Model-View-Controller Architecture Pattern: Usage, Advantages, Examples

Model-View-Controller Architecture Pattern: Usage, Advantages, Examples

Programming a complex application and dealing with a large amount of code written in one script is difficult for understanding and making changes to avoid mistakes. It also takes a huge amount of time. But there’s a way to boost your programming speed as well as make the integration with code smoother and easier while working within a team.

This can be achieved with the help of partitioning the code and the simultaneous work of several developers on each part of the code separately. The tool which will help you do this is called Model-view-controller architecture (MVC). It is a pattern used for developing user interfaces.  MVC is applicable to different types of applications – both server-side web applications and desktop (client) applications. It is not tied to any particular programming language and does not require the use of object-oriented programming or other paradigms.

In this article, we will learn how the MVC architecture is built, how the code is structured and it can benefit your work. Of course, we will highlight some disadvantages of the architecture, as it may not be applicable to the type of application you are programming. Without further ado, let’s jump into the details of the MVC architecture.

MVC Architecture Overview

Traditional approach of programming works on Input -> Process -> Output. In that way, UI coding, business logic, and the application’s data domain are written into a single file. It creates a lack of maintainability, testability as well as scalability of the application.

The main idea behind MVC is that every section of the code has a different purpose. Some of your code preserves data, some are in charge of its appearance, while other controls how the app functions. MVC separates the input logic, business logic, and UI logic, thus breaking up frontend and backend code into separate components. This provides loose coupling between the elements. The MVC pattern specifies where each kind of logic should be located in the application.

MVC organizes the main functions of the code into its own neatly organized boxes. The file structure for using MVC is quite simple: there are folders for views, models, and controllers, which are connected to each other through one directory (catalog).

MVC Architecture Patterns consists of three main components:

– Model – View – Controller

Let’s puzzle out the functions of each component and what they are responsible for.

Model

Model is the lowest level of architecture. It implements the logic for the application’s data domain and as well as defines the components of the app. For example, if you are creating a To-Do app, the model code will define what is a "task" and what is a "list" since those are the core components of the app.

The model responds to the requests of the controller, as the letter doesn’t interact with the database directly. The model, after taking the information out of the database, gives the needed data back to the controller. But the data is still raw. Here is where the next component comes into action.

View

The view is a component that displays the application’s user interface (UI). It is created from the model data, though the data is not taken directly. It is provided by the controller, as the view interacts only with this section.

A view is similar to application templates appropriate for a specific page layout type, mobile view, or a specific theme. It will display all the markups and CSS that are traditionally used for creating a static web page.

Controller

The controller acts as an intermediary between the view and the model, enabling the interconnection between those two components. It is also known as the brain of the app. The controller’s task is to determine which model to call and then open the appropriate function within that model.

It doesn’t define the data logically, it gives the command to the model to do it. It receives the data, sends it to the view, and explains how to represent it to the user. The controller also handles and responds to user input and interaction. For example, the controller handles query-string values and passes these values to the model, which in turn might use these values to query the database.

Examples of Using MVC Architecture

Let’s see how MVC works using the example of the Shopping list application.

The model section defines what data the application should contain. If the state of this data changes, then the model usually notifies the view, and sometimes the controller if different logic is needed to control the updated view. So for the shopping list application, the model will specify what data the list items should contain: item, price, and others, and which list items are already present.

The view determines how the data should be displayed in the app. In a Shopping list application, the view will present a list to the user and will display the data received from the model. The controller contains logic that updates the model in response to the user’s interaction with the application.

A Shopping list might contain input forms and buttons that allow to add or remove items. The model is updated according to those actions. The user’s request is sent to the controller, which then manages the model to send the updated data to the view. However, you can also update the view to display the data in a different format, such as reordering items alphabetically or from lowest to highest price. In this case, the controller can handle it directly without updating the model.

When do we recommend our clients to use MVC architecture?

MVC architecture is widely used when you need to organize large-size web applications. The three levels of code separation make it easy to divide and organize application logic. Working with segregated code levels makes it easy to find necessary pieces of code quickly and easily add new functions. Still, it requires a significant team of DevOps to manage the process.

If you need to build faster loading web applications, the MVC architecture will come in useful, as it supports synchronous Method Invocation (AMI). It means that MVC applications can be made to work even with PDF files, site-specific browsers, and also for desktop widgets.

Code partitioning also helps to speed up the development process, if you are working under tough deadlines or for any other reasons. Compared to other development models MVC accelerates development to speed up to three times. MVC model allows several developers to work simultaneously on separate selections, for example, one can deal with the View, while another works on Controller.

Last but not least, MVC architecture is useful for those who develop SEO-friendly web applications, as it provides an easy way out to develop SEO-friendly RESTful URLs.

Advantages and Disadvantages of Model-view-controller

As you have already noticed, the MVC architecture has multiple advantages. Let’s go over the most useful features that will benefit the work of the developer, helping to produce clean, scalable, powerful, and fast code in less time with minimal effort.**

Easily Modifiable

MVC makes it easy to implement modifications to the entire app. Adding or updating the view is simplified in the MVC pattern, as each section is independent. The changes made in one section will not affect the entire architecture. Thus it increases the flexibility and scalability of the application.

Easy planning and maintenance

The MVC paradigm helps a developer in the initial planning phase of the application because it gives an outline of how to arrange ideas into actual code.

Returns data without formatting

With the help of MVC developers can create their own view engine by receiving raw data. Any type of data can be formatted using HTML, but with the MVC framework, the dev can also format the data using the Macromedia Flash or Dream viewer, so the same components can be re-used without an interface.

Supports TTD (test-driven development)

Multiple levels are structurally defined and properly written in the application, so each unit cant be tested separately. Thus large-scale applications can be debugged easier.

Multiple Views

In the MVC architecture you can develop different view components for the model component. It separates data and business logic, limiting code duplication.

Along with the multiple advantages, MVC have also blank sides:

• The complexity of framework navigation, as it introduces new layers of abstraction and requires users to adapt to the decomposition criteria of MVC;

• Scattering is caused by decomposing a feature into three artifacts. Thus developers have to  maintain the consistency of multiple representations at once;

• The inefficiency of data access;

• Not suitable for small applications;

• Several programmers needed;

• Knowledge of several technologies is required. The developer knows the client-side code and the HTML code.

Conclusion

MVC makes the development process smoother compared to the traditional approaches. MVC is a great tool to translate your ideas into the code and you can easily come back to your code since you are aware of which code does what. The principle of partitioning lies in its core, so you have the input logic, business logic, and UI as separate components. It makes it possible to reuse the code and work simultaneously on several features, which accelerates development speed up to three times. Also, the way code is organized within MVC makes it easy for other developers to understand your code.

It helps to work on one of the most important skills for the developers, such as learning how code interacts with other code and collaborating with other developers. Thinking about how to adapt your app for the MVC framework will level up your skills as a developer by teaching you both.

Recently I wrote an article about another Architecture Pattern - Client-Server Architecture. Read it out if you like this article.