从 Redis 缓存数据库中获取所有键

Question

我正在将 Redis 缓存用于缓存目的（特别是 stackexchange.Redis C# driver。想知道是否有任何方法可以在任何时间点获取缓存中可用的所有键。我的意思是我可以做类似的事情ASP.NET cache 对象（代码示例下方）

var keys = Cache.GetEnumerator();                               
while(keys.MoveNext())
{
     keys.Key.ToString() // Key
}

Redis documentation talks about KESY command 但 stackexchange.Redis 有该命令的实现。

通过 connection.GetDataBase() 实例调试，我没有看到任何方法/属性。

有什么想法吗？

Answer 1

您需要的功能在IServer接口下，可以通过以下方式实现：

ConnectionMultiplexer m = CreateConnection();
m.GetServer("host").Keys();

请注意，在 2.8 版之前的 redis 服务器将使用您提到的 KEYS 命令，并且在某些情况下可能会非常慢。但是，如果您使用 redis 2.8+ - 它将改用 SCAN 命令，这样性能更好。还要确保您确实需要获取所有密钥，在我的实践中我从来不需要这个。

Answer 2

尝试使用这个代码片段，它对我有用：

IServer server = Connection.GetServer("yourcache.redis.cache.windows....", 6380);
foreach (var key in server.Keys())
{
   Console.WriteLine(key);
}

source

Answer 3

string connectionString = "my_connection_string";
ConfigurationOptions options = ConfigurationOptions.Parse(connectionString);
ConnectionMultiplexer connection = ConnectionMultiplexer.Connect(options);
IDatabase db = connection.GetDatabase();
EndPoint endPoint = connection.GetEndPoints().First();
RedisKey[] keys = connection.GetServer(endPoint).Keys(pattern: "*").ToArray();

Answer 4

您需要数据库来区分在哪里寻找键。所以 MTZ4 答案的最后一行变成：

RedisKey[] keys = connection.GetServer(endPoint).Keys(database: db.Database, pattern: "*").ToArray();

其中 db.Database 是您要查询的 Redis 数据库的数字标识符。

Answer 5

ASP.Net核心3.1

将以下 packages 添加到您的 .csproj

<ItemGroup>
  <PackageReference Include="Microsoft.Extensions.Caching.StackExchangeRedis" Version="3.1.15" />
  <PackageReference Include="StackExchange.Redis.Extensions.AspNetCore" Version="7.0.1" />
  <PackageReference Include="StackExchange.Redis.Extensions.Core" Version="7.0.1" />
  <PackageReference Include="StackExchange.Redis.Extensions.Newtonsoft" Version="7.0.1" />
</ItemGroup>

在 Startup.cs 中，您可以通过这种方式注册 Redis Client 准备好注入您的工作流代码。

public class Startup
{
  public void ConfigureServices(IServiceCollection services)
  {
    // ... other registrations

    // Used By : Sample Below : RedisCacheHelperController (Method 1 Only)
    services.AddSingleton<IConnectionMultiplexer>(
            ConnectionMultiplexer.Connect(DbHelper.GetRedisConnectionHost(Options.IsDevDb()))
        );

    // Used By : Sample Below : DistributedCacheController (Method 2 Only)
    services.AddStackExchangeRedisCache(options => 
            options.Configuration = DbHelper.GetRedisConnectionHost(Options.IsDevDb())
        );

    // ... other registrations
  }
}

注：

DbHelper.GetRedisConnectionHost(Options.IsDevDb()) :>>> is my way to resolve the connection information/string for my Redis instance respective to my environment. You can have your own way here for that or you can hard-code it here if you like to begin with.

方法一

所以，有了上面的东西，就可以将 Redis IConnectionMultiplexer 注入你的 Controllers 或 Services。

public class RedisCacheHelperController : ControllerBase
{
    private readonly IConnectionMultiplexer multiplexer;

    public RedisCacheHelperController(IConnectionMultiplexer multiplexer)
    {
        this.multiplexer = multiplexer;
    }
}

下面是帮助程序 API，用于演示如何使用 IConnectionMultiplexer。

public class RedisCacheHelperController : ControllerBase
{
    private readonly IConnectionMultiplexer multiplexer;

    public RedisCacheHelperController(IConnectionMultiplexer multiplexer)
    {
        this.multiplexer = multiplexer;
    }

    [HttpGet("{key}")]
    public async Task<IActionResult> GetCacheByKey([FromRoute] string key)
    {
        var responseContent = await multiplexer.GetDatabase().StringGetAsync(key);

        return Content(
           responseContent,
           Constants.ContentTypeHeaderValueJson // "application/json"
       );
    }

    [HttpPost("{key}")]
    public async Task<IActionResult> PostCacheByKey([FromRoute] string key, [FromBody] object data)
    {
        var requestContent = data.Json(); // JsonConvert.SerializeObject(data)
        await multiplexer.GetDatabase().StringSetAsync(key, requestContent);
        return Ok(key);
    }

    [HttpDelete("{key}")]
    public async Task<IActionResult> DeleteCacheByKey([FromRoute] string key)
    {
        await multiplexer.GetDatabase().KeyDeleteAsync(key);
        return Ok(key);
    }

    [HttpGet("CachedKeys")]
    public IActionResult GetListCacheKeys([FromQuery] [DefaultValue("*")] string pattern)
    {
        var keys = multiplexer
            .GetServer(multiplexer
                .GetEndPoints()
                .First())
            .Keys(pattern: pattern ?? "*")
            .Select(x => x.Get());

        return Ok(keys);
    }
   
    // ... could have more Reids supported operations here
}

现在上面是 use-case 您想要访问 Redis Client 并执行更多 Redis 特定内容的地方。我们在上面 .csproj 中包含的包 Microsoft.Extensions.Caching.StackExchangeRedis 支持 Reids 作为 IDistributedCache 注册和注入。接口 IDistributedCache 由 Microsoft 定义并支持 basic/common 不同分布式缓存解决方案的功能，其中 Redis 是其中之一。

意味着如果您的目的仅限于 set and/or get 缓存作为 key-value pair，您更愿意在 [=36= 中这样做] 下面。

方法二

public class DistributedCacheController : ControllerBase
{
    private readonly IDistributedCache distributedCache;

    public DistributedCacheController(IDistributedCache distributedCache)
    {
        this.distributedCache = distributedCache;
    }
    
    [HttpPost("{key}")]
    public async Task<IActionResult> PostCacheByKey([FromRoute] string key, [FromBody] object data)
    {
        var requestContent = data.Json(); // JsonConvert.SerializeObject(data)
        await distributedCache.SetStringAsync(key, requestContent);
        return Ok(key);
    }

    [HttpGet("{key}")]
    public async Task<IActionResult> GetCacheByKey([FromRoute] string key)
    {
        var responseContent = await distributedCache.GetStringAsync(key);

        if (!string.IsNullOrEmpty(responseContent))
        {
            return Content(
               responseContent,
               Constants.ContentTypeHeaderValueJson // "application/json"
            );
        }

        return NotFound();
    }

    [HttpDelete("{key}")]
    public async Task<IActionResult> DeleteCacheByKey([FromRoute] string key)
    {
        await distributedCache.RemoveAsync(key);
        return Ok(key);
    }
}

Answer 6

获得 IDatabase 实例后，我将在我们说话时使用它：

        var endpoints = _Cache.Multiplexer.GetEndPoints();
        var server = _Cache.Multiplexer.GetServer(endpoints[0]);
        var keys = server.Keys();

从 Redis 缓存数据库中获取所有键

Get all keys from Redis Cache database

c#

caching

stackexchange.redis