String 操作

Redis String 是最简单的数据类型，可以存储字符串、整数或浮点数。

Set_ - 设置键值

基本设置

oRedis.Set_ "name", "张三"
oRedis.Set_ "age", "25"
oRedis.Set_ "city", "北京"

设置过期时间

' 设置过期时间（秒）
oRedis.Set_ "session", "abc123", , 3600  ' 1小时后过期

' 设置过期时间（毫秒）
oRedis.Set_ "token", "xyz789", , 60000  ' 1分钟后过期

Get_ - 获取键值

Dim sValue As String
sValue = oRedis.Get_("name")
Debug.Print sValue  ' 输出: 张三

Incr - 自增

将键中的数值加 1：

' 初始化计数器
oRedis.Set_ "counter", "10"

' 自增
Dim lValue As Long
lValue = oRedis.Incr("counter")
Debug.Print lValue  ' 输出: 11

' 再次自增
lValue = oRedis.Incr("counter")
Debug.Print lValue  ' 输出: 12

用途：

• 计数器
• ID 生成
• 访问统计

Decr - 自减

将键中的数值减 1：

' 自减
lValue = oRedis.Decr("counter")
Debug.Print lValue  ' 输出: 10

MGet - 批量获取

同时获取多个键的值：

' 同时获取多个键
Dim vValues As Variant
vValues = oRedis.MGet("name", "age", "city")

If IsArray(vValues) Then
    Dim i As Long
    For i = 0 To UBound(vValues)
        Debug.Print vValues(i)
    Next
End If

返回值说明：

• 键存在时，返回对应的值
• 键不存在时，返回空字符串

MSet - 批量设置

批量设置多个键值对：

' 批量设置键值对
oRedis.MSet "name", "李四", "age", "25", "city", "北京"

应用场景

1. 用户会话管理

Sub UserSession()
    Dim oRedis As New cRedisClient

    If Not oRedis.Connect() Then Exit Sub

    Dim sUserId As String
    sUserId = "user:12345"

    ' 创建会话
    oRedis.Set_ sUserId & ":name", "张三"
    oRedis.Set_ sUserId & ":email", "zhangsan@example.com"
    oRedis.Set_ sUserId & ":login_time", CStr(Now())

    ' 设置会话过期时间为 30 分钟
    oRedis.Expire sUserId & ":name", 1800
    oRedis.Expire sUserId & ":email", 1800
    oRedis.Expire sUserId & ":login_time", 1800

    ' 获取会话信息
    Dim vSession As Variant
    vSession = oRedis.MGet(sUserId & ":name", sUserId & ":email")
    If IsArray(vSession) Then
        Debug.Print "用户: " & vSession(0)
        Debug.Print "邮箱: " & vSession(1)
        Debug.Print "剩余时间: " & oRedis.TTL(sUserId & ":name") & " 秒"
    End If

    oRedis.DisConnect
End Sub

2. 计数器

Sub CounterExample()
    Dim oRedis As New cRedisClient

    If Not oRedis.Connect() Then Exit Sub

    ' 页面访问计数
    Dim sPage As String
    sPage = "page:/home"

    ' 增加访问次数
    Dim lCount As Long
    lCount = oRedis.Incr(sPage)
    Debug.Print "页面访问次数: " & lCount

    ' 文章点赞计数
    oRedis.Incr "article:1001:likes"
    oRedis.Incr "article:1001:likes"
    oRedis.Incr "article:1001:likes"

    Debug.Print "文章点赞数: " & oRedis.Get_("article:1001:likes")

    oRedis.DisConnect
End Sub

3. 分布式 ID 生成

Function GenerateId(ByVal sPrefix As String) As String
    Static oRedis As cRedisClient

    If oRedis Is Nothing Then
        Set oRedis = New cRedisClient
        If Not oRedis.Connect() Then
            Debug.Print "连接失败"
            Exit Function
        End If
    End If

    Dim lId As Long
    lId = oRedis.Incr("id:" & sPrefix)

    GenerateId = sPrefix & ":" & lId
End Function

Sub TestIdGeneration()
    Debug.Print GenerateId("order")    ' 输出: order:1
    Debug.Print GenerateId("order")    ' 输出: order:2
    Debug.Print GenerateId("user")     ' 输出: user:1
    Debug.Print GenerateId("order")    ' 输出: order:3
End Sub

4. 限流器

Function RateLimit(ByVal sUserId As String, ByVal lLimit As Long) As Boolean
    Static oRedis As cRedisClient

    If oRedis Is Nothing Then
        Set oRedis = New cRedisClient
        If Not oRedis.Connect() Then
            Exit Function
        End If
    End If

    Dim sKey As String
    sKey = "ratelimit:" & sUserId

    Dim lCount As Long
    lCount = oRedis.Incr(sKey)

    ' 第一次请求时设置过期时间（1分钟）
    If lCount = 1 Then
        oRedis.Expire sKey, 60
    End If

    ' 检查是否超过限制
    If lCount > lLimit Then
        Debug.Print "超过限制，当前请求: " & lCount
        RateLimit = False
    Else
        RateLimit = True
    End If
End Function

Sub TestRateLimit()
    Dim i As Long
    For i = 1 To 12
        Debug.Print "请求 " & i & ": " & IIf(RateLimit("user123", 10), "允许", "拒绝")
    Next i
End Sub

5. 缓存管理

Function GetCachedData(ByVal sKey As String, ByVal sDefault As String) As String
    Static oRedis As cRedisClient

    If oRedis Is Nothing Then
        Set oRedis = New cRedisClient
        oRedis.Connect
    End If

    Dim sValue As String
    sValue = oRedis.Get_(sKey)

    If sValue = "" Then
        ' 缓存不存在，返回默认值
        GetCachedData = sDefault

        ' 将默认值存入缓存，过期时间 1 小时
        oRedis.Set_ sKey, sDefault, , 3600
    Else
        GetCachedData = sValue
    End If
End Function

Sub TestCache()
    Debug.Print "第一次获取: " & GetCachedData("config:appname", "MyApp")
    Debug.Print "第二次获取: " & GetCachedData("config:appname", "MyApp")
End Sub

完整示例

Sub Example_StringOperations()
    Dim oRedis As New cRedisClient

    If Not oRedis.Connect() Then
        Debug.Print "连接失败: " & oRedis.LastError
        Exit Sub
    End If

    ' 设置值
    oRedis.Set_ "name", "张三"
    oRedis.Set_ "age", "25"

    ' 获取值
    Debug.Print "姓名: " & oRedis.Get_("name")
    Debug.Print "年龄: " & oRedis.Get_("age")

    ' 设置过期时间
    oRedis.Expire "name", 300

    ' 检查剩余时间
    Debug.Print "name 的剩余生存时间: " & oRedis.TTL("name") & " 秒"

    ' 计数器示例
    oRedis.Set_ "counter", "10"
    Debug.Print "初始值: " & oRedis.Get_("counter")
    Debug.Print "自增后: " & oRedis.Incr("counter")
    Debug.Print "再自增: " & oRedis.Incr("counter")
    Debug.Print "自减: " & oRedis.Decr("counter")

    ' 批量操作
    oRedis.MSet "user:1", "张三", "user:2", "李四", "user:3", "王五"
    Dim vUsers As Variant
    vUsers = oRedis.MGet("user:1", "user:2", "user:3")

    Debug.Print vbCrLf & "批量获取结果:"
    Dim i As Long
    If IsArray(vUsers) Then
        For i = 0 To UBound(vUsers)
            Debug.Print "  用户" & (i + 1) & ": " & vUsers(i)
        Next
    End If

    oRedis.DisConnect
End Sub