Dart IO and Streams the right way
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library io_testing; | |
import 'dart:async'; | |
import 'dart:io'; | |
import 'dart:convert'; | |
class UpperCaseConverter extends Converter<String, String> { | |
@override | |
String convert(String input) => input.toUpperCase(); | |
@override | |
Sink<String> startChunkedConversion(Sink<String> sink) { | |
return StringEventConverterSink(sink, this); | |
} | |
} | |
class StringEventConverterSink extends StringConversionSinkBase { | |
EventSink<String> innerSink; | |
Converter<String, String> converter; | |
StringEventConverterSink(Sink<String> sink, Converter<String, String> converter) { | |
this.innerSink = sink; | |
this.converter = converter; | |
} | |
@override | |
void addSlice(String str, int start, int end, bool isLast) { | |
innerSink.add(converter.convert(str)); | |
} | |
@override | |
void close() { | |
innerSink.close(); | |
} | |
} | |
Future main() async { | |
var config = File(Platform.script.toFilePath()); | |
Stream<List<int>> inputStream = config.openRead(); | |
var lines = inputStream | |
.transform(utf8.decoder) | |
.transform(LineSplitter()) | |
.transform(UpperCaseConverter()); | |
try { | |
await for (var line in lines) { | |
print('Got ${line.length} characters from stream'); | |
print(line); | |
} | |
print('file is now closed'); | |
} catch (e) { | |
print(e); | |
} | |
} |
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library io_expedition; | |
import 'dart:async'; | |
import 'dart:io'; | |
import 'dart:convert'; | |
class StringConverter extends Converter<String, String> { | |
String Function(String x) convertFunction; | |
StringConverter(this.convertFunction); | |
@override | |
String convert(String input) => convertFunction(input); | |
@override | |
Sink<String> startChunkedConversion(Sink<String> sink) => StringEventConverterSink(sink, this); | |
} | |
class UpperCaseConverter extends Converter<String, String> { | |
@override | |
String convert(String input) => input.toUpperCase(); | |
@override | |
Sink<String> startChunkedConversion(Sink<String> sink) => StringEventConverterSink(sink, this); | |
} | |
class StringEventConverterSink extends StringConversionSinkBase { | |
EventSink<String> innerSink; | |
Converter<String, String> converter; | |
StringEventConverterSink(this.innerSink, this.converter); | |
@override | |
void addSlice(String str, int start, int end, bool isLast) => innerSink.add(converter.convert(str)); | |
@override | |
void close() => innerSink.close(); | |
} | |
Future main() async { | |
var config = File(Platform.script.toFilePath()); | |
Stream<List<int>> inputStream = config.openRead(); | |
var lines = inputStream | |
.transform(utf8.decoder) | |
.transform(LineSplitter()) | |
.transform(StringConverter((String x) => x.toUpperCase())); | |
try { | |
await for (var line in lines) { | |
print('Got ${line.length} characters from stream'); | |
print(line); | |
} | |
print('file is now closed'); | |
} catch (e) { | |
print(e); | |
} | |
} |
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