How do you manage user input in object oriented web apps?

2 Why use object oriented design for user input?

User input is a complex and dynamic feature of web apps, as it can come from various sources, such as menus or voice commands, and can have different formats. To manage user input effectively, object oriented design can be used to encapsulate the logic and data related to user input into separate objects. This abstraction of details from the rest of the system allows for common functionality and behavior to be inherited and reused for different types of user input. Moreover, the behavior of user input objects can be polymorphic and adapted according to different contexts or scenarios.

3 How to design user input objects?

When designing user input objects, it is important to identify the responsibilities and collaborations of each object. Responsibilities are things that an object knows or does, while collaborations refer to the relationships or interactions between objects. Different techniques can be used to identify responsibilities and collaborations, such as use cases, scenarios, or CRC cards. For example, a use case for user input could involve a user entering their name and email address in a registration form, the system validating the name and email address and displaying an error message if they are invalid, and the system saving the name and email address in the database and sending a confirmation email to the user. From this use case, some possible user input objects can be identified, such as a RegistrationForm object that knows the input fields and their values, a NameValidator and an EmailValidator object that know the validation rules for the name and email address, and a RegistrationController object that knows how to communicate with the database and the email service.

4 How to apply design patterns for user input?

Design patterns are proven solutions to common problems in software design, offering a common vocabulary and template for designing user input objects. There are many design patterns that can be useful, but some of the most common ones are the Model-View-Controller (MVC) pattern, the Strategy pattern, and the Observer pattern. The MVC pattern separates user input into three components: the model, view, and controller. This helps to decouple user input from the rest of the system and enables multiple views and controllers for the same model. The Strategy pattern allows for interchangeable algorithms to be selected at runtime, helping to encapsulate different behaviors for user input objects such as validation rules, error handling, or formatting. Lastly, the Observer pattern defines a one-to-many dependency between objects; when one object changes state, all its dependents are notified and updated automatically. This helps to synchronize user input objects with the rest of the system, ensuring consistency and responsiveness.

5 How to follow best practices for user input?

When managing user input in web apps, it is important to not only use object oriented design principles and patterns, but also adhere to some best practices. Validate user input on both the client-side and the server-side to prevent malicious or invalid input from compromising your system or user experience. Sanitize user input before storing or displaying it, and secure user input by using encryption, hashing, or tokens. Additionally, design a user-friendly and accessible user interface that provides clear and consistent feedback, guidance, and error messages, while also supporting different input methods like keyboard, mouse, touch, or voice.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?