Omar Karmil

💡 .𝗡𝗘𝗧 𝐓𝐢𝐩 - 𝟯 𝗪𝗮𝘆𝘀 𝘁𝗼 𝗖𝗿𝗲𝗮𝘁𝗲 𝗖𝘂𝘀𝘁𝗼𝗺 𝗠𝗶𝗱𝗱𝗹𝗲𝘄𝗮𝗿𝗲 𝗶𝗻 𝗔𝗦𝗣.𝗡𝗘𝗧 𝗖𝗼𝗿𝗲 Want to run your own logic during the request pipeline? 🔥 Middleware in ASP.NET Core lets you plug in behaviors like logging, exception handling, or custom headers, all while keeping your app clean and modular. In this article, I walk through 3 different ways to create middleware: 1️⃣ Using a Request Delegate 2️⃣ Convention-Based Middleware 3️⃣ Factory-Based Middleware ✨ Each approach has its use case, and knowing them helps you build more flexible and maintainable applications. 👉 Read the full article here: https://lnkd.in/geb6qdqf 💬 What’s your preferred way of building middleware in .NET? Let’s discuss 👇 🧠 Let me know what you think — and don’t forget to subscribe to my newsletter .𝙉𝙀𝙏 𝙒𝙚𝙚𝙠𝙡𝙮 𝙏𝙞𝙥𝙨 𝙗𝙮 𝙋𝙤𝙤𝙧𝙣𝙖 to get more content like this delivered to your inbox! ♻️ If you found this helpful, consider reposting to help others in the community.  👉 Follow me, Poorna Soysa, and hit the 🔔 on my profile so you don’t miss upcoming .NET tips and deep dives. Thanks for reading — let’s keep learning .NET together!

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🚀 𝗦𝗶𝗺𝗽𝗹𝗶𝗳𝘆 .𝗡𝗘𝗧 𝗕𝗮𝗰𝗸𝗴𝗿𝗼𝘂𝗻𝗱 𝗧𝗮𝘀𝗸𝘀 𝗨𝘀𝗶𝗻𝗴 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲 Building background processes in .NET? 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲 is your go-to framework for managing background jobs 𝗿𝗲𝗹𝗶𝗮𝗯𝗹𝘆, 𝘀𝗰𝗮𝗹𝗮𝗯𝗹𝘆, 𝗮𝗻𝗱 𝘄𝗶𝘁𝗵 𝘇𝗲𝗿𝗼 𝗵𝗮𝘀𝘀𝗹𝗲. 🔧 𝗪𝗵𝘆 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲? Hangfire lets you run background tasks without writing custom threading code or managing your own workers. It handles: • ✅ Job queuing • 🔁 Retries • 💥 Error handling • 💾 Persistence • 📊 Real-time monitoring 🧱 𝗧𝘆𝗽𝗲𝘀 𝗼𝗳 𝗝𝗼𝗯𝘀 𝗶𝗻 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲: 1️⃣ 𝗙𝗶𝗿𝗲-𝗮𝗻𝗱-𝗙𝗼𝗿𝗴𝗲𝘁 – Run immediately in the background 2️⃣ 𝗗𝗲𝗹𝗮𝘆𝗲𝗱 𝗝𝗼𝗯 – Scheduled to run after a delay 3️⃣ 𝗥𝗲𝗰𝘂𝗿𝗿𝗶𝗻𝗴 𝗝𝗼𝗯 – Based on CRON schedules 4️⃣ 𝗖𝗼𝗻𝘁𝗶𝗻𝘂𝗮𝘁𝗶𝗼𝗻 𝗝𝗼𝗯 – Runs after another job completes 5️⃣ 𝗕𝗮𝘁𝗰𝗵 & 𝗕𝗮𝘁𝗰𝗵 𝗖𝗼𝗻𝘁𝗶𝗻𝘂𝗮𝘁𝗶𝗼𝗻 – Grouped or dependent jobs 📦 𝗖𝗼𝗿𝗲 𝗖𝗼𝗺𝗽𝗼𝗻𝗲𝗻𝘁𝘀: • 🖥️ 𝗗𝗮𝘀𝗵𝗯𝗼𝗮𝗿𝗱 – Real-time job monitoring • 🛢️ 𝗦𝘁𝗼𝗿𝗮𝗴𝗲 – SQL Server, Redis, PostgreSQL • 🔁 𝗥𝗲𝘁𝗿𝗶𝗲𝘀 – Built-in error handling • ⚙️ 𝗙𝗶𝗹𝘁𝗲𝗿𝘀 – Custom job behaviors • 📡 𝗦𝗰𝗮𝗹𝗮𝗯𝗶𝗹𝗶𝘁𝘆 – Works across multiple servers 📌 𝗪𝗵𝗲𝗻 𝘁𝗼 𝗨𝘀𝗲 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲? Use it when you need: • A full-featured 🖥️ monitoring dashboard • 💾 Persistence across app restarts • 🕒 Recurring jobs (CRON-style) • 🔁 Automatic retries + error logs • 🔗 Chained or dependent jobs • 🚀 Production-ready background workers ⚖️ 𝗔𝗹𝘁𝗲𝗿𝗻𝗮𝘁𝗶𝘃𝗲𝘀 𝘁𝗼 𝗛𝗮𝗻𝗴𝗳𝗶𝗿𝗲: 🔸 𝗤𝘂𝗮𝗿𝘁𝘇.𝗡𝗘𝗧 – Powerful scheduler, CRON-friendly 🔸 𝗖𝗔𝗣 – Event-based background processing 🔸 𝗠𝗮𝘀𝘀𝗧𝗿𝗮𝗻𝘀𝗶𝘁 + 𝗥𝗮𝗯𝗯𝗶𝘁𝗠𝗤 – Distributed message queues 🔸 𝗔𝘇𝘂𝗿𝗲 𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀 – Serverless background jobs 🔸 𝗪𝗼𝗿𝗸𝗲𝗿 𝗦𝗲𝗿𝘃𝗶𝗰𝗲 – Lightweight OS-level background tasks 📖 𝗥𝗲𝗮𝗱 𝘁𝗵𝗲 𝗮𝗿𝘁𝗶𝗰𝗹𝗲 👉 https://lnkd.in/dwb_vSb4 💻 𝗦𝗼𝘂𝗿𝗰𝗲 𝗖𝗼𝗱𝗲 👉 https://lnkd.in/dRnWurjt 💬 𝗪𝗵𝗮𝘁’𝘀 𝘆𝗼𝘂𝗿 𝗳𝗮𝘃𝗼𝗿𝗶𝘁𝗲 𝗯𝗮𝗰𝗸𝗴𝗿𝗼𝘂𝗻𝗱 𝗷𝗼𝗯 𝗳𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸 𝗶𝗻 .𝗡𝗘𝗧? 𝗟𝗲𝘁’𝘀 𝗱𝗶𝘀𝗰𝘂𝘀𝘀 👇 👉 Follow me (Kanaiya Katarmal) and hit the 🔔 on my profile so you don’t miss upcoming .NET tips and deep dives. 𝗧𝗵𝗮𝗻𝗸𝘀 𝗳𝗼𝗿 𝗿𝗲𝗮𝗱𝗶𝗻𝗴 𝗹𝗲𝘁’𝘀 𝗰𝗼𝗻𝘁𝗶𝗻𝘂𝗲 𝗴𝗿𝗼𝘄𝗶𝗻𝗴 𝗮𝗻𝗱 𝗹𝗲𝗮𝗿𝗻𝗶𝗻𝗴 .𝗡𝗘𝗧 𝘁𝗼𝗴𝗲𝘁𝗵𝗲𝗿! 👉 𝗦𝘂𝗯𝘀𝗰𝗿𝗶𝗯𝗲 𝘁𝗼 𝗺𝘆 𝗻𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿: https://lnkd.in/dp7tz_3V #𝗱𝗼𝘁𝗻𝗲𝘁 #𝗰𝘀𝗵𝗮𝗿𝗽 #𝗮𝘀𝗽𝗻𝗲𝘁𝗰𝗼𝗿𝗲 #𝗵𝗮𝗻𝗴𝗳𝗶𝗿𝗲 #𝗯𝗮𝗰𝗸𝗴𝗿𝗼𝘂𝗻𝗱𝗷𝗼𝗯𝘀 #𝗴𝗶𝘁𝗵𝘂𝗯 #𝗺𝗶𝗰𝗿𝗼𝘀𝗲𝗿𝘃𝗶𝗰𝗲𝘀 #𝗾𝘂𝗮𝗿𝘁𝘇𝗻𝗲𝘁 #𝗰𝗮𝗽 #𝗺𝗮𝘀𝘀𝘁𝗿𝗮𝗻𝘀𝗶𝘁

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Deadlock in Async Programming — Why it can still happen with async/await? Many developers assume that using async/await guarantees immunity from deadlocks. Unfortunately, that’s not always true — especially in UI applications (WinForms, WPF) or the legacy ASP.NET SynchronizationContext. The Problem: The most common mistake is calling an async method synchronously, like this: var result = GetDataAsync().Result; // or .Wait() What happens behind the scenes: The UI or request thread blocks, waiting for the async call to complete. The async method tries to resume on the same thread/context after the await. That thread is already blocked → Deadlock! The Solution Always use await instead of .Result or .Wait(). For library or non-UI code: var result = await GetDataAsync().ConfigureAwait(false); This prevents context capture, avoids deadlocks, and often improves performance. Pro Tips: In ASP.NET Core, there’s no SynchronizationContext by default → fewer deadlocks. In UI apps, never block the UI thread — keep async flow end-to-end. Use ConfigureAwait(false) consistently in reusable libraries. Have you ever run into a deadlock caused by Task.Result or Wait() in your projects? How did you solve it? #DotNet #CSharp #AsyncProgramming #Deadlock #Concurrency #Multithreading #SoftwareDevelopment #CodingBestPractices

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🔍 Understanding IEnumerable, ICollection and IList in C# The difference, use cases and why they matter 🚀 1️⃣ IEnumerable – The "Read-Only Tour Guide" 🚶‍♂️ 📌 What it is: Lets you go through a collection one item at a time, but you can’t change it. 📌 Analogy: Imagine going through a photo album 📷 — you can flip pages and view, but you can’t add or remove pictures. 📌 When to use: ✅ Looping over a list of items ✅ Fetching data from a database or API without modifying it 💻 Example: IEnumerable<string> languages = new List<string> { "C#", "Java", "Python" }; foreach (var lang in languages) { Console.WriteLine(lang); // Only reading } --- 2️⃣ ICollection – The "Editable Shelf" 📚 📌 What it is: Everything IEnumerable can do plus you can add, remove, and count items. 📌 Analogy: Think of a bookshelf 📚 where you can take books out, add new ones or count them. 📌 When to use: ✅ When you need CRUD (Create, Read, Update, Delete) operations on a collection ✅ When you care about knowing the total count 💻 Example: ICollection<string> languages = new List<string>(); languages.Add("C#"); languages.Add("Java"); languages.Remove("Java"); Console.WriteLine(languages.Count); // Can count items --- 3️⃣ IList – The "Exact Spot Organizer" 📦 📌 What it is: Everything ICollection can do plus you can access items by index like in an array. 📌 Analogy: A row of lockers 🏫 where you can go directly to Locker #3 and change what's inside. 📌 When to use: ✅ When you need direct access to elements by position ✅ When order and indexing matter 💻 Example: IList<string> languages = new List<string> { "C#", "Java", "Python" }; languages[1] = "JavaScript"; // Directly update by index Console.WriteLine(languages[0]); // Access first item --- 📊 Quick Comparison Table Feature IEnumerable ICollection IList 🔄 Iterate Items ✅ ✅ ✅ ➕ Add / Remove Items ❌ ✅ ✅ 📏 Count Items ❌ ✅ ✅ 🎯 Index Access ❌ ❌ ✅ --- 💡 Tip for Recruiters & Developers: IEnumerable = Best for read-only data iteration (low memory usage). ICollection = Best for managing a collection. IList = Best for ordered, index-based operations. --- 📢 If this helped you, hit 👍 & share with your dev network. Let’s make C# easier for everyone! 💙💻

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🚀 .NET Interview Tip of the Day Q: What is Dependency Injection (DI) in .NET and why is it important? Answer: Dependency Injection is a design pattern that helps create loosely coupled applications by injecting dependencies instead of creating them inside classes. 🔹 Without DI • Classes create their own dependencies → tight coupling. • Harder to test and maintain. 🔹 With DI • Dependencies are provided (injected) at runtime. • Achieves loose coupling and testability. In .NET Core / .NET 5+: • DI is built-in with IServiceCollection and IServiceProvider. Benefits: ✅ Easier Unit Testing ✅ More Maintainable Code ✅ Clear Separation of Concerns #DotNet #CSharp #AsyncAwait #CodingTips #InterviewPrep #DotNetDevelopers #SoftwareDevelopment #WebDevelopment #BackendDevelopment #CleanCode #SystemDesign #ProgrammingTips #TechCareers #Developers #CodingLife #TechCommunity #LearningInPublic #CodeNewbie #MicrosoftDotNet

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🚀 .NET Interview Q&A – Real-World Scenarios Are you preparing for a .NET developer role? Many interviews now focus on practical scenarios, not just syntax. Here are 5 scenario-based questions to test your readiness: 1️⃣ How would you handle a memory leak in a .NET application? ✅ Use profiling tools like dotMemory or PerfView. Analyze object retention paths, dispose unmanaged resources, and avoid static references where not needed. 2️⃣ How do you implement caching in a .NET web API? ✅ Use IMemoryCache or IDistributedCache in .NET Core. Consider sliding/absolute expiration and invalidation strategy. 3️⃣ What’s your approach to handling large file uploads in ASP.NET Core? ✅ Stream the file directly to disk or cloud storage using buffered or streamed request reading. 4️⃣ How do you design a scalable architecture for high-traffic .NET web apps? ✅ Apply principles like microservices, caching layers, async processing, and queue-based messaging (e.g., Azure Service Bus). 5️⃣ How would you troubleshoot high CPU usage in a live .NET app? ✅ Use dotnet-trace, analyze thread stacks, GC stats, and performance counters. 🔍 Interviews today require you to think like a system designer, not just a coder. 📩 Let me know if you'd like a PDF version or infographic of these Q&As! #DotNet #SoftwareEngineering #TechInterviews #BackendDev #DotNetCore #InterviewTips #CleanCode #SystemDesign #LinkedInLearning #CSharp

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⚡ Boot an ASP.NET Core app inside your tests ⚠️ The Problem Many teams spin up containers or rely on shared servers for integration tests. That slows tests down, adds flakiness, and requires infrastructure. ✅ The Solution Subclass WebApplicationFactory to create a reusable Test Application instead of using the WebApplicationFactory directly. This allows you to pack shared configuration and features in the Test Application, making your test suite easier to evolve. 🧠 Under the Hood WebApplicationFactory runs your app entirely in memory, while giving you an HttpClient bound to the test server. 🎯 The Result The Test Application pattern: - Real ASP.NET Core pipeline (middleware, DI, routing). - No ports, no containers, no infrastructure. - Clean code, configurable for each test, reusable across test cases. This pattern brings integration-test confidence with near-unit-test speed. A pattern I leveraged in my latest book. 💬 Would you swap containers for in-memory test apps in your setup? 💬 Are you already using WebApplicationFactory? 💬 What are your success/failure stories? This post continues my series on HttpClient & integration testing. It expands the original proxy testing article with bite-sized tips and new topics. (Link in comments 👇) #dotnet #testing #aspnetcore

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🚀 𝐖𝐡𝐚𝐭’𝐬 𝐭𝐡𝐞 𝐃𝐢𝐟𝐟𝐞𝐫𝐞𝐧𝐜𝐞 𝐁𝐞𝐭𝐰𝐞𝐞𝐧 ‘𝐔𝐬𝐞’, ‘𝐌𝐚𝐩’, 𝐚𝐧𝐝 ‘𝐑𝐮𝐧’ 𝐢𝐧 𝐀𝐒𝐏.𝐍𝐄𝐓 𝐂𝐨𝐫𝐞 𝐌𝐢𝐝𝐝𝐥𝐞𝐰𝐚𝐫𝐞? 🚀 ⁉️ 𝐄𝐯𝐞𝐫 𝐛𝐞𝐞𝐧 𝐜𝐨𝐧𝐟𝐮𝐬𝐞𝐝 𝐚𝐛𝐨𝐮𝐭 𝐰𝐡𝐞𝐧 𝐭𝐨 𝐜𝐡𝐨𝐨𝐬𝐞 𝐔𝐬𝐞, 𝐌𝐚𝐩, 𝐨𝐫 𝐑𝐮𝐧 𝐢𝐧 𝐀𝐒𝐏.𝐍𝐄𝐓 𝐂𝐨𝐫𝐞? Let’s break it down in a clear and simple way 👇 🧱 𝑾𝒉𝒂𝒕 𝒊𝒔 𝑴𝒊𝒅𝒅𝒍𝒆𝒘𝒂𝒓𝒆? In ASP.NET Core, middleware is a component that handles HTTP requests and responses. Each component can: Decide whether to pass the request to the next component in the pipeline. Perform actions before and/or after the next component executes. ⚙️ 𝑾𝒉𝒂𝒕 𝑨𝒓𝒆 𝑹𝒆𝒒𝒖𝒆𝒔𝒕 𝑫𝒆𝒍𝒆𝒈𝒂𝒕𝒆𝒔? Request delegates process HTTP requests and they’re configured using Use, Map, and Run. Here’s how they differ: 🔁 𝐔𝐬𝐞 – 𝐂𝐡𝐚𝐢𝐧 Use lets you chain multiple delegates together. You get a next parameter, and you can choose whether to call it or not. ✅ If you skip next(), the pipeline ends there — this is called short-circuiting. ⛔ 𝐑𝐮𝐧 – 𝐄𝐧𝐝 𝐭𝐡𝐞 𝐏𝐢𝐩𝐞𝐥𝐢𝐧𝐞 Run is a terminal middleware. It does not receive a next parameter and stops the pipeline when called. A̳n̳y̳ ̳m̳i̳d̳d̳l̳e̳w̳a̳r̳e̳ ̳r̳e̳g̳i̳s̳t̳e̳r̳e̳d̳ ̳a̳f̳t̳e̳r̳ ̳R̳u̳n̳ ̳w̳i̳l̳l̳ ̳n̳o̳t̳ ̳b̳e̳ ̳e̳x̳e̳c̳u̳t̳e̳d̳.̳ 🌳 𝐌𝐚𝐩 – 𝐁𝐫𝐚𝐧𝐜𝐡 𝐭𝐡𝐞 𝐏𝐢𝐩𝐞𝐥𝐢𝐧𝐞 If you need to branch the pipeline, you can use Map. What is branching?  It is used like a convention. For instance, if the request path starts with the given path, the branch is executed.   This is great for modularizing your app and handling specific routes differently. 💬 Which one do you use most often? And did you learn something new today? Let’s discuss in the comments 👇 #dotnet #aspnetcore #middleware #csharp #backend #webdevelopment #programming

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