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Sérgio Rodrigues Loureiro shared thisMy previous post about C# abstract class vs interface was out-of-date and forgotten. Updating:
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Sérgio Rodrigues Loureiro shared thisAn offensive resume filled with nonsense landed a man 29 interviewsAn offensive resume filled with nonsense landed a man 29 interviews
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Sérgio Rodrigues Loureiro posted thisGood night. Given it is impossible for me answer to everybody and every message I received wishing me an Happy Birthday personally, I will send this generic message thanking you all for remembering such special date for me. Boa noite. Dado que me é impossível responder a toda a gente e a todas as mensagens que recebi a dar-me os Parabéns pessoalmente, vou enviar esta mensagem genérica a agracer-vos a todos por se lembrarem desta data especial para mim.
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Sérgio Rodrigues Loureiro posted thisNão páro muito para os lados do meu perfil aqui; mesmo assim, sendo impossível eu responder a todas as mensagens que cá me vieram dar os parabéns, quero deixar aqui o meu obrigado.
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Sérgio Rodrigues Loureiro shared thisBlockchain explicado pelo Miguel Sousa Tavares! 😂😂😂😂 https://lnkd.in/dc67u33Sérgio Rodrigues Loureiro shared this#Blockchain explicado 😱 Não sei como reagir a isto... Tenho todo o respeito pelo Miguel Sousa Tavares mas estou perplexo com esta peça.
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Sérgio Rodrigues Loureiro shared thishttps://lnkd.in/dRwgdQn
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Sérgio Rodrigues Loureiro posted thisObrigado todos/as que se lembraram de me dar os parabéns.
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Sérgio Rodrigues Loureiro replied to a comment
12h
Jason Schwartz M.Sc., GISP Another reason why Python sucks. In C++ for loops can actually be parallelized.
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Sérgio Rodrigues Loureiro liked thisSérgio Rodrigues Loureiro liked this💡𝐂#/.𝐍𝐄𝐓 𝐀𝐬𝐲𝐧𝐜 𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧 𝐓𝐢𝐩 🚀 💎𝐇𝐨𝐰 𝐚𝐧𝐝 𝐰𝐡𝐞𝐧 𝐭𝐨 𝐮𝐬𝐞 ‘𝐚𝐬𝐲𝐧𝐜’ 𝐚𝐧𝐝 ‘𝐚𝐰𝐚𝐢𝐭’ 💡 '𝐚𝐬𝐲𝐧𝐜' and '𝐚𝐰𝐚𝐢𝐭' keywords introduced in C# 5.0 were designed to make it easier to write asynchronous code, which can run in the background while other code is executing. The "async" keyword marks a method asynchronous, meaning it can be run in the background while another code executes. ⚡ When using 𝐚𝐬𝐲𝐧𝐜 and 𝐚𝐰𝐚𝐢𝐭 the compiler generates a state machine in the background. 🔥 Let's look at the other high-level details in the example; 🔸 𝐓𝐚𝐬𝐤<𝐢𝐧𝐭> 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 = 𝐋𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧𝐀𝐬𝐲𝐧𝐜(); starts executing 𝐋𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧. 🔸 Independent work is done on let's assume the Main Thread (Thread ID = 1) then 𝐚𝐰𝐚𝐢𝐭 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 is reached. 🔸 Now, if the 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 hasn't finished and it is still running, 𝐃𝐨𝐒𝐨𝐦𝐞𝐭𝐡𝐢𝐧𝐠𝐀𝐬𝐲𝐧𝐜() will return to its calling method, this the main thread doesn't get blocked. When the 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 is done then a thread from the ThreadPool (can be any thread) will return to 𝐃𝐨𝐒𝐨𝐦𝐞𝐭𝐡𝐢𝐧𝐠𝐀𝐬𝐲𝐧𝐜() in its previous context and continue execution (in this case printing the result to the console). ✅ A second case would be that the 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 has already finished its execution and the result is available. When reaching the 𝐚𝐰𝐚𝐢𝐭 𝐥𝐨𝐧𝐠𝐑𝐮𝐧𝐧𝐢𝐧𝐠𝐓𝐚𝐬𝐤 we already have the result so the code will continue executing on the very same thread. (in this case printing result to console). Of course this is not the case for in the example, where there's a 𝐓𝐚𝐬𝐤.𝐃𝐞𝐥𝐚𝐲(1000) involved. 🎯 𝐖𝐡𝐚𝐭 𝐝𝐨 𝐲𝐨𝐮 𝐭𝐡𝐢𝐧𝐤 𝐚𝐛𝐨𝐮𝐭 𝐚𝐬𝐲𝐧𝐜 𝐨𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧𝐬? #csharp #dotnet #programming #softwareengineering #softwaredevelopment
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Sérgio Rodrigues Loureiro liked thisSérgio Rodrigues Loureiro liked thisWhat's a breaking change for an API? Here are a few examples: - Removing or renaming APIs or API parameters - Changing the behavior of existing APIs - Changing the API error codes A breaking change means you need to version your API. Otherwise, you risk breaking existing consumers. Luckily, ASPNET Core makes it easy to introduce versioning. Check out this article on API Versioning: https://lnkd.in/dc62ZQFV Here's a hot take for you to ponder. Did we make a mistake as an industry with API versioning? P.S. If you want to learn how to build production-ready REST APIs using the latest ASPNET Core features and best practices, this is for you: https://lnkd.in/dU6Psx5t
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Sérgio Rodrigues Loureiro liked thisSérgio Rodrigues Loureiro liked this𝗖𝗹𝗲𝗮𝗻 𝗖𝗼𝗻𝗳𝗶𝗴 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 𝘄𝗶𝘁𝗵 𝗢𝗽𝘁𝗶𝗼𝗻𝘀 𝗣𝗮𝘁𝘁𝗲𝗿𝗻 You’re not writing clean ASP .NET Core code If you’re still doing this: 𝘷𝘢𝘳 𝘮𝘢𝘹𝘚𝘪𝘻𝘦 = 𝘊𝘰𝘯𝘧𝘪𝘨𝘶𝘳𝘢𝘵𝘪𝘰𝘯["𝘍𝘪𝘭𝘦𝘜𝘱𝘭𝘰𝘢𝘥:𝘔𝘢𝘹𝘚𝘪𝘻𝘦𝘉𝘺𝘵𝘦𝘴"]; This looks harmless. But in real systems, it creates: - Silent runtime errors - Magic strings everywhere - Zero validation - Painful refactoring One typo = production issue. Here is a real example Bad Approach: public class FileService(IConfiguration config) { public bool CanUpload(long fileSizeInBytes) { var maxSize = long.Parse(config["FileUpload:MaxSizeBytes"]); return fileSizeInBytes <= maxSize; } } With Options Pattern, you can rewrite in a clean way: 𝘱𝘶𝘣𝘭𝘪𝘤 𝘤𝘭𝘢𝘴𝘴 𝘍𝘪𝘭𝘦𝘜𝘱𝘭𝘰𝘢𝘥𝘚𝘦𝘵𝘵𝘪𝘯𝘨𝘴 { 𝘱𝘶𝘣𝘭𝘪𝘤 𝘭𝘰𝘯𝘨 𝘔𝘢𝘹𝘚𝘪𝘻𝘦𝘉𝘺𝘵𝘦𝘴 { 𝘨𝘦𝘵; 𝘴𝘦𝘵; } } 𝘱𝘶𝘣𝘭𝘪𝘤 𝘤𝘭𝘢𝘴𝘴 𝘍𝘪𝘭𝘦𝘚𝘦𝘳𝘷𝘪𝘤𝘦( 𝘐𝘖𝘱𝘵𝘪𝘰𝘯𝘴<𝘍𝘪𝘭𝘦𝘜𝘱𝘭𝘰𝘢𝘥𝘚𝘦𝘵𝘵𝘪𝘯𝘨𝘴> 𝘰𝘱𝘵𝘪𝘰𝘯𝘴) { 𝘱𝘶𝘣𝘭𝘪𝘤 𝘣𝘰𝘰𝘭 𝘊𝘢𝘯𝘜𝘱𝘭𝘰𝘢𝘥(𝘭𝘰𝘯𝘨 𝘧𝘪𝘭𝘦𝘚𝘪𝘻𝘦𝘐𝘯𝘉𝘺𝘵𝘦𝘴) { 𝘷𝘢𝘳 𝘮𝘢𝘹𝘚𝘪𝘻𝘦 = 𝘰𝘱𝘵𝘪𝘰𝘯𝘴.𝘝𝘢𝘭𝘶𝘦.𝘔𝘢𝘹𝘚𝘪𝘻𝘦𝘉𝘺𝘵𝘦𝘴; 𝘳𝘦𝘵𝘶𝘳𝘯 𝘧𝘪𝘭𝘦𝘚𝘪𝘻𝘦𝘐𝘯𝘉𝘺𝘵𝘦𝘴 <= 𝘮𝘢𝘹𝘚𝘪𝘻𝘦; } } In Program.cs, you can register your options model, setup fluent validation, and request to ValidateOnStart 𝘣𝘶𝘪𝘭𝘥𝘦𝘳.𝘚𝘦𝘳𝘷𝘪𝘤𝘦𝘴.𝘈𝘥𝘥𝘖𝘱����𝘪𝘰𝘯𝘴<𝘍𝘪𝘭𝘦𝘜𝘱𝘭𝘰𝘢𝘥𝘚𝘦𝘵𝘵𝘪𝘯𝘨𝘴>() .𝘉𝘪𝘯𝘥(𝘣𝘶𝘪𝘭𝘥𝘦𝘳.𝘊𝘰𝘯𝘧𝘪𝘨𝘶𝘳𝘢𝘵𝘪𝘰𝘯.𝘎𝘦𝘵𝘚𝘦𝘤𝘵𝘪𝘰𝘯("𝘍𝘪𝘭𝘦𝘜𝘱𝘭𝘰𝘢𝘥")) .𝘝𝘢𝘭𝘪𝘥𝘢𝘵𝘦(𝘹 => 𝘹.𝘔𝘢𝘹𝘚𝘪𝘻𝘦𝘉𝘺𝘵𝘦𝘴 > 0) .𝘝𝘢𝘭𝘪𝘥𝘢𝘵𝘦𝘖𝘯𝘚𝘵𝘢𝘳𝘵(); What changed? - No magic strings - Strong typing - Centralized config - Validation at startup - Cleaner, testable code This way you catch config issues before your app starts. Not after your users complain. Options Pattern is not “nice to have”. It’s the difference between: Code that survives production And code that breaks silently Where are you still using raw IConfiguration today? --------------------- ♻️ Repost if you think this is useful ➕ Follow me ( Aram Tchekrekjian ) to improve your .NET Skills 🔔 Turn on the notifications
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Sérgio Rodrigues Loureiro liked thisSérgio Rodrigues Loureiro liked this🚀 Your API works locally… …but will it survive real-world traffic? 👀 Most .NET developers build APIs… but very few build production-ready APIs 😬 Let’s fix that 👇 ⚡ ASP.NET Core API Best Practices (Real-World) 🔹 1. Use Proper Status Codes 👉 200, 201, 400, 404, 500 👉 Makes your API predictable 🔹 2. Validate Everything 👉 Never trust client input 👉 Use FluentValidation or DataAnnotations 🔹 3. Use DTOs (Always) 👉 Don’t expose EF Core entities 👉 Keep request/response clean 🔹 4. Global Exception Handling 👉 Handle errors in one place 👉 Return consistent responses 🔹 5. Logging (Structured) 👉 Log important events only 👉 Use Serilog / built-in logging 🔹 6. Version Your APIs 👉 /api/v1/products 👉 Avoid breaking existing clients 🔹 7. Secure Your API 👉 Authentication + Authorization 👉 Never expose sensitive data ⚡ Production Rule 👉 If your API breaks → users leave 👉 If your API is stable → users trust 🔥 Why this matters? ❌ No standards → messy APIs ❌ Poor handling → production issues ✔ Best practices → reliable systems ✔ Clean APIs → long-term scalability #dotnet #aspnetcore #webapi #backenddeveloper #csharp #softwaredevelopment #cleanarchitecture
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Sérgio Rodrigues Loureiro liked this⚡ 3 async/await mistakes I see in almost every .NET codebase I review. Each one silently kills your app's performance — or worse, causes deadlocks with zero obvious error. Mistake 1 — async void Exceptions disappear into thin air. Your app crashes and you have no idea why. Always return Task. Mistake 2 — .Result and .Wait() Blocking on async in ASP.NET is a deadlock waiting to happen. Go async all the way down — no exceptions. Mistake 3 — await inside a loop 10 calls × 200ms = 2 seconds. Use Task.WhenAll() and run them in parallel. Same result in 200ms. These three fixes alone can cut your API response times by 60-80%. Which one have YOU been guilty of? 👇 No judgment — we've all been there! 😄 🔗 Follow Asma Shaikh for weekly .NET, C# & Azure tips from real production systems. #csharp #dotnet #asyncawait #performance #dotnet9 #backend #cleancode #devtips #programming #microsoft
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Sérgio Rodrigues Loureiro liked thisSérgio Rodrigues Loureiro liked this💡 𝗖#/.𝗡𝗘𝗧 - 𝐑𝐞𝐭𝐮𝐫𝐧 𝐓𝐲𝐩𝐞 𝗧𝗶𝗽 🔥 💎 𝗥𝗲𝘁𝘂𝗿𝗻 𝗮𝗻 𝗲𝗺𝗽𝘁𝘆 𝗰𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻 𝗶𝗻𝘀𝘁𝗲𝗮𝗱 𝗼𝗳 𝗻𝘂𝗹𝗹 💡 𝗪𝗵𝘆 𝘁𝗵𝗶𝘀 𝗺𝗮𝘁𝘁𝗲𝗿𝘀 Returning null from collection methods forces callers to add defensive null checks before every iteration. This creates code clutter and opens the door to NullReferenceException when those checks are forgotten. ✅ 𝗧𝗵𝗲 𝗯𝗲𝘁𝘁𝗲𝗿 𝗮𝗽𝗽𝗿𝗼𝗮𝗰𝗵 Return an empty collection instead. It's memory-efficient (singleton instance), allows safe iteration without null checks, and follows Microsoft's official Framework Design Guidelines for .NET 10. 🔥 𝗕𝗲𝘀𝘁 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗲𝘀 𝗶𝗻 .𝗡𝗘𝗧 𝟭𝟬 ◾ For IEnumerable: Enumerable.Empty<T>() or []. ◾ For arrays: Array.Empty<T>() or [] ◾ For lists: new List<T>(). ◾ Modern C# 12+: Use collection expressions [] (IDE0301 analyzer recommends this). 🤔 𝗪𝗵𝗶𝗰𝗵 𝗮𝗽𝗽𝗿𝗼𝗮𝗰𝗵 𝗱𝗼 𝘆𝗼𝘂 𝘂𝘀𝗲? #csharp #dotnet #programming #softwareengineering #softwaredevelopment
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