rar-stream

Fast RAR archive streaming for Node.js and browsers. Zero dependencies, pure Rust.

Features

• 🚀 Fast: Native Rust implementation with NAPI bindings
• 📦 Zero dependencies: No external runtime dependencies
• 🌐 Cross-platform: Works on Linux, macOS, Windows
• 🔄 Streaming: Stream files directly from RAR archives
• 📚 Multi-volume: Supports split archives (.rar, .r00, .r01, ...)
• 🗜️ Full decompression: LZSS, PPMd, and VM filters
• 🌍 Browser support: WASM build available

Installation

npm install rar-stream
# or
yarn add rar-stream
# or
pnpm add rar-stream

Quick Start

import { LocalFileMedia, RarFilesPackage } from 'rar-stream';

// Single RAR file
const media = new LocalFileMedia('./archive.rar');
const pkg = new RarFilesPackage([media]);

// Parse archive and get inner files
const files = await pkg.parse();

for (const file of files) {
  console.log(`${file.name}: ${file.length} bytes`);
  
  // Read entire file
  const buffer = await file.readToEnd();
  
  // Or read a specific range
  const chunk = await file.createReadStream({ start: 0, end: 1024 });
}

API Reference

LocalFileMedia

Represents a local RAR file.

class LocalFileMedia {
  constructor(path: string);
  
  readonly name: string;
  readonly length: number;
  
  createReadStream(opts: { start: number; end: number }): Promise<Buffer>;
}

RarFilesPackage

Parses single or multi-volume RAR archives.

class RarFilesPackage {
  constructor(files: LocalFileMedia[]);
  
  parse(opts?: {
    maxFiles?: number;
  }): Promise<InnerFile[]>;
}

InnerFile

Represents a file inside the RAR archive.

class InnerFile {
  readonly name: string;
  readonly length: number;
  
  readToEnd(): Promise<Buffer>;
  createReadStream(opts: { start: number; end: number }): Promise<Buffer>;
}

Utility Functions

// Check if buffer contains RAR signature
function isRarArchive(buffer: Buffer): boolean;

// Parse RAR header from buffer (useful for detecting files)
function parseRarHeader(buffer: Buffer): RarFileInfo | null;

Multi-Volume Archives

import { LocalFileMedia, RarFilesPackage } from 'rar-stream';

// Load all volumes
const volumes = [
  new LocalFileMedia('./archive.rar'),
  new LocalFileMedia('./archive.r00'),
  new LocalFileMedia('./archive.r01'),
];

const pkg = new RarFilesPackage(volumes);
const files = await pkg.parse();

// Files spanning multiple volumes are handled automatically
const content = await files[0].readToEnd();

Browser Usage (WASM)

import init, { isRarArchive, WasmRarDecoder } from 'rar-stream/wasm';

await init();

// Check if data is a RAR archive
const buffer = new Uint8Array(/* ... */);
if (isRarArchive(buffer)) {
  // Create decoder
  const decoder = new WasmRarDecoder(unpackedSize);
  const decompressed = decoder.decompress(compressedData);
}

Compression Support

Performance

Benchmarks on M1 MacBook Pro:

Migrating from v3.x

rar-stream v4.0 is a complete Rust rewrite with the same API. It's a drop-in replacement:

// Works the same in v3.x and v4.x
import { LocalFileMedia, RarFilesPackage } from 'rar-stream';

const media = new LocalFileMedia('./archive.rar');
const pkg = new RarFilesPackage([media]);
const files = await pkg.parse();

Breaking Changes

• Node.js 18+ required (was 14+)
• WASM module path changed to rar-stream/wasm
• Native Rust implementation (faster, lower memory)

License

MIT © beam.cat

Credits

• Based on unrar reference implementation
• PPMd algorithm by Dmitry Shkarin