藤本  結衣

藤本 結衣

1649903160

React、Ether.js、Ceramicを使用してWeb3認証フローを構築します

Web3の重要な側面は、ブロックチェーンウォレットと公開鍵暗号化を使用してアカウントを識別できることです。この記事では、Ether.jsライブラリを使用してブロックチェーンと対話し、ブロックチェーンウォレットを使用してワンクリックで暗号的に安全なログインフローを作成する方法について説明します。

暗号的に安全なブロックチェーンは何に使用されますか?

上記のように、暗号的に安全なブロックチェーンは、その性質の結果として、秘密鍵を使用してデータに署名することにより、アカウントの所有権を証明します。これらの暗号化署名は、トランザクションをブロックチェーンに書き込むためにも使用できます。

ユーザーのパブリックアドレスを識別子として使用して、メッセージ署名ベースの認証メカニズムの構築に進みます。

Web3ウォレットは何に使用されますか?

Web3ウォレットは、Web3環境での認証に使用されます。この記事の執筆時点では、3つの主要なWeb3ウォレットオプションがあります。

  1. MetaMask
  2. WalletConnect
  3. Web3Auth

このチュートリアルではMetaMaskを使用します。プロジェクトのレイアウトが完了したので、始めましょう。

セラミックを使用したReactアプリのセットアップ

セラミックを使用するには、Node.js≥v14およびnpm≥v6が必要であり、Next.jsを使用して新しいReactアプリケーションを作成します。

yarn create next-app --typescript web3-auth

依存関係をインストールします。

yarn add web3modal ethers @ceramicnetwork/http-client key-did-resolver @ceramicnetwork/3id-did-resolver key-did-provider-ed25519 @stablelib/random
@ceramicnetwork/stream-tile dids

セラミックは、すべてのブロックチェーンウォレットと互換性のあるユーザーアカウントの分散識別子(DID)標準に依存しています。DIDは、アカウントの真の所有者を確認する方法として、任意のWeb3ウォレットアドレスまたは公開鍵からCeramicアカウントをアンバンドルするのに役立つため便利です。

セラミックによるデータのホスティング

私たちのアプリケーションは、データの保存、変更、取得をセラミックデータネットワークに依存します。セラミックのデータモデルに基づいて、基本的なユーザーレジストリを作成し、レジストリ内のユーザーアカウントは標準のDID仕様に準拠します。セラミッククライアントは、認証されたアカウントがネットワーク上でトランザクションを実行できるようにします。

セラミックユーザーレジストリの作成

以下は、Ceramicユーザーレジストリを作成するために必要なコードです。これhttp-clientにより、アプリケーションはHTTPを介してリモートのCeramicノードに接続し、ストリームの読み取りと書き込みを行うことができます。このプロジェクト全体を通して、TypeScriptが使用されます。

mkdir utils
touch client.tsx

import { CeramicClient } from "@ceramicnetwork/http-client";
import KeyDidResolver from "key-did-resolver";
import ThreeIdResolver from "@ceramicnetwork/3id-did-resolver";
import { Ed25519Provider } from "key-did-provider-ed25519";
import { randomBytes } from "@stablelib/random";
import { TileDocument } from "@ceramicnetwork/stream-tile";
import { DID } from "dids";

// set ceramic node URL
const API_URL = "https://ceramic-clay.3boxlabs.com";

// generate seed
const seed = randomBytes(32);

// create provider
const provider = new Ed25519Provider(seed);

// create ceramic instance
const ceramic = new CeramicClient(API_URL);

// set provider to ceramic
ceramic.did?.setProvider(provider);

await ceramic.did?.authenticate();

// DID methods to authenticate writes
const resolver = {
  ...KeyDidResolver.getResolver(),
  ...ThreeIdResolver.getResolver(ceramic),
};

// create a DID instance
const did = new DID({ resolver });

// set DID instance
ceramic.did = did;

const doc = await TileDocument.create(ceramic, { broadcast: "Hello" });

export const users: any = { doc };

ReactでのWeb3認証フローの実装

APIはauth、ユーザーのアカウントがユーザーレジストリに存在するかどうかを確認します。そのようなユーザーが作成されていない場合は、新しいユーザーが作成され、暗号ナンスが割り当てられます。

touch src/pages/api/auth.tsx
code src/pages/api/auth.tsx
import type { NextApiRequest, NextApiResponse } from "next";

import { users } from "../../utils/client";
export default async function auth(req: NextApiRequest, res: NextApiResponse) {
  const { address } = req.query;
  let user = users[address as string];

  // check if user exists in register
  if (!user) {
    user = {
      address,
      // update user nonce
      nonce: Math.floor(Math.random() * 10000000),
    };
    users[address as string] = user;
  } else {
    // create nonce for new user
    const nonce = Math.floor(Math.random() * 10000000);
    // assign nonce to new user
    user.nonce = nonce;
    users[address as string] = user;
  }
  res.status(200).json(user);
}

認証ファイルで生成されたナンスは、クライアントからの要求に署名するための一意の文字列として使用されます。これにより、サーバー上のトランザクションの認証が可能になります。署名が作成されると、リクエストとともに送信されます。

touch pages/api/confirm.tsx
code pages/api/confirm.tsx

ナンスはサーバー上のトランザクションをデコードするために使用されるため、非常に重要です。デコードされた文字列が発信者のアドレスと一致することを確認すると、システムはトランザクションが同じユーザーによって送信されたことを確認できます。

ファイルではconfirm.tsx、デコードされた文字列がチェックされ、呼び出し元のアドレスと一致することが確認されます。

import type { NextApiRequest, NextApiResponse } from "next";
import { ethers } from "ethers";
import { users } from "../../utils/client";

export default function transactionCheck(
  req: NextApiRequest,
  res: NextApiResponse
) {
  let authenticated = false;

  const { address1, signature } = req.query;
  const user = users[address1 as string];
  const address = address1 as string;
  const decodedAddress = ethers.utils.verifyMessage(
    user.nonce.toString(),
    signature as string
  );
  if (address.toLowerCase() === decodedAddress.toLowerCase())
    authenticated = true;
  res.status(200).json({ authenticated });
}

Web3Modalで複数のプロバイダーを追加する

Web3ModalライブラリはシンプルなWeb3/Ethereumプロバイダーソリューションであり、アプリケーションで複数のプロバイダーのサポートを追加できます。Web3Modalライブラリは、このプロジェクトで依存する注入されたプロバイダーであるMetaMaskとTor.usをサポートします。

このHome.module.cssファイルで、アプリケーションコンテナとログインボタンのスタイルを作成します。

touch styles/Home.module.css
.container {
  width: 30rem;
  margin: 100px auto;
}

.button {
  width: 100%;
  margin: 0.2rem;
  padding: 0.8rem;
  border: none;
  background-color: purple;
  color: white;
  font-size: 16;
  cursor: pointer;
}touch pages/index.tsx
import type { NextPage } from "next";
import React, { useState } from "react";
import { ethers } from "ethers";
import Web3Modal from "web3modal";
import styles from "../styles/Home.module.css";

const Home: NextPage = () => {
  const [account, setAccount] = useState("");
  const [connection, setConnection] = useState(false);
  const [loggedIn, setLoggedIn] = useState(false);

  async function getWeb3Modal() {
    let Torus = (await import("@toruslabs/torus-embed")).default;
    const web3modal = new Web3Modal({
      network: "mainnet",
      cacheProvider: false,
      providerOptions: {
        torus: {
          package: Torus,
        },
      },
    });
    return web3modal;
  }

  async function connect() {
    const web3modal = await getWeb3Modal();
    const connection = await web3modal.connect();
    const provider = new ethers.providers.Web3Provider(connection);
    const accounts = await provider.listAccounts();
    setConnection(connection);
    setAccount(accounts[0]);
  }

  async function Login() {
    const authData = await fetch(`/api/authenticate?address=${account}`);
    const user = await authData.json();
    const provider = new ethers.providers.Web3Provider(connection as any);
    const signer = provider.getSigner();
    const signature = await signer.signMessage(user.nonce.toString());
    const response = await fetch(
      `/api/verify?address=${account}&signature=${signature}`
    );
    const data = await response.json();
    setLoggedIn(data.authenticated);
  }

  return (
    <div className={styles.container}>
      {!connection && (
        <button className={styles.button} onClick={connect}>
          Connect Wallet
        </button>
      )}
      {connection && !loggedIn && (
        <>
          <button className={styles.button} onClick={Login}>
            Login
          </button>
        </>
      )}
      {loggedIn && <h2>Let's get started, {account}</h2>}
    </div>
  );
};

export default Home;

このconnect関数は、Web3Modalを使用するユーザーに、アプリケーションで指定された利用可能な注入されたTor.usWeb3ウォレットを使用してログインするように求めます。

このlogin関数は、ユーザーレジストリを接続し、ユーザーのナンスを更新します。ナンスが署名からサーバー上で検証されると、UIが更新されます。

結論

この記事では、暗号的に安全なログインフローを構築し、デジタル署名をユーザーのナンスで確認する方法について説明しました。また、nonceを使用してアカウントの所有権を証明し、認証を提供する方法についても説明しました。 

ソース:https ://blog.logrocket.com/build-web3-authentication-flow-react-ether-js-ceramic/#hosting-data-ceramic

#react-native #authentication #web3 #ceramic 

What is GEEK

Buddha Community

React、Ether.js、Ceramicを使用してWeb3認証フローを構築します
Autumn  Blick

Autumn Blick

1598839687

How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

  • Performance: It delivers optimal performance.
  • Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
  • UI design: React Native enables you to design simple and responsive UI for your mobile app.
  • 3rd party plugins: This framework supports 3rd party plugins.
  • Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

  • Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
  • Near-native user experience: React Native provides several native components, and these are platform agnostic.
  • The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

sophia tondon

sophia tondon

1621250665

Top React JS Development Company | React JS Development Services

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#hire react js developer #react.js developer #react.js developers #hire reactjs development company #react js development india #react js developer

NBB: Ad-hoc CLJS Scripting on Node.js

Nbb

Not babashka. Node.js babashka!?

Ad-hoc CLJS scripting on Node.js.

Status

Experimental. Please report issues here.

Goals and features

Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.

Additional goals and features are:

  • Fast startup without relying on a custom version of Node.js.
  • Small artifact (current size is around 1.2MB).
  • First class macros.
  • Support building small TUI apps using Reagent.
  • Complement babashka with libraries from the Node.js ecosystem.

Requirements

Nbb requires Node.js v12 or newer.

How does this tool work?

CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).

Usage

Install nbb from NPM:

$ npm install nbb -g

Omit -g for a local install.

Try out an expression:

$ nbb -e '(+ 1 2 3)'
6

And then install some other NPM libraries to use in the script. E.g.:

$ npm install csv-parse shelljs zx

Create a script which uses the NPM libraries:

(ns script
  (:require ["csv-parse/lib/sync$default" :as csv-parse]
            ["fs" :as fs]
            ["path" :as path]
            ["shelljs$default" :as sh]
            ["term-size$default" :as term-size]
            ["zx$default" :as zx]
            ["zx$fs" :as zxfs]
            [nbb.core :refer [*file*]]))

(prn (path/resolve "."))

(prn (term-size))

(println (count (str (fs/readFileSync *file*))))

(prn (sh/ls "."))

(prn (csv-parse "foo,bar"))

(prn (zxfs/existsSync *file*))

(zx/$ #js ["ls"])

Call the script:

$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs

Macros

Nbb has first class support for macros: you can define them right inside your .cljs file, like you are used to from JVM Clojure. Consider the plet macro to make working with promises more palatable:

(defmacro plet
  [bindings & body]
  (let [binding-pairs (reverse (partition 2 bindings))
        body (cons 'do body)]
    (reduce (fn [body [sym expr]]
              (let [expr (list '.resolve 'js/Promise expr)]
                (list '.then expr (list 'clojure.core/fn (vector sym)
                                        body))))
            body
            binding-pairs)))

Using this macro we can look async code more like sync code. Consider this puppeteer example:

(-> (.launch puppeteer)
      (.then (fn [browser]
               (-> (.newPage browser)
                   (.then (fn [page]
                            (-> (.goto page "https://clojure.org")
                                (.then #(.screenshot page #js{:path "screenshot.png"}))
                                (.catch #(js/console.log %))
                                (.then #(.close browser)))))))))

Using plet this becomes:

(plet [browser (.launch puppeteer)
       page (.newPage browser)
       _ (.goto page "https://clojure.org")
       _ (-> (.screenshot page #js{:path "screenshot.png"})
             (.catch #(js/console.log %)))]
      (.close browser))

See the puppeteer example for the full code.

Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet macro is similar to promesa.core/let.

Startup time

$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)'   0.17s  user 0.02s system 109% cpu 0.168 total

The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx this adds another 300ms or so, so for faster startup, either use a globally installed nbb or use $(npm bin)/nbb script.cljs to bypass npx.

Dependencies

NPM dependencies

Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.

Classpath

To load .cljs files from local paths or dependencies, you can use the --classpath argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs relative to your current dir, then you can load it via (:require [foo.bar :as fb]). Note that nbb uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar in the namespace name becomes foo_bar in the directory name.

To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:

$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"

and then feed it to the --classpath argument:

$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]

Currently nbb only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar files will be added later.

Current file

The name of the file that is currently being executed is available via nbb.core/*file* or on the metadata of vars:

(ns foo
  (:require [nbb.core :refer [*file*]]))

(prn *file*) ;; "/private/tmp/foo.cljs"

(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"

Reagent

Nbb includes reagent.core which will be lazily loaded when required. You can use this together with ink to create a TUI application:

$ npm install ink

ink-demo.cljs:

(ns ink-demo
  (:require ["ink" :refer [render Text]]
            [reagent.core :as r]))

(defonce state (r/atom 0))

(doseq [n (range 1 11)]
  (js/setTimeout #(swap! state inc) (* n 500)))

(defn hello []
  [:> Text {:color "green"} "Hello, world! " @state])

(render (r/as-element [hello]))

Promesa

Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core namespace is included with the let and do! macros. An example:

(ns prom
  (:require [promesa.core :as p]))

(defn sleep [ms]
  (js/Promise.
   (fn [resolve _]
     (js/setTimeout resolve ms))))

(defn do-stuff
  []
  (p/do!
   (println "Doing stuff which takes a while")
   (sleep 1000)
   1))

(p/let [a (do-stuff)
        b (inc a)
        c (do-stuff)
        d (+ b c)]
  (prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3

Also see API docs.

Js-interop

Since nbb v0.0.75 applied-science/js-interop is available:

(ns example
  (:require [applied-science.js-interop :as j]))

(def o (j/lit {:a 1 :b 2 :c {:d 1}}))

(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1

Most of this library is supported in nbb, except the following:

  • destructuring using :syms
  • property access using .-x notation. In nbb, you must use keywords.

See the example of what is currently supported.

Examples

See the examples directory for small examples.

Also check out these projects built with nbb:

API

See API documentation.

Migrating to shadow-cljs

See this gist on how to convert an nbb script or project to shadow-cljs.

Build

Prequisites:

  • babashka >= 0.4.0
  • Clojure CLI >= 1.10.3.933
  • Node.js 16.5.0 (lower version may work, but this is the one I used to build)

To build:

  • Clone and cd into this repo
  • bb release

Run bb tasks for more project-related tasks.

Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb 
License: EPL-1.0

#node #javascript

Mathew Rini

1615544450

How to Select and Hire the Best React JS and React Native Developers?

Since March 2020 reached 556 million monthly downloads have increased, It shows that React JS has been steadily growing. React.js also provides a desirable amount of pliancy and efficiency for developing innovative solutions with interactive user interfaces. It’s no surprise that an increasing number of businesses are adopting this technology. How do you select and recruit React.js developers who will propel your project forward? How much does a React developer make? We’ll bring you here all the details you need.

What is React.js?

Facebook built and maintains React.js, an open-source JavaScript library for designing development tools. React.js is used to create single-page applications (SPAs) that can be used in conjunction with React Native to develop native cross-platform apps.

React vs React Native

  • React Native is a platform that uses a collection of mobile-specific components provided by the React kit, while React.js is a JavaScript-based library.
  • React.js and React Native have similar syntax and workflows, but their implementation is quite different.
  • React Native is designed to create native mobile apps that are distinct from those created in Objective-C or Java. React, on the other hand, can be used to develop web apps, hybrid and mobile & desktop applications.
  • React Native, in essence, takes the same conceptual UI cornerstones as standard iOS and Android apps and assembles them using React.js syntax to create a rich mobile experience.

What is the Average React Developer Salary?

In the United States, the average React developer salary is $94,205 a year, or $30-$48 per hour, This is one of the highest among JavaScript developers. The starting salary for junior React.js developers is $60,510 per year, rising to $112,480 for senior roles.

* React.js Developer Salary by Country

  • United States- $120,000
  • Canada - $110,000
  • United Kingdom - $71,820
  • The Netherlands $49,095
  • Spain - $35,423.00
  • France - $44,284
  • Ukraine - $28,990
  • India - $9,843
  • Sweden - $55,173
  • Singapore - $43,801

In context of software developer wage rates, the United States continues to lead. In high-tech cities like San Francisco and New York, average React developer salaries will hit $98K and $114per year, overall.

However, the need for React.js and React Native developer is outpacing local labour markets. As a result, many businesses have difficulty locating and recruiting them locally.

It’s no surprise that for US and European companies looking for professional and budget engineers, offshore regions like India are becoming especially interesting. This area has a large number of app development companies, a good rate with quality, and a good pool of React.js front-end developers.

As per Linkedin, the country’s IT industry employs over a million React specialists. Furthermore, for the same or less money than hiring a React.js programmer locally, you may recruit someone with much expertise and a broader technical stack.

How to Hire React.js Developers?

  • Conduct thorough candidate research, including portfolios and areas of expertise.
  • Before you sit down with your interviewing panel, do some homework.
  • Examine the final outcome and hire the ideal candidate.

Why is React.js Popular?

React is a very strong framework. React.js makes use of a powerful synchronization method known as Virtual DOM, which compares the current page architecture to the expected page architecture and updates the appropriate components as long as the user input.

React is scalable. it utilises a single language, For server-client side, and mobile platform.

React is steady.React.js is completely adaptable, which means it seldom, if ever, updates the user interface. This enables legacy projects to be updated to the most new edition of React.js without having to change the codebase or make a few small changes.

React is adaptable. It can be conveniently paired with various state administrators (e.g., Redux, Flux, Alt or Reflux) and can be used to implement a number of architectural patterns.

Is there a market for React.js programmers?
The need for React.js developers is rising at an unparalleled rate. React.js is currently used by over one million websites around the world. React is used by Fortune 400+ businesses and popular companies such as Facebook, Twitter, Glassdoor and Cloudflare.

Final thoughts:

As you’ve seen, locating and Hire React js Developer and Hire React Native developer is a difficult challenge. You will have less challenges selecting the correct fit for your projects if you identify growing offshore locations (e.g. India) and take into consideration the details above.

If you want to make this process easier, You can visit our website for more, or else to write a email, we’ll help you to finding top rated React.js and React Native developers easier and with strives to create this operation

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sophia tondon

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