Redis caching with ServiceStack OrmLite and SQL Server persistence - redis

Question

We have a Web app (ASP.NET/C#) with SQL Server backend. We use ServiceStack OrmLite as our POCO Micro ORM. We would now like to extend a part of our app to cache frequently-read data (mainly a collection of POCO objects as values, with numeric keys). But I'm not sure how to go about integrating a simple caching solution (in-memory or Redis based) that works seamlessly with OrmLite and MSSQL as the Master database.
I've read about the ServiceStack Redis Client, MemoryCacheClient and Multi nested database connections (OrmLiteConnectionFactory), but I couldn't find any examples, tutorial or code samples to learn more about implementing caching that works with OrmLite.
Any suggestions or links will be helpful and much appreciated.

Answer 1

I use this extension to help simplify the integration between the db and the cache.
public static class ICacheClientExtensions
{
public static T ToResultUsingCache<T>(this ICacheClient cache, string cacheKey, Func<T> fn, int hours = 1) where T : class
{
var cacheResult = cache.Get<T>(cacheKey);
if (cacheResult != null)
{
return cacheResult;
}
var result = fn();
if (result == null) return null;
cache.Set(cacheKey, result, TimeSpan.FromHours(hours));
return result;
}
}
public class MyService : Service
{
public Data Get(GetData request)
{
var key = UrnId.Create<Data>(request.Id);
Func<Data> fn = () => Db.GetData(request.Id);
return Cache.ToResultUsingCache(key, fn);
}
[Route("/data/{id}")]
public class GetData: IReturn<Data>
{
public int Id{ get; set; }
}
}

Answer 2

You'd need to implement the caching logic yourself, but it's not much work - here's a pseudocode example:
public class QueryObject
{
public DateTime? StartDate { get; set; }
public string SomeString { get; set; }
}
public class Foo
{
public DateTime DateTime { get; set; }
public string Name { get; set; }
}
public class FooResponse
{
public List<Dto> Data { get; set; }
}
public FooResponse GetFooData(QueryObject queryObject)
{
using (var dbConn = connectionFactory.OpenDbConnection())
using (var cache = redisClientsManager.GetCacheClient())
{
var cacheKey = string.Format("fooQuery:{0}", queryObject.GetHashCode()); //insert your own logic for generating a cache key here
var response = cache.Get<Response>(cacheKey);
//return cached result
if (response != null) return response;
//not cached - hit the DB and cache the result
response = new FooResponse()
{
Data =
dbConn.Select<Foo>(
x => x.DateTime > queryObject.StartDate.Value && x.Name.StartsWith(queryObject.SomeString)).ToList()
};
cache.Add(cacheKey, response, DateTime.Now.AddMinutes(15)); //the next time we get the same query in the next 15 mins will return cached result
return response;
}
}

Answer 3

Have you checked Service stack caching wiki. It gives detailed info about caching. Now in your case from the details you are providing I can say that you can go for any kind of caching. As of now it will not make any difference.
PS: A piece of advice caching should be done when there is no option or the only thing pending in application. Because it comes with it's own problem is invalidating caching, managing and all that. So, if you application is not too big, just leave it for now.