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Description:

flutter dotenv

flutter_dotenv #

Load configuration at runtime from a .env file which can be used throughout the application.

The twelve-factor app stores config in environment variables
(often shortened to env vars or env). Env vars are easy to change
between deploys without changing any code... they are a language- and
OS-agnostic standard.

About #
This library is a fork of mockturtl/dotenv dart library, initially with slight changes to make it work with flutter.
An environment is the set of variables known to a process (say, PATH, PORT, ...).
It is desirable to mimic the production environment during development (testing,
staging, ...) by reading these values from a file.
This library parses that file and merges its values with the built-in
Platform.environment map.
Usage #

Create a .env file in the root of your project with the example content:

FOO=foo
BAR=bar
FOOBAR=$FOO$BAR
ESCAPED_DOLLAR_SIGN='$1000'
# This is a comment
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Note: If deploying to web server, ensure that the config file is uploaded and not ignored. (Whitelist the config file on the server, or name the config file without a leading .)

Add the .env file to your assets bundle in pubspec.yaml. Ensure that the path corresponds to the location of the .env file!

assets:
- .env
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Remember to add the .env file as an entry in your .gitignore if it isn't already unless you want it included in your version control.

*.env
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Load the .env file in main.dart. Note that flutter_dotenv >=5.0.0 has a slightly different syntax for consuming the DotEnv data.

v5.0.0 and later
import 'package:flutter_dotenv/flutter_dotenv.dart';

// DotEnv dotenv = DotEnv() is automatically called during import.
// If you want to load multiple dotenv files or name your dotenv object differently, you can do the following and import the singleton into the relavant files:
// DotEnv another_dotenv = DotEnv()

Future main() async {
// To load the .env file contents into dotenv.
// NOTE: fileName defaults to .env and can be omitted in this case.
// Ensure that the filename corresponds to the path in step 1 and 2.
await dotenv.load(fileName: ".env");
//...runapp
}
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You can then access variables from .env throughout the application
import 'package:flutter_dotenv/flutter_dotenv.dart';
dotenv.env['VAR_NAME'];
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Before v5.0.0
import 'package:flutter_dotenv/flutter_dotenv.dart' as DotEnv;

Future main() async {
await DotEnv.load(fileName: ".env");
//...runapp
}
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Access env using:
import 'package:flutter_dotenv/flutter_dotenv.dart';
env['VAR_NAME'];
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Optionally you could map env after load to a config model to access a config with types.
Advanced usage #
Refer to the test/dotenv_test.dart file for a better idea of the behaviour of the .env parser.
Referencing #
You can reference variables defined above other within .env:
FOO=foo
BAR=bar
FOOBAR=$FOO$BAR
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You can escape referencing by wrapping the value in single quotes:
ESCAPED_DOLLAR_SIGN='$1000'
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Merging #
You can merge a map into the environment on load:
await DotEnv.load(mergeWith: { "FOO": "foo", "BAR": "bar"});
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You can also reference these merged variables within .env:
FOOBAR=$FOO$BAR
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Using in tests #
There is a testLoad method that can be used to load a static set of variables for testing.
// Loading from a static string.
dotenv.testLoad(fileInput: '''FOO=foo
BAR=bar
''');

// Loading from a file synchronously.
dotenv.testLoad(fileInput: File('test/.env').readAsStringSync());
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Null safety #
To avoid null-safety checks for variables that are known to exist, there is a get() method that
will throw an exception if the variable is undefined. You can also specify a default fallback
value for when the variable is undefined in the .env file.
Future<void> main() async {
await dotenv.load();

String foo = dotenv.get('VAR_NAME');

// Or with fallback.
String bar = dotenv.get('MISSING_VAR_NAME', fallback: 'sane-default');

// This would return null.
String? baz = dotenv.maybeGet('MISSING_VAR_NAME', fallback: null);
}
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Usage with Platform Environment #
The Platform.environment map can be merged into the env:
// For example using Platform.environment that contains a CLIENT_ID entry
await DotEnv.load(mergeWith: Platform.environment);
print(env["CLIENT_ID"]);
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Like other merged entries described above, .env entries can reference these merged Platform.Environment entries if required:
CLIENT_URL=https://$CLIENT_ID.dev.domain.com
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Discussion #
Use the issue tracker for bug reports and feature requests.
Pull requests are welcome.
Prior art #

mockturtl/dotenv (dart)
bkeepers/dotenv (ruby)
motdotla/dotenv (node)
theskumar/python-dotenv (python)
joho/godotenv (go)
slapresta/rust-dotenv (rust)
chandu/dotenv (c#)
tpope/lein-dotenv, rentpath/clj-dotenv (clojure)
mefellows/sbt-dotenv (scala)
greenspun/dotenv (half of common lisp)

license: MIT #