5 Rules For DTOs

Tutorial: 5 Rules for Writing Better DTOs

Step 1: Understanding DTOs

• Definition: DTO stands for Data Transfer Object. It is used to transfer data between different parts of a system, often serialized to formats like JSON or XML.
• Purpose: DTOs should only contain data values and should not have any logic or behavior.

Step 2: Rule 1: DTOs Should Not Have Logic

• Guideline: DTOs should not contain any behavior as the receiver of the data may deserialize it into a different type.
• Example: Use a simple person DTO with only data properties.

Step 3: Rule 2: Immutability and Serialization

• Immutability: DTOs can be immutable to ensure consistency.
• Serialization: Serialize DTOs to formats like JSON and ensure round-trip serialization.

Step 4: Rule 3: Use Properties, Not Fields

• Best Practice: Prefer using properties over fields in DTOs for better support and serialization.
• Example: Create an order DTO using properties for values.

Step 5: Rule 4: Naming Convention

• Suffix Usage: Use "DTO" as a suffix for DTO names. Avoid excessive suffixes like "Request" or "Response" unless necessary.

Step 6: Rule 5: Specific DTO Types

• Purposeful Naming: Use specific names for different types of DTOs like API request, response objects, MVC view models, etc.
• Example: Create separate DTO types for commands, queries, and events.

Step 7: Validation and Attributes

• Validation: Add attributes to DTO properties for validation purposes.
• Example: Use attributes like minimum length for properties like email and password.

Step 8: Fluent Validation

• Fluent Validation: Consider using Fluent Validation for more complex validation scenarios.
• Implementation: Create separate validators for each DTO type for custom validation rules.

Step 9: Sharing and Feedback

• Share Rules: Share these DTO rules with colleagues for better understanding and implementation.
• Feedback: Leave comments for any questions or suggestions for future videos.

By following these rules and guidelines, you can create well-structured and effective DTOs for your applications. Feel free to experiment with the provided examples and explore further improvements in your DTO implementation.