async_zip 0.0.1

Asynchronous reading and writing of Zip files.

Asynchronous Zip library

This package allows reading and writing Zip archives asynchronously and with low memory consumption.

There is already a standard archive library for Dart. But the standard library has two major issues:

• It cannot be used asynchronously
• It reads Zip files completely to memory and unpacks them from there. This is an issue when reading large Zip files on low or medium range devices.

Zip files can be read and written synchronously as well as asynchronously. Synchronous access may be faster in some situations. Choose whatever you need.

Make sure to call close() in any case after having worked with a Zip file. You are leaking resources otherwise or risk ending up with an unfinished Zip file when working with ZipFileWriter(Async).

Reading Zip files

Reading data synchronously

import 'package:async_zip/async_zip.dart';

final reader = ZipFileReader();
try {
  reader.open(File('path-to-archive.zip'));
  
  // Get all Zip entries
  final entries = reader.entries();
  for (final entry in entries) {
    print('${entry.name} ${entry.size}');
  }

  // Read a specific file
  reader.readFile('specific-image.jpg', File('/somewhere/on/disk/image.jpg'));

  // Read specific data as Uint8List
  final data = reader.readFile('README.md');

} on ZipException catch (ex) {
  print('Could not read Zip file: ${$ex.message}');
} finally {
  reader.close();
}

Reading data asynchronously

import 'package:async_zip/async_zip.dart';

final reader = ZipFileReaderAsync();
try {
  reader.open(File('path-to-archive.zip'));
  
  // Get all Zip entries
  final entries = await reader.entries();
  for (final entry in entries) {
    print('${entry.name} ${entry.size}');
  }

  // Read a specific file
  await reader.readFile('specific-image.jpg', File('/somewhere/on/disk/image.jpg'));

  // Read specific data as Uint8List
  final data = await reader.readFile('README.md');

} on ZipException catch (ex) {
  print('Could not read Zip file: ${$ex.message}');
} finally {
  await reader.close();
}

Writing Zip files

Writing data synchronously

import 'package:async_zip/async_zip.dart';

final reader = ZipFileWriter();
try {
  reader.create(File('path-to-archive.zip'));

  // Write a file to the Zip file
  reader.writeFile('image.jpg', File('/somewhere/on/disk/image.jpg'));

  // Write Uint8List data to the Zip file
  Uint8List data = ...; // some binary data
  reader.writeData('data.txt', data);

} on ZipException catch (ex) {
  print('Could not create Zip file: ${$ex.message}');
} finally {
  reader.close();
}

Write data asynchronously

import 'package:async_zip/async_zip.dart';

final reader = ZipFileWriter();
try {
  await reader.create(File('path-to-archive.zip'));

  // Write a file to the Zip file
  await reader.writeFile('image.jpg', File('/somewhere/on/disk/image.jpg'));

  // Write Uint8List data to the Zip file
  Uint8List data = ...; // some binary data
  await reader.writeData('data.txt', data);

} on ZipException catch (ex) {
  print('Could not create Zip file: ${$ex.message}');
} finally {
  await reader.close();
}

Internals

This package uses the following C library for reading and writing:
https://github.com/kuba--/zip

The library is integrated using Dart's foreign function interface (FFI).