using-in-memory-data-source.md

Using a in-memory data source provider

With a in-memory data source provider, you can define rules and manage them in-memory, and you can also manage their lifetime in memory.

There are 2 configuration possibilities:

1. Setting the in-memory data source attached to rules engine lifetime.

   RulesEngine<ContentTypes, ConditionTypes> rulesEngine = RulesEngineBuilder.CreateRulesEngine()
       .WithContentType<ContentTypes>()
       .WithConditionType<ConditionTypes>()
       .SetInMemoryDataSource()
       .Build();

2. Registering in-memory data source on dependency injection and using service provider.

       // Registering in-memory data source on dependency injection.
       (...)
       services.AddInMemoryRulesDataSource<ContentTypes, ConditionTypes>(ServiceLifetime.Singleton);
       (...)
   
       // Creating the rules engine specifying as parameter the service provider.
   RulesEngine<ContentTypes, ConditionTypes> rulesEngine = RulesEngineBuilder.CreateRulesEngine()
       .WithContentType<ContentTypes>()
       .WithConditionType<ConditionTypes>()
       .SetInMemoryDataSource(serviceProvider)
       .Build();

Keep in mind that a in-memory data source is volatile, and will need you to build a rules engine and add rules everytime you start your application.