Storing Objects in Redis

Saving your custom objects is not out-of-box supported with Redis. We will need to map C# types to Redis types and vice versa.

There can be two approaches to dealing with this :

• Use Json or Protobuf to represent your object as string/binary in redis values
• Map your object yourself to Redis types like Hashes, List, Set etc and store as separate keys

We will use the Json serializer, and create an extension to IDatabasee interface to add two new methods for saving and reading objects from Redis:

using System.Text.Json;
using System.Threading.Tasks;
using StackExchange.Redis;

namespace ConsoleApp
{
  public static class RedisJsonStorageExtension
  {
    public static Task SaveObjectAsync<T>(this IDatabase db, string key, T data)
    {
      var json = JsonSerializer.Serialize(data);
      return db.StringSetAsync(key, json);
    }
    
    public static async Task<T?> GetObjectAsync<T>(this IDatabase db, string key)
    {
      var json = await db.StringGetAsync(key);
      if (json.HasValue)
      {
        return JsonSerializer.Deserialize<T>(json.ToString());
      }

      return default(T);
    }
  }
}

Now use this to save and fetch objects from Redis

public static async Task SaveAndGetObject(IDatabase db)
{
  var person1 = Person.Create("Person 1");
  var person2 = Person.Create("Person 2", new []{"red", "blue"}, new []{"Delhi", "Mumbai"});
  var person3 = Person.Create("Person 3", new []{"red", "blue"}, new []{"Mumbai", "Delhi"});
  var person4 = Person.Create("Person 3");

  await db.SaveObjectAsync("one", person1);
  await db.SaveObjectAsync("two", person2);
  await db.SaveObjectAsync("thee", person3);
  await db.SaveObjectAsync("four", person4);

  var person1Read = await db.GetObjectAsync<Person>("one");
  var person2Read = await db.GetObjectAsync<Person>("two");
  var person3Read = await db.GetObjectAsync<Person>("thee");
  var person4Read = await db.GetObjectAsync<Person>("four");
  var nonExisting = await db.GetObjectAsync<Person>("unknown-key");

  var allValuesEqual =
    person1.Equals(person1Read) &&
    person2.Equals(person2Read) &&
    person3.Equals(person3Read) &&
    person4.Equals(person4Read) &&
    nonExisting == null;

  Console.WriteLine(
    allValuesEqual ? "Successfully handled objects" : "Failed to correctly handle objects");
}