Multi-Tenancy

The multi-tenancy behavior ensures tenant context is present and validated for operations that require it.

Core Interfaces

ITenantContext

Provides current tenant information:

public interface ITenantContext
{
    string? TenantId { get; }
    bool HasTenant { get; }
    string? TenantName { get; }
}

ITenantAware

Mark messages that belong to a specific tenant:

public interface ITenantAware
{
    string? TenantId { get; }
}

Using the Attribute

[RequiresTenant]
public record GetTenantDataQuery(string DataKey) : IQuery<TenantData>;

Tenant-Aware Messages

public record CreateTenantDocumentCommand(
    string TenantId,
    string Title,
    string Content
) : ICommand<Document>, ITenantAware;

Configuration

builder.Services.AddTurboMediator(m =>
{
    m.WithMultiTenancy<IMessage, object>();
    m.WithTenantContext<HttpTenantContext>();
});

Implementing ITenantContext

public class HttpTenantContext : ITenantContext
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public HttpTenantContext(IHttpContextAccessor httpContextAccessor)
    {
        _httpContextAccessor = httpContextAccessor;
    }

    public string? TenantId =>
        _httpContextAccessor.HttpContext?.Request.Headers["X-Tenant-Id"].FirstOrDefault()
        ?? _httpContextAccessor.HttpContext?.User?.FindFirst("tenant_id")?.Value;

    public bool HasTenant => !string.IsNullOrEmpty(TenantId);

    public string? TenantName =>
        _httpContextAccessor.HttpContext?.User?.FindFirst("tenant_name")?.Value;
}

Validation Rules

The TenantBehavior validates:

If [RequiresTenant] is present, ITenantContext.HasTenant must be true
If the message implements ITenantAware, the message's TenantId must match ITenantContext.TenantId
Throws an exception if validation fails

Practical Example

// Tenant-isolated queries
[RequiresTenant]
public record GetTenantUsersQuery : IQuery<IReadOnlyList<User>>;

public class GetTenantUsersHandler : IQueryHandler<GetTenantUsersQuery, IReadOnlyList<User>>
{
    private readonly ITenantContext _tenantContext;
    private readonly IUserRepository _repository;

    public GetTenantUsersHandler(ITenantContext tenantContext, IUserRepository repository)
    {
        _tenantContext = tenantContext;
        _repository = repository;
    }

    public async ValueTask<IReadOnlyList<User>> Handle(
        GetTenantUsersQuery query, CancellationToken ct)
    {
        // TenantId is guaranteed to be present by the behavior
        return await _repository.GetByTenantAsync(_tenantContext.TenantId!, ct);
    }
}

The tenant behavior should be registered before the handler in the pipeline to ensure tenant validation happens early. Register it after authentication/authorization.

Multi-Tenancy

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