govt_documents_validator

A comprehensive Flutter package for validating Indian Government Documents including Aadhar, PAN, and GSTIN with checksum verification, masking, formatting, and batch validation utilities.

Features

• Aadhar Validation - Verhoeff algorithm checksum verification
• PAN Validation - Format validation with case-insensitive support
• GST Validation - Luhn mod 36 algorithm with state code verification
• Document Masking - Securely mask sensitive document numbers
• Document Formatting - Format documents with proper separators
• Batch Validation - Validate multiple documents at once
• Type Detection - Auto-detect document type from input
• String Extensions - Convenient validation methods on String
• Detailed Errors - Get error codes and messages for failed validations
• Null-Safe - Full null-safety support

Supported Documents

Document	Length	Format	Algorithm
Aadhar	12 digits	1234-5678-9012	Verhoeff
PAN	10 chars	ABCDE1234F	Regex Pattern
GSTIN	15 chars	27-AABCU9603R-1Z-M	Luhn mod 36

Demo

App Interface

Successful Validation

The example app demonstrates:

• Real-time validation for Aadhar, PAN, and GST numbers
• Clear success/error feedback
• Modern Material Design UI
• All package features showcased

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  govt_documents_validator: ^1.0.0

Then run:

flutter pub get

Usage

Basic Validation

import 'package:govt_documents_validator/govt_documents_validator.dart';

// Aadhar validation
AadharValidator aadharValidator = AadharValidator();
bool isValidAadhar = aadharValidator.validate('234123412346');

// PAN validation
PANValidator panValidator = PANValidator();
bool isValidPAN = panValidator.validate('ABCDE1234F');

// GST validation
GSTValidator gstValidator = GSTValidator();
bool isValidGST = gstValidator.validate('27AABCU9603R1ZM');

String Extensions (Recommended)

import 'package:govt_documents_validator/govt_documents_validator.dart';

// Direct validation
bool isValid = '234123412346'.isValidAadhar();
bool isValid = 'ABCDE1234F'.isValidPAN();
bool isValid = '27AABCU9603R1ZM'.isValidGSTIN();

// Auto-detect and validate
bool isValid = '234123412346'.isValidDocument();

// Get document type
DocumentType type = '234123412346'.documentType; // DocumentType.aadhar

Document Masking

// Mask sensitive data for display
String masked = '234123412346'.maskDocument(); // "XXXX-XXXX-9012"
String masked = 'ABCDE1234F'.maskDocument();   // "XXXXXX234F"
String masked = '27AABCU9603R1ZM'.maskDocument(); // "27XXXXXXXXXR1ZM"

// Or use the utility class
String masked = DocumentMasker.maskAadhar('234123412346');

Document Formatting

// Format with proper separators
String formatted = '234123412346'.formatDocument(); // "1234-5678-9012"
String formatted = 'abcde1234f'.formatDocument();   // "ABCDE1234F"

// Clean formatted input
String clean = '1234-5678-9012'.cleanDocument(); // "123456789012"

Batch Validation

final batchValidator = BatchValidator();

// Validate multiple documents
final results = batchValidator.validateAll({
  'customer_aadhar': '234123412346',
  'customer_pan': 'ABCDE1234F',
  'company_gst': '27AABCU9603R1ZM',
});

// Results: Map<String, bool>
results.forEach((key, isValid) {
  print('$key: ${isValid ? "Valid" : "Invalid"}');
});

Detailed Validation

final batchValidator = BatchValidator();

// Get detailed results with error codes
final detailedResults = batchValidator.validateAllDetailed({
  'aadhar': '123456789013', // Invalid
});

ValidationResult result = detailedResults['aadhar']!;
if (!result.isValid) {
  print('Error: ${result.errorMessage}');
  print('Code: ${result.errorCode}');
}

Type Detection

// Auto-detect document type
DocumentType type = BatchValidator.detectType('234123412346');
// Returns: DocumentType.aadhar

// Or use extension
DocumentType type = '234123412346'.documentType;

Use Cases

Form Validation

String? validateAadharInput(String? value) {
  if (value == null || value.isEmpty) {
    return 'Please enter Aadhar number';
  }
  
  if (!value.isValidAadhar()) {
    return 'Invalid Aadhar number';
  }
  
  return null;
}

Secure Display

Widget buildDocumentCard(String aadharNumber) {
  return Card(
    child: ListTile(
      title: Text('Aadhar Number'),
      subtitle: Text(aadharNumber.maskDocument()),
    ),
  );
}

Multi-Document Validation

Future<bool> validateCustomerDocuments(Map<String, String> documents) async {
  final validator = BatchValidator();
  final results = validator.validateAll(documents);
  
  return results.values.every((isValid) => isValid);
}

API Reference

Validators

• AadharValidator().validate(String) - Validate Aadhar number
• PANValidator().validate(String) - Validate PAN number
• GSTValidator().validate(String) - Validate GSTIN

String Extensions

• .isValidAadhar() - Check if string is valid Aadhar
• .isValidPAN() - Check if string is valid PAN
• .isValidGSTIN() - Check if string is valid GSTIN
• .isValidDocument() - Auto-detect and validate
• .documentType - Get document type
• .maskDocument() - Mask the document
• .formatDocument() - Format the document
• .cleanDocument() - Remove formatting

Utilities

• DocumentMasker.maskAadhar(String) - Mask Aadhar number
• DocumentMasker.maskPAN(String) - Mask PAN number
• DocumentMasker.maskGSTIN(String) - Mask GSTIN
• DocumentFormatter.formatAadhar(String) - Format Aadhar
• DocumentFormatter.formatPAN(String) - Format PAN
• DocumentFormatter.formatGSTIN(String) - Format GSTIN
• BatchValidator().validateAll(Map) - Batch validation
• BatchValidator.detectType(String) - Detect document type

Models

• DocumentType - Enum for document types (aadhar, pan, gstin, unknown)
• ValidationResult - Detailed validation result with error codes
• ValidationErrorCodes - Standard error codes

Error Codes

• EMPTY_INPUT - Input is empty
• INVALID_LENGTH - Incorrect length
• INVALID_FORMAT - Format doesn't match pattern
• INVALID_CHECKSUM - Checksum verification failed
• INVALID_STATE_CODE - Invalid state code (GST only)
• INVALID_CHARACTERS - Contains invalid characters

Example

Check out the example directory for a complete Flutter app demonstrating all features.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

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

Acknowledgments

• Aadhar validation uses the Verhoeff algorithm
• GST validation uses the Luhn mod 36 algorithm
• Inspired by the need for reliable government document validation in Indian fintech apps

Support

For issues, feature requests, or questions, please file an issue on GitHub.

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