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European ASP.NET Core 9.0 Hosting - HostForLIFE :: Using.NET 9's New GUID

clock August 5, 2024 10:42 by author Peter

Unique identifying codes that ensure uniqueness are referred to as GUIDs (Globally Unique Identifier) and UIDs (Universally Unique Identifiers). They aren't precisely the same, though. In the realm of programming, the term UUID is used widely across many platforms, languages, and environments. Multiple iterations of the UUID standard are used to create distinct IDs. In the Microsoft ecosystem, UUIDs are referred to as GUIDs when they are utilized. This is a result of Microsoft using the UUID version 4 definition. Thus, GUID is included within the more general name UUID.

Why do we use GUID?
The most common use case for GUIDs is to identify unique records, components, or objects across different systems and databases. GUIDs can be used to identify unique records in databases, COM components (in the past), message identifiers in message queuing systems, session IDs and transaction IDs for session management, token identifiers in security and authentication scenarios, and so on.

Current Scenario

In C#, generating GUID is very simple, as shown below.
Guid g = Guid.NewGuid();
Console.WriteLine(g);

Problem
Although we have a guarantee that the GUID generated using the above code will always be unique, there are several use cases where this can be problematic.

Let’s create five different GUIDs.
Console.WriteLine(Guid.NewGuid());
Console.WriteLine(Guid.NewGuid());
Console.WriteLine(Guid.NewGuid());
Console.WriteLine(Guid.NewGuid());
Console.WriteLine(Guid.NewGuid());

Output
d61f4b57-31e9-4158-86a7-104c3cb16875
e7120f4f-bce1-488b-bdb3-4738793525bd
021baa3e-bf52-4d2e-8303-e1bdddea786b
c2e0c9f8-f04d-4d91-928e-cad5aca5b83f
96f8ae8c-808b-4fc1-a9b8-8e3066acdc50

As you can see from the above output, we cannot identify the order of GUIDs. This means we cannot sort on a field that stores GUIDs. This is essential if we store IDs in a database table and need to retrieve them in sorted order.

New Approach

The new approach is to use version 7 of UUID (instead of version 4) to generate GUIDs. Why version 7? Let’s discuss. If you refer to the original documentation of UUID Version 7, you will notice the description saying that it’s a time-ordered value field derived from the widely implemented and well-known Unix Epoch timestamp source, the number of milliseconds since midnight 1 Jan 1970 UTC, leap seconds excluded. Generally, UUIDv7 has improved entropy characteristics over UUIDv1 (Section 5.1) or UUIDv6 (Section 5.6).

The GUIDs have 5 parts (as you can see from the above example output). For UUID version 7, the first 48 bits (out of 128) will represent the Unix timestamp.

Basically, the IDs generated will be in order of time they generated. As a result, we will be able to sort columns storing GUIDs.
Console.WriteLine(Guid.CreateVersion7());
Console.WriteLine(Guid.CreateVersion7());
Console.WriteLine(Guid.CreateVersion7());
Console.WriteLine(Guid.CreateVersion7());
Console.WriteLine(Guid.CreateVersion7());


Output
5dad1927-6f23-4a07-a033-9dadae005ff7
5dad1927-6f23-4fe7-bfac-1f4dbbcd63ce
5dad1927-6f23-48ba-9044-99ba700770d5
5dad1927-6f23-481f-aa80-bbb32c54ec1c
5dad1927-6f23-4f8f-b639-bdff99b44b55

As you can see from the above output, the first few bits (“5dad1927–6f23”) are common, this is because they were created with the same timestamp. In fact, there is an overload of CreateVersion7 which can take the timestamp provider to control the timestamp.

var guid7 = Guid.CreateVersion7(timeProvider.GetUtcNow());


The advantages of using our own timestamp provider include the ability to provide past or future timestamps and using a DI container to provide our own fake provider.

An additional advantage is that we can always extract the date/time from the GUID if needed.

However, please note that from a performance perspective, version 7 takes longer than the existing version. So, if you are creating a large number of GUIDs, it's best to use the existing code and create another column for sorting.

Conclusion
We learned that GUID is an implementation of a specific version of UUID and is very specific to the Microsoft ecosystem. Further, starting from .NET 9, you can use GUIDs that can be sorted and created using a timestamp provider.



European ASP.NET Core 9.0 Hosting - HostForLIFE :: How to Generating PDFs in .NET Core Web API?

clock July 29, 2024 07:51 by author Peter

Web applications frequently need to generate PDF documents on the fly, whether they be invoices, certifications, reports, or some other kind of document. We'll go over how to use the iText7 library to generate PDFs in a.NET Core Web API in this tutorial. To illustrate how to generate a certificate PDF, we will develop a sample project.


Step 1: Create a project for your.NET Core Web API

Make a new project for a web API
To start a new Web API project, open a terminal or command prompt and type the following command.

dotnet new webapi -n PdfGenerationDemo
cd PdfGenerationDemo

Install Necessary NuGet packages
We will use iText7 for PDF generation. Install it using the following command.

dotnet add package itext7

Step 2. Create Your Models
Create a model to represent the data needed for the certificate. Add a new class CertificateModel.cs in the Models folder.
namespace PdfGenerationDemo.Models
{
    public class CertificateModel
    {
        public string Full_Name { get; set; }
        public string University_Name { get; set; }
        public string Mobile_Number { get; set; }
        public string Email { get; set; }
        public string CampName { get; set; }
        public string From_Date { get; set; }
        public string To_Date { get; set; }
        public string Description { get; set; }
        public string Duration { get; set; }
        public string Institute_Name { get; set; }
        public string Nss_Logo { get; set; }
        public string ProfileImageBase64 { get; set; }
    }
}


Step 3. Create Your Controller
Add a new controller CertificateController.cs in the Controllers folder.
using Microsoft.AspNetCore.Mvc;
using PdfGenerationDemo.Models;
using System;
using System.IO;
using System.Threading.Tasks;
using iText.Html2pdf;
using iText.Kernel.Pdf;
namespace PdfGenerationDemo.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class CertificateController : ControllerBase
    {
        [HttpPost]
        [Route("GenerateCertificate")]
        public async Task<IActionResult> GenerateCertificate([FromBody] CertificateModel request)
        {
            if (request == null)
            {
                return BadRequest("Invalid request data.");
            }

            try
            {
                byte[] pdfBytes = GeneratePDF(request);
                string base64String = Convert.ToBase64String(pdfBytes);

                return Ok(new { Success = true, PdfBase64 = base64String });
            }
            catch (Exception ex)
            {
                return StatusCode(500, $"Internal server error: {ex.Message}");
            }
        }
        private byte[] GeneratePDF(CertificateModel request)
        {
            string body = Template_Body(request);
            using (MemoryStream outputStream = new MemoryStream())
            {
                PdfWriter writer = new PdfWriter(outputStream);
                PdfDocument pdfDoc = new PdfDocument(writer);
                pdfDoc.SetDefaultPageSize(iText.Kernel.Geom.PageSize.A4);

                HtmlConverter.ConvertToPdf(body, pdfDoc);

                return outputStream.ToArray();
            }
        }
        private string Template_Body(CertificateModel request)
        {
            string logoBase64 = request.Logo;
            string photoBase64 = Convert.ToBase64String(Convert.FromBase64String(request.ProfileImageBase64));

            return $@"
<html>
<head>
    <style type='text/css'>
        body, html {{
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
            font-family: Georgia, serif;
        }}
        .container {{
            border: 15px solid #888;
            width: 90%;
            margin: 0 auto;
            padding: 20px;
            background-color: white;
            box-shadow: 0 0 10px rgba(0,0,0,0.5);
            text-align: center;
        }}
        .logo img {{
             width: 300px;
             margin-bottom: 15px;
        }}
        .marquee {{
            color: tan;
            font-size: 36px;
            margin: 10px 0;
        }}
        .assignment {{
            font-size: 20px;
            margin: 20px 0;
        }}
        .person {{
            border-bottom: 2px solid black;
            font-size: 24px;
            font-style: italic;
            margin: 20px auto;
            width: 80%;
            display: inline-block;
        }}
        .details {{
            font-size: 18px;
            margin: 20px 0;
        }}
        .photo img {{
            border: 1px solid #ddd;
            border-radius: 100%;
            padding: 0px;
            width: 150px;
        }}
        .reason {{
            margin: 20px 0;
            font-size: 18px;
        }}
        .signature {{
            margin-top: 50px;
            font-size: 18px;
        }}
        .signature .sig-line {{
            border-bottom: 1px solid black;
            width: 50%;
            margin: 20px auto;
        }}
        .footer {{
            font-size: 14px;
            color: #aaa;
            margin-top: 30px;
        }}
    </style>
</head>
<body>
    <div class='container'>
        <div class='logo'>
            <img src='data:image/png;base64,{logoBase64}' alt='Logo'>
        </div>
        <div class='marquee'>
            Certificate of NSS
        </div>
        <div class='assignment'>
            {request.University_Name}
        </div>
        <div class='assignment'>
            This certificate is presented to
        </div>
        <div class='photo'>
            <img src='data:image/jpeg;base64,{photoBase64}' alt='Student Photo'>
        </div>
        <div class='person'>
            {request.Full_Name}
        </div>
        <div class='details'>
            <p>Number: {request.Mobile_Number}</p>
            <p>Email: {request.Email}</p>
            <p>Camp Name: {request.CampName}</p>
            <p>Camp Time: {request.From_Date} To {request.To_Date}</p>
            <p>Description: {request.Description}</p>
        </div>
        <div class='reason'>
            For Participation in Camp of {request.Duration}  With College<br />
        </div>
       <div class='reason'>
               {request.Institute_Name}<br />
       </div>
        <div class='signature'>
            <p>Authorized Signature</p>
            <div class='sig-line'></div>
        </div>
        <div class='footer'>
            <p>© 2024 An Organization. All Rights Reserved.</p>
        </div>
    </div>
</body>
</html>";
        }
    }
}


Step 4. Testing the API
You can test the API using a tool like Postman. Here’s how you can do it.

Run Your Project
dotnet run

Get the Response

The response will contain a base64 encoded string of the generated PDF.

The response will contain a base64 encoded string of the generated PDF.


Conclusion
We have covered in this post how to use the iText7 library to generate PDFs in a.NET Core Web API. We went through how to set up the project, write the controller, create models, and test the API. This method can be expanded upon and altered to suit different use cases requiring the creation of dynamic PDFs.



European ASP.NET Core 9.0 Hosting - HostForLIFE :: How to Building a AI Chatbot with .NET Core?

clock July 23, 2024 08:21 by author Peter

Providing prompt and efficient communication is essential in the quickly changing digital world of today, particularly for educational platforms and technical blogs that serve programmers, students, and IT professionals. Similar to C# Corner, Codingvila is a technical blog that has made a name for itself as a place where computer enthusiasts can go to get help through tutorials, articles, and community assistance. The implementation of an AI chatbot can transform the way users engage with the platform and improve this support system. In order to provide real-time support and interactive learning opportunities, the "Codingvila Chatbot" makes use of.NET Core.

Why a Chatbot?

  • Instant Support: A chatbot can provide immediate answers to common queries, reducing wait times and improving user satisfaction.
  • Scalability: As the user base grows, a chatbot can effortlessly handle multiple queries at once, unlike human counterparts.
  • 24/7 Availability: It offers round-the-clock support, crucial for users in different time zones or those working on projects outside typical office hours.
  • Personalized Learning: The chatbot can recommend articles and tutorials based on the user's past interactions and preferences.
  • Community Engagement: By handling routine questions, the chatbot allows community managers to focus on more complex queries and community-building activities.

Setting Up the Project
Ensure you have the .NET Core SDK installed to begin. Set up a new project using the command line.
dotnet new console -n HostforlifeChatbot
cd HostforlifeChatbot

This creates a basic .NET Core console application which serves as the foundation for our chatbot.

Integrating Microsoft Bot Framework

Utilize Microsoft's Bot Framework for robust chatbot functionalities. Install the necessary packages.
dotnet add package Microsoft.Bot.Builder
dotnet add package Microsoft.Bot.Builder.Integration.AspNet.Core


These tools enable the use of advanced features like dialogues and conversation flows, essential for an interactive chatbot.
Creating the Bot
 
1. Bot Framework Setup
Implement the HostforlifeBot.cs to manage interactions.
using Microsoft.Bot.Builder;
using Microsoft.Bot.Schema;
using System.Threading.Tasks;

public class HostforlifeBot : IBot
{
    public async Task OnTurnAsync(ITurnContext turnContext, CancellationToken cancellationToken = default)
    {
        if (turnContext.Activity.Type == ActivityTypes.Message)
        {
            string userInput = turnContext.Activity.Text;
            string response = ProcessInput(userInput);
            await turnContext.SendActivityAsync(MessageFactory.Text(response), cancellationToken);
        }
    }

    private string ProcessInput(string input)
    {
        if (input.Contains("hello"))
        {
            return "Hello! Welcome to Hostforlife.com, How can I assist you today?";
        }
        else if (input.Contains("help"))
        {
            return "Here are some things you can ask me...";
        }
        else
        {
            return "I'm not sure how to help with that, but I'm learning more every day!";
        }
    }
}


2. Configure Services and Middleware
Adjust Startup.cs to set up services for the bot.
public void ConfigureServices(IServiceCollection services)
{
    services.AddBot<HostforlifeBot>(options =>
    {
        options.State.Add(new ConversationState(new MemoryStorage()));
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseDefaultFiles();
    app.UseStaticFiles();
    app.UseBotFramework();
}


Running the Chatbot
Execute the application
dotnet run

Your chatbot, "Hostforlife Chatbot" is now operational locally. It can be extended to support various platforms like Microsoft Teams, Slack, or Facebook Messenger.

Summary

The Hostforlife Chatbot, developed with .NET Core and Microsoft Bot Framework, is designed to enhance the educational resources of Hostforlife by providing an interactive, responsive, and engaging user experience. This AI-driven tool not only supports real-time communication but also encourages an interactive learning environment, making technology more accessible and comprehensible to its audience.

 



European ASP.NET Core 9.0 Hosting - HostForLIFE :: Authentication and Authorization in ASP.NET Core

clock July 17, 2024 08:49 by author Peter

Web application security relies heavily on authentication and authorization to make sure users are who they say they are and to control what actions they can do. Robust means for integrating authorization and authentication into your apps are provided by ASP.NET Core. We'll go into great detail about these ideas in this post, including key elements, recommended procedures, and real-world application examples.

Understanding Authentication and Authorization
Authentication verifies the identity of users attempting to access your application. It answers the question, "Who are you?" Common authentication methods include.

  • Cookie-based Authentication: Uses encrypted cookies to authenticate users.
  • Token-based Authentication: Utilizes JWT (JSON Web Tokens) or OAuth tokens for authentication.
  • External Authentication Providers: Allows users to log in using external providers like Google, Facebook, etc.
  • Windows Authentication: Uses Windows credentials for intranet applications.

Authorization, on the other hand, determines what authenticated users are allowed to do within the application. It answers the question, "What are you allowed to do?" Authorization can be role-based, policy-based, or claim-based, where.
Role-based Authorization: Assigns roles (admin, user, manager) to users and restricts access based on roles.
Policy-based Authorization: Defines access policies that evaluate a combination of roles, claims, and requirements.
Claim-based Authorization: Grants access based on specific claims associated with the user's identity.

Implementing Authentication in ASP.NET Core
Cookie Authentication: Cookie authentication is commonly used for web applications that require user sessions. ASP.NET Core provides built-in middleware to handle cookie-based authentication.
    // Startup.cs
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
            .AddCookie(options =>
            {
                options.Cookie.Name = "YourAppCookie";
                options.LoginPath = "/Account/Login";
                options.AccessDeniedPath = "/Account/AccessDenied";
            });
    }

Token-based Authentication: Token-based authentication is suitable for APIs and single-page applications (SPA). ASP.NET Core supports JWT (JSON Web Tokens) authentication out of the box.
// Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
        .AddJwtBearer(options =>
        {
            options.TokenValidationParameters = new TokenValidationParameters
            {
                ValidateIssuer = true,
                ValidateAudience = true,
                ValidateLifetime = true,
                ValidateIssuerSigningKey = true,
                ValidIssuer = Configuration["Jwt:Issuer"],
                ValidAudience = Configuration["Jwt:Issuer"],
                IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(Configuration["Jwt:Key"]))
            };
        });
}

Implementing Authorization in ASP.NET Core: Authorization is configured using policies and requirements. Define policies in Startup.cs and apply them using the [Authorize] attribute in controllers or actions.
// Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthorization(options =>
    {
        options.AddPolicy("AdminOnly", policy => policy.RequireRole("Admin"));
        options.AddPolicy("MinimumAge", policy =>
            policy.Requirements.Add(new MinimumAgeRequirement(18)));
    });
}
// Controller
[Authorize(Policy = "AdminOnly")]
public IActionResult AdminDashboard()
{
    return View();
}


Summary
In this article, we've explored the fundamentals of authentication and authorization in ASP.NET Core. Understanding these concepts is crucial for building secure and scalable web applications. ASP.NET Core provides flexible and powerful tools to implement various authentication and authorization mechanisms tailored to your application's needs. By leveraging these capabilities effectively, you can ensure that your application remains secure and compliant with modern security standards.

Implementing authentication and authorization involves configuring middleware, defining policies, and applying attributes correctly across your application. Whether you choose cookie-based authentication for web applications or token-based authentication for APIs, ASP.NET Core offers comprehensive support and flexibility to meet your security requirements.

By following best practices and staying updated with the latest security trends, you can build robust and secure ASP.NET Core applications that protect user data and maintain user trust.



European ASP.NET Core 9.0 Hosting - HostForLIFE :: Task: Synchronous vs. Asynchronous.Task and WaitAll.WhenEverything in.NET

clock July 9, 2024 07:09 by author Peter

Asynchronous programming in C# frequently entails doing several tasks at once. Task and Split are two popular approaches to managing many tasks.Task.WhenAll and WaitAll. Despite their apparent similarities, they have different functions and are employed in various contexts. The distinctions between Task.WaitAll and Task.WhenAll are examined in this article, along with real-world examples to show how to use both.


What is Task.WaitAll?
Assignment.The synchronous function WaitAll stops the calling thread after each of the supplied tasks is finished. It's helpful when you have to make sure that a group of tasks is completed before moving on, but it does so in a blocking way, meaning that Task is called by the thread.Until every task is completed, WaitAll is in use.

Example Usage of Task.WaitAll
using System;
using System.Threading.Tasks;
class Program
{
    static void Main()
    {
        Task task1 = Task.Run(() => PerformTask(1));
        Task task2 = Task.Run(() => PerformTask(2));
        Task task3 = Task.Run(() => PerformTask(3));
        Task.WaitAll(task1, task2, task3); // Blocks until all tasks complete
        Console.WriteLine("All tasks completed.");
    }
    static void PerformTask(int taskId)
    {
        Console.WriteLine($"Task {taskId} starting.");
        Task.Delay(1000).Wait(); // Simulate work
        Console.WriteLine($"Task {taskId} completed.");
    }
}


In this example, Task.WaitAll blocks the main thread until all three tasks are complete.

What is Task.WhenAll?

Task.WhenAll is an asynchronous method that returns a single task that is completed when all the provided tasks have been completed. Unlike Task.WaitAll, it does not block the calling thread. Instead, it allows the calling code to continue executing asynchronously.

Example Usage of Task.WhenAll

using System;
using System.Threading.Tasks;
class Program
{
    static async Task Main()
    {
        Task task1 = Task.Run(() => PerformTask(1));
        Task task2 = Task.Run(() => PerformTask(2));
        Task task3 = Task.Run(() => PerformTask(3));
        await Task.WhenAll(task1, task2, task3); // Waits for all tasks to complete asynchronously
        Console.WriteLine("All tasks completed.");
    }
    static void PerformTask(int taskId)
    {
        Console.WriteLine($"Task {taskId} starting.");
        Task.Delay(1000).Wait(); // Simulate work
        Console.WriteLine($"Task {taskId} completed.");
    }
}


In this example, Task.WhenAll allows the main method to await the completion of all tasks without blocking the calling thread.

Key Differences
Blocking vs. Non-blocking

  • Task.WaitAll: Blocks the calling thread until all tasks are complete.
  • Task.WhenAll: Returns a task that can be awaited, allowing the calling thread to continue execution asynchronously.

Return Type

  • Task.WaitAll: Does not return a value.
  • Task.WhenAll: Returns a Task that represents the completion of all provided tasks.

Usage Scenario

  • Task.WaitAll: Used when you need to block until tasks are complete, typically in non-UI or console applications.
  • Task.WhenAll: Used in asynchronous programming, especially in UI applications where blocking the main thread is undesirable.

Practical Use Cases
When to Use Task.WaitAll

  • In console applications where you need to ensure that certain tasks are completed before moving on.
  • When you are dealing with legacy code that doesn’t support async/await patterns.

When to Use Task.WhenAll

  • In UI applications keep the interface responsive.
  • In web applications handle multiple asynchronous operations without blocking the main thread.

Conclusion
Task.WaitAll and Task.WhenAll are essential tools in C# for handling multiple tasks. Use Task.WaitAll when you need to block the calling thread until tasks are complete, and Task.WhenAll for asynchronous waiting. Understanding their differences and appropriate use cases can help you write more efficient and responsive applications.



European ASP.NET Core 9.0 Hosting - HostForLIFE :: Resilience in a.NET 8 Web API Implementation

clock July 2, 2024 08:16 by author Peter

Creating robust APIs is more important than ever in the age of modern web development, especially with all these third-party integration we rely on. In this Blog, We will be guiding you how to introduce resilience in. Create an HTTP Client in a. Extensions. Http. Resilience library. In this section, we will take a look at features like setting up retry policies with exponential backoff and timeouts to make your API more resilient against the transient faults.

Step 1. Create a new. NET 8 Web API project Step First, if you have no existing Project then create new with. NET CLI dotnet new web or starting with the default Web API template.

Step 2. Install the Microsoft.AspNetCore. Extensions. Http. Resilience library via NuGet:
dotnet add package Microsoft.Extensions.Http.Resilience --version 8.0.0

Step 3. Configure Resilience in Program.cs
Modify the Program.cs file to set up HttpClient with resilience policies provided by Microsoft.Extensions.Http.Resilience. Here, we will define retry policies and timeouts.
//Add resilience pipeline
builder.Services.AddResiliencePipeline("default", x =>
{
    x.AddRetry(new Polly.Retry.RetryStrategyOptions
    {
        ShouldHandle = new PredicateBuilder().Handle<Exception>(),
        Delay = TimeSpan.FromSeconds(2),
        MaxRetryAttempts = 2,
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true
    })
    .AddTimeout(TimeSpan.FromSeconds(30));
});

Step 4. Use the Resilient HttpClient in a Service
Next, we'll inject and use the configured HttpClient in your Service. This example shows how to fetch data from an external API using the resilient HttpClient.
public class WeatherService
{
    private readonly HttpClient _httpClient;
    private readonly ResiliencePipelineProvider<string> _resiliencePipelineProvider;
    public WeatherService(HttpClient httpClient,
                         ResiliencePipelineProvider<string> resiliencePipelineProvider)
    {
        _httpClient = httpClient;
        _resiliencePipelineProvider = resiliencePipelineProvider;

    }
    public async Task<string> GetWeatherAsync()
    {
        var pipeline = _resiliencePipelineProvider.GetPipeline("default");
        var response = await pipeline
            .ExecuteAsync( async ct=> await _httpClient.GetAsync($"https://localhost:7187/weatherforecast",ct));

        return await response.Content.ReadAsStringAsync();
    }

}


Step 5. Add the endpoint in the Program.cs
app.MapGet("/weatherService/weather", async (WeatherService weatherService) =>
{
    var result = await weatherService.GetWeatherAsync();
    return result;
})
    .WithName("GetWeather")
    .WithOpenApi();


Step 6. Run the Application
Finally, run your application and navigate to the endpoint to see the resilient HttpClient in action.
References

Please refer to the below links for more details.

  • Building resilient cloud services with .NET 8
  • Learning from Microsoft

Conclusion
By following these steps, you have integrated resilience into your .NET 8 Web API project using Microsoft.Extensions.Http.Resilience library. The retry policies, circuit breaker settings, and timeouts will help ensure your API is robust against transient faults, improving its reliability and user experience.

 



European ASP.NET Core 9.0 Hosting - HostForLIFE :: Caching Strategies in Angular and .NET Core

clock June 25, 2024 08:07 by author Peter

One essential tactic for enhancing the scalability and performance of web applications is caching. Caching can be done in a variety of methods inside the frameworks of Angular (a client-side framework) and.NET Core (a server-side framework), each appropriate for a particular set of circumstances. The following are some typical caching techniques for both:

Angular Caching
Caching HTTP Requests with an HTTP Interceptor

  • To cache HTTP responses, use an HTTP interceptor. By delivering cached responses when appropriate, this can assist lower the amount of HTTP queries made to the server.
  • For instance. Construct an HTTP interceptor that looks through the cache before sending a network request, and a caching service that saves responses.
import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { tap } from 'rxjs/operators';
@Injectable()
export class CacheInterceptor implements HttpInterceptor {
  private cache = new Map<string, any>();
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    if (req.method !== 'GET') {
      return next.handle(req);
    }
    const cachedResponse = this.cache.get(req.url);
    if (cachedResponse) {
      return of(cachedResponse);
    }
    return next.handle(req).pipe(
      tap(event => {
        this.cache.set(req.url, event);
      })
    );
  }
}


Service Worker for Offline Caching
  • Use Angular's built-in service worker support to cache assets and API responses for offline access and faster load times.
  • Example. Enable the Angular service worker by running ng add @angular/pwa and configure caching in the ngsw-config.json file.
Local Storage or IndexedDB
Store data in the browser's local storage or IndexedDB for long-term caching. This can be useful for storing user preferences or large datasets that rarely change.
Example. Use Angular's localStorage or IndexedDB wrappers to store and retrieve data.
localStorage.setItem('key', JSON.stringify(data));
const cachedData = JSON.parse(localStorage.getItem('key'));

Caching in .NET Core
In-Memory Caching
Store cache data in the memory of the web server. This is useful for small amounts of data that change frequently.
Example. Use the IMemoryCache interface to cache data in memory.
public class MyService
{
    private readonly IMemoryCache _memoryCache;
    public MyService(IMemoryCache memoryCache)
    {
        _memoryCache = memoryCache;
    }
    public string GetData()
    {
        string cacheKey = "myCacheKey";
        if (!_memoryCache.TryGetValue(cacheKey, out string cachedData))
        {
            cachedData = "Data from database";
            _memoryCache.Set(cacheKey, cachedData, TimeSpan.FromMinutes(5));
        }
        return cachedData;
    }
}


Distributed Caching
  • Store cache data in a distributed cache like Redis or SQL Server. This is useful for data that needs to be shared across multiple servers.
  • Example. Use the IDistributedCache interface to cache data in Redis.
public class MyService
    {
        private readonly IDistributedCache _distributedCache;
        public MyService(IDistributedCache distributedCache)
        {
            _distributedCache = distributedCache;
        }
        public async Task<string> GetDataAsync()
        {
            string cacheKey = "myCacheKey";
            var cachedData = await _distributedCache.GetStringAsync(cacheKey);
            if (cachedData == null)
            {
                cachedData = "Data from database";
                await _distributedCache.SetStringAsync(cacheKey, cachedData, new DistributedCacheEntryOptions
                {
                    AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(5)
                });
            }
            return cachedData;
        }
    }

Response Caching Middleware
  • Cache HTTP responses at the server level to improve performance for subsequent requests.
  • Example. Configure response caching middleware in the Startup class.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddResponseCaching();
    }
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        app.UseResponseCaching();
        app.Use(async (context, next) =>
        {
            context.Response.GetTypedHeaders().CacheControl =
                new Microsoft.Net.Http.Headers.CacheControlHeaderValue()
                {
                    Public = true,
                    MaxAge = TimeSpan.FromSeconds(60)
                };
            await next();
        });
    }


Combining Angular and .NET Core Caching

To achieve optimal performance, you can combine caching strategies in Angular and .NET Core:

Client-Side Caching

Cache static assets and API responses in Angular using service workers or local storage.
Implement HTTP interceptors to cache responses and reduce server requests.

Server-Side Caching
Use in-memory or distributed caching in .NET Core to store frequently accessed data.
Implement response caching middleware to cache entire HTTP responses.

Conclusion
You can build a strong and effective caching strategy that greatly improves the efficiency and scalability of your Angular and.NET Core applications by utilizing both client-side and server-side caching.



European ASP.NET Core 9.0 Hosting - HostForLIFE :: How to Exploring the Experimental Attribute in C#?

clock June 20, 2024 13:52 by author Peter

In software development, the introduction of new features often involves a period of testing and feedback. During this period, developers need a way to indicate that certain features are not fully mature and may be subject to change. The Experimental attribute in C# serves this purpose by marking classes, methods, or other members as experimental. This blog will delve into what the Experimental attribute is, why it's useful, how to implement it, and provide detailed code snippets to illustrate its usage.


What is the Experimental Attribute?

The Experimental attribute is a custom attribute that can be applied to various members of your codebase (e.g., classes, methods, properties). It indicates that the marked feature is experimental, meaning it's in a testing phase and may undergo significant changes or might even be removed in future releases.
Why Do We Need It?

  • Communication: It communicates to other developers that the marked feature is not yet stable and should be used with caution.
  • Encapsulation: It helps encapsulate features that are still under development, making it easier to manage their lifecycle.
  • Documentation: It serves as a form of documentation, indicating the experimental nature directly in the code.


Implementing the Experimental Attribute
Step 1. Define the Experimental Attribute
First, you need to define the Experimental attribute. This is a simple custom attribute class.
using System;
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method | AttributeTargets.Property)]
public class ExperimentalAttribute : Attribute
{
    public string Message { get; }
    public ExperimentalAttribute(string message)
    {
        Message = message;
    }
}


Step 2. Applying the Experimental Attribute
You can apply the Experimental attribute to various parts of your codebase to indicate that they are experimental.
using System;
[Experimental("This class is experimental and may change in the future.")]
public class ExperimentalFeature
{
    [Experimental("This method is experimental and may change in the future.")]
    public void ExperimentalMethod()
    {
        Console.WriteLine("This is an experimental method.");
    }
    [Experimental("This property is experimental and may change in the future.")]
    public string ExperimentalProperty { get; set; }
}

Step 3. Using the Experimental Features
When using the experimental features, it’s important to handle them with care, knowing that their behavior might change.
public class Program
{
    public static void Main()
    {
        ExperimentalFeature feature = new ExperimentalFeature();
        feature.ExperimentalMethod();
        feature.ExperimentalProperty = "Testing";
        Console.WriteLine(feature.ExperimentalProperty);
    }
}


Detailed Explanation of Code Snippets
Defining the Attribute

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method | AttributeTargets.Property)]
public class ExperimentalAttribute : Attribute
{
    public string Message { get; }
    public ExperimentalAttribute(string message)
    {
        Message = message;
    }
}

  • [AttributeUsage]: Specifies the program elements to which the attribute can be applied. Here, it can be applied to classes, methods, and properties.
  • Constructor: Initializes the attribute with a message that provides additional context or warnings about the experimental feature.

Applying the Attribute
[Experimental("This class is experimental and may change in the future.")]
public class ExperimentalFeature
{
    [Experimental("This method is experimental and may change in the future.")]
    public void ExperimentalMethod()
    {
        Console.WriteLine("This is an experimental method.");
    }
    [Experimental("This property is experimental and may change in the future.")]
    public string ExperimentalProperty { get; set; }
}

  • Class Level: Marks the entire class as experimental.
  • Method Level: Marks a specific method within the class as experimental.
  • Property Level: Marks a property within the class as experimental.

Using the Experimental Features
public class Program
{
    public static void Main()
    {
        ExperimentalFeature feature = new ExperimentalFeature();
        feature.ExperimentalMethod();
        feature.ExperimentalProperty = "Testing";
        Console.WriteLine(feature.ExperimentalProperty);
    }
}


Creating an Instance: An instance of the ExperimentalFeature class is created and its experimental method and property are used. This is straightforward, but developers should be aware of the experimental status.

Conclusion

The Experimental attribute in C# is a powerful tool for marking features as experimental, providing clear communication to other developers about the stability and maturity of the code. By defining and applying this custom attribute, you can better manage the development and evolution of new features, ensuring that everyone involved in the project is aware of their experimental nature.

Using the Experimental attribute helps in documenting and encapsulating the experimental features effectively, making your codebase more maintainable and understandable. While the examples provided are simple, the approach can be scaled to larger and more complex projects, enhancing the overall development process.



European ASP.NET Core 8.0.1 Hosting - HostForLIFE :: How to Frozen Collections in .NET 8?

clock June 11, 2024 10:38 by author Peter

With the release of .NET 8, Microsoft has introduced several new features and improvements to enhance performance and developer productivity. Among these, one of the most notable additions is the concept of "Frozen Collections." This article explores what frozen collections are, their benefits, and how to use them effectively in your .NET applications.

Frozen Collections: What Are They?
A new kind of immutable collection called frozen collections is intended to improve access speed and reduce memory usage in order to maximize performance. Frozen collections are intentionally made to be immutable from the beginning, in contrast to conventional read-only collections, which are frequently nested inside changeable collections. Once a collection is frozen, its immutability ensures that it cannot be altered, which has various performance benefits.

Key Benefits of Frozen Collections
1. Performance Optimization
The primary advantage of frozen collections lies in their performance. By guaranteeing immutability, the .NET runtime can make several optimizations.

  • Memory Efficiency: Since frozen collections do not change, they can be stored in a compact form, reducing the overall memory footprint.
  • Access Speed: Lookup operations are faster because the underlying data structure can be optimized for read access.
  • Thread Safety: Frozen collections are inherently thread-safe, eliminating the need for synchronization mechanisms when accessing them concurrently.


2. Predictable Behavior
Immutable collections provide predictable behavior, which simplifies debugging and reasoning about code. When a collection is guaranteed not to change, developers can avoid common pitfalls related to concurrent modifications and side effects.

3. Simplified Code

Using frozen collections can lead to cleaner and more maintainable code. Since the collections cannot be altered, functions that operate on them do not need to account for modifications, leading to simpler and more readable implementations.

Using Frozen Collections in .NET 8
To use frozen collections in .NET 8, you can leverage the new FrozenCollection<T> class available in the System.Collections.Immutable namespace. Here’s a basic example to illustrate how to create and use a frozen collection.
using System;
using System.Collections.Immutable;

class Program
{
    static void Main()
    {
        var mutableList = new List<int> { 1, 2, 3, 4, 5 };

        // Create a frozen collection from the mutable list
        var frozenCollection = mutableList.ToFrozenCollection();

        // Attempting to modify the frozen collection will result in a compile-time error
        // frozenCollection.Add(6); // Not allowed

        // Accessing elements is fast and efficient
        Console.WriteLine(frozenCollection[0]); // Output: 1

        // The collection is inherently thread-safe
        Parallel.ForEach(frozenCollection, item => {
            Console.WriteLine(item);
        });
    }
}

public static class Extensions
{
    public static FrozenCollection<T> ToFrozenCollection<T>(this IEnumerable<T> source)
    {
        var builder = new FrozenCollectionBuilder<T>();
        foreach (var item in source)
        {
            builder.Add(item);
        }
        return builder.ToFrozenCollection();
    }
}

Creating a Frozen Collection
In the example above, we start with a mutable list of integers. Using an extension method, we convert this list into a FrozenCollection<T>. The FrozenCollectionBuilder<T> class is used to add elements to the collection before it is frozen.

Accessing Elements

Once the collection is frozen, we can access its elements just like a regular collection. However, any attempt to modify the collection will result in a compile-time error, ensuring immutability.

Thread Safety

The inherent thread safety of frozen collections allows for safe concurrent access without additional synchronization, making them ideal for use in multi-threaded environments.

Conclusion

Frozen collections in .NET 8 represent a significant advancement in collection management, providing developers with powerful tools to create high-performance, immutable data structures. By leveraging these collections, you can achieve better memory efficiency, faster access times, and simplified code. As .NET continues to evolve, features like frozen collections will play a crucial role in enabling developers to build robust and efficient applications.



European ASP.NET Core 8.0.1 Hosting - HostForLIFE :: Increasing Code Quality: The Best Methods for Successful Code Reviews

clock June 3, 2024 07:40 by author Peter

Clarify goals and expectations prior to starting a code review. Make sure that the review's goal is understood, whether it is to verify code quality, find errors, impart knowledge, or uphold coding standards. Establishing specific goals guarantees that reviewers concentrate on the most pertinent parts of the code and speeds up the review process.

Specify the codes
Specify recommended practices and coding standards that all developers should follow. This covers standards for code organization, formatting rules, naming conventions, and documentation. Adhering to coding standards consistently makes the codebase easier to read, maintain, and scale, which in turn makes it easier for developers to communicate and work together on code.

Conduct regular reviews
Regularly incorporate code reviews into the development process. Establish systems that enable peer reviews for each code update, such as pull requests or code review software. Frequent reviews guarantee that code quality is maintained at a high level throughout the development process, assist find problems early, and prevent the building of technical debt.

Keep reviews small and focused

Divide code modifications into more digestible, smaller pieces to enable targeted and effective assessments. Big code changes are frequently intimidating and prone to problems that go unnoticed. Smaller, more targeted evaluations allow reviewers to give more insightful criticism and developers to handle issues more skillfully.

Foster a collaborative culture

Encourage a cooperative and positive atmosphere when conducting code reviews. Urge reviewers to focus on the code rather than the developer and to offer constructive criticism in a courteous manner. Promote transparent communication, stimulate dialogue, and take use of evaluations as a means of imparting information and providing mentorship.

Automate where possible
Automate repetitive tasks and checks to streamline the code review process. Use automated tools for static code analysis, code formatting, and unit testing to identify common issues and enforce coding standards automatically. Automation reduces manual effort, improves consistency, and frees up time for reviewers to focus on higher-level concerns.

Prioritize feedback and follow-up

Prioritize feedback based on its severity, impact, and urgency. Address critical issues and blockers promptly to prevent delays in the development process. Keep track of feedback and action items, follow up on unresolved issues, and ensure that all feedback is addressed satisfactorily before closing the review.

Encourage learning and growth
View code reviews as opportunities for learning and professional growth. Encourage developers to seek feedback, ask questions, and engage in discussions to deepen their understanding of coding principles and best practices. Provide constructive feedback, mentorship, and guidance to help developers improve their skills and grow as professionals.



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