hashstorage-cli v1.3.2

hashstorage-cli

hashstorage-cli is a JS library that implements a convenient API to interact with a hashstorage backend (https://github.com/fomalhaut88/hashstorage). It includes a number of high level functions to create key pairs, encrypt, decrypt and sign data and request the hashstorage backend through its REST API. The mission of the library is to help your project provide a better security on the client side. As far as hashstorage-cli is written in Rust and compiled into WASM, it supports asynchronous import.

A simple example:

(async () => {
    // Import the library
    const hsc = await import('hashstorage-cli')

    // Define a hashstorage backend API object
    const api = hsc.Api.new("https://hashstorage-cloud.com")

    // Get version on hashstorage backend
    const version = await api.getVersion()
    console.log(version)
})()

Installation from source

1. Ensure you have wasm-pack installed (https://rustwasm.github.io/wasm-pack/installer/):

curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh

2. Clone hashstorage-cli repository:

git clone git+https://github.com/fomalhaut88/hashstorage-cli.git --depth 1

3. Build the project:

wasm-pack build --release --target bundler --out-dir hashstorage-cli-pkg

4. Install the package. For example:

npm i path/to/built/hashstorage-cli-pkg

Usage example

As far as hashstorage-cli is powered by Rust, the package must be imported asynchronously.

const hsc = await import('hashstorage-cli')

To access the node, there is API object.

const api = hsc.Api.new("https://hashstorage-cloud.com")

Every interaction through API is implemented as a promise.

const version = await api.getVersion()
const groups = await api.getGroup(
    "F97CF0EA9BA1C36BE29045A14AAC32ED" +
    "9ECD8D67A9D6823D623E161B2600ED3B" +
    "4D3FA95A1580FED6068BD67013C99052" +
    "4DCCE132350EAC38948E3E15BC3E1E60"
)
const keys = await api.getKeys(
    "F97CF0EA9BA1C36BE29045A14AAC32ED" +
    "9ECD8D67A9D6823D623E161B2600ED3B" +
    "4D3FA95A1580FED6068BD67013C99052" +
    "4DCCE132350EAC38948E3E15BC3E1E60",
    "mygroup"
)

Profile stores public and private keys to sign and check blocks. Also public key is a user identifier in hashtorage. Profile object can be created from application id, username and password.

const profile = hsc.Profile.new("appidstring", "alex", "Qwerty123")
const publicKey = profile.publicKey()

There are methods to access hashstorage instance.

const groups = await profile.groups(api)
const keys = await profile.keys(api, "mygroup")
const blockJson = await profile.getBlockJson(api, "mygroup", "mykey")

Profile can be saved and loaded in localStorage.

const existsInLocalStorage = hsc.Profile.exists()
const profile = hsc.Profile.load()
const isValid = profile.check()
profile.save()
profile.clear()

With profile it is possible to sign and check blocks.

const signature = profile.buildSignature(...)
const isCorrect = hsc.Profile.checkSignature(publicKey, ...)

Block represents a wrapper for data to store in hashstorage. It contains the identifier (public key, group and key), version, signature and data itself. It can be created from public key, group and key or from block JSON provided by profile.getBlockJson.

const block1 = hsc.Block.new(profile.publicKey(), "mygroup", "mykey")
const block2 = hsc.Block.fromBlockJson(blockJson)

Block attributes can be extracted by their names.

const publicKey = block.publicKey()
const group = block.group()
const key = block.key()
const version = block.version()
const data = block.data()
const signature = block.signature()

Some data can be modified:

block.setData("new data")
block.setVersion(123)

There are methods to work with the signature:

const isSigned = block.isSigned()
block.sign(profile)
block.clearSignature()

There are two similar methods to save block in hashstorage. update just requests with the current data. save increments the version, builds signature and after that calls update.

await block.update(api)
await block.save(api, profile)

How to use hashstorage-cli in JS worker

The work with JS workers has some specials because there is no access to the window object, to localStorage and other familiar things. Thus the project must be compiled in a different way, not as an ordinary package.

wasm-pack build --release --target no-modules --no-typescript --out-dir hashstorage-cli-wasm

The example of worker is following:

/* worker.js */

importScripts("hashstorage-cli-wasm/hashstorage_cli.js?v=0.0")

(async () => {
    await wasm_bindgen("hashstorage-cli-wasm/hashstorage_cli_bg.wasm")
    hsc = wasm_bindgen;

    self.addEventListener('message', e => {
        console.log("Message:", e)
        let result = e.data[0] + e.data[1];
        postMessage(result)
    })
})()

The example of create a worker:

let myWorker = new Worker('worker.js')

myWorker.addEventListener('message', e => {
    console.log(e)
}, false)

// In some cases it must be called is a while (100 ms for example)
// after creating the worker, because before the worker can handle the message
// it must be loaded that is done asynchronously.
// For example, it can be called with setTimeout.
myWorker.postMessage([42, 23])

Note! You are unable to make HTTP requests inside of a JS worker, because this operation requires the window object to exist. So you are unable to use the methods of the API object. A solution is you can send the data from the worker with postMessage and perform the HTTP requests in the main script.

Local storage version checker (LSVC)

This feature was added in version 1.3.0

If you want to check on the client side whether there was a replacement with an old record on the server side (Hashstorage instance) you can use LSVC (local storage version checker). LSVC saves the last version of a block in localStorage and can compare it. It is recommended to save the version of a block after successful saving and to check it every time after getting the block from the Hashstorage instance. The check result will be false if the version exists in the local storage and its value is higher than the version of just received block, othervise the check result is true. The use of LSVC is recommended but optional because it may be consuming in some cases. Below there is a simple example of using LSVC.

// Create a LSVC object
const lsvc = hsc.LSVC.new()

// Get block from the Hashstorage instance
const blockJson = await profile.getBlockJson(api, "mygroup", "mykey")
const block = hsc.Block.fromBlockJson(blockJson)

// Check the version
const isCorrect = lsvc.checkVersion(block)

// ... after some modifications save the block
await block.save(api, profile)

// Save the version with LSVC after successful saving the block above
lsvc.saveVersion(block)