Dart

Unzip a Text File Entry into a StringBuilder Using ZipEntry.UnzipToSb

See more Zip Examples

This example demonstrates how to use the ZipEntry.UnzipToSb method to inflate a text file entry directly into a StringBuilder object.

The ZIP entry is uncompressed entirely in memory and appended to the StringBuilder without creating a temporary file on disk.

This is useful when:

• Processing text files directly in memory
• Avoiding temporary filesystem files
• Reading configuration files, JSON, XML, CSV, or source code from ZIP archives
• Automatically converting line endings while inflating the text

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as:

• utf-8
• utf-16
• windows-1252

The lineEndingBehavior argument controls line-ending conversion:

• 0 — Leave line endings unchanged
• 1 — Convert all line endings to bare LF
• 2 — Convert all line endings to CRLF

Suppose the ZIP archive contains:

config/settings.json

The example inflates the JSON file directly into a StringBuilder.

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  var success = false;

  final zip = CkZip();

  // Open an existing ZIP archive.
  try {
    zip.openZip('qa_data/zips/configFiles.zip');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Locate the JSON file entry within the ZIP archive.
  final entry = CkZipEntry();

  success = zip.entryOf('config/settings.json', entry);
  if (!success) {
    print('ZIP entry not found.');
    zip.closeZip();
    return;
  }

  // ------------------------------------------------------------
  // Inflate the ZIP entry directly into a StringBuilder.
  // 
  // The uncompressed text is appended to the StringBuilder.
  // 
  final sb = CkStringBuilder();

  // Leave line endings unchanged.
  final lineEndingBehavior = 0;

  // Interpret the uncompressed bytes as UTF-8 text.
  final srcCharset = 'utf-8';

  try {
    entry.unzipToSb(lineEndingBehavior, srcCharset, sb);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Uncompressed text:');
  print('');
  print(sb.getAsString());

  zip.closeZip();

  print('Done.');
}