Hany Ouf

  Understanding the C4 Model for Software Architecture The C4 Model is a structured approach to visualizing and documenting software architecture. Created by Simon Brown , it organizes system design into four hierarchical levels: Context, Container, Component, and Code . This model helps both technical and non-technical stakeholders understand the structure of a system at varying levels of detail. Why Use the C4 Model? Traditional UML (Unified Modeling Language) diagrams can be complex and difficult to maintain. The C4 Model simplifies architectural descriptions, making them more accessible and easier to manage. It allows teams to: ✅ Clearly communicate architecture across different roles. ✅ Maintain flexibility across monolithic and microservices-based architectures. ✅ Focus on essential details without unnecessary complexity. The Four Levels of the C4 Model with Sample Diagrams 1. Context Diagram (High-Level Overview) Purpose : Shows how the system fits within its e...

Cell-Based Architecture: A Scalable Approach to System Design Introduction In modern computing, system architecture plays a crucial role in ensuring efficiency, scalability, and reliability. One such architectural paradigm that has gained attention is Cell-Based Architecture (CBA). This approach enhances modularity, fault tolerance, and performance, making it ideal for complex distributed systems. This article explores the principles, benefits, and applications of Cell-Based Architecture, providing insights into how it improves system design in various industries. What is Cell-Based Architecture? Cell-Based Architecture is a decentralized system design approach in which a system is divided into independent, self-contained units called cells. Each cell functions autonomously, handling a subset of the system’s overall workload. Cells can communicate with each other but do not share dependencies that could create bottlenecks or single points of failure. Each cell typically includes: Proce...

  Building Resilient .NET Applications with Resilience Pipelines In modern software development, applications must be resilient to failures, network issues, and unexpected downtimes. The Resilience Pipelines introduced in .NET offer a structured way to implement fault tolerance and improve system stability. This article explores the concept of resilience pipelines, their benefits, and how to implement them using the Polly resilience library in .NET. What Are Resilience Pipelines? A resilience pipeline is a structured approach to handling transient failures in distributed systems. It consists of multiple resilience strategies , such as: Retry: Automatically retrying failed requests. Circuit Breaker: Preventing excessive failures by stopping requests for a period. Timeouts: Limiting the time a request can take before failing. Fallbacks: Providing alternative responses in case of failure. These strategies are combined into a pipeline to ensure robust failure handling...

  Polling vs. SignalR: A Detailed Comparison Both Polling and SignalR are techniques used to fetch or receive real-time updates from a server, but they work differently. Here’s a comprehensive comparison to help you choose the right approach. 1. Overview 2. How They Work Polling The client repeatedly sends requests at fixed intervals (e.g., every 5 seconds). The server responds with data (whether there are changes or not). If no new data, the response is wasted network traffic . 🔹 Example (Polling in .NET Core) public async Task<List<Message>> PollMessagesAsync() { using var httpClient = new HttpClient(); var response = await httpClient.GetAsync("https://api.example.com/messages"); return await response.Content.ReadAsAsync<List<Message>>(); } Problem: If data updates once every minute , but polling occurs every 5 seconds , that’s 11 wasted requests before useful data arrives. SignalR The client establishes a pers...

  Polling in Software Systems Polling is a technique where a system repeatedly checks for changes or new data at regular intervals . It is often used when event-driven notifications (e.g., WebSockets, SQL Server notifications) are not available or feasible. 1. Types of Polling a) Regular Polling (Fixed Interval) The system checks for updates at a fixed time interval (e.g., every 10 seconds). Simple to implement but can cause unnecessary load if updates are infrequent. 🔹 Example: A background service in .NET Core checking for new database records every minute. public class PollingService : BackgroundService { private readonly ILogger<PollingService> _logger; public PollingService(ILogger<PollingService> logger) { _logger = logger; } protected override async Task ExecuteAsync(CancellationToken stoppingToken) { while (!stoppingToken.IsCancellationRequested) { _logger.LogInformation("Checking fo...

  If you cache a SQL Server table in .NET Core , you need a way to refresh the cache when data changes. There are several approaches to achieve this: 1. Using SQL Server Query Notifications (SqlDependency) Best for: Applications that need real-time cache updates with minimal overhead. How It Works SQL Server notifies your application when data changes, so you can refresh the cache. Uses SqlDependency to listen for changes. Requires Service Broker to be enabled in SQL Server. Implementation Steps Step 1: Enable Service Broker in SQL Server Run this SQL command: ALTER DATABASE YourDatabase SET ENABLE_BROKER; Step 2: Configure SQL Dependency Install the necessary package: dotnet add package Microsoft.Data.SqlClient Step 3: Implement Caching with Notifications using Microsoft.Data.SqlClient; using Microsoft.Extensions.Caching.Memory; public class ProductCacheService { private readonly IMemoryCache _cache; private readonly string _connectionString; ...

🎯 Decorator Design Pattern – بالبلدي كده الـ Decorator Pattern هو واحد من الـ Structural Design Patterns فكرته ببساطة إنه بيسمحلك تزود سلوك (Behavior) على Object معيّن في وقت التشغيل (Runtime) من غير ما: تعدّل في الكلاس الأصلي ولا تعمل inheritance على الفاضي وده بيحصل عن طريق إنك تلفّ الـ object جوه object تاني (الـ Decorator) يزوّد له شغل إضافي. يعني بدل ما تغيّر العربية نفسها، بتزوّد لها إكسسوارات 😄 ⏰ نستخدم Decorator إمتى؟ نستخدمه لما: تكون محتاج تزود شغل على object من غير ما تغيّر الكود الأصلي الوراثة (Inheritance) تعملك انفجار كلاسّات وصعوبة صيانة تكون محتاج تركيبات مختلفة من السلوك تتضاف وتشيلها وقت التشغيل 🧩 مكوّنات Decorator Pattern 1️⃣ Component Interface أو Abstract Class بيحدد الـ contract المشترك 2️⃣ Concrete Component التنفيذ الأصلي ده الـ object الأساسي اللي عايز تزود عليه شغل 3️⃣ Decorator كلاس abstract بيلفّ الـ Component ممكن يغيّر أو يزوّد سلوكه 4️⃣ Concrete Decorator التنفيذ الفعلي بيضيف وظيفة جديدة، وفي نفس الوقت بينادي...