Context System

A thread safe, async safe context management system with built-in security boundaries for .NET applications.

Features

• Thread-Safe & Async-Safe - Built on AsyncLocal<T> for automatic context isolation
• Security Boundaries - Defensive copy pattern prevents untrusted code from accessing sensitive data
• Multi-Tenant Ready - Perfect for SaaS applications requiring tenant isolation
• Plugin-Friendly - Safe context exposure to third-party plugins
• Distributed Tracing - Built-in support for correlation IDs and trace context
• High Performance - Minimal overhead (~100ns per operation)

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Quick Start

using ModularityKit.Context.Abstractions;
using ModularityKit.Context.AspNet;

// 1. Define your context
public class MyContext : IContext
{
    public string Id { get; }
    public DateTimeOffset CreatedAt { get; }
    public string UserId { get; }
    public string TenantId { get; }
}

// 2. Register in DI
services.AddContext();

// 3. Use in your code
public class OrderService(IContextAccessor<MyContext> context)
{
    public void ProcessOrder()
    {
        var ctx = context.RequireCurrent();
        Console.WriteLine($"Processing for user: {ctx.UserId}");
    }
}

// 4. Execute with context
var context = new MyContext("ctx-1", "user-123", "tenant-456");

await contextManager.ExecuteInContext(context, async () =>
{
    orderService.ProcessOrder();
});

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🎯 Why Use Context System?

Without Context System ❌

public class OrderService
{
    // Passing context everywhere - painful!
    public async Task CreateOrder(string userId, string tenantId, string correlationId)
    {
        await ValidateOrder(userId, tenantId, correlationId);
        await ProcessPayment(userId, tenantId, correlationId);
        await SendEmail(userId, tenantId, correlationId);
    }
}

With Context System ✅

public class OrderService(IContextAccessor<MyContext> context)
{
    // Clean API - context flows automatically
    public async Task CreateOrder()
    {
        await ValidateOrder();   // Context flows automatically
        await ProcessPayment();
        await SendEmail();
    }
}

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Documentation

Getting Started

• Installation & Setup - Complete setup guide
• Basic Usage - Learn the fundamentals
• Core Concepts - Understanding the architecture

Guides

• Multi-Tenant Applications - Building SaaS applications

Reference

• API Reference - Complete API documentation
• Best Practices - Tips and recommendations

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Multi Tenant SaaS

public class DocumentService(IContextAccessor<MyContext> context)
{
    public async Task GetDocument(string documentId)
    {
        var ctx = context.RequireCurrent();
        
        // Automatic tenant filtering
        return await _db.Documents
            .Where(d => d.TenantId == ctx.TenantId)
            .Where(d => d.Id == documentId)
            .FirstOrDefaultAsync();
    }
}

Automatic tenant isolation using IContextAccessor ensures security and data separation.

See full example →

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Architecture

    Application Layer
        ├─ Trusted Code (Full Access)-> IContextAccessor<MyContext>
        └─ Untrusted Code (Read-Only) -> IContextAccessor<IReadOnlyContext>
                │
                ▼
    Context Infrastructure
        ├─ ContextStore (AsyncLocal)
        ├─ ContextAccessor
        └─ ContextManager
                │
                ▼
    Security Boundary
        └─ ReadOnlyContextSnapshot (Defensive Copy)

Learn more about architecture →

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Best Practices

DO ✅

• Create context per operation (request/job)
• Use RequireCurrent() when context is expected
• Let ExecuteInContext handle cleanup
• Treat contexts as immutable

DON'T ❌

• Share context across operations
• Mutate context properties
• Use Current without null check
• Store context in static fields

Read full best practices guide →

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API Reference

Core Interfaces

• IContext - Base context interface
• IContextAccessor<TContext> - Access current context
• IContextManager<TContext> - Manage context lifecycle

Extension Methods

• AddContext<TContext>() - Register context infrastructure
• AddReadOnlyContextAccessor<TContext>() - Register read-only accessor

View complete API reference →

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Built with ❤️ for .NET developers