https://github.com/joegasewicz/shelf-form-validator
A lightweight, extensible validation framework for Dart form data. Ideal for backend or CLI apps.
https://github.com/joegasewicz/shelf-form-validator
dart dartlang form form-validation server-side shelf shelf-form-validation validation
Last synced: 6 months ago
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A lightweight, extensible validation framework for Dart form data. Ideal for backend or CLI apps.
- Host: GitHub
- URL: https://github.com/joegasewicz/shelf-form-validator
- Owner: joegasewicz
- License: mit
- Created: 2025-04-10T16:29:50.000Z (6 months ago)
- Default Branch: master
- Last Pushed: 2025-04-10T17:27:18.000Z (6 months ago)
- Last Synced: 2025-04-10T18:02:01.324Z (6 months ago)
- Topics: dart, dartlang, form, form-validation, server-side, shelf, shelf-form-validation, validation
- Language: Dart
- Homepage: https://pub.dev/packages/shelf_form_validator
- Size: 10.7 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# shelf_form_validator
A lightweight, extensible Dart validation framework designed for form data in backend apps using Shelf, or any Dart CLI/VM environment.
---
## 📦 Installation
Add this to your `pubspec.yaml`:
```yaml
dependencies:
shelf_form_validator: ^0.1.0
```
Then run:
```bash
dart pub get
```
Or install it via the command line:
```bash
dart pub add shelf_form_validator
```
---
## ✨ Features
- Simple API for form validation
- Plug-and-play validator classes (e.g. `EmptyString`, `StringLength`, `ValidEmail`, etc.)
- Provides reflection helper functions for schema validation
- Can validate any schema object with a `final` field structure
---
## ✨ Quick Start
### Validator
```dart
final validator = Validator(schema: data)
..addValidator('email', [EmptyString(), ValidEmail()])
..addValidator('password', [EmptyString(), StringLength(stringLength: 8)]);
validator.validate();
```
### Create a Dart Schema
```dart
class Login {
final String email;
final String password;
Login({required this.email, required this.password});
}
```
### Combined Your Schema & Validator
```dart
class Login {
final String email;
final String password;
Login({required this.email, required this.password});
factory Login.fromFormData(Map formData) {
final login = Login(
email: formData['email'] ?? '',
password: formData['password'] ?? '',
);
final validator = Validator(schema: login)
..addValidator('email', [EmptyString(), ValidEmail()])
..addValidator('password', [EmptyString(), StringLength(stringLength: 8)]);
validator.validate();
return login;
}
}
```
---
Minimal example using just two fields:
```dart
class Login {
final String email;
final String password;
Login({required this.email, required this.password});
factory Login.fromFormData(Map formData) {
final login = Login(
email: formData['email'] ?? '',
password: formData['password'] ?? '',
);
final validator = Validator(schema: login)
..addValidator('email', [EmptyString(), ValidEmail()])
..addValidator('password', [EmptyString(), StringLength(stringLength: 8)]);
validator.validate();
return login;
}
}
```
---
## ✨ Example Usage
### Define your schema:
```dart
import 'package:web/utils/validation.dart';
class Register {
final String firstName;
final String lastName;
final String email;
final String emailConfirm;
final String password;
Register({
required this.firstName,
required this.lastName,
required this.email,
required this.emailConfirm,
required this.password,
});
factory Register.fromFormData(Map formData) {
final register = Register(
firstName: formData["first_name"] ?? "",
lastName: formData["last_name"] ?? "",
email: formData["email"] ?? "",
emailConfirm: formData["email_confirm"] ?? "",
password: formData["password"] ?? "",
);
// Create and run validator
Validator validator = Validator(schema: register)
..addValidator("firstName", [EmptyString(), StringLength(stringLength: 2)])
..addValidator("lastName", [EmptyString(), StringLength(stringLength: 2)])
..addValidator("email", [EmptyString(), ValidEmail()])
..addValidator("emailConfirm", [EmptyString(), FieldsMatch(matchField: "email")])
..addValidator("password", [EmptyString(), StringLength(stringLength: 8)]);
validator.validate();
return register;
}
}
```
---
## 🔄 Using `ValidationException` Inside a Shelf handler
```dart
@override
Future post(Request request) async {
final body = await request.readAsString();
final formData = Uri.splitQueryString(body);
try {
final registerData = Register.fromFormData(formData);
// Proceed with successful data
} on ValidationException catch (error) {
print("Validation errors: ${error.errors}");
return Response.badRequest(body: jsonEncode(error.errors));
}
}
```
---
## 🏃 Validators
| Validator | Description | Example Usage |
|----------------|--------------------------------------------------|--------------------------------------------------------------------------------|
| `EmptyString` | Fails if the string is empty or only whitespace | `addValidator('name', [EmptyString()])` |
| `StringLength` | Ensures string is at least a certain length | `addValidator('password', [StringLength(stringLength: 8)])` |
| `ValidEmail` | Validates a basic email format | `addValidator('email', [ValidEmail()])` |
| `FieldsMatch` | Verifies one field matches another | `addValidator('confirmPassword', [FieldsMatch(matchField: 'password')])` |
---
## 🔧 Extending with Custom Validators
```dart
class MinNumber extends ValidationBase {
final int min;
MinNumber(this.min);
@override
void validate(String value, String attrName, ValidationType validationErrors, {Object? schema}) {
if (int.tryParse(value) == null || int.parse(value) < min) {
validationErrors[attrName] ??= [];
validationErrors[attrName]!.add({"error": "Must be at least \$min"});
}
}
}
```
---
## ⚖️ License
MIT