unstorage

Universal Storage Layer

• Works in all environments (Browser, NodeJS and Workers)
• Asynchronous API
• Unix-style mountable paths (multi driver)
• Default in-memory storage
• Tree-shakable and lightweight core
• Native aware value serialization and deserialization
• Restore initial state (hydration)
• State snapshot
• Driver agnostic watcher
• HTTP Storage server (cli and programmatic)

Table of Contents

• Usage
• Storage Interface
  • storage.hasItem(key)
  • storage.getItem(key)
  • storage.setItem(key, value)
  • storage.removeItem(key)
  • storage.getKeys(base?)
  • storage.clear(base?)
  • storage.dispose()
  • storage.mount(mountpoint, driver)
  • storage.unmount(mountpoint, dispose = true)
  • storage.watch(callback)
• Utils
  • snapshot(storage, base?)
  • restoreSnapshot(storage, data, base?)
• Storage Server
• Drivers
  • fs (node)
  • localStorage (browser)
  • memory (universal)
  • http (universal)
  • redis
• Making custom drivers
• Contribution
• License

Usage

Install unstorage npm package:

yarn add unstorage
# or
npm i unstorage

import { createStorage } from 'unstorage'

const storage = createStorage(/* opts */)

await storage.getItem('foo:bar') // or storage.getItem('/foo/bar')

Options:

• driver: Default driver (using memory if not provided)

Storage Interface

storage.hasItem(key)

Checks if storage contains a key. Resolves to either true or false.

await storage.hasItem('foo:bar')

storage.getItem(key)

Gets value of a key in storage. Resolves to either string or null.

await storage.getItem('foo:bar')

storage.setItem(key, value)

Add Update a value to storage.

If value is not string, it will be stringified.

If value is undefined, it is same as calling removeItem(key).

await storage.setItem('foo:bar', 'baz')

storage.removeItem(key)

Remove a value from storage.

await storage.removeItem('foo:bar')

storage.getKeys(base?)

Get all keys. Returns an array of string.

If a base is provided, only keys starting with base will be returned also only mounts starting with base will be queried. Keys still have full path.

await storage.getKeys()

storage.clear(base?)

Removes all stored key/values. If a base is provided, only mounts matching base will be cleared.

await storage.clear()

storage.dispose()

Disposes all mounted storages to ensure there are no open-handles left. Call it before exiting process.

Note: Dispose also clears in-memory data.

await storage.dispose()

storage.mount(mountpoint, driver)

By default, everything is stored in memory. We can mount additional storage space in a Unix-like fashion.

When operating with a key that starts with mountpoint, instead of default storage, mounted driver will be called.

import { createStorage } from 'unstorage'
import fsDriver from 'unstorage/drivers/fs'

// Create a storage container with default memory storage
const storage = createStorage({})

storage.mount('/output', fsDriver({ base: './output' }))

//  Writes to ./output/test file
await storage.setItem('/output/test', 'works')

// Adds value to in-memory storage
await storage.setItem('/foo', 'bar')

storage.unmount(mountpoint, dispose = true)

Unregisters a mountpoint. Has no effect if mountpoint is not found or is root.

await storage.unmount('/output')

storage.watch(callback)

Starts watching on all mountpoints. If driver does not supports watching, only emits even when storage.* methods are called.

await storage.watch((event, key) => { })

Utils

snapshot(storage, base?)

Snapshot from all keys in specified base into a plain javascript object (string: string). Base is removed from keys.

import { snapshot } from 'unstorage'

const data = await snapshot(storage, '/etc')

restoreSnapshot(storage, data, base?)

Restore snapshot created by snapshot().

await restoreSnapshot(storage, { 'foo:bar': 'baz' }, '/etc2')

Storage Server

We can easily expose unstorage instance to a http server to allow remote connections. Request url is mapped to key and method/body mapped to function. See below for supported http methods.

🛡️ Security Note: Server is unprotected by default. You need to add your own authentication/security middleware like basic authentication. Also consider that even with authentication, unstorage should not be exposed to untrusted users since it has no protection for abuse (DDOS, Filesystem escalation, etc)

Programmatic usage:

import { listen } from 'listhen'
import { createStorage } from 'unstorage'
import { createStorageServer } from 'unstorage/server'

const storage = createStorage()
const storageServer = createStorageServer(storage)

// Alternatively we can use `storage.handle` as a middleware
await listen(storage.handle)

Using CLI:

npx unstorage .

Supported HTTP Methods:

• GET: Maps to storage.getItem. Returns list of keys on path if value not found.
• HEAD: Maps to storage.hasItem. Returns 404 if not found.
• PUT: Maps to storage.setItem. Value is read from body and returns OK if operation succeeded.
• DELETE: Maps to storage.removeIterm. Returns OK if operation succeeded.

Drivers

fs (node)

Maps data to real filesystem using directory structure for nested keys. Supports watching using chokidar.

import { createStorage } from 'unstorage'
import fsDriver from 'unstorage/drivers/memory'

const storage = createStorage({
  driver: fsDriver({ base: './tmp' })
})

Options:

• base: Base directory to isolate operations on this directory
• ignore: Ignore patterns for watch
• watchOptions: Additional chokidar options.

localStorage (browser)

Store data in localStorage.

import { createStorage } from 'unstorage'
import localStorageDriver from 'unstorage/drivers/memory'

const storage = createStorage({
  driver: localStorageDriver({ base: 'app:' })
})

Options:

• base: Add ${base}: to all keys to avoid collision
• localStorage: Optionally provide localStorage object
• window: Optionally provide window object

memory (universal)

Keeps data in memory using Set.

By default it is mounted to top level so it is unlikely you need to mount it again.

import { createStorage } from 'unstorage'
import memoryDriver from 'unstorage/drivers/memory'

const storage = createStorage({
  driver: memoryDriver()
})

http (universal)

Use a remote HTTP/HTTPS endpoint as data storage. Supports built-in http server methods.

import { createStorage } from 'unstorage'
import httpDriver from 'unstorage/drivers/http'

const storage = createStorage({
  driver: httpDriver({ base: 'http://cdn.com' })
})

Options:

• base: Base URL for urls

Supported HTTP Methods:

• getItem: Maps to http GET. Returns deserialized value if response is ok
• hasItem: Maps to http HEAD. Returns true if response is ok (200)
• setItem: Maps to http PUT. Sends serialized value using body
• removeIterm: Maps to DELETE
• clear: Not supported

redis

Store data in a redis storage using ioredis.

import { createStorage } from 'unstorage'
import redisDriver from 'unstorage/drivers/redis'

const storage = createStorage({
  driver: redisDriver({
     base: 'storage:'
  })
})

Options:

• base: Prefix all keys with base
• url: (optional) connection string

See ioredis for all available options.

lazyConnect option is enabled by default so that connection happens on first redis operation.

Making custom drivers

It is possible to extend unstorage by creating custom drives.

• Keys are always normalized in foo:bar convention
• Mount base is removed
• Returning promise or direct value is optional
• You should cleanup any open watcher and handlers in dispose
• Value returned by getItem can be a serializable object or string
• Having watch method, disables default handler for mountpoint. You are responsible to emit event on getItem, setItem and removeItem.

See src/drivers to inspire how to implement them. Methods can

Example:

import { createStorage, defineDriver } from 'unstorage'

const myStorageDriver = defineDriver((_opts) => {
  return {
    async hasItem (key) {},
    async getItem (key) {},
    async setItem(key, value) {},
    async removeItem (key) {},
    async getKeys() {},
    async clear() {},
    async dispose() {},
    // async watch(callback) {}
  }
})

const storage = createStorage({
  driver: myStorageDriver()
})

Contribution

• Clone repository
• Install dependencies with yarn install
• Use yarn dev to start jest watcher verifying changes
• Use yarn test before push to ensure all tests and lint checks passing

License

MIT