enven

Generate environment variables from a .env file at compile time with optional obfuscation.

Motivation

Sometimes, it is necessary to have secrets embedded in your app to avoid your API being abused.

While flutter_dotenv is great, it puts the environment variables in the assets folder in clear text which is too easy to reverse engineer.

The solution by envied requires you to write a verbose env.dart file which is not very DRY.

With enven, you just need to write a .env file and run dart run enven to generate a env.g.dart file.

Table of Contents

• Getting Started
• Configuration
• Overrides
• Mocking

Getting Started

Step 1: Add dependency

# pubspec.yaml
dev_dependencies:
  enven: <version>
  build_runner: <version> # OPTIONAL

Step 2: Write a .env file in the project root directory.

API_KEY=1234567890
API_ENDPOINT=https://example.com

Step 3: Generate dart file

dart run enven

If you just check out the project, you can also run build_runner.

Be careful because it only works once. (Subsequent runs won't notice changes.)

dart run build_runner build -d

Step 4: Access

import 'package:your_package/gen/env.g.dart';

int apiKey = Env.apiKey; // 1234567890
String apiEndpoint = Env.apiEndpoint; // https://example.com

Configuration

Comments starting with #enven: are treated as configuration.

#enven:output=lib/gen/env.g.dart

#enven:obfuscate
#enven:type=String
API_KEY=1234567890

#enven:obfuscate
#enven:name=endpoint
API_ENDPOINT=https://example.com

Key	Applies to	Type	Usage	Default
output	file	String	Specify output file path	lib/gen/env.g.dart
seed	file	String	Specify seed for obfuscation	(random)
obfuscate	variable	bool	Obfuscate the environment variable.	false
const	variable	bool	Generate as const	false
type	variable	String, int, double, bool	Specify exact type	(inferred)
name	variable	String	Specify variable name	(inferred)

Overrides

You may want to have default values. In this case, you should commit .env to your repository.

For production, you can override the values by creating a .env.prod file.

# File: .env
API_KEY=abcdefg
API_ENDPOINT=https://dev.example.com
APP_NAME=My App

# File: .env.prod
API_KEY=my-secret-key
API_ENDPOINT=https://prod.example.com

// Production
String apiKey = Env.apiKey; // my-secret-key
String apiEndpoint = Env.apiEndpoint; // https://prod.example.com
String appName = Env.appName; // My App <-- from .env

Here is the precedence:

1. .env.production
2. .env.prod
3. .env.development
4. .env.dev
5. .env

Mocking

You can also mock the environment variables by setting Env.instance to a mocked object.

import 'package:your_package/gen/env.g.dart';

class MockEnvData implements EnvData {
  String get apiKey => 'I am mocked';
}

void main() {
  print(Env.apiKey); // "abcdefg"
  Env.instance = MockEnvData();
  print(Env.apiKey); // "I am mocked"
}

You can also use with EnvData instead of implements EnvData to only override some variables. Be aware that variables annotated with #enven:const cannot be overridden.

License

MIT License

Copyright (c) 2023 Tien Do Nam

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.