fcg_network_interceptor 0.0.2

A Dio interceptor that automatically encrypts request bodies using the encrypt_secure package.

FCG Network Interceptor (fcg_network_interceptor)

A Dio interceptor that automatically encrypts request bodies using sodium_libs (ChaCha20-Poly1305).

Features

• Automatic Encryption: Intercepts POST, PUT, and PATCH requests and automatically encrypts the JSON body.
• Request Wrapping: Wraps the encrypted string in a standardized JSON structure: {"request": "ENCRYPTED_STRING"}.
• Selective Encryption: Provides a mechanism to skip encryption for specific requests (e.g., standard application/x-www-form-urlencoded submissions).
• Error Handling: Catches encryption errors and wraps them in DioException for consistent error handling.

Installation

Add the following to your pubspec.yaml:

dependencies:
  fcg_network_interceptor: ^0.0.1
  dio: ^5.0.0
  sodium_libs: ^3.4.6+4

Usage

1. Initialization

Add the EncryptionInterceptor to your Dio instance. You must provide a base64-encoded key.

import 'package:dio/dio.dart';
import 'package:fcg_network_interceptor/fcg_network_interceptor.dart';

void main() {
  final dio = Dio();
  
  // Create a 32-byte key, base64 encoded
  const myBase64Key = 'YOUR_BASE64_ENCODED_32_BYTE_KEY';

  // Add the interceptor to the chain
  dio.interceptors.add(EncryptionInterceptor(base64Key: myBase64Key));
}

2. Making Encrypted Requests

By default, any POST, PUT, or PATCH request with a JSON body (Map<String, dynamic>) will be encrypted.

// This request body will be automatically encrypted
final response = await dio.post(
  '/api/secure-endpoint',
  data: {
    'userId': '12345',
    'action': 'update_profile'
  },
);

What happens over the network: The body sent to the server will look like:

{
  "request": "U2FsdGVkX1+..."
}

3. Skipping Encryption

If you need to send a request without encryption (e.g., for application/x-www-form-urlencoded or public endpoints), use the skipEncryption option in extra.

final response = await dio.post(
  '/api/public-endpoint',
  data: {
    'grant_type': 'password',
    'username': 'user',
    'password': 'password'
  },
  options: Options(
    contentType: Headers.formUrlEncodedContentType,
    extra: {
      'skipEncryption': true, // Disables the interceptor for this request
    },
  ),
);

Dependencies

• dio: A powerful Http client for Dart.
• sodium_libs: Libsodium for Dart.

License

MIT License. See LICENSE for details.

Copyright (c) 2026 Fakeeh Tech.