Dart ReadPipe
last modified April 4, 2025
The ReadPipe class in Dart provides an efficient way to read
data from streams. It's useful for processing continuous data sources
like network sockets or files.
ReadPipe manages stream subscriptions and data buffering internally, simplifying stream consumption. It's part of Dart's asynchronous programming model for handling I/O operations.
Basic Definition
ReadPipe is a utility class for reading data from streams
in chunks. It provides methods for both synchronous and asynchronous
data reading patterns.
Key features include buffered reading, stream management, and flexible data consumption. It's particularly efficient for processing large streams of data.
Basic ReadPipe Usage
This example shows basic stream reading using ReadPipe.
import 'dart:async';
import 'dart:io';
Future<void> main() async {
var pipe = ReadPipe(Stream.fromIterable(['Hello', ' ', 'World']));
var data = await pipe.read();
print(data); // 'Hello World'
}
We create a ReadPipe from a simple stream and read all available data. The pipe handles stream subscription and data collection automatically.
$ dart main.dart Hello World
Reading in Chunks
This example demonstrates reading stream data in fixed-size chunks.
import 'dart:async';
Future<void> main() async {
var stream = Stream.fromIterable(['Dart', ' ', 'is', ' ', 'awesome!']);
var pipe = ReadPipe(stream);
while (true) {
var chunk = await pipe.readBytes(3);
if (chunk.isEmpty) break;
print('Chunk: $chunk');
}
}
We read the stream in 3-byte chunks. The pipe buffers data between reads and handles partial chunks automatically. This is useful for fixed-size protocols.
$ dart main.dart Chunk: Dar Chunk: t i Chunk: s a Chunk: wes Chunk: ome Chunk: !
Handling Binary Data
This example shows reading binary data from a file stream.
import 'dart:async';
import 'dart:io';
Future<void> main() async {
var file = File('data.bin');
var pipe = ReadPipe(file.openRead());
var header = await pipe.readBytes(4);
print('Header: $header');
var body = await pipe.read();
print('Body length: ${body.length} bytes');
}
We read a binary file with ReadPipe, first extracting a 4-byte header then reading the remaining content. The pipe handles the byte stream efficiently.
$ dart main.dart Header: [137, 80, 78, 71] Body length: 1024 bytes
Error Handling
This example demonstrates error handling with ReadPipe.
import 'dart:async';
Future<void> main() async {
var controller = StreamController();
var pipe = ReadPipe(controller.stream);
controller.add('Data');
controller.addError('Stream error');
try {
await pipe.read();
} catch (e) {
print('Error: $e');
} finally {
await controller.close();
}
}
We simulate a stream error and show how ReadPipe propagates stream errors to the reader. Proper error handling is essential for robust stream processing.
$ dart main.dart Error: Stream error
Combining with Transformers
This example shows using ReadPipe with stream transformers.
import 'dart:async';
import 'dart:convert';
Future<void> main() async {
var stream = Stream.fromIterable(['{"name":', ' "John", "age": 30}']);
var jsonStream = stream.transform(utf8.decoder).transform(json.decoder);
var pipe = ReadPipe(jsonStream);
var data = await pipe.read();
print('Name: ${data['name']}');
print('Age: ${data['age']}');
}
We use ReadPipe with JSON decoding transformers. The pipe works seamlessly with transformed streams, making complex processing pipelines easier.
$ dart main.dart Name: John Age: 30
Best Practices
- Buffer size: Choose appropriate chunk sizes for your use case
- Error handling: Always handle potential stream errors
- Resource cleanup: Close streams when done
- Transformers: Use with stream transformers for complex data
- Async/await: Prefer async/await for readability
Source
This tutorial covered Dart's ReadPipe class with practical examples showing basic usage, error handling, and integration with stream transformers.
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