Implementing JWT Authentication in .NET Core

JWT (JSON Web Token) is a popular way to implement secure authentication in modern web applications. It provides a lightweight and stateless mechanism to authenticate users, ensuring secure data transfer. In this blog post, we’ll explore how to implement JWT authentication in a C# ASP.NET Core application with a step-by-step example.

What is JWT?

A JWT is a token that is used to securely transmit information between two parties (client and server). It is digitally signed, ensuring that the data it contains can be trusted. JWT consists of three parts:

1. Header: Specifies the algorithm used to generate the signature, typically HMAC SHA256 or RSA.
2. Payload: Contains the claims or the data being transmitted (such as user ID, roles, etc.).
3. Signature: Ensures that the token hasn’t been tampered with.

The general structure looks like this:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1bmlxdWVfbmFtZSI6InVzZXIwMSIsIm5iZiI6MTczMTIxMDQ4OCwiZXhwIjoxNzMxMjExNjg4LCJpYXQiOjE3MzEyMTA0ODh9.2adOgvFCgF4FfzwWS3VbT-AOUvXvwwMmI76HrdTXFW4

Why JWT?

• Stateless: No need to store sessions on the server.
• Scalable: The server doesn’t need to store or retrieve session information.
• Cross-domain: JWT can be easily used across different domains, making it ideal for distributed applications like microservices.

Forms in Angular - A Comprehensive Guide to Building Reactive and Template-Driven Forms

Forms are a fundamental part of any web application, enabling users to interact with the app, provide information, and submit data. In Angular, forms can be implemented using two main approaches: Template-driven and Reactive forms. Each approach has unique benefits, so understanding how to use them effectively can elevate your Angular app development.

In this post, we'll dive into the following:

1. Template-driven forms
2. Reactive forms
3. Form validation
4. Comparing the two approaches

1. Template-Driven Forms

Template-driven forms in Angular rely heavily on Angular's two-way data binding. They’re built directly in the HTML template using directives like ngModel. Template-driven forms are ideal for simpler forms and are particularly helpful when you don’t need to programmatically control form behavior.

Angular Signals : A Practical Guide with Examples

Angular 17 recently introduced the concept of Signals to improve reactivity and simplify state management. Signals allow Angular applications to handle state changes in a more predictable, efficient, and declarative way. This blog will cover what Signals are, why they matter, and how to use them with practical examples.

What are Signals?

In Angular, a Signal is a reactive primitive that provides a new approach to managing and responding to state changes. With Signals, you can track changes to specific data points (variables or objects), allowing the app to automatically react when the data changes without needing complex change detection.

Why Use Signals?

Signals offer several benefits:

• Predictable reactivity: Signals enable precise control over when a component updates, leading to more predictable behavior.
• Improved performance: With Signals, Angular avoids unnecessary re-renders by updating only the affected parts.

Service Discovery in Microservices with C# and .NET

Service Discovery is a key pattern in microservice architectures, where services need to find each other dynamically. Unlike monolithic applications, where all components are contained within a single executable, microservices are distributed across multiple instances, often across different servers, virtual machines, or containers. Service discovery simplifies the way these services locate one another, allowing for load balancing, failover, and flexibility.

What is Service Discovery?

Service Discovery refers to the process by which services in a distributed system dynamically find each other. Instead of hard-coding the addresses of service instances (which can change in a dynamic environment like Kubernetes), services register themselves with a centralized service registry. Other services query this registry to find the addresses of the services they need to communicate with.

Benefits:

• Scalability: New instances of services can be added dynamically.
• Load Balancing: Requests can be routed to different instances of the same service.
• Fault Tolerance: Dead services can be automatically removed from the registry.

Types of Service Discovery:

Client-Side Discovery

In client-side service discovery, the client directly queries the service registry to discover service instances and choose one to send a request to. This method requires the client to implement the logic for discovery and load balancing.

Implementing an API gateway in a .NET Core application

The API Gateway Pattern is a design pattern used in microservices architecture. It acts as a single entry point for clients, managing all interactions between them and the backend services. This pattern simplifies client interactions by encapsulating the complexities of multiple microservices, providing features like request routing, load balancing, caching, and security.

Why Use an API Gateway?

1. Centralized Entry Point: Clients interact with one endpoint rather than multiple services.
2. Decoupling of Client and Services: The gateway handles communication with services, hiding service details from clients.
3. Cross-cutting Concerns: It manages functionalities like authentication, logging, rate-limiting, etc., across services.
4. Load Balancing: Distributes incoming traffic efficiently to backend services.
5. Security: Acts as a gatekeeper, providing security features like SSL termination and token validation.