Module: Tello::Client

Defined in:
lib/tello/client.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Attribute Details

#connected ⇒ Object

Returns the value of attribute connected.



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# File 'lib/tello/client.rb', line 7

def connected
  @connected
end

#ip ⇒ Object

Returns the value of attribute ip.



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# File 'lib/tello/client.rb', line 7

def ip
  @ip
end

#ping ⇒ Object

Returns the value of attribute ping.



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# File 'lib/tello/client.rb', line 7

def ping
  @ping
end

#port ⇒ Object

Returns the value of attribute port.



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# File 'lib/tello/client.rb', line 7

def port
  @port
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/tello/client.rb', line 7

def state
  @state
end

Class Method Details

.connect(ssid = nil, ip = nil, bind_port = 8890) ⇒ Object

Create a UDP connection



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# File 'lib/tello/client.rb', line 12

def connect(ssid = nil, ip = nil, bind_port=8890)

  # Connect to Tello wifi
  if ssid.to_s.upcase == 'AP'
    unless valid_ipv4?(ip)
      puts "Error: Cannot connect to Tello#{$edu} in AP mode due to invalid IPv4: '#{ip}'"
      return false
    end
  else
    if !Tello::Wifi.connect(ssid)
      puts "Error: Could not connect to Tello#{$edu} 😢"
      return false
    end
    ip = '192.168.10.1'
  end

  # If already connected, disconnect
  if @connected
    puts "Reconnecting..."
    disconnect
  end

  p({ssid: ssid, ip: ip})

  # Set IP and port numbers
  @ip = (Tello.testing ? 'localhost' : ip)
  @port = 8889

  # Create UDP client, bind to a previous source IP and port if availble
  @client = UDPSocket.new unless @client
  if @source_ip && @source_port
    p({source_ip: @source_ip, source_port: @source_port})
    @client.bind(@source_ip, @source_port)
  end

  # Connect to destination, save IP and port assigned by the OS
  @client.connect(@ip, @port)
  @source_ip = @client.addr[3]
  @source_port = @client.addr[1]

  # Create server to get Tello state
  unless @state_server
    @state_server = UDPSocket.new
    @state_server.bind('0.0.0.0', bind_port)
  end

  # Check to see if test server is up
  if Tello.testing
    print "Connecting to test server..."
    @client.send('command', 0)
    sleep 0.5
    unless read_nonblock
      puts "\n#{'Error:'.error} Could not find Tello#{$edu} test server.",
            "Did you run `tello#{$edu.to_s.downcase} server` in another terminal window?"
      return false
    end
    puts "connected!"
  end

  # Tello should be connected over wifi and UDP
  @connected = true

  # Threads for real Tello connection only
  unless Tello.testing
    # Create thread to keep Tello alive (must recieve command every 15 sec)
    if @ping then @ping.exit end
    @ping = Thread.new do
      loop do
        begin
          @client.send('command', 0)
        rescue Errno::EADDRNOTAVAIL
          puts "#{'Error:'.error} No response from Tello#{$edu}! Try reconnecting."
          @ping.exit
        end
        sleep(14.5)
      end
    end

    # Get Tello state
    if @state then @state.exit end
    @state = Thread.new do
      loop do
        Tello.store_state(@state_server.recv(256))
      end
    end
  end

  puts "Ready to fly! 🚁"
  true
end

.connected? ⇒ Boolean

Get Tello connection status



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# File 'lib/tello/client.rb', line 104

def connected?
  if @connected
    true
  else
    puts "Tello#{$edu} is not yet connected. Run `connect` first."
    false
  end
end

.disconnect ⇒ Object

Disconnect the Tello



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# File 'lib/tello/client.rb', line 114

def disconnect
  return false unless @connected
  unless Tello.testing
    @state.exit
    @ping.exit
  end
  @client.close
  @client = nil
  @connected = false
  true
end

.read_nonblock ⇒ Object

Read the UDP response without blocking



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# File 'lib/tello/client.rb', line 127

def read_nonblock
  begin
    res = @client.recv_nonblock(256)
  rescue IO::WaitReadable
    res = nil
  rescue Errno::ECONNREFUSED, Errno::EADDRNOTAVAIL
    puts "#{'Error:'.error} Cannot communicate with Tello!"
    @connected
  end
end

.return_bool(res) ⇒ Object

Change ‘ok’ and ‘error’ to boolean response instead



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# File 'lib/tello/client.rb', line 147

def return_bool(res)
  case res
  when 'ok'
    true
  when 'error'
    false
  end
end

.return_num(res) ⇒ Object

Change string to number response instead



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# File 'lib/tello/client.rb', line 157

def return_num(res)
  if res then res.to_i else res end
end

.send(cmd) ⇒ Object

Send a native Tello command string



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# File 'lib/tello/client.rb', line 139

def send(cmd)
  return false unless connected?
  while read_nonblock do end  # flush previous response data
  @client.send(cmd, 0)
  @client.recv(256).strip
end

.valid_ipv4?(ip) ⇒ Boolean 



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# File 'lib/tello/client.rb', line 161

def valid_ipv4?(ip)
  ## May be improved further
  (ip.to_s) =~ /^((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])$/
end