Add dotenv configuration provider

This commit is contained in:
Sambo Chea 2021-03-24 13:52:20 +07:00
parent 77a4f6064f
commit a51d5fe00b
9 changed files with 194 additions and 1 deletions

2
.env Normal file
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app.name = 'CUBETIQ Solution'
export NAME='Sambo Chea'

3
example/example.dart Normal file
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void main() {
print('Example');
}

54
lib/dotenv/dotenv.dart Normal file
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/// Loads environment variables from a `.env` file.
///
/// ## usage
///
/// Once you call [load], the top-level [env] map is available.
/// You may wish to prefix the import.
///
/// import 'package:dotenv/dotenv.dart' show load, env;
///
/// void main() {
/// load();
/// var x = env['foo'];
/// // ...
/// }
///
/// Verify required variables are present:
///
/// const _requiredEnvVars = const ['host', 'port'];
/// bool get hasEnv => isEveryDefined(_requiredEnvVars);
library dotenv;
import 'dart:io';
import 'package:meta/meta.dart';
part 'parser.dart';
var _env = Map<String, String>.from(Platform.environment);
/// A copy of [Platform.environment](dart:io) including variables loaded at runtime from a file.
Map<String, String> get env => _env;
/// Overwrite [env] with a new writable copy of [Platform.environment](dart:io).
Map clean() => _env = Map.from(Platform.environment);
/// True if all supplied variables have nonempty value; false otherwise.
/// Differs from [containsKey](dart:core) by excluding null values.
/// Note [load] should be called first.
bool isEveryDefined(Iterable<String> vars) =>
vars.every((k) => _env[k] != null && (_env[k]?.isNotEmpty ?? false));
/// Read environment variables from [filename] and add them to [env].
/// Logs to [stderr] if [filename] does not exist.
void load([String filename = '.env', Parser psr = const Parser()]) {
var file = File.fromUri(Uri.file(filename));
var lines = _verify(file);
_env.addAll(psr.parse(lines));
}
List<String> _verify(File file) {
if (file.existsSync()) return file.readAsLinesSync();
stderr.writeln('[dotenv] Load failed: file not found: $file');
return [];
}

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lib/dotenv/parser.dart Normal file
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part of dotenv;
/// Creates key-value pairs from strings formatted as environment
/// variable definitions.
class Parser {
static const _singleQuot = "'";
static const _keyword = 'export';
static final _comment = RegExp(r'''#.*(?:[^'"])$''');
static final _surroundQuotes = RegExp(r'''^(['"])(.*)\1$''');
static final _bashVar = RegExp(r'(?:\\)?(\$)(?:{)?([a-zA-Z_][\w]*)+(?:})?');
/// [Parser] methods are pure functions.
const Parser();
/// Creates a [Map](dart:core) suitable for merging into [Platform.environment](dart:io).
/// Duplicate keys are silently discarded.
Map<String, String> parse(Iterable<String> lines) {
var out = <String, String>{};
lines.forEach((line) {
var kv = parseOne(line, env: out);
if (kv.isEmpty) return;
out.putIfAbsent(kv.keys.single, () => kv.values.single);
});
return out;
}
/// Parses a single line into a key-value pair.
@visibleForTesting
Map<String, String> parseOne(String line,
{Map<String, String> env: const {}}) {
var stripped = strip(line);
if (!_isValid(stripped)) return {};
var idx = stripped.indexOf('=');
var lhs = stripped.substring(0, idx);
var k = swallow(lhs);
if (k.isEmpty) return {};
var rhs = stripped.substring(idx + 1, stripped.length).trim();
var quotChar = surroundingQuote(rhs);
var v = unquote(rhs);
if (quotChar == _singleQuot) {
return {k: v};
}
return {k: interpolate(v, env)};
}
/// Substitutes $bash_vars in [val] with values from [env].
@visibleForTesting
String interpolate(String val, Map<String, String> env) =>
val.replaceAllMapped(_bashVar, (m) {
var k = m.group(2)!;
return (!_has(env, k)) ? _tryPlatformEnv(k) ?? '' : env[k] ?? '';
});
/// If [val] is wrapped in single or double quotes, returns the quote character.
/// Otherwise, returns the empty string.
@visibleForTesting
String surroundingQuote(String val) {
if (!_surroundQuotes.hasMatch(val)) return '';
return _surroundQuotes.firstMatch(val)!.group(1)!;
}
/// Removes quotes (single or double) surrounding a value.
@visibleForTesting
String unquote(String val) =>
val.replaceFirstMapped(_surroundQuotes, (m) => m[2]!).trim();
/// Strips comments (trailing or whole-line).
@visibleForTesting
String strip(String line) => line.replaceAll(_comment, '').trim();
/// Omits 'export' keyword.
@visibleForTesting
String swallow(String line) => line.replaceAll(_keyword, '').trim();
bool _isValid(String s) => s.isNotEmpty && s.contains('=');
/// [null] is a valid value in a Dart map, but the env var representation is empty string, not the string 'null'
bool _has(Map<String, String> map, String key) =>
map.containsKey(key) && map[key] != null;
String? _tryPlatformEnv(String key) {
if (!_has(Platform.environment, key)) {
return '';
}
return Platform.environment[key];
}
}

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import 'package:configurable/configuration_provider.dart';
import 'package:configurable/dotenv/dotenv.dart' show env;
class DotenvConfigurationProvider implements ConfigurationProvider {
@override
bool containsKey(String key) {
return env.containsKey(key);
}
@override
String? getOrNull(String key, {String? defaultValue}) {
var value = env[key];
if (value == null) {
return defaultValue;
}
return value;
}
}

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@ -135,7 +135,7 @@ packages:
source: hosted
version: "0.12.10"
meta:
dependency: transitive
dependency: "direct main"
description:
name: meta
url: "https://pub.dartlang.org"

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@ -8,6 +8,7 @@ environment:
dependencies:
test: ^1.16.8
meta: ^1.3.0
dev_dependencies:
pedantic: ^1.9.0

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@ -10,4 +10,5 @@ void main() {
expect(value, equals(result));
expect(value, equals(SystemConfig.getOrNull(key)));
});
}

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test/dotenv_test.dart Normal file
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import 'package:configurable/dotenv/dotenv.dart';
import 'package:test/test.dart';
void main() {
test('just call env', () {
load();
var result = env['app.name'];
expect('CUBETIQ Solution', equals(result));
});
test('get export variable', () {
load();
var result = env['NAME'];
expect('Sambo Chea', equals(result));
});
}