Stratara.Sessions 4.4.4

Stratara.Sessions

Derived. The behaviour described here is specified under openspec/specs/. Those specifications are the source; this page explains and illustrates them.

License: MIT.

Concrete session-context provider + ASP.NET Core middleware for Stratara's Actor/Subject session model. Reads tenant + user identity from JWT claims (with optional X-Tenant-Id / X-Client-Id header fallbacks), populates the ambient ISessionContextProvider, and exposes the Actor/Subject pair to every request.

Since 3.0.10: the X-Tenant-Id header fallback is opt-in via SessionContextOptions.AllowTenantHeader = true (default false). Without the gate, any authenticated principal could pick the tenant their request operated against in hosts whose JWT does not carry the tenant claim. Embed the tenant id in the JWT claim set, or opt in explicitly when an upstream platform-admin role check guards the header.

Quick start

// Program.cs / Startup.cs
builder.Services.AddSessionContext();

// In the middleware pipeline:
app.UseMiddleware<SessionContextMiddleware>();

Then resolve in any scoped service:

public sealed class SomeHandler(ISessionContextProvider sessionContextProvider)
{
    public async Task HandleAsync(...) {
        var session = sessionContextProvider.Current
            ?? throw new InvalidOperationException("Session context not set");

        // session.TenantId        = Subject (data owner) — used for filtering / encryption AAD
        // session.UserId          = Subject user (nullable)
        // session.ActorTenantId   = Actor (who triggered) — audit trail
        // session.ActorUserId     = Actor user — audit trail
    }
}

What's in the box

• SessionContextProvider — internal sealed impl of ISessionContextProvider, scoped per request. Writes Activity tags (correlation.id, causation.id, tenant.id, user.id) automatically on Set / Clear.
• SessionContextMiddleware — ASP.NET Core middleware that extracts tenant + user from ClaimTypes.NameIdentifier + stratara:tenant_id claim (with optional X-Tenant-Id header fallback gated by SessionContextOptions.AllowTenantHeader) and constructs a SessionContext whose actor tenant and data-owner tenant are the claimed tenant, whose actor user is the claimed user, and whose data-owner user is left unset. It stays unset on purpose: the scope a protected field is encrypted under follows the data owner, so filling in the user would move every protected field written from a request to a per-user scope.
• SessionContextOptions — configuration controlling the header fallback gate. AddSessionContext() reads it from the SessionContext section of the host's configuration; services.Configure<SessionContextOptions>(...) after that call takes precedence. Since 4.2.0 the section is read — an "AllowTenantHeader": true that did nothing before turns the fallback on.
• StrataraClaimTypes — claim-name constants (stratara:tenant_id).
• DefaultTenantIdentifier — sentinel Guid used when no tenant claim or header is present (typically anonymous / system flows).
• AddSessionContext() DI extension — registers the concrete provider as a scoped service against ISessionContextProvider.

Adopting the Actor/Subject model

For most operations the actor's tenant is the data-owner tenant — a user acts on their own tenant's data — while the data-owner user stays unset unless the application sets it. The tenants only diverge for:

• PlatformAdmin cross-tenant operations (Subject = customer tenant, Actor = admin tenant)
• Anonymous endpoints (Actor = Guid.Empty, Subject = the just-minted tenant)
• System / saga flows (Actor = SessionContext.SystemActorTenantId / SystemActorUserId)

Consumers that reject ambient context (libraries that prefer explicit TenantId parameters everywhere) do not need to take this package — Stratara.Mediator and the rest of the framework work without an ISessionContextProvider registered as long as no path requires it.

Dependencies

• Stratara.Abstractions — for ISessionContextProvider.
• Stratara.Contracts — for the SessionContext record (wire-level).
• Stratara.Diagnostics — for ApplicationDiagnostics activity tags.
• Microsoft.AspNetCore.Http.Abstractions — for HttpContext / RequestDelegate.
• Microsoft.Extensions.DependencyInjection.Abstractions.
• OpenTelemetry.Api.