archive #

Overview #

A Dart library to encode and decode various archive and compression formats.

The archive library currently supports the following decoders:

• Zip (Archive)
• Tar (Archive)
• ZLib [Inflate decompression]
• GZip [Inflate decompression]
• BZip2 [decompression]
• XZ [decompression]

And the following encoders:

• Zip (Archive)
• Tar (Archive)
• ZLib [Deflate compression]
• GZip [Deflate compression]
• BZip2 [compression]
• XZ [uncompressed data only]

Usage #

There are two versions of the Archive library:

package:archive/archive.dart

• Can be used for web applications since it has no dependency on 'dart:io'.

package:archive/archive_io.dart

• For Flutter and server applications, with direct file access to reduce memory usage. All classes and functions of archive.dart are included in archive_io.dart.

archive_io #

The archive_io library contains classes and functions for accessing the file system. These classes and functions can significantly reduce memory usage for decoding archives directly to disk.

Using InputFileStream and OutputFileStream to reduce memory usage:

import 'package:archive/archive_io.dart';
// ...
  // Use an InputFileStream to access the zip file without storing it in memory.
  final inputStream = InputFileStream('test.zip');
  // Decode the zip from the InputFileStream. The archive will have the contents of the
  // zip, without having stored the data in memory. 
  final archive = ZipDecoder().decodeBuffer(inputStream);
  // For all of the entries in the archive
  for (var file in archive.files) {
    // If it's a file and not a directory 
    if (file.isFile) {
      // Write the file content to a directory called 'out'.
      // In practice, you should make sure file.name doesn't include '..' paths
      // that would put it outside of the extraction directory.
      // An OutputFileStream will write the data to disk.
      final outputStream = OutputFileStream('out/${file.name}');
      // The writeContent method will decompress the file content directly to disk without
      // storing the decompressed data in memory. 
      file.writeContent(outputStream);
      // Make sure to close the output stream so the File is closed.
      outputStream.close();
    }
  }

extractFileToDisk

extractFileToDisk is a convenience function to extract the contents of an archive file directory to an output directory. The type of archive it is will be determined by the file extension.

import 'package:archive/archive_io.dart';
// ...
extractFileToDisk('test.zip', 'out');

extractArchiveToDisk

extractArchiveToDisk is a convenience function to write the contents of an Archive to an output directory.

import 'package:archive/archive_io.dart';
// ...
// Use an InputFileStream to access the zip file without storing it in memory.
final inputStream = InputFileStream('test.zip');
// Decode the zip from the InputFileStream. The archive will have the contents of the
// zip, without having stored the data in memory. 
final archive = ZipDecoder().decodeBuffer(inputStream);
extractArchiveToDisk(archive, 'out');