DAPP v1 done.

.gitignore

@@ -49,7 +49,6 @@ Temporary Items
 /ML-AI-sample/.vscode
 /java_basic/*.class
 /py_Parallel/.idea
-<<<<<<< HEAD
 /java_aop/.idea
 =======
 /py_Parallel/process_allinone/*.pyc
@@ -69,19 +68,15 @@ Temporary Items
 /java-junit-sample/*.iml
 /java-junit-sample/.idea
 /daily_tools/SyncTags/src/main/java/com/inif/数据库连接.java
-<<<<<<< HEAD
 /java_aop/*.iml
 /daily_tools/jiankongbao/.idea
 /daily_tools/jiankongbao/*.iml
 /daily_tools/jiankongbao/jiankongbao/*.exe
 =======
->>>>>>> 2f15e2490f29f9d1f35be53e4e05ba51a457abb4
->>>>>>> 2a3f6f5341f23b9d2bd1bb8551b139f0a18aeb6a
 /tensorflow/.idea
 /tensorflow/tf_in_action/*.meta
 /tensorflow/tf_in_action/*.index
 /tensorflow/tf_in_action/*.data-00000-of-00001
-<<<<<<< HEAD
 /MachineLearn-DeepLearn-AI/.idea
 /make_python_package/.idea
 /make_python_package/MyPackage/__pycache__/*.pyc
@@ -95,7 +90,6 @@ Temporary Items
 /aliyun_java_edu/aliyun-r00xx/target/classes/util/*.class
 /golang_natural_blockchain/.idea
 /why_backend_use_golang/.idea
->>>>>>> 361ebd811267c236128f185aecb34f1c58fe326b
 /golang_basic/.idea
 /golang_rpc/.idea
 /golang_coroutine_sample/.idea
@@ -125,3 +119,6 @@ ms_react_guide/mslearn-react/code/0-starter/node_modules
 /springCloudSampleDemo/.idea
 /springCloudSampleDemo/service-hi/.mvn/wrapper
 /springCloudSampleDemo/eureka-server/.mvn/wrapper
+.env
+contract-abi.json
+web3/alchemy_sample/tutorial/hello-world/artifacts

web3/alchemy_sample/go_sample/c1.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+  "context"
+  "fmt"
+  "log"
+
+  "github.com/ethereum/go-ethereum/common"
+  "github.com/ethereum/go-ethereum/ethclient"
+)
+
+func main() {
+  client, err := ethclient.Dial("https://eth-goerli.g.alchemy.com/v2/Ocf_EETGbdsBqKJ3f-DNC4YfxK7F1JB9")
+  if err != nil {
+    log.Fatal(err)
+  }
+
+  // Get the balance of an account
+  account := common.HexToAddress("0x9851099eF06BAD791045281c193847CF32da70E8")
+  balance, err := client.BalanceAt(context.Background(), account, nil)
+  if err != nil {
+    log.Fatal(err)
+  }
+  fmt.Println("Account balance:", balance) // 25893180161173005034
+
+  // Get the latest known block
+  block, err := client.BlockByNumber(context.Background(), nil)
+  if err != nil {
+    log.Fatal(err)
+  }
+  fmt.Println("Latest block:", block.Number().Uint64())
+}
+
+
+

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/.gitignore

@@ -0,0 +1,30 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+package-lock.json
+node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# production
+/build
+
+# misc
+.DS_Store
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# solidity
+solidity-stuff/
+
+#env

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/README.md

@@ -0,0 +1,12 @@
+# 📝 Hello World Part Four Tutorial
+
+This repository contains the starter files (`starter-files`) and completed version (`completed`) of Alchemy's [Hello World Part 4 Tutorial](https://app.gitbook.com/@alchemyapi/s/alchemy/tutorials/hello-world-smart-contract/creating-a-full-stack-dapp). 
+
+## ℹ️ About the tutorial
+
+In this tutorial, we'll teach you how to create a full stack dApp by connecting your Hello World smart contract to a React frontend using Metamask and Web3 tools.
+
+## 🤔 Note
+
+Niether the `starter-files` nor `completed` have their `node_modules` folder. Before running `npm start` in your terminal to start the React project, run `npm install` to download all the package dependencies.
+

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/README.md

@@ -0,0 +1,16 @@
+# ✅ [Completed]  Hello World Part 4 Tutorial
+
+This project contains the COMPLETED files for [Alchemy's Hello World Part 4](https://docs.alchemy.com/alchemy/tutorials/hello-world-smart-contract/creating-a-full-stack-dapp), in which we teach you how to create a full stack dApp by connecting your Hello World smart contract to a React frontend using Metamask and Web3 tools.
+
+# 🪜 Installation
+To use this dApp, you'll need to do the following:
+
+1. Run `npm install` to download the `node_modules` folder.
+2. Download the [dotenv package](https://www.npmjs.com/package/dotenv) in your project directory by running `npm install dotenv --save` in your terminal
+3. Create a `.env` file in the root directory this `nft-minter` by entering the following on your command line: `vim .env` and then add your [Alchemy API Key](https://docs.alchemy.com/alchemy/tutorials/hello-world-smart-contract/creating-a-full-stack-dapp#establish-an-api-connection-to-the-ethereum-chain). Altogether, your `.env` file should just look like so:
+
+```
+REACT_APP_ALCHEMY_KEY = wss://eth-ropsten.ws.alchemyapi.io/v2/<key>
+```
+4. Run `npm start`in your terminal to open the dApp in your browswer at http://localhost:3000/.
+

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/package.json

@@ -0,0 +1,39 @@
+{
+  "name": "hello-world-part-four",
+  "version": "0.1.0",
+  "private": true,
+  "dependencies": {
+    "@testing-library/jest-dom": "^5.11.4",
+    "@testing-library/react": "^11.1.0",
+    "@testing-library/user-event": "^12.1.10",
+    "dotenv": "^9.0.0",
+    "react": "^17.0.2",
+    "react-dom": "^17.0.2",
+    "react-scripts": "4.0.3",
+    "web-vitals": "^1.0.1"
+  },
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "eslintConfig": {
+    "extends": [
+      "react-app",
+      "react-app/jest"
+    ]
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  }
+}

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/public/index.html

@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="theme-color" content="#000000" />
+    <meta
+      name="description"
+      content="Web site created using create-react-app"
+    />
+    <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
+    <!--
+      manifest.json provides metadata used when your web app is installed on a
+      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
+    -->
+    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <!--
+      Notice the use of %PUBLIC_URL% in the tags above.
+      It will be replaced with the URL of the `public` folder during the build.
+      Only files inside the `public` folder can be referenced from the HTML.
+
+      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
+      work correctly both with client-side routing and a non-root public URL.
+      Learn how to configure a non-root public URL by running `npm run build`.
+    -->
+    <title>Hello World Part 4 by Alchemy</title>
+  </head>
+  <body>
+    <noscript>You need to enable JavaScript to run this app.</noscript>
+    <div id="root"></div>
+    <!--
+      This HTML file is a template.
+      If you open it directly in the browser, you will see an empty page.
+
+      You can add webfonts, meta tags, or analytics to this file.
+      The build step will place the bundled scripts into the <body> tag.
+
+      To begin the development, run `npm start` or `yarn start`.
+      To create a production bundle, use `npm run build` or `yarn build`.
+    -->
+  </body>
+</html>

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/public/manifest.json

@@ -0,0 +1,25 @@
+{
+  "short_name": "React App",
+  "name": "Create React App Sample",
+  "icons": [
+    {
+      "src": "favicon.ico",
+      "sizes": "64x64 32x32 24x24 16x16",
+      "type": "image/x-icon"
+    },
+    {
+      "src": "logo192.png",
+      "type": "image/png",
+      "sizes": "192x192"
+    },
+    {
+      "src": "logo512.png",
+      "type": "image/png",
+      "sizes": "512x512"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#000000",
+  "background_color": "#ffffff"
+}

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/src/App.css

@@ -0,0 +1,38 @@
+.App {
+  text-align: center;
+}
+
+.App-logo {
+  height: 40vmin;
+  pointer-events: none;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .App-logo {
+    animation: App-logo-spin infinite 20s linear;
+  }
+}
+
+.App-header {
+  background-color: #282c34;
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(10px + 2vmin);
+  color: white;
+}
+
+.App-link {
+  color: #61dafb;
+}
+
+@keyframes App-logo-spin {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(360deg);
+  }
+}

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/src/App.js

@@ -0,0 +1,12 @@
+import HelloWorld from './HelloWorld'
+import './App.css';
+
+function App() {
+  return (
+    <div className="App">
+    <HelloWorld></HelloWorld>
+    </div>
+  );
+}
+
+export default App;

web3/alchemy_sample/tutorial/hello-world-part-four-tutorial/completed/src/App.test.js

@@ -0,0 +1,8 @@
+import { render, screen } from '@testing-library/react';
+import App from './App';
+
+test('renders learn react link', () => {
+  render(<App />);
+  const linkElement = screen.getByText(/learn react/i);
+  expect(linkElement).toBeInTheDocument();
+});