Visual Basic .NET - IP Connection

This is the description of the Visual Basic .NET 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 Visual Basic .NET API bindings is part of their general description.

Examples

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

Enumerate

Download (ExampleEnumerate.vb)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Imports Tinkerforge

Module ExampleEnumerate
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223

    Sub EnumerateCB(ByVal sender As IPConnection, _
                    ByVal uid As String, _
                    ByVal connectedUid As String, _
                    ByVal position As Char, _
                    ByVal hardwareVersion() As Short, _
                    ByVal firmwareVersion() As Short, _
                    ByVal deviceIdentifier As Integer, _
                    ByVal enumerationType As Short)
        System.Console.WriteLine("UID:               {0}", uid)
        System.Console.WriteLine("Enumeration Type:  {0}", enumerationType)

        If enumerationType = IPConnection.ENUMERATION_TYPE_DISCONNECTED Then
            System.Console.WriteLine("")
            Return
        End If

        System.Console.WriteLine("Connected UID:     {0}", connectedUid)
        System.Console.WriteLine("Position:          {0}", position)
        System.Console.WriteLine("Hardware Version:  {0}.{1}.{2}", _
                                 hardwareVersion(0), hardwareVersion(1), hardwareVersion(2))
        System.Console.WriteLine("Firmware Version:  {0}.{1}.{2}", _
                                 firmwareVersion(0), firmwareVersion(1), firmwareVersion(2))
        System.Console.WriteLine("Device Identifier: {0}", deviceIdentifier)
        System.Console.WriteLine("")
    End Sub

    Sub Main()
        ' Create connection and connect to brickd
        Dim ipcon As New IPConnection()
        ipcon.Connect(HOST, PORT)

        ' Register Enumerate Callback
        AddHandler ipcon.EnumerateCallback, AddressOf EnumerateCB

        ' Trigger Enumerate
        ipcon.Enumerate()

        System.Console.WriteLine("Press key to exit")
        System.Console.ReadLine()
        ipcon.Disconnect()
    End Sub
End Module

Authenticate

Download (ExampleAuthenticate.vb)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Imports Tinkerforge

Module ExampleAuthenticate
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223
    Const SECRET As String = "My Authentication Secret!"

    Sub ConnectedCB(ByVal sender As IPConnection, _
                    ByVal connectReason As Short)
        Select Case connectReason
            Case IPConnection.CONNECT_REASON_REQUEST
                System.Console.WriteLine("Connected by request")
            Case IPConnection.CONNECT_REASON_AUTO_RECONNECT
                System.Console.WriteLine("Auto-Reconnect")
        End Select

        ' Authenticate first...
        Try
            sender.Authenticate(SECRET)
            System.Console.WriteLine("Authentication succeeded")
        catch
            System.Console.WriteLine("Could not authenticate")
            Exit Sub
        End Try

        ' ...then trigger enumerate
        sender.Enumerate()
    End Sub

    Sub EnumerateCB(ByVal sender As IPConnection, _
                    ByVal uid As String, _
                    ByVal connectedUid As String, _
                    ByVal position As Char, _
                    ByVal hardwareVersion() As Short, _
                    ByVal firmwareVersion() As Short, _
                    ByVal deviceIdentifier As Integer, _
                    ByVal enumerationType As Short)
        System.Console.WriteLine("UID: {0}, Enumeration Type: {1}", uid, enumerationType)
    End Sub

    Sub Main()
        ' Create IPConnection and connect to brickd
        Dim ipcon As New IPConnection()

        ' Register Connected Callback
        AddHandler ipcon.Connected, AddressOf ConnectedCB

        ' Register Enumerate Callback
        AddHandler ipcon.EnumerateCallback, AddressOf EnumerateCB

        ' Connect to brickd
        ipcon.Connect(HOST, PORT)

        System.Console.WriteLine("Press key to exit")
        System.Console.ReadLine()
        ipcon.Disconnect()
    End Sub
End Module

API

Basic Functions

Class IPConnection()

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.

Sub IPConnection.Connect(ByVal host As String, ByVal port As Integer)

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.

Sub IPConnection.Disconnect()

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

Sub IPConnection.Authenticate(ByVal secret As String)

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.

Function IPConnection.GetConnectionState() As Short

Can return the following states:

  • IPConnection.CONNECTION_DISCONNECTED (0): No connection is established.
  • IPConnection.CONNECTION_CONNECTED (1): A connection to the Brick Daemon or the WIFI/Ethernet Extension is established.
  • IPConnection.CONNECTION_PENDING (2): IP Connection is currently trying to connect.
Sub IPConnection.SetAutoReconnect(ByVal autoReconnect As Boolean)

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 currently existing connection is lost. Therefore, auto-reconnect only does something after a successful Connect() call.

Default value is true.

Function IPConnection.GetAutoReconnect() As Boolean

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

Sub IPConnection.SetTimeout(ByVal timeout As Integer)

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

Default timeout is 2500.

Function IPConnection.GetTimeout() As Integer

Returns the timeout as set by SetTimeout().

Sub IPConnection.Enumerate()

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

Sub IPConnection.Wait()

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.

Sub IPConnection.Unwait()

Unwaits the thread previously stopped by Wait()

Wait and Unwait act in the same way as Acquire and Release of a semaphore.

Callbacks

Callbacks can be registered to be notified about events. The registration is done by appending your callback handler to the corresponding event:

Sub MyCallback(ByVal sender As IPConnection, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler ipcon.ExampleCallback, AddressOf MyCallback

The available events are described below.

Event IPConnection.EnumerateCallback(ByVal sender As IPConnection, ByVal uid As String, ByVal connectedUid As String, ByVal position As Char, ByVal hardwareVersion() As Short, ByVal firmwareVersion() As Short, ByVal deviceIdentifier As Integer, ByVal enumerationType As Short)

The Event receives seven parameters:

  • uid: The UID of the device.
  • connectedUid: 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).
  • hardwareVersion: Major, minor and release number for hardware version.
  • firmwareVersion: Major, minor and release number for firmware version.
  • deviceIdentifier: A number that represents the device.
  • enumerationType: Type of enumeration.

Possible enumeration types are:

  • IPConnection.ENUMERATION_TYPE_AVAILABLE (0): Device is available (enumeration triggered by user: IPConnection.Enumerate()). This enumeration type can occur multiple times for the same device.
  • 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 enumerationType 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.

Event IPConnection.ConnectedCallback(ByVal sender As IPConnection, ByVal connectReason As Short)

This event is triggered 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.
Event IPConnection.DisconnectedCallback(ByVal sender As IPConnection, ByVal disconnectReason As Short)

This event is triggered 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.