Diamond.Core.AspNetCore.Swagger 10.1.1

Diamond.Core Patterns

Diamond.Core Patterns is a production-ready C# library that provides enterprise-grade implementations of common design patterns for .NET applications. Published as a suite of focused NuGet packages under the Diamond.Core.* namespace, it is authored by Daniel M. Porrey and targets .NET 10.0.

---

Table of Contents

• Overview
• NuGet Packages
• Getting Started
• Design Patterns
  • Repository
  • Unit of Work
  • Decorator
  • Specification
  • Rules Engine
  • Workflow / State Machine
  • Dependency Injection Extensions
  • Hosting Extensions
  • Command Line
  • ASP.NET Core Utilities
  • AutoMapper Extensions
  • Clonable
  • System Utilities
  • WPF Support
• Examples
• Design Philosophy
• Requirements
• License

---

Overview

Diamond.Core Patterns provides a cohesive set of 67 projects organized into 18 functional areas. Every pattern follows the same three-layer structure:

Diamond.Core.[Pattern].Abstractions    ← Interfaces and contracts only
Diamond.Core.[Pattern]                 ← Core implementation
Diamond.Core.[Pattern].[Provider]      ← Provider-specific (e.g., EntityFrameworkCore, SqlServer)

This separation ensures your application code can depend only on abstractions, keeping it testable and decoupled from implementation details.

---

NuGet Packages

All packages are published to NuGet.org and versioned at 10.1.0 (aligned with the .NET 10 target framework).

Core Abstractions

Package	Description
Diamond.Core.Abstractions	Shared interfaces used across all patterns

Repository

Package	Description
Diamond.Core.Repository.Abstractions	Repository interfaces (IReadOnlyRepository, IWritableRepository, etc.)
Diamond.Core.Repository	Core repository base classes
Diamond.Core.Repository.EntityFrameworkCore	EF Core repository implementation
Diamond.Core.Repository.DateTimeModel	DateTime-aware entity model base

Unit of Work

Package	Description
Diamond.Core.UnitOfWork.Abstractions	IUnitOfWork and IUnitOfWorkFactory interfaces
Diamond.Core.UnitOfWork	Unit of Work base implementation

Rules Engine

Package	Description
Diamond.Core.Rules.Abstractions	IRule, IRuleResult, IRulesFactory interfaces
Diamond.Core.Rules	RuleTemplate base class and engine

Workflow

Package	Description
Diamond.Core.Workflow.Abstractions	IWorkflowManager, IWorkflowItem, IContext interfaces
Diamond.Core.Workflow.State.Abstractions	State-based workflow interfaces
Diamond.Core.Workflow	Workflow engine implementation
Diamond.Core.Workflow.Steps	Built-in workflow step base classes

Decorator

Package	Description
Diamond.Core.Decorator.Abstractions	IDecorator interface and factory
Diamond.Core.Decorator	DecoratorTemplate base class

Specification

Package	Description
Diamond.Core.Specification.Abstractions	ISpecification<TResult> and ISpecification<TParameter, TResult> interfaces
Diamond.Core.Specification	Specification base classes with LinqKit support

Dependency Injection Extensions

Package	Description
Diamond.Core.Extensions.DependencyInjection.Abstractions	IDependencyFactory interface
Diamond.Core.Extensions.DependencyInjection	IServiceCollection extension methods
Diamond.Core.Extensions.DependencyInjection.EntityFrameworkCore	EF Core DI helpers
Diamond.Core.Extensions.DependencyInjection.SqlServer	SQL Server DI helpers
Diamond.Core.Extensions.DependencyInjection.PostgreSQL	PostgreSQL DI helpers
Diamond.Core.Extensions.DependencyInjection.MySql	MySQL DI helpers
Diamond.Core.Extensions.DependencyInjection.Sqlite	SQLite DI helpers
Diamond.Core.Extensions.DependencyInjection.Oracle	Oracle DI helpers
Diamond.Core.Extensions.DependencyInjection.Cosmos	Azure Cosmos DB DI helpers
Diamond.Core.Extensions.DependencyInjection.InMemory	In-memory database DI helpers

Hosting

Package	Description
Diamond.Core.Extensions.Hosting.Abstractions	IStartup and startup lifecycle interfaces
Diamond.Core.Extensions.Hosting	IHost / IHostBuilder extension methods

Command Line

Package	Description
Diamond.Core.CommandLine.Abstractions	ICommand, IRootCommand interfaces
Diamond.Core.CommandLine.Model	CLI option and argument models
Diamond.Core.CommandLine	System.CommandLine-based implementation

ASP.NET Core

Package	Description
Diamond.Core.AspNetCore.DoAction.Abstractions	IDoAction<TInputs, TResult> controller action interfaces
Diamond.Core.AspNetCore.DoAction	DoAction base implementation
Diamond.Core.AspNetCore.DataTables	DataTables server-side processing
Diamond.Core.AspNetCore.Rfc7807	RFC 7807 Problem Details support
Diamond.Core.AspNetCore.Hosting	ASP.NET Core hosting integration
Diamond.Core.AspNetCore.Swagger	Swagger / OpenAPI helpers

Other Utilities

Package	Description
Diamond.Core.AutoMapperExtensions	AutoMapper DI integration
Diamond.Core.Clonable.Abstractions	IObjectCloneFactory interface
Diamond.Core.Clonable	Base cloning implementation
Diamond.Core.Clonable.Microsoft	Microsoft serializer-based deep clone
Diamond.Core.Clonable.Newtonsoft	Newtonsoft.Json-based deep clone
Diamond.Core.Performance	Performance measurement utilities
Diamond.Core.System.Base36	Base36 encoding/decoding
Diamond.Core.System.Text	Text manipulation helpers
Diamond.Core.System.TemporaryFolder	Temporary folder lifecycle management
Diamond.Core.Wpf.Abstractions	WPF IWindow, IMainWindow interfaces
Diamond.Core.Wpf	WPF MVVM command helpers

---

Getting Started

Install the packages you need via the .NET CLI. It is recommended to reference only the *.Abstractions packages in your domain/business logic projects and reference the implementation packages in your composition root (startup project).

# Core abstractions
dotnet add package Diamond.Core.Abstractions

# Example: Repository pattern with EF Core
dotnet add package Diamond.Core.Repository.Abstractions
dotnet add package Diamond.Core.Repository.EntityFrameworkCore
dotnet add package Diamond.Core.Extensions.DependencyInjection.SqlServer

# Example: Rules engine
dotnet add package Diamond.Core.Rules.Abstractions
dotnet add package Diamond.Core.Rules

Basic Host Setup

using Diamond.Core.Extensions.Hosting;

IHost host = Host.CreateDefaultBuilder(args)
    .ConfigureDiamondCore()          // registers Diamond.Core services
    .ConfigureServices((ctx, services) =>
    {
        services.AddTransient<IMyRepository, MyRepository>();
        services.AddTransient<IMyRule, MyValidationRule>();
    })
    .Build();

await host.RunAsync();

---

Design Patterns

Repository Pattern

The Repository pattern separates data-access logic from business logic. The library provides read/write-separated interfaces and a full Entity Framework Core implementation.

Key interfaces (Diamond.Core.Repository.Abstractions):

public interface IReadOnlyRepository<TInterface> : IRepository<TInterface>
    where TInterface : IEntity
{
    Task<IEnumerable<TInterface>> GetAllAsync();
    Task<IEnumerable<TInterface>> GetAsync(Expression<Func<TInterface, bool>> predicate);
}

public interface IWritableRepository<TInterface> : IRepository<TInterface>
    where TInterface : IEntity
{
    Task<TInterface> AddAsync(TInterface item);
    Task<TInterface> UpdateAsync(TInterface item);
    Task<bool> DeleteAsync(TInterface item);
}

Implementing a repository with Entity Framework Core:

// 1. Define your entity interface
public interface IEmployeeEntity : IEntity
{
    string Name { get; set; }
    bool Active { get; set; }
}

// 2. Implement the entity
public class EmployeeEntity : IEmployeeEntity { ... }

// 3. Create the repository
public class EmployeeRepository
    : EntityFrameworkRepository<IEmployeeEntity, EmployeeEntity, MyDbContext>
{
    public EmployeeRepository(MyDbContext context, IEntityFactory<IEmployeeEntity> factory)
        : base(context, factory) { }

    protected override DbSet<EmployeeEntity> MyDbSet(MyDbContext context)
        => context.Employees;
}

// 4. Register in DI
services.AddTransient<IReadOnlyRepository<IEmployeeEntity>, EmployeeRepository>();

// 5. Use via IRepositoryFactory
IReadOnlyRepository<IEmployeeEntity> repo =
    await repositoryFactory.GetReadOnlyAsync<IEmployeeEntity>();

IEnumerable<IEmployeeEntity> active = await repo.GetAsync(e => e.Active);

---

Unit of Work Pattern

The Unit of Work pattern coordinates transactions that span multiple repositories or aggregates into a single atomic operation.

Key interfaces (Diamond.Core.UnitOfWork.Abstractions):

public interface IUnitOfWork<TResult, TSourceItem> : IUnitOfWork
{
    Task<TResult> CommitAsync(TSourceItem item);
}

Example usage:

// Define your unit of work
public class PromoteEmployeeUnitOfWork
    : IUnitOfWork<(bool Success, IEmployeeEntity Employee),
                  (int EmployeeId, string NewTitle, decimal PercentRaise)>
{
    public async Task<(bool, IEmployeeEntity)> CommitAsync(
        (int EmployeeId, string NewTitle, decimal PercentRaise) input)
    {
        // Retrieve, update, and save in a single transaction
    }
}

// Resolve and execute
var uow = await unitOfWorkFactory
    .GetAsync<(bool, IEmployeeEntity), (int, string, decimal)>(WellKnown.UnitOfWork.PromoteEmployee);

var (success, employee) = await uow.CommitAsync((employeeId, "Senior Engineer", 0.10m));

---

Decorator Pattern

The Decorator pattern wraps a subject to add behavior. Diamond.Core provides a generic decorator abstraction and factory for resolving decorators by key.

Key interfaces (Diamond.Core.Decorator.Abstractions):

public interface IDecorator<TDecoratedItem, TResult> : IDecorator
{
    TDecoratedItem Item { get; set; }
    Task<TResult> TakeActionAsync();
    Task<TResult> TakeActionAsync(TDecoratedItem item);
}

Implementing a decorator:

public class EmployeePromotionDecorator
    : DecoratorTemplate<IEmployeeEntity, (bool Success, IEmployeeEntity Result, string Message)>
{
    public EmployeePromotionDecorator(ILogger<EmployeePromotionDecorator> logger,
        IUnitOfWorkFactory uowFactory, IRulesFactory rulesFactory)
        : base(logger) { ... }

    protected override async Task<(bool, IEmployeeEntity, string)> OnTakeActionAsync(
        IEmployeeEntity employee)
    {
        // validate rules, execute unit of work, return result
    }
}

// Resolve via factory and execute
IDecorator<IEmployeeEntity, (bool, IEmployeeEntity, string)> decorator =
    await decoratorFactory.GetAsync<IEmployeeEntity, (bool, IEmployeeEntity, string)>(
        WellKnown.Decorator.EmployeePromotion);

var (ok, updated, message) = await decorator.TakeActionAsync(employee);

---

Specification Pattern

The Specification pattern encapsulates a query as an object. This keeps query logic out of repositories and controllers and makes it reusable and testable.

Key interfaces (Diamond.Core.Specification.Abstractions):

// No input parameters
public interface ISpecification<TResult> : ISpecification
{
    Task<TResult> ExecuteSelectionAsync();
}

// With input parameters
public interface ISpecification<TParameter, TResult> : ISpecification
{
    Task<TResult> ExecuteSelectionAsync(TParameter inputs);
}

Implementing a specification:

public class ActiveEmployeeIdsSpecification
    : SpecificationTemplate<IEnumerable<int>>
{
    public ActiveEmployeeIdsSpecification(IRepositoryFactory repositoryFactory)
        => this.RepositoryFactory = repositoryFactory;

    public override async Task<IEnumerable<int>> ExecuteSelectionAsync()
    {
        using IReadOnlyRepository<IEmployeeEntity> repo =
            await this.RepositoryFactory.GetReadOnlyAsync<IEmployeeEntity>();
        return (await repo.GetAsync(e => e.Active)).Select(e => e.Id);
    }
}

---

Rules Engine

The Rules Engine evaluates one or more business rules against a model, returning pass/fail results and error messages.

Key interfaces (Diamond.Core.Rules.Abstractions):

public interface IRule<TItem, TResult> : IRule
{
    Task<TResult> ValidateAsync(TItem item);
}

public interface IRule<TItem> : IRule<TItem, IRuleResult> { }

public interface IRuleResult
{
    bool Passed { get; set; }
    string ErrorMessage { get; set; }
}

Implementing a rule:

public class GoodStandingRule : RuleTemplate<IEmployeeEntity>
{
    // "EmployeePromotion" is the group key used to batch-evaluate all related rules
    public GoodStandingRule() : base(WellKnown.Rules.EmployeePromotion) { }

    protected override Task<IRuleResult> OnValidateAsync(IEmployeeEntity employee)
    {
        bool passed = !employee.HasRecentWarnings;
        return Task.FromResult<IRuleResult>(new RuleResult
        {
            Passed = passed,
            ErrorMessage = passed ? null : "Employee has recent disciplinary warnings."
        });
    }
}

// Evaluate all rules in a group
string failureMessage = await rulesFactory.EvaluateAsync(
    WellKnown.Rules.EmployeePromotion, employee);

---

Workflow / State Machine

The Workflow engine executes a series of ordered steps (each implementing IWorkflowItem) against a shared IContext. Two built-in managers control execution behavior:

• LinearCompleteWorkflowManager — runs all steps even if one fails
• LinearHaltWorkflowManager — stops on the first failed step

Key interfaces (Diamond.Core.Workflow.Abstractions):

public interface IWorkflowManager
{
    string ServiceKey { get; set; }
    IWorkflowItem[] Steps { get; }
    Task<bool> ExecuteWorkflowAsync(IContext context);
}

public interface IWorkflowItem
{
    int Ordinal { get; set; }
    string Name { get; set; }
    double Weight { get; set; }
    bool AlwaysExecute { get; set; }
    Task<bool> ExecuteStepAsync(IContext context);
}

Creating a workflow:

// Define the manager
public class OnboardingWorkflow : LinearHaltWorkflowManager
{
    public OnboardingWorkflow(ILogger<OnboardingWorkflow> logger,
        IWorkflowItemFactory stepFactory)
        : base(logger, stepFactory)
    {
        this.ServiceKey = WellKnown.Workflow.Onboarding;
    }
}

// Define a step
public class CreateAccountStep : WorkflowItemTemplate
{
    public override string Name => "Create User Account";
    public override int Ordinal => 1;

    protected override async Task<bool> OnExecuteStepAsync(IContext context)
    {
        string username = context.Properties.Get<string>("username");
        // ... create account ...
        return true;
    }
}

// Execute
IWorkflowManager workflow = await workflowFactory.GetAsync(WellKnown.Workflow.Onboarding);
bool success = await workflow.ExecuteWorkflowAsync(context);

---

Dependency Injection Extensions

Diamond.Core extends IServiceCollection with helpers for registering repositories and database contexts across all major EF Core providers.

// Register EF Core with SQL Server
services.AddDiamondSqlServer<MyDbContext>(options =>
    options.UseSqlServer(connectionString));

// Register EF Core with SQLite
services.AddDiamondSqlite<MyDbContext>(options =>
    options.UseSqlite(connectionString));

// Register EF Core with PostgreSQL
services.AddDiamondPostgreSQL<MyDbContext>(options =>
    options.UseNpgsql(connectionString));

// Supported providers: SqlServer, PostgreSQL, MySql, Sqlite, Oracle, Cosmos, InMemory

---

Hosting Extensions

Diamond.Core extends the generic host with a modular startup pipeline, enabling separate classes for each lifecycle phase.

Key interfaces (Diamond.Core.Extensions.Hosting.Abstractions):

public interface IStartupConfigureServices : IStartup
{
    void ConfigureServices(HostBuilderContext context, IServiceCollection services);
}

public interface IStartupConfigureLogging : IStartup
{
    void ConfigureLogging(HostBuilderContext context, ILoggingBuilder logging);
}

Usage:

IHost host = Host.CreateDefaultBuilder(args)
    .ConfigureDiamondCore()
    .Build();

---

Command Line

Built on top of System.CommandLine, this module provides a DI-friendly command abstraction with naming-convention binding.

// Implement a command
public class GreetCommand : ICommand
{
    public string Name => "greet";
    public string Description => "Greets a user by name";

    public async Task<int> ExecuteAsync(string name)
    {
        Console.WriteLine($"Hello, {name}!");
        return 0;
    }
}

---

ASP.NET Core Utilities

DoAction Pattern

Moves controller logic out of action methods into dedicated, DI-resolved action classes, keeping controllers thin.

// Define the action
public class GetEmployeeAction
    : IDoAction<int, IEmployeeEntity>
{
    public async Task<IControllerActionResult<IEmployeeEntity>> ExecuteActionAsync(int id)
    {
        IEmployeeEntity employee = await this.repository.GetByIdAsync(id);
        return employee is not null
            ? this.Ok(employee)
            : this.NotFound();
    }
}

// In the controller
[HttpGet("{id}")]
public async Task<IActionResult> GetEmployee(int id)
{
    IDoAction<int, IEmployeeEntity> action =
        await this.doActionFactory.GetAsync<int, IEmployeeEntity>(WellKnown.DoAction.GetEmployee);
    IControllerActionResult<IEmployeeEntity> result = await action.ExecuteActionAsync(id);
    return this.StatusCode(result.StatusCode, result.Result);
}

Other ASP.NET Core Packages

• Diamond.Core.AspNetCore.DataTables — Server-side processing for jQuery DataTables
• Diamond.Core.AspNetCore.Rfc7807 — Standardized error responses per RFC 7807
• Diamond.Core.AspNetCore.Swagger — Swagger/OpenAPI document configuration helpers

---

AutoMapper Extensions

Simplifies AutoMapper registration within the Diamond.Core DI container.

services.AddAutoMapper(typeof(MyMappingProfile).Assembly);
// Diamond.Core wires AutoMapper profiles discovered via DI

---

Clonable Pattern

Provides deep object cloning with pluggable serialization backends.

Key interface (Diamond.Core.Clonable.Abstractions):

public interface IObjectCloneFactory
{
    T CloneInstance<T>(T instance) where T : ICloneable;
}

Usage:

// Register the Newtonsoft.Json-backed implementation
services.AddNewtonsoftClonable();

// Clone an object
IEmployeeEntity copy = cloneFactory.CloneInstance(employee);

Available backends:

• Diamond.Core.Clonable.Newtonsoft — Newtonsoft.Json serialization
• Diamond.Core.Clonable.Microsoft — System.Text.Json serialization

---

System Utilities

Performance Measurement

IMeasureAction measure = serviceProvider.GetRequiredService<IMeasureAction>();
await measure.ExecuteAsync("LongOperation", async () =>
{
    await DoSomethingExpensiveAsync();
});

Base36 Encoding

string encoded = Base36.Encode(12345678L);  // "7CLZI"
long decoded   = Base36.Decode("7CLZI");    // 12345678

Temporary Folders

ITemporaryFolder folder = await tempFolderFactory.GetAsync();
// folder.Path is an auto-created temp directory
// folder is IDisposable — deletes itself on Dispose()

Text Utilities

Diamond.Core.System.Text provides string manipulation and formatting helpers used throughout the library.

---

WPF Support

Diamond.Core.Wpf and Diamond.Core.Wpf.Abstractions provide WPF-friendly DI integration including IWindow/IMainWindow interfaces, enabling window resolution from the DI container.

// Register main window
services.AddTransient<IMainWindow, MainWindow>();

// Resolve and show
IMainWindow window = serviceProvider.GetRequiredService<IMainWindow>();
((Window)window).Show();

---

Examples

The repository ships with fully working example projects under Src/Examples/:

Example	Description
Diamond.Core.Example.BasicConsole	Comprehensive console app demonstrating Repository, Rules, Unit of Work, Workflow, Decorator, and Specification patterns together using SQLite and SQL Server
Diamond.Core.Example.Web	ASP.NET Core web API using the DoAction pattern with EF Core
Diamond.Core.Example.Wpf	WPF application demonstrating DI-resolved windows and commands
Diamond.Core.Example.ConsoleCommand	Console app with System.CommandLine-based command routing
Diamond.Core.Example.AutoMapperDependency	AutoMapper + Diamond.Core DI integration
Diamond.Core.Example.DbContext	EF Core DbContext setup and multiple-provider configuration
Diamond.Core.Example.LoadServices	Scanning and auto-registering services from assemblies
Diamond.Core.Example.KeyedServices	Keyed / named service registration with the DI extensions

To run the BasicConsole example:

cd Src/Examples/Diamond.Core.Example.BasicConsole
dotnet run

---

Design Philosophy

1. Abstraction-first — every pattern ships a separate *.Abstractions package so application code can depend only on interfaces.
2. Database-agnostic repositories — the same repository pattern works across SQL Server, PostgreSQL, MySQL, SQLite, Oracle, Cosmos DB, and in-memory providers; the provider is selected at DI registration time.
3. Consistent extension-method DI setup — every pattern registers itself into IServiceCollection via fluent extension methods.
4. Template base classes — abstract base classes such as DecoratorTemplate, RuleTemplate, and WorkflowItemTemplate eliminate boilerplate, letting you focus on business logic.
5. Composed, not inherited — heavy use of the Decorator and Factory patterns composes behavior at runtime rather than through deep inheritance hierarchies.

---

Requirements

Requirement	Version
.NET SDK	10.0+
C#	13.0+
Entity Framework Core	compatible with .NET 10
AutoMapper (optional)	16.x

---

License

This library is licensed under the GNU Lesser General Public License v3.0 or later (LGPL-3.0-or-later).
See the LICENSE file for full details.

Copyright © Daniel Porrey 2019–2026