Configurable prefix for redis key

[sizzle168]

Hey,

thanks for providing this useful package. I was wondering if there is a way to configure a prefix for the redis key? Currently, it could lead to problems if several applications share the same redis database.

Thanks in advance.

[cristipufu]

Hi @sizzle168,

Yes, you can configure a prefix for the redis key, here's a related issue: #93

[sizzle168]

@cristipufu
Thank's for your answer. Actually I meant a prefix for the whole key. Looking at https://github.com/cristipufu/aspnetcore-redis-rate-limiting/blob/master/src/RedisRateLimiting/FixedWindow/RedisFixedWindowManager.cs, it doesn't seem to be possible or is there any other way?

RateLimitKey = new RedisKey($"rl:{{{partitionKey}}}");

I need a prefix before "rl:"

[cristipufu]

You can play around with partitionKey - does it have to be before "rl:"?

[sizzle168]

That wouldn't be that helpful. We have different applications running on the same redis db with a app-specific redis key-prefix and I would want to put that rate limit values under the prefix of our app.

[cristipufu]

You can do something like:

return RedisRateLimitPartition.GetFixedWindowRateLimiter($"{appName}", _ =>
               new RedisFixedWindowRateLimiterOptions
               {
                   ConnectionMultiplexerFactory = () => connectionMultiplexer,
                   PermitLimit = 2,
                   Window = TimeSpan.FromSeconds(1)                                   
               });

The key in Redis would be "rl:{appName}"

[hacst]

Recently I was also searching for an option to easily add prefixes. Though in my case it was for parallel test execution with a real redis during integration tests. There is WithKeyPrefix on the IDatabase but that doesn't work for something that wants a multiplexer factory. Adjusting part of the partition key for this was definitely a possibility. However in the end I went with creating a DispatchProxy for IConnectionMultiplexer that uses WithKeyPrefix on each IDatabase returned by GetDatabase. That way everything using the factory, including the rate limiters, always uses the prefix and I don't have to figure out how to do it for everything that uses redis. In case it is helpful to someone:

  public static class IConnectionMultiplexerExtensions
  {
    public static IConnectionMultiplexer WithKeyPrefix(this IConnectionMultiplexer multiplexer, string prefix)
    {
      if (String.IsNullOrEmpty(prefix)) {
        return multiplexer;
      }
      return GetDatabaseWithKeyPrefixProxy.Decorate(multiplexer, prefix);
    }

    private class GetDatabaseWithKeyPrefixProxy : DispatchProxy
    {
      public string? Prefix { get; private set; }
      public IConnectionMultiplexer? Target { get; private set; }
      protected override object? Invoke(MethodInfo? targetMethod, object?[]? args)
      {
        if (targetMethod?.Name == nameof(IConnectionMultiplexer.GetDatabase)) {
          return ((IDatabase?)targetMethod?.Invoke(Target, args))?.WithKeyPrefix(Prefix);
        }
        return targetMethod?.Invoke(Target, args);
      }

      public static IConnectionMultiplexer Decorate(IConnectionMultiplexer multi, String prefix)
      {
        var proxy = (Create<IConnectionMultiplexer, GetDatabaseWithKeyPrefixProxy>() as GetDatabaseWithKeyPrefixProxy)!;
        proxy.Target = multi;
        proxy.Prefix = prefix;
        return (proxy as IConnectionMultiplexer)!;
      }
    }
  }

It works just fine for me but I only use it for tests. I imagine due to the dynamic nature of this and the breadth of IConnectionMultiplexer there might be cases where this breaks down.