File System (WNFS)

Working with the Webnative File System (WNFS)

The Web Native File System (WNFS) is a file system built on top of the InterPlanetary Linked Data model (IPLD). Each Webnative user has their own WNFS, and apps store user files and data in it.

Each file system has a public tree and a private tree, much like your macOS, Windows, or Linux desktop file system. The public tree is "live" and publicly accessible on the Internet. The private tree is encrypted so that only the owner can see the contents.

All information (links, data, metadata, etc.) in the private tree is encrypted. Decryption keys are stored so that access to a given directory grants access to all of its subdirectories.

WNFS is structured and functions similarly to a Unix-style file system, with one notable exception: it's a Directed Acyclic Graph (DAG), meaning that a given child can have more than one parent (think symlinks but without the "sym").


A Webnative app assumes full access to the file system unless given a permissions object in the configuration, then it assumes authorization to parts of the filesystem will be granted when requesting capabilities from another app.


WNFS uses directory and file paths built from path segments by path functions.

const { RootBranch } = wn.path

// Creates a directory path equivalent to "public/some/directory/"
const publicDirectoryPath ="public", "some", "directory")

// Creates a directory path equivalent to "private/some/directory/"
const privateDirectoryPath ="private", "some", "directory")

// Creates a file path equivalent to "public/some/file"
const publicFilePath = wn.path.file("public", "some", "file")

// Creates a file path equivalent to "private/some/file"
const privateFilePath = wn.path.file("private", "some", "file")

// Paths can also use RootBranch.Public and RootBranch.Private constants
const anotherPublicPath = wn.path.file(RootBranch.Public, "another", "file")
const anotherPrivatePath = wn.path.file(RootBranch.Private, "another", "file")

All WNFS operations expect paths created by path functions. See the path API documentation for more path utility functions.

Path Objects. The path functions create objects like { directory: ["public", "some", "directory"] } or { file: ["public", "some", "file"] }. We recommend you use path functions because they validate paths to make sure they are well-formed.

File System Interface

WNFS exposes a POSIX-style interface:

  • write: write to a file

  • read: read from a file

  • exists: check if a file or directory exists

  • ls: list a directory

  • mkdir: create a directory

  • mv: move a file or directory

  • rm: remove a file or directory

// App info is the namespace used when initializing the Webnative program
const appInfo = { creator: "Nullsoft", name: "Winamp" }

// After retrieving a session or loading the file system manually
const fs = session.fs // or program.loadFileSystem(username)

// List the user's public files

// List the user's private files that belong to a specific app

// Create a sub directory and write to a file
await fs.write(
  wn.path.appData(appInfo, wn.path.file("Sub Directory", "hello.txt")),
  new TextEncoder().encode("👋")

// Persist changes and announce them to your other devices
await fs.publish()

// Read from a file
const content = new TextDecoder().decode(
    wn.path.appData(appInfo, wn.path.file("Sub Directory", "hello.txt"))


The publish function synchronizes your file system with the Fission API and IPFS. WNFS does not publish changes automatically because it is more practical to batch changes in some cases. For example, a large data set is better published once than over multiple calls to publish.

Returns: CID the updated root CID for the file system.

Remember to publish! If you do not call publish after making changes, user data will not be persisted to WNFS.

API Summary


Methods for interacting with the filesystem all use absolute paths.

Paths created by path functions have a FilePath or DirectoryPath type. Methods with a DistinctivePath param accept either a FilePath or a DirectoryPath.

The FileContentthat WNFS can store includes FileContentRaw, Blob, string, number, and boolean. FileContentRaw is Uint8Array. In addition, the private file system can store Objects.


Writes to a file at a given path.


  • path: FilePath required

  • content: FileContentrequired

Returns: CID the updated root CID for the file system


const content = new TextEncoder().encode("hello world")

// create a file called "file" at "public/path/to/a/"
await fs.write(
  wn.path.file("public", "path", "to", "a", "file"),


Reads from a file at a given path.


  • path: FilePath required

Returns: FileContent


const content = await"public", "some", "file"))


Checks if there is anything located at a given path.


  • path: DistinctivePath required

Returns: boolean


const bool = await fs.exists(wn.path.file("private", "some", "file"))


Retrieves the node at the given path, either a File or Tree object


  • path: DistinctivePath required

Returns: Tree | File | null


const node = await fs.get("public", "some", "directory"))


Returns a list of links at a given directory path


  • path: DirectoryPath required

Returns: { [name: string]: Link } Object with the file name as the key and its Link as the value.


// public directory
const publicPath ="public", "some", "directory")
const publicLinksObject = await

// private directory
const privatePath ="private", "some", "directory")
const privateLinksObject = await

// convert private links object to a list
const links = Object.entries(privateLinksObject)

// working with links
const data = await Promise.all([name, _]) => {
    wn.path.file("private", "some", "directory", name)


Creates a directory at the given path


  • path: DirectoryPath required

Returns: CID the updated root CID for the file system


// create a directory called "directory" at "public/some/"
const updatedCID = await fs.mkdir("public", "some", "directory"))


Move a directory or file from one path to another.


  • from: DistinctivePath required

  • to: DistinctivePath required

Returns: CID the updated root CID for the file system


const fromPath = wn.path.file("public", "")
const toPath = wn.path.file("private", "Documents", "")
const updatedCID = await, toPath)


Removes a file or directory at a given path.


  • path: DistinctivePath required

Returns: CID the updated root CID for the file system


const updatedCID = await fs.rm(wn.path.file("private", "some", "file"))


Each file and directory has a history property, which you can use to get an earlier version of that item. We use the delta variable as the order index, primarily because the timestamps can be slightly out of sequence due to device inconsistencies.

const articlePath = wn.path.file("private", "Blog Posts", "")
const file = await fs.get(articlePath)

// { delta: -1, timestamp: 1606236743 }
// { delta: -2, timestamp: 1606236532 }

// List more than (by default) 5 versions

// Get the previous version

// Go back two versions
const delta = -2

// Get a version strictly before a timestamp
// The first version (delta -2) is prior to
// the second version (delta -1) timestamp

Requesting many versions with file.history.list can be slow. The acceptable delay will depend on your application.

File system utilities

A Webnative program includes a set of utility functions for working with the file system:

export type FileSystemShortHands = {
  addPublicExchangeKey: (fs: FileSystem) => Promise<void>
  addSampleData: (fs: FileSystem) => Promise<void>
  hasPublicExchangeKey: (fs: FileSystem) => Promise<boolean>
  load: (username: string) => Promise<FileSystem>
  recover: (params: RecoverFileSystemParams) => Promise<{ success: boolean }>
  • addPublicExchangeKey. Stores the public part of the exchange key in the DID format in the /public/.well-known/exchange/DID_GOES_HERE/ directory of the user's file system.

  • addSampleData. Add sample directories and a file to the file system for quick experimentation.

  • hasPublicExchangeKey. Checks if the public exchange key was added in the well-known location.

  • load. Loads the user's file system.

  • recover. Recovers a file system.

See Sharing Private Data for more information on addPublicExchangeKey and hasPublicExchangeKey.

Loading the file system

The file system is loaded by Webnative at program initialization, but there are times when you may want to delay loading it. For example, you may want to load the file system in a Worker.

You can load a file system with load function:

const fs = await program.fileSystem.load(username)

Recovering a file system

File system recovery is a utility for recovering a user's data when their account cannot be fully recovered. Your app must store a user's username and file system encryption key in a recovery kit or secure storage such as a password manager or iCloud.

A recovery kit might be a text file that looks like:

username: llama
key: SmnsBR3krWxhNm+tnUDX+2pm3gnyXnnBNxEhXnt4jp0=

The username is available on program.session. You can access the encryption key with the following:

import * as uint8arrays from 'uint8arrays'
import { retrieve } from 'webnative/common/root-key'

const accountDID = await program.accountDID(username)
const key = await retrieve({ crypto, accountDID })

// Base64 encode the key to store it as a string
const encodedKey = uint8arrays.toString(key, 'base64pad')

The recover function works by assigning the file system to a new user:

import * as uint8arrays from 'uint8arrays'

// Convert the key to a Uint8Array
const key = uint8arrays.fromString(encodedKey, 'base64pad')

const { success } = program.fileSystem.recover({ newUsername, oldUsername, key })

The recover function will automatically register newUsername. You must check that the new username is valid and available before calling recover with it.

File system event listeners

A Webnative program emits events on local changes to the file system and when the file system is published.

program.fileSystem.on("local-change", ({ path, root }) => {
  console.log("The file system has changed locally 🔔")
  console.log("Changed path:", path)
  console.log("New data root CID:", root)

program.fileSystem.on("publish", ({ root }) => {
  console.log("The file system has been published 🚀")
  console.log("New data root CID:", root)

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