top of page
  • Writer's pictureAppsec360 Team

Pattern: Input Validation - NodeJS


Pattern: Input Validation - NodeJS

What is a Pattern?

A pattern for software development is a reusable solution to a common software design problem. It is a general approach that can be applied in various situations to solve similar problems. Patterns are usually documented in a standard format, which includes a name, a problem statement, a solution, and the consequences of applying the pattern.

Patterns are intended to provide developers with a way to describe and share proven solutions to common software development problems. They can help ensure that software is designed and developed in a way that is flexible, maintainable, and extensible.

There are various types of patterns, including:

  • Creational patterns: These patterns deal with object creation mechanisms, trying to create objects in a manner suitable to the situation.

  • Structural patterns: These patterns deal with object composition. They describe how objects are connected to one another to form larger structures.

  • Behavioral patterns: These patterns deal with communication between objects, how objects collaborate with one another to perform tasks.

Patterns are typically classified into categories based on their scope and level of abstraction. For example, architecture patterns describe the overall structure of a software system, while design patterns describe solutions to smaller, more specific design problems within a system.

By using patterns, developers can reduce the amount of time and effort required to solve common problems, improve the quality of their software, and create more robust and maintainable code.


NodeJS focused input validation pattern


When building software applications in Node.js, input validation is an essential step to ensure that user data is clean and valid. Here is a Node.js focused input validation pattern that you can use to validate user input:


1. Define validation rules: First, define the validation rules that apply to the input data. These rules can include data type, length, format, and any other relevant constraints.

const validationRules = {
  email: {
    presence: true,
    email: true
  },
  password: {
    presence: true,
    length: { minimum: 6 }
  },
  age: {
    numericality: {
      greaterThan: 18
    }
  }
};

2. Use a validation library: Node.js has several popular validation libraries such as Joi, Validator.js, and Yup. Use one of these libraries to simplify the validation process and reduce the amount of code you need to write.

const Joi = require('joi');

const schema = Joi.object({
  email: Joi.string().email().required(),
  password: Joi.string().min(6).required(),
  age: Joi.number().min(18).required(),
});

const result = schema.validate({ email: 'example@example.com', password: 'mypassword', age: 25 });

3. Implement server-side validation: Server-side validation is critical because it ensures that the input data is validated before it is processed. Implement validation logic on the server-side using the validation library you have chosen.

const validateInput = (input) => {
  const schema = Joi.object({
    email: Joi.string().email().required(),
    password: Joi.string().min(6).required(),
    age: Joi.number().min(18).required(),
  });

  const result = schema.validate(input);
  if (result.error) {
    throw new Error(result.error.message);
  }

  // Input is valid
};

4. Implement client-side validation: Although server-side validation is crucial, client-side validation is also essential to provide real-time feedback to the user. Implement client-side validation using HTML5 form validation or JavaScript validation libraries.


Using HTML5 form validation:

<form>
  <label>Email:</label>
  <input type="email" name="email" required>
  
  <label>Password:</label>
  <input type="password" name="password" minlength="6" required>
  
  <label>Age:</label>
  <input type="number" name="age" min="18" required>
  
  <input type="submit" value="Submit">
</form>

Using jQuery validation library:

<form id="my-form">
  <label>Email:</label>
  <input type="email" name="email" required>
  
  <label>Password:</label>
  <input type="password" name="password" minlength="6" required>
  
  <label>Age:</label>
  <input type="number" name="age" min="18" required>
  
  <input type="submit" value="Submit">
</form>

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script src="https://cdn.jsdelivr.net/jquery.validation/1.16.0/jquery.validate.min.js"></script>

<script>
  $('#my-form').validate();
</script>

5. Handle validation errors: When validation errors occur, handle them appropriately. This can include providing error messages to the user, logging errors for debugging purposes, and preventing the invalid data from being processed.

try {
  validateInput({ email: 'example.com', password: 'password', age: 15 });
} catch (err) {
  console.error(err.message);
  // Output: "email must be a valid email"
}

6. Test the validation logic: Test the validation logic thoroughly to ensure that it works as expected. Use unit tests to test the validation library and integration tests to ensure that the validation logic is integrated correctly with the rest of the application.

const { validateInput } = require('./input-validation');

describe('Input validation', () => {
  test('Valid input', () => {
    expect(() => {
      validateInput({ email: 'example@example.com', password: 'mypassword', age: 25 });
    }).not.toThrow();
  });

  test('Invalid input', () => {
    expect(() => {
      validateInput({ email: 'example.com', password: 'password', age: 15 });
    }).toThrow();
  });
});

By following this input validation pattern, you can ensure that user data is clean, valid, and secure, which can help prevent security vulnerabilities and data breaches.


0 views0 comments
bottom of page