configurable/lib/dotenv/dotenv_parser.dart
Sambo Chea 33b6355bcf Add configurable with functions
Add more tests for call functions and fixed
2021-03-24 14:10:25 +07:00

88 lines
2.5 KiB
Dart

part of dotenv;
class DotenvParser {
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]*)+(?:})?');
// constructor for parser
const DotenvParser();
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('=');
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];
}
}