7z-iterator

7z-iterator

Extract contents from 7z archive type using an iterator API using streams or paths. Use stream interface and pipe transforms to add decompression algorithms.

// asyncIterator

var assert = require('assert');
var fs = require('fs');
var SevenZipIterator = require('7z-iterator');

(async function() {
  let iterator = new SevenZipIterator('/path/to/archive');

  try {
    const links = [];
    for await (const entry of iterator) {
      if (entry.type === 'link') links.unshift(entry);
      else if (entry.type === 'symlink') links.push(entry);
      else await entry.create(dest, options);
    }

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    }

  iterator.destroy();
  iterator = null;
})();

(async function() {
  let iterator = new SevenZipIterator(fs.createReadStream('/path/to/archive'));

  try {
    const links = [];
    for await (const entry of iterator) {
      if (entry.type === 'link') links.unshift(entry);
      else if (entry.type === 'symlink') links.push(entry);
      else await entry.create(dest, options);
    }

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    }

  iterator.destroy();
  iterator = null;
})();

// Async / Await

var assert = require('assert');
var SevenZipIterator = require('7z-iterator');

// one by one
(async function() {
  let iterator = new SevenZipIterator('/path/to/archive');

  const links = [];
  let entry = await iterator.next();
  while (entry) {
    if (entry.type === 'link') links.unshift(entry);
    else if (entry.type === 'symlink') links.push(entry);
    else await entry.create(dest, options);
    entry = await iterator.next();
  }

  // create links after directories and files
  for (entry of links) {
    await entry.create(dest, options);
  }
  iterator.destroy();
  iterator = null;
})();

// infinite concurrency
(async function() {
  let iterator = new SevenZipIterator('/path/to/archive');

  try {
    const links = [];
    await iterator.forEach(
      async function (entry) {
        if (entry.type === 'link') links.unshift(entry);
        else if (entry.type === 'symlink') links.push(entry);
        else await entry.create(dest, options);
      },
      { concurrency: Infinity }
    );

    // create links after directories and files
    for (const entry of links) await entry.create(dest, options);
  } catch (err) {
    aseert.ok(!err);
  }

  iterator.destroy();
  iterator = null;
})();

// Callbacks

var assert = require('assert');
var Queue = require('queue-cb');
var SevenZipIterator = require('7z-iterator');

var iterator = new SevenZipIterator('/path/to/archive');

// one by one
var links = [];
iterator.forEach(
  function (entry, callback) {
    if (entry.type === 'link') {
      links.unshift(entry);
      callback();
    } else if (entry.type === 'symlink') {
      links.push(entry);
      callback();
    } else entry.create(dest, options, callback);
  },
  { callbacks: true, concurrency: 1 },
  function (err) {

    // create links after directories and files
    var queue = new Queue();
    for (var index = 0; index < links.length; index++) {
      var entry = links[index];
      queue.defer(entry.create.bind(entry, dest, options));
    }
    queue.await(callback);

    iterator.destroy();
    iterator = null;
  }
);

Limitations

Node.js Version Compatibility

This library supports Node.js 0.8+ but has memory limits on older versions:

LZMA1 vs LZMA2

• LZMA2: Streams incrementally, memory efficient, works on all Node versions
• LZMA1: Requires loading entire folder into memory before decompression. Fails on archives with folders larger than the buffer limit above.

Archive Size Limits by Node Version

For large LZMA1 archives, use Node 8+ or re-archive using LZMA2 format.