// TODO: This doc is out of date... And shit...

MultiTenancyMiddleware

It's a little black box... kind of

This library allows you to incorporate multitenancy into a .net core 2.0 web api project. After setting up a handful of things (outlined below), you will be able to make a request, and by adding a header to said request containing the account id of the tenant for whose data you want to access you can get said data.

How do you implement it?

• Write a concrete implementation of the provided MultiTenancyResolverService abstract class / IMultiTenancyResolverService interface.

  • There only has to be a ConnectionString property and a SetConnectionStringByAccountId(string accountId) method that sets the ConnectionString property.

• In the Startup.cs file, we'll have to do a couple of things:

  • Add your implementation to the built-in DI container a la:

    services.AddScoped<IMultiTenancyResolverService, ExampleMultiTenancyResolverService>();

    where ExampleMultiTenancyResolverService is the name of your concrete implementation of the provided MultiTenancyResolverService abstract class / IMultiTenancyResolverService interface

  • Add the options for the middleware. This only contains a UseHeaderKey property and a HeaderKey property and this will be the header key used in the request that contains the account id of the tenant whose database you want to reference for the particular request... Or set UseHeaderKey to false if your code will be doing things a different way.

    var multiTenancyMiddlewareOptions = new MultiTenancyMiddlewareOptions
    {
        UseHeaderKey = true,
        TenantIdHeaderKey = "Account-Id"
    
    };
    
    services.AddSingleton(multiTenancyMiddlewareOptions);
    

• Database context class for the tenant template database:

  • Inject the IMultiTenancyResolver into the constructor, and store in private variable:

  private IMultiTenancyResolverService _multiTenancyResolverService;

  • Add the following method:

       protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
       {
           optionsBuilder.UseSqlServer(_multiTenancyResolverService.ConnectionString);
           base.OnConfiguring(optionsBuilder);
       }

How do you use it?

• For any controller/method utilizing multitenancy add the following attribute

  [MiddlewareFilter(typeof(MultiTenancyPipeline))]

• Any time a request is made to said controllers/methods, a header will have to exist on the request that has the key specified in the Startup.cs class, and will have to have a value of the account id.