Architecture — Technology Stack¶

Everything below is read from the five .csproj files and Startup.cs. All five projects target net6.0.

Platform¶

Component	Version	Notes
.NET	6.0	`<TargetFramework>net6.0</TargetFramework>` in all five projects
ASP.NET Core MVC	6.0	Classic `Program.cs` + `Startup.cs` hosting model, not minimal APIs
Entity Framework Core	6.0.15	SQL Server provider. *Lazy loading is not* enabled** — see the note below
Database	SQL Server	Two application databases plus a Hangfire store
Identity	ASP.NET Core Identity 6.0.15	`ApplicationUser`, EF stores, custom `ApplicationUserManager`
View engine	Razor with runtime compilation	`AddRazorRuntimeCompilation()` — views can be edited without a rebuild

Packages by purpose¶

Data & identity¶

Package	Version
`Microsoft.EntityFrameworkCore` · `.Relational` · `.SqlServer` · `.Proxies` · `.Design` · `.Tools`	6.0.15
`Microsoft.AspNetCore.Identity.EntityFrameworkCore` · `Microsoft.Extensions.Identity.Stores`	6.0.15
`Microsoft.AspNetCore.Authentication.JwtBearer`	6.0.15
`BCrypt.Net-Next`	4.0.2
`IdentityModel`	5.1.0

Passwords are hashed with BCrypt through a custom BCryptPasswordHasher rather than the Identity default. Note that it is not wired through DI: ApplicationUserManager's constructor assigns PasswordHasher = new BCryptPasswordHasher() directly, and the two services.AddTransient<BCryptPasswordHasher>() registrations in Startup.cs (the same line twice) are never resolved.

Lazy loading is referenced but never switched on

Microsoft.EntityFrameworkCore.Proxies is referenced, and the entity classes declare their navigation properties virtual as the proxy provider requires — but UseLazyLoadingProxies() is never called. Neither AddDbContext registration in Startup.cs enables it, and NKO_DBEntities1.OnConfiguring only calls ConfigureWarnings(...). Lazy loading is therefore off: an un-Included navigation property is null, not a database round-trip. Treat the package as part of R1-4 (referenced but unused), and assume every query must .Include(...) what it needs.

Background work — three schedulers¶

Package	Version	Used for
`Quartz.AspNetCore`	3.6.2	`UpdateNextUserJob` (daily 03:00) and `ExportHistoryJob`, wired in `Program.cs`
`Hangfire.Core` · `Hangfire.AspNetCore`	1.7.24	Fire-and-forget warehouse exports (`BackgroundJob.Enqueue`)
`Hangfire.SqlServer`	1.8.6	Job store — note the version gap against Hangfire 1.7.24
`Cronos`	0.7.1	Cron parsing for the hand-rolled `IHostedService` scheduler

Having three independent scheduling mechanisms in one application is unusual — see External Services.

Documents & reporting¶

Package	Version	Used for
`EPPlus`	6.1.3	Excel export — used in 9 files
`DocumentFormat.OpenXml`	2.19.0	Word/Office document generation
`Rotativa.AspNetCore`	1.2.0	PDF rendering via wkhtmltopdf — used in 22 files
`QRCoder`	1.4.1	QR codes on printed documents
`System.Drawing.Common`	6.0.0	Image handling — Windows-only from .NET 6 onward

AWS¶

Package	Version	Used for
`AWSSDK.S3`	3.7.103.21	Document storage behind `IS3ServiceHandler`
`AWSSDK.Core` · `AWSSDK.Extensions.NETCore.Setup`	3.7.x	SDK plumbing
`AWSSDK.SimpleNotificationService`	3.7.101.20	Registered in DI but never injected anywhere

Web & UI¶

Package	Version	Used for
`Microsoft.AspNetCore.Mvc.NewtonsoftJson`	6.0.15	JSON with reference-loop handling
`Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation`	6.0.14	Runtime view compilation
`X.PagedList` · `X.PagedList.Mvc.Core`	8.4.6 / 8.4.5	The `int? page` paging on every grid
`BuildBundlerMinifier`	3.2.449	Static asset bundling
`Microsoft.Extensions.FileProviders.Embedded`	5.0.8	Serving views embedded in `NKO.Shared`

SignalR ships in the framework and is added with services.AddSignalR(); the hub is mapped at /hub.

Referenced but not used¶

Five dependencies are declared and never exercised. They still restore, compile in and enlarge the deployment.

Package	Evidence
`Microsoft.EntityFrameworkCore.Proxies` 6.0.15	`UseLazyLoadingProxies()` appears nowhere in the solution, so the proxy provider is never activated despite the `virtual` navigation properties.
`Refit` 6.3.2 · `Refit.HttpClientFactory` 6.0.94	Zero Refit interfaces in the solution — no `[Get("…")]` / `[Post("…")]` attribute anywhere. Referenced by both `NKO.Main` and `NKO.Shared`; the only trace is a `using Refit;` in `Startup.cs`. Refit is not wired to anything.
`Twilio` 5.59.0	One stray `using Twilio.Rest.Proxy.V1.Service.Session;` in `ProvidersController.cs`. No SMS is ever sent.
`MailKit` 4.0.0 · `MimeKit` 4.0.0	Only `using` statements at the top of `EmailManager.cs`; the code below uses `System.Net.Mail.SmtpClient`.
`AWSSDK.SimpleNotificationService`	`IAmazonSimpleNotificationService` appears once — its own registration in `Startup.cs`. Nothing resolves it, yet it builds an authenticated SNS client at startup.

Tracked as R1-4 in Recommendations.

Version consistency¶

ASP.NET Core 2.2 packages inside a .NET 6 application

Five Microsoft.AspNetCore.* packages are pinned at 2.2.x alongside the 6.0.15 ones — Mvc.Core 2.2.5, Http.Abstractions 2.2.0, Identity 2.2.0, Mvc.ViewFeatures 2.2.0 and Mvc.Razor.ViewCompilation 2.2.0. On net6.0 these types come from the shared framework, so referencing the old standalone packages risks duplicate-type and assembly-load conflicts. This is R7-13 in Recommendations.

Smaller drifts in the same family: Mvc.Razor.RuntimeCompilation is 6.0.14 while everything else Microsoft is 6.0.15, and Hangfire.SqlServer 1.8.6 runs against Hangfire.Core 1.7.24.

Build & tooling¶

Solution: NKO.Main/ERP-System.sln
Startup project: NKO.Main/NKO.Main
EF tooling: Microsoft.EntityFrameworkCore.Tools + a local .config/dotnet-tools.json; migrations must be applied per context (-Context NKO_DBEntities1 / -Context WarehouseDBContext)
Configuration: appsettings.json — not committed. appsettings.example.json shows the shape: three connection strings, StorageConfigs (region / clientId / clientSecret), SysUrl, logging levels and ScheduledJobsSettings.