Connection Management

Basic Connection

Connect to Local Redis Server

Dim oRedis As New cRedisClient

' Connect to local Redis server
If oRedis.Connect() Then
    Debug.Print "Connected successfully!"
Else
    Debug.Print "Connection failed: " & oRedis.LastError
End If

Connect to Specified Server

Dim oRedis As New cRedisClient

' Connect to specified address and port
If oRedis.Connect("192.168.1.100", 6379) Then
    Debug.Print "Connected successfully!"
End If

Connect with Password Authentication

Dim oRedis As New cRedisClient

' Connect and use password authentication
If oRedis.Connect("127.0.0.1", 6379, "mypassword") Then
    Debug.Print "Connected successfully!"
End If

Connect with ACL Username and Password (Redis 6.0+)

Dim oRedis As New cRedisClient

' Use ACL authentication (requires Redis 6.0+ with ACL user configured)
If oRedis.Connect("127.0.0.1", 6379, "mypassword", "myusername") Then
    Debug.Print "ACL authentication connected successfully!"
End If

Set Timeout

Dim oRedis As New cRedisClient

' Set timeout to 10 seconds
oRedis.Timeout = 10
If oRedis.Connect() Then
    Debug.Print "Connected successfully!"
End If

Disconnect

oRedis.DisConnect

Connection Status Check

Check connection status before executing operations:

' Check internal connection flag
If Not oRedis.Connected Then
    Debug.Print "Not connected to Redis server"
End If

' Check actual Socket connection status (more accurate, syncs internal flag)
If Not oRedis.IsConnected Then
    Debug.Print "Socket disconnected, attempting to reconnect..."
    If Not oRedis.Connect() Then
        Debug.Print "Reconnection failed: " & oRedis.LastError
        Exit Sub
    End If
End If

Event Handling

OnDisconnected - Disconnection Event

' Declare WithEvents variable in class module
Private WithEvents m_oRedis As cRedisClient

Private Sub m_oRedis_OnDisconnected()
    Debug.Print "Redis connection lost"
    ' Implement reconnection logic here
End Sub

OnError - Error Event

Private Sub m_oRedis_OnError(ByVal ErrorMsg As String)
    Debug.Print "Redis error: " & ErrorMsg
    ' Implement error handling logic here
End Sub

Connection Best Practices

1. Using Pattern

Sub DoRedisWork()
    Dim oRedis As New cRedisClient

    If Not oRedis.Connect() Then
        Debug.Print "Connection failed"
        Exit Sub
    End If

    ' Execute operations
    oRedis.Set_ "key", "value"

    ' Ensure disconnection
    oRedis.DisConnect
    Set oRedis = Nothing
End Sub

2. Error Handling

Sub SafeRedisOperation()
    Dim oRedis As New cRedisClient

    On Error GoTo ErrorHandler

    If Not oRedis.Connect() Then
        Debug.Print "Connection failed: " & oRedis.LastError
        Exit Sub
    End If

    ' Execute operations
    oRedis.Set_ "key", "value"

    ' Check for errors
    If oRedis.LastError <> "" Then
        Debug.Print "Operation error: " & oRedis.LastError
    End If

    Exit Sub

ErrorHandler:
    Debug.Print "Error occurred: " & Err.Description
    If oRedis.Connected Then
        oRedis.DisConnect
    End If
End Sub

3. Heartbeat Keep-alive

Dim oRedis As New cRedisClient

' Connect to Redis
If oRedis.Connect("127.0.0.1", 6379, "mypassword") Then
    ' Set heartbeat interval (seconds), default 30 seconds
    oRedis.HeartbeatInterval = 30
    
    ' Start heartbeat (periodically sends PING to keep connection active)
    oRedis.StartHeartbeat
    
    ' Execute business operations...
    oRedis.Set_ "key", "value"
    
    ' Stop heartbeat and disconnect
    oRedis.StopHeartbeat
    oRedis.DisConnect
End If

4. Connection Pool Example

' Simple connection manager example
Private m_oRedis As cRedisClient

Function GetRedisConnection() As cRedisClient
    If m_oRedis Is Nothing Then
        Set m_oRedis = New cRedisClient
        If Not m_oRedis.Connect() Then
            Debug.Print "Failed to create connection: " & m_oRedis.LastError
            Set GetRedisConnection = Nothing
            Exit Function
        End If
    End If

    ' Check if connection is still valid
    If Not m_oRedis.Connected Then
        If Not m_oRedis.Connect() Then
            Debug.Print "Reconnection failed: " & m_oRedis.LastError
            Set GetRedisConnection = Nothing
            Exit Function
        End If
    End If

    Set GetRedisConnection = m_oRedis
End Function

Sub CloseRedisConnection()
    If Not m_oRedis Is Nothing Then
        m_oRedis.StopHeartbeat  ' Stop heartbeat first
        m_oRedis.DisConnect
        Set m_oRedis = Nothing
    End If
End Sub

Automatic Reconnection

Since v1.x, auto-reconnect is enabled by default. When connection drops unexpectedly:

• Connected / IsConnected returns False
• Commands will automatically try to reconnect once
• If reconnection succeeds, command continues; if fails, error is raised
• Combined with heartbeat mechanism to detect dead connections promptly

' Disable auto-reconnect (not recommended)
oRedis.AutoReconnect = False

' Enable auto-reconnect (default)
oRedis.AutoReconnect = True