Understanding the main project templates available for ASP.NET Core

ASP.NET Core’s versatility is encapsulated in its range of project templates, each designed to cater to different web development needs. These templates not only offer a jumpstart for your projects but also integrate best practices, guiding you toward a structured and efficient development process. In this section, we’ll delve deeper into each primary template, offering a richer perspective to aid you in selecting the most fitting template for your specific project requirements.

MVC

The MVC template in ASP.NET Core serves as a robust foundation for building web applications that are scalable, maintainable, and testable. This in-depth exploration will unpack the MVC architecture, elucidating how each component operates within the framework and how this architecture facilitates a clean separation of concerns – a principle that’s vital for complex application development.

The MVC pattern is a well-established design paradigm in web application development that’s not only used by the .NET platform but by other technologies as well. ASP.NET Core’s MVC template forces the implementation of a clear pattern for web development that helps teams build complex applications while retaining simplicity and consistency in terms of software architecture. Understanding the roles and responsibilities of each component in this architectural pattern is crucial for leveraging its full potential:

• Model: In MVC, the Model represents the application’s domain. It encapsulates the data and the business rules that govern access to and modifications of this data. In ASP.NET Core, models are typically implemented as classes with properties and methods. They can include data validation rules to enforce business logic, ensuring data integrity and consistency. Models aren’t just data structures; they embody the business logic of the application, making decisions and performing calculations based on the rules defined within them.
• View: The View is responsible for rendering the user interface in an MVC application. It displays data from the model to the user and sends user commands to the controller. In ASP.NET Core, views are often created using the Razor view engine, which allows developers to write HTML with embedded C# code. Razor views are dynamic and can react to the model data they receive, enabling the creation of interactive and data-driven user interfaces. This separation of UI rendering from business logic and input handling makes the views manageable and modular.
• Controller: A Controller is a coordinator in the MVC pattern. Controllers handle user input, work with the model to perform necessary actions or calculations, and determine which view should be rendered. In ASP.NET Core, controllers are C# classes that can contain multiple actions. These actions are methods that respond to different HTTP requests, invoking changes in the model and selecting views for response. Therefore, controllers act as an intermediary, translating user inputs into actions on the model and selecting views based on the outcomes of those actions.

The MVC template is particularly advantageous for developers looking to build applications with a clear separation of concerns, thereby facilitating easier testing, maintenance, and scaling. It comes pre-configured with essential features such as routing, authentication, and authorization, allowing you to focus on developing unique application features rather than boilerplate code. This project template has the following benefits:

• Separation of concerns: By dividing the application into three interconnected components, MVC naturally promotes a clean separation of concerns. This separation enhances the maintainability of the application as developers can work on models, views, or controllers independently without significant overlap in functionality.
• Testability: The clear delineation of responsibilities in the MVC pattern facilitates more straightforward testing. Models can be tested independently of user interfaces, controllers can be tested for correct routing and response, and views can be verified to render correctly given a model. ASP.NET Core further supports this testability with features such as DI, which can be used to inject mock implementations for testing.
• Modularity and flexibility: The MVC template’s compartmentalized structure allows for modular development and flexibility. Developers can iterate on the design, presentation, and business logic layers separately, adapting to new requirements or design changes with minimal impact on the overall code base.
• A rich ecosystem and community support: Given its popularity, MVC benefits from extensive community support, a wealth of documentation, tutorials, and a plethora of libraries that can be leveraged to add functionality to your application. ASP.NET Core’s MVC framework is no exception, with strong support from Microsoft and a vibrant community, ensuring developers have access to a wealth of resources and best practices.

The MVC template in ASP.NET Core is a powerful choice for developers looking to build web applications with a proven architecture that promotes clean coding practices, testability, and separation of concerns. Its structure is conducive to developing applications that aren’t only robust and scalable but also adaptable to evolving business requirements. By understanding and utilizing the MVC architecture to its full potential, developers can create dynamic, efficient, and maintainable web applications that stand the test of time. In the next few chapters of this book, you’ll have the opportunity to experience how to create applications using the MVC architecture while following a hands-on approach.

ASP.NET Core Web API

The API project template in ASP.NET Core is meticulously designed to streamline the creation of RESTful web services. This template is a boon for developers focusing on the backend services that power web and mobile applications, IoT devices, and more. Here, we’ll delve deeper into the components and features that make the API project template a go-to choice for building high-performance and scalable APIs. The following points clarify the main features of the ASP.NET Core Web API project template:

• Foundation for RESTful services: The API project template lays the groundwork for adhering to REST principles, which emphasize stateless communication, resource identification through URIs, and the use of standard HTTP methods (GET, POST, PUT, and DELETE). This adherence simplifies the design of your API and aligns it with web standards, making it intuitive and straightforward to consume.
• Controller-based architecture: At the heart of the API template is the controller-based architecture. Controllers in ASP.NET Core serve as the entry point for handling HTTP requests and responding with data or status codes. Each controller is typically associated with a specific resource or a related group of resources, encapsulating the logic required to process incoming requests and generate responses.
• Routing and URL mapping: The API template configures routing to ensure that HTTP requests are directed to the appropriate controllers and actions. ASP.NET Core’s routing engine is capable of handling complex URL patterns and can be customized to fit the needs of your API, enabling you to define clear and descriptive routes that reflect your API’s resource hierarchy.
• Content negotiation and serialization: ASP.NET Core’s built-in support for content negotiation allows your API to serve data in various formats (such as JSON or XML) based on the client’s preferences or request headers. The framework automatically handles the serialization and deserialization of data, ensuring that your API can communicate effectively with different clients and systems.
• Model binding and validation: The API project template leverages ASP.NET Core’s model binding and validation features to streamline data processing. Model binding automatically maps data from HTTP requests to action method parameters, while applying validation attributes to your models helps ensure that incoming data meets your business rules before your application processes it.
• Error handling: Robust error handling is crucial for maintaining a reliable API. The API project template includes basic error handling mechanisms that you can extend to create a comprehensive error response strategy. This ensures that your API can gracefully handle and respond to various error conditions, providing meaningful feedback to the client.
• Testability: Just like other ASP.NET Core applications, APIs built using the API project template are highly testable. The framework’s support for DI, combined with the separation of concerns inherent in the controller-based architecture, allows you to write unit and integration tests that cover your business logic, routing, and response generation.
• Swagger integration: Developers often enhance APIs built with this template by integrating Swagger (OpenAPI), which provides interactive documentation, client SDK generation, and API discoverability. Although not included in the template by default, adding Swagger support is straightforward and significantly improves the developer experience when you’re working with your API.

By leveraging the API project template in ASP.NET Core, developers can create well-structured, performant, and scalable web services. This template not only provides the scaffolding necessary for RESTful API development but also ensures that the APIs are maintainable, testable, and compliant with industry standards, laying a solid foundation for any application’s backend services.

Razor Pages

Razor Pages, introduced in ASP.NET Core as an alternative to the MVC template, offers a streamlined approach to building web applications, emphasizing page-focused scenarios. This framework simplifies web development by integrating the server-side logic directly within the page markup, offering a more intuitive and productive way to construct dynamic web content. Let’s embark on a detailed exploration of Razor Pages, highlighting its architecture, advantages, and how it differentiates itself within the ASP.NET Core suite:

• Page-based programming model: Razor Pages centers around a page-based programming model that’s a departure from the controller and view-based MVC model. Each Razor Page is a self-contained unit consisting of a .cshtml file (which combines HTML markup with Razor syntax) and a code-behind file. This structure allows developers to encapsulate the page’s UI and business logic cohesively, promoting a high degree of modularity and maintainability.
• Code-behind model: The code-behind file in Razor Pages, typically a .cshtml.cs file, contains the server-side logic to handle user actions, data access, and other server-side operations. This separation keeps the markup clean and focused on presentation while maintaining a close association with the page’s logic. Developers can handle events, such as form submissions, directly within the page model, streamlining the development process.
• Razor syntax: Razor syntax is a powerful feature within Razor Pages that allows developers to embed C# code directly into their HTML markup. This syntax is intuitive and designed to work seamlessly with HTML, providing a robust way to dynamically generate content, control page flow, and interact with data. Razor’s syntax simplifies many common tasks, such as iterating over data collections, conditionally rendering content, and handling form inputs.
• Strongly typed data models: Razor Pages supports strongly typed data models, enabling developers to work with well-defined C# classes within their pages. This strong typing enhances code clarity, compile-time checks, and IntelliSense support in IDEs, reducing errors and improving developer productivity.
• Tag Helpers: Razor Pages leverages Tag Helpers to enable server-side code to participate in creating and rendering HTML elements in Razor files. Tag Helpers are a more readable and HTML-friendly way to define server-side logic compared to traditional MVC helpers. They can be used to easily bind form elements to data models, generate links, create forms, and more, all while maintaining a clear separation between HTML and C#.
• Routing and URL generation: Razor Pages introduces a simplified routing system that’s based on the file structure of the Pages folder. By default, the URL of a Razor Page corresponds to its location within the Pages directory. This convention-based routing reduces the complexity of defining routes and makes URL generation more intuitive.
• Built-in security features: Razor Pages come with built-in security features, such as request verification and cross-site scripting (XSS) protection, that safeguard the application against common web vulnerabilities. The framework enforces best practices such as automatically encoding output and validating request tokens to prevent CSRF attacks.
• Extensibility and customization: While Razor Pages provides a streamlined development experience out of the box, it also offers extensive options for customization and extensibility. Developers can create custom Tag Helpers, filters, and middleware to enhance functionality or integrate third-party libraries to extend the capabilities of their Razor Pages applications.

In conclusion, Razor Pages in ASP.NET Core presents a highly productive, page-focused framework for building web applications. Its integration of a UI and business logic within individual pages, support for Razor syntax and Tag Helpers, and a simplified routing model make it an attractive choice for developers seeking an alternative to the traditional MVC approach. Razor Pages strikes a balance between simplicity and power, offering a compelling model for constructing interactive, data-driven web applications.

A deep dive into Blazor Server and Blazor WebAssembly

Blazor is a groundbreaking project type in ASP.NET Core that fundamentally changes how interactive web applications can be built using the .NET ecosystem. With the introduction of .NET 9, Blazor has matured even further, offering new features and enhancements that bolster its performance, ease of development, and functionality. This deep dive explores both Blazor Server and Blazor WebAssembly, elucidating their architectures, key features, and the enhancements brought by .NET 9.

Blazor Server

Blazor Server allows you to build interactive web applications where the application logic and state management are handled on the server side. User interactions are managed through a SignalR connection, providing a robust, real-time communication channel between the client and server. The following points illuminate the key features of the Blazor Server project type and the advancements introduced in .NET 9:

• SignalR-based state management: In Blazor Server, the client’s UI state is maintained in the server’s memory. When a user interacts with the UI, the event is sent to the server over a SignalR connection and processed, after which the required UI updates are sent back to the browser. This architecture minimizes the amount of data that’s transferred over the network and leverages the server’s capabilities for heavy lifting.
• .NET 9 enhancements: With the advent of .NET 9, Blazor Server has seen improvements in performance and development experience. Enhancements in SignalR and rendering efficiencies reduce latency and improve the responsiveness of Blazor Server applications. Furthermore, improved hot reload capabilities in .NET 9 enhanced the developer experience, making UI adjustments and debugging more intuitive and faster.

Blazor WebAssembly

Blazor WebAssembly is the client-side counterpart of Blazor that enables running C# code directly in the browser using a WebAssembly-based .NET runtime. This model is akin to JavaScript frameworks but leverages the full power of .NET. The following points illuminate the key features of the Blazor WebAssembly project type and the advancements introduced in .NET 9:

• WebAssembly runtime: The Blazor WebAssembly model downloads the .NET runtime, your application, and its dependencies to the browser, executing the application directly in the browser’s sandbox. This allows for rich interactive experiences without server roundtrips, something that’s ideal for offline-capable applications, complex client-side computations, and reduced server load.
• .NET 9 enhancements: Blazor WebAssembly with .NET 9 introduces performance optimizations, smaller download sizes, and faster startup times. The runtime and tooling improvements in .NET 9 have made Blazor WebAssembly applications more efficient and quicker to load, enhancing the user experience, especially in resource-constrained environments.

Common features and improvements – Blazor Server and Blazor WebAssembly

The following are some common features and improvements that can be found in both Blazor Server and Blazor WebAssembly:

• Component model: Both Blazor Server and Blazor WebAssembly utilize a component-based architecture that promotes reusability and maintainability. Components are the building blocks of Blazor applications and encapsulate markup, logic, and styling. They can be nested, reused, and shared between projects, fostering a modular development approach.
• JavaScript interoperability: Blazor provides extensive interoperability with JavaScript, allowing developers to leverage existing JavaScript libraries and frameworks. This interoperability is crucial for accessing browser APIs not exposed through Blazor and for integrating with third-party JavaScript-based UI libraries.
• .NET 9-specific features: .NET 9 introduces more granular control over component rendering, improved error handling, and enhanced component life cycle methods. These features provide developers with more tools to optimize their applications and improve user experience.
• Mobile Blazor Bindings: With .NET 9, developers can experiment with Mobile Blazor Bindings, an exciting feature that allows Blazor components to be used to build native mobile applications using web technologies, extending the reach of Blazor beyond web browsers.
• PWA support: Blazor WebAssembly supports building progressive web applications (PWAs) out of the box. This feature enables applications to be installed on a user’s device, work offline, and leverage native device features, bridging the gap between web and native applications.

In summary, Blazor in .NET 9 continues to evolve, offering a compelling model for building web applications using C#. Whether you choose Blazor Server for its real-time capabilities and server-side processing or Blazor WebAssembly for its client-side execution and offline support, Blazor provides a robust platform for building modern web applications. The ongoing enhancements in .NET 9 further cement Blazor’s position as a versatile, performant, and developer-friendly framework in the .NET ecosystem.

Worker Service

The Worker Service template in ASP.NET Core is a versatile template that’s designed to help developers create background services for a variety of applications. These services can run in the background, executing tasks independently of user interfaces or web requests. This exhaustive overview delves into the architecture, key features, and practical applications of Worker Service templates, providing insights into how they can be utilized effectively in your .NET applications. The following points elucidate the main aspects of the Worker Service project type:

• Core architecture: At its heart, a Worker Service in ASP.NET Core is a long-running console application that leverages the generic host (HostBuilder), which is also used in ASP.NET Core web applications. This shared foundation allows for the use of familiar features such as DI, logging, and configuration systems, making it easier for developers to transition between web and worker services.
• Background task execution: The Worker Service template is ideal for executing background tasks such as processing queues, polling databases, or performing timely operations. The template provides a base class, BackgroundService, from which you can derive to implement your long-running tasks. This class offers methods such as ExecuteAsync, which you can override to define the logic of your background tasks.
• Integration with hosted services: A Worker Service template can be registered as a hosted service within the .NET Core generic host. Each hosted service can run in parallel and independently, starting and stopping together with the application. This model provides a clean abstraction for implementing different background tasks that need to run throughout the life of the application.
• DI and configuration: Utilizing the built-in DI in ASP.NET Core, Worker Service can easily access configured services and settings, enhancing its modularity and testability. Configuration values can be read from various sources, such as appsettings.json, environment variables, or command-line arguments, allowing for flexible deployment and runtime behavior.
• Logging: ASP.NET Core’s logging infrastructure is fully supported in Worker Service, enabling you to integrate robust logging mechanisms that can log to various outputs, such as the console, files, or external data stores. This is crucial for monitoring the health and performance of your background services.
• Health checks: Worker Service can implement health checks, providing insights into the health and performance of the application. This feature is especially important for services running in production as it allows for proactive monitoring and maintenance.
• Windows services and Linux daemons: One of the significant advantages of Worker Service is its ability to be hosted as Windows services or Linux daemons. This means that your Worker Service template can run automatically in the background as a system service, without requiring a user to log in.
• Containerization: Worker Service is well-suited for containerization with Docker. Running a Worker Service template in a container allows for the creation of lightweight, isolated, and scalable deployments. This is particularly beneficial in microservices architectures, where different components of the application can be deployed and scaled independently.
• Practical use cases: Worker Service can be used in a myriad of practical scenarios, such as sending batch emails, file processing, data imports/exports, or interacting with APIs for data synchronization. It’s also ideal for microservices that need to perform background work independently of user requests.

In summary, the Worker Service template in ASP.NET Core provides a robust foundation for building background services that can perform a wide range of tasks. Its integration with the broader .NET Core features, such as DI, configuration, and logging, makes it a powerful and flexible choice for developing background processes in your applications. Whether you’re processing jobs, polling resources, or performing scheduled tasks, Worker Service offers a structured yet flexible framework to build reliable and scalable background services.

Now that we understand the main aspects of the project templates available for ASP.NET Core projects, let’s move on to the next section, where we’ll explore the high-level aspects of the ASP.NET Core architecture and its features.