  `wait` and `unwait` act in the same way as `acquire` and `release` of a semaphore.

### Callback Configuration Functions

`IPConnection``#``register_callback`(id) { |param [, ...]| block } → nil

  Parameters: | id -- int

  Registers a callback with ID `id` to the block `callback`.

  The available IDs with corresponding callback function signatures are described below.

### Callbacks

Callbacks can be registered to be notified about events. The registration is done with the `#register_callback` function. The first parameter is the callback ID and the second parameter is a block:

    ipcon.register_callback IPConnection::CALLBACK_EXAMPLE, do |param|
      puts "#{param}"
    end

The available constants with inherent number and type of parameters are described below.

`IPConnection``::``CALLBACK_ENUMERATE`

  Parameters:

  - uid -- str
  - connected_uid -- str
  - position -- chr
  - hardware_version -- [int, int, int]
  - firmware_version -- [int, int, int]
  - device_identifier -- int
  - enumeration_type -- int

  The callback has seven parameters:

  - `uid`: The UID of the device.
  - `connected_uid`: UID where the device is connected to. For a Bricklet this will be a UID of the Brick where it is connected to. For a Brick it will be the UID of the bottom Master Brick in the stack. For the bottom Master Brick in a stack this will be "0". With this information it is possible to reconstruct the complete network topology.
  - `position`: For Bricks: '0' - '8' (position in stack). For Bricklets: 'a' - 'd' (position on Brick).
  - `hardware_version`: Major, minor and release number for hardware version.
  - `firmware_version`: Major, minor and release number for firmware version.
  - `device_identifier`: A number that represents the device.
  - `enumeration_type`: Type of enumeration.

  Possible enumeration types are:

  - IPConnection::ENUMERATION_TYPE_AVAILABLE (0): Device is available (enumeration triggered by user).
  - IPConnection::ENUMERATION_TYPE_CONNECTED (1): Device is newly connected (automatically send by Brick after establishing a communication connection). This indicates that the device has potentially lost its previous configuration and needs to be reconfigured.
  - IPConnection::ENUMERATION_TYPE_DISCONNECTED (2): Device is disconnected (only possible for USB connection). In this case only `uid` and `enumeration_type` are valid.

  It should be possible to implement plug-and-play functionality with this (as is done in Brick Viewer).

  The device identifier numbers can be found here. There are also constants for these numbers named following this pattern:

      <device-class>::DEVICE_IDENTIFIER

  For example: `BrickMaster::DEVICE_IDENTIFIER` or `BrickletAmbientLight::DEVICE_IDENTIFIER`.

`IPConnection``::``CALLBACK_CONNECTED`

  Parameters: | connect_reason -- int

  This callback is called whenever the IP Connection got connected to a Brick Daemon or to a WIFI/Ethernet Extension, possible reasons are:

  - IPConnection::CONNECT_REASON_REQUEST (0): Connection established after request from user.
  - IPConnection::CONNECT_REASON_AUTO_RECONNECT (1): Connection after auto-reconnect.

`IPConnection``::``CALLBACK_DISCONNECTED`

  Parameters: | disconnect_reason -- int

  This callback is called whenever the IP Connection got disconnected from a Brick Daemon or from a WIFI/Ethernet Extension, possible reasons are:

  - IPConnection::DISCONNECT_REASON_REQUEST (0): Disconnect was requested by user.
  - IPConnection::DISCONNECT_REASON_ERROR (1): Disconnect because of an unresolvable error.
  - IPConnection::DISCONNECT_REASON_SHUTDOWN (2): Disconnect initiated by Brick Daemon or WIFI/Ethernet Extension.

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