avfs

Another Virtual File System

Description

The goal of this project is to reproduce the Node.js core fs API essentially for testing/mocking purpose.

It creates a virtual file system stored directly in memory.

Supported Node.js versions

• v0.10
• v0.12
• v4
• v5
• v6
• v7
• v8

Usage

// The module exports an AVFS constructor

var AVFS = require('avfs');

// Instantiate a fs

var fs = new AVFS();

// Use it as the core fs module

fs.mkdirSync('/tmp');

fs.writeFileSync('/tmp/file', 'Hello, friend.');

var stats = fs.statSync('/tmp/file');

fs.open('/tmp/test.txt', 'r', function (error, fd) {
  var buffer = new Buffer(6);

  fs.read(fd, buffer, 0, 6, null, function (error, bytesRead, buffer) {
    if (bytesRead > 0) {
      console.log(buffer.toString());
    }
  });
});

Caveats

• File types support

AVFS only support basic file types (file, directory and symlink).

Other types (socker, FIFO, block device, character device) are not supported.

• Changes watching API

Watching functions (watch, watchFile and unwatchFile) are only placeholder.

They work as their core fs module couterparts but will not emit events.

Motivation

Initially, this project has been started in order to create a file system independent of the host. The idea was to run file dependent tests in a consistent environment on all systems. This project should have hidden the specificities between the file systems (system directories, access rights ...).

But some more effective and reliable solutions to these issues have now become standard. The best example is certainly the use of docker containers to run tests.

Despite this, I decided to continue this project at least to a first release. It allowed me to dive a little deeper into the node's core in a different way than simply reading the code. And maybe someone could find some use to this module.

License

See License