Configuration and Usage

Configuration

Finbuckle.MultiTenant uses the standard application builder pattern for its configuration. In addition to adding the services, configuration for one or more MultiTenant Stores and MultiTenant Strategies are required. A typical configuration for an ASP.NET Core application might look like this:

using Finbuckle.MultiTenant;

var builder = WebApplication.CreateBuilder(args);

// ...add app services

// add Finbuckle.MultiTenant services
builder.Services.AddMultiTenant<TenantInfo>()
    .WithHostStrategy()
    .WithConfigurationStore();

var app = builder.Build();

// add the Finbuckle.MultiTenant middleware
app.UseMultiTenant();

// ...add other middleware

app.Run();

Adding the Finbuckle.MultiTenant Service

Use the AddMultiTenant<TTenantInfo> extension method on IServiceCollection to register the basic dependencies needed by the library. It returns a MultiTenantBuilder<TTenantInfo> instance on which the methods below can be called for further configuration. Each of these methods returns the same MultiTenantBuilder<TTenantInfo> instance allowing for chaining method calls.

Configuring the Service

WithStore Variants

Adds and configures an IMultiTenantStore to the application. Only the last store configured will be used. See MultiTenant Stores for more information on each type.

WithStore<TStore>
WithInMemoryStore<TTenantStore>
WithConfigurationStore<TTenantStore>
WithEFCoreStore<TTenantStore>
WithDistributedCacheStore<TTenantStore>
WithHttpRemoteStore<TTenantStore>

WithStrategy Variants

Adds and configures an IMultiTenantStore to the application. Multiple strategies can be configured and each will be used in the order registered. See MultiTenant Strategies for more information on each type.

WithStrategy<TStrategy>
WithBasePathStrategy
WithClaimStrategy
WithDelegateStrategy
WithHeaderStrategy
WithHostStrategy
WithRouteStrategy
WithSessionStrategy
WithStaticStrategy

WithPerTenantAuthentication

Configures support for per-tenant authentication. See Per-Tenant Authentication for more details.

Per-Tenant Options

Finbuckle.MultiTenant id designed to integrate with the standard .NET Options pattern (see also the ASP.NET Core Options pattern) and lets apps customize options distinctly for each tenant. See Per-Tenant Options for more details.

Tenant Resolution and Usage

Finbuckle.MultiTenant will perform tenant resolution using the context, strategies, and stores as configured.

The context will determine on the type of app. For an ASP.NET Core web app the context is the HttpContext for each request and a tenant will be resolved for each request. For other types of apps the context will be different. For example, a console app might resolve the tenant once at startup or a background service monitoring a queue might resolve the tenant for each message it receives.

Tenant resolution is performed by the TenantResolver class. The class requires a list of strategies and a list of stores as well as some options. The class will try each strategy generally in the order added, but static and per-tenant authentication strategies will run at a lower priority. If a strategy returns a tenant identifier then each store will be queried in the order they were added. The first store to return a TenantInfo object will determine the resolved tenant. If no store returns a TenantInfo object then the next strategy will be tried and so on. The UseMultiTenant middleware for ASP.NET Core uses TenantResolver internally.

The TenantResolver options are configured in the AddMultiTenant<TTenantInfo> method with the following properties:

IgnoredIdentifiers - A list of tenant identifiers that should be ignored by the resolver.
Events - A set of events that can be used to hook into the resolution process:
- OnStrategyResolveCompleted - Called after each strategy has attempted to resolve a tenant identifier. The IdentifierFound property will be true if the strategy resolved a tenant identifier. The Identifier property contains the resolved tenant identifier and can be changed by the event handler to override the strategy's result.
- OnStoreResolveCompleted - Called after each store has attempted to resolve a tenant. The TenantFound property will be true if the store resolved a tenant. The TenantInfo property contains the resolved tenant and can be changed by the event handler to override the store's result. A non-null TenantInfo object will stop the resolver from trying additional strategies and stores.
- OnTenantResolveCompleted - Called once after a tenant has been resolved. The MultiTenantContext property contains the resolved multi-tenant context and can be changed by the event handler to override the resolver's result.

Getting the Current Tenant

There are several ways an app can see the current tenant:

Dependency Injection

IMultiTenantContextAccessor and IMultiTenantContextAccessor<TTeenantInfo> are available via dependency injection and behave similar to IHttpContextAccessor. Internally an AsyncLocal<T> is used to track state and in parent async contexts any changes in tenant will not be reflected. For example, the accessor will not reflect a tenant in the post-endpoint processing in ASP.NET Core middleware registered prior to UseMultiTenant. Use the HttpContext extension GetMultiTenantContext<TTenantInfo> to avoid this caveat.
IMultiTenantContextSetter is available via dependency injection and can be used to set the current tenant. This is useful in advanced scenarios and should be used with caution. Prefer using the HttpContext extension method TrySetTenantInfo<TTenantInfo> in use cases where HttpContext is available.

Prior versions of Finbuckle.MultiTenant also exposed IMultiTenantContext, ITenantInfo, and their implementations via dependency injection. This was removed as these are not actual services, similar to how HttpContext is not a service and not available directly via dependency injection.

`HttpContext` Extension Methods

For web apps these convenience methods are also available:

GetMultiTenantContext<TTenantInfo>

Use this HttpContext extension method to get the MultiTenantContext<TTenantInfo> instance for the current request. This should be preferred to IMultiTenantContextAccessor or IMultiTenantContextAccessor<TTenantInfo> when possible.

var tenantInfo = HttpContext.GetMultiTenantContext<TenantInfo>().TenantInfo;

if(tenantInfo != null)
{
  var tenantId = tenantInfo.Id;
  var identifier = tenantInfo.Identifier;
  var name = tenantInfo.Name;
  var something = tenantInfo.Items["something"];
}

SetTenantInfo<TTenantInfo>

For most cases the middleware sets the TenantInfo and this method is not needed. Use only if explicitly overriding the TenantInfo set by the middleware.

Use this 'HttpContext' extension method to the current tenant to the provided TenantInfo. Returns true if successful. Optionally it can also reset the service provider scope so that any scoped services already resolved will be resolved again under the current tenant when needed. This has no effect on singleton or transient services. Setting the TenantInfo with this method sets both the StoreInfo and StrategyInfo properties on the MultiTenantContext<TTenantInfo> to null.
```
var newTenantInfo = new TenantInfo(...);

if(HttpContext.TrySetTenantInfo(newTenantInfo, resetServiceProvider: true))
{
    // This will be the new tenant.
    var tenant = HttpContext.GetMultiTenantContext().TenantInfo;

    // This will regenerate the options class.
    var optionsProvider = HttpContext.RequestServices.GetService<IOptions<MyScopedOptions>>();
}
```