1649903160
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。
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、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。
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。
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。
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 };
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。
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。
#react-native #authentication #web3 #ceramic
1598839687
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.
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:
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:
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
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1632537859
Not babashka. Node.js babashka!?
Ad-hoc CLJS scripting on Node.js.
Experimental. Please report issues here.
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:
Nbb requires Node.js v12 or newer.
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).
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
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
.
$ 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
.
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.
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.
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"
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]))
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.
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:
:syms
.-x
notation. In nbb, you must use keywords.See the example of what is currently supported.
See the examples directory for small examples.
Also check out these projects built with nbb:
See API documentation.
See this gist on how to convert an nbb script or project to shadow-cljs.
Prequisites:
To build:
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
1615544450
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.
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.
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.
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.
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.
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
#hire-react-js-developer #hire-react-native-developer #react #react-native #react-js #hire-react-js-programmer
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Looking to hire top dedicated Reactjs developers from India at affordable prices? Our 5+ years of average experienced Reactjs developers comprise proficiency in delivering the most complex and challenging web apps.
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Planning to outsource** Reactjs development company in India** ? Or would you like to hire a team of Reactjs developers? Get in touch for a free quote!
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