🧠 RomBaseDomain – Your Validatable Domain Base Class

Welcome, dev! 👋
This package helps you create cleaner and more robust domain models by handling validation in a smart way. It combines the power of C# DataAnnotations with your own custom validation rules. The result? A single place to manage and check all domain-related validations. No more clutter. 🚀

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💡 What’s This For?

RomBaseDomain is an abstract base class designed for your domain models. By inheriting from it, you automatically get:

• ✅ Validation using [Required], [Range], and other DataAnnotations
• 🧠 Support for custom validation logic
• 📋 Friendly, serialized validation error lists for frontends or APIs
• 🛡️ Internal handling that won’t expose methods or internal validation when converting to JSON

It’s built with a naming convention:

• Prefixes like List for anything that's a list
• Suffix Domain for domain models
• Suffix DataTransfer for DTOs

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🚀 How To Use It

1. Inherit From RomBaseDomain

You define your domain model like this:

public class UserDomain : RomBaseDomain
{
    [Required]
    public string Name { get; set; }

    [Range(18, 120)]
    public int Age { get; set; }

    [EmailAddress]
    public string Email { get; set; }

    [StringLength(12, MinimumLength = 6)]
    public string Username { get; set; }

    [Phone]
    public string PhoneNumber { get; set; }

    [Url]
    public string Website { get; set; }

    [Compare("Password")]
    public string ConfirmPassword { get; set; }

    public string Password { get; set; }
}

2. Validate The Entity

var user = new UserDomain
{
    Name = "",                 // Required field is empty
    Age = 15,                  // Too young!
    Email = "not-an-email",   // Invalid format
    Username = "usr",         // Too short
    PhoneNumber = "abc",      // Invalid phone
    Website = "not-a-url",    // Invalid URL
    Password = "123456",
    ConfirmPassword = "654321" // Doesn’t match
};

bool isValid = user.IsValidDomain; // false

var errors = user.ListValidationError;

foreach (var error in errors)
{
    Console.WriteLine($"Field: {error.Field} | Message: {error.Message}");
}

This will output all the field-level and global errors in a nice, serializable format.

3. Custom Validation

You can also add your own validation logic by overriding the Validate method:

protected override void Validate()
{
    if (string.IsNullOrEmpty(Username))
    {
        AddValidationError("Username", "Username cannot be empty.");
    }
    if (Password != ConfirmPassword)
    {
        AddValidationError("ConfirmPassword", "Passwords do not match.");
    }
}

This will add custom validation errors to the list, which can be serialized and returned to the client.

4. Serialization

The validation errors are serialized in a way that’s easy to consume by frontends or APIs. You can use them directly in your response models.

public class ApiResponse
{
    public bool Success { get; set; }
    public List<ValidationError> Errors { get; set; }
}
public class ValidationError
{
    public string Field { get; set; }
    public string Message { get; set; }
}

5. Example API Response

{
    "Success": false,
    "Errors": [
        {
            "Field": "Name",
            "Message": "The Name field is required."
        },
        {
            "Field": "Age",
            "Message": "The field Age must be between 18 and 120."
        },
        {
            "Field": "Email",
            "Message": "The Email field is not a valid e-mail address."
        },
        {
            "Field": "Username",
            "Message": "The field Username must be a string or array type with a minimum length of '6'."
        },
        {
            "Field": "PhoneNumber",
            "Message": "The PhoneNumber field is not a valid phone number."
        },
        {
            "Field": "Website",
            "Message": "The Website field is not a valid fully-qualified http, https, or ftp URL."
        },
        {
            "Field": "",
            "Message": "'ConfirmPassword' and 'Password' do not match."
        }
    ]
}

This response can be easily consumed by any frontend framework or API client.

6. Notes

• The ListValidationError property is a list of all validation errors, both field-level and global.
• The IsValidDomain property returns true if there are no validation errors, and false otherwise.
• The Validate method is called automatically when you access the IsValidDomain property, so you don’t need to call it manually.
• The AddValidationError method is used to add custom validation errors to the list. You can use it to add any validation errors that are not covered by the DataAnnotations.
• The ValidationError class is used to represent a validation error. It has two properties: Field and Message. The Field property is the name of the field that caused the validation error, and the Message property is the error message.
• The ValidationError class is serializable, so you can use it directly in your API responses.

7. Conclusion

RomBaseDomain is a powerful tool for managing domain validation in your C# applications. By using this package, you can ensure that your domain models are clean, maintainable, and easy to validate. It’s a great way to keep your code organized and reduce the risk of validation errors in your application.

📦 Installation

You can install the RomBaseDomain package via NuGet:

dotnet add package RomBaseDomain

Or by using the NuGet Package Manager in Visual Studio.

Install-Package RomBaseDomain

🛠️ Contributing

We welcome contributions! If you have suggestions, bug reports, or feature requests, please open an issue or submit a pull request.

📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

Author

Romulo Ribeiro

instagram: @romuloar