Input Validation
Why Input Validation is Important
- •Prevents malformed data from corrupting application logic
- •Protects against injection attacks
- •Ensures data integrity
- •Improves user experience with meaningful error messages
- •Reduces server load by rejecting invalid requests early
Types of Validation
- •Presence Validation: Ensuring required fields are present
- •Type Validation: Checking data is of correct type (string, number, etc.)
- •Format Validation: Verifying data follows specific formats (email, URL,
- •Range Validation: Checking values are within acceptable ranges
- •Custom Validation: Application-specific validation rules
Validation Approaches
- •Client-side validation (UX improvement, not security)
- •Server-side validation (mandatory for security)
- •Database constraints (last line of defense)
Express Validator
Param and Query Validation
Custom Validators
Schema Validation with Joi
MongoDB Schema Validation
Recommended Image
A diagram showing the validation flow in an Express.js application, with client
requests passing through different layers of validation before reaching the
database.
Further Reading
- •[Express Validator Documentation](https://express-validator.github.io/docs/)
- •[Input Validation Best Practices](https://cheatsheetseries.owasp.org/cheatsheets/Input_Validation_Cheat_Sheet.html)
- •[Joi Validation in Express.js](https://medium.com/@rossbulat/joi-for-node-exploring-javascript-object-schema-validation-50dd4b8e1b0f)
- •[MongoDB Validation Best Practices](https://mongoosejs.com/docs/validation.html)