Request context

ContextService is an AsyncLocalStorage-backed singleton — per-request isolation without request-scoped DI. ContextMiddleware populates it from headers.

Accessor	Source
userId	x-user-id header / JWT
tenant	x-tenant header
lang	accept-language / x-language (raw string; consumer parses to a locale)
token, user, permissions	filled by AuthGuard after JWT validation
hasPermission(code)	checks the synced permissions set
getCustom<T>(key)	reads a consumer value from ctx.custom

The library keeps only framework-generic keys. Domain values go in ctx.custom, or add typed fields via declaration merging:

declare module '@sdcorejs/nestjs/core' {
  interface RequestContext {
    departmentCode?: string;
    isSystemAdmin?: boolean;
  }
}

Configure which headers populate the context via SdCoreModule.forRoot({ context: { headers: { tenant: 'x-tenant', userId: 'x-user-id' } } }).