Refs #654 -- Add content about using Pyth oracle to retrieve price (#656

)

* added randomNumbers to espace/tutorials/oracle/Pyth/

* updated Pyth/priceFeed

* update priceFeed.md

* update priceFeed.md

* add _category_.json to scaffoldCfx

* update _cateorgy_.json in pyth

* Update docs/espace/tutorials/oracle/_category_.json

Co-authored-by: darwintree <[email protected]>

---------

Co-authored-by: darwintree <[email protected]>

docs/espace/tutorials/oracle/Pyth/_category_.json

@@ -0,0 +1,9 @@
+{
+    "label": "Pyth",
+    "position": 1,
+    "link": {
+      "type": "generated-index",
+      "description": "Tutorial on how to use a Pyth oracle on Conflux eSpace"
+    }
+  }
+

docs/espace/tutorials/oracle/Pyth/priceFeed.md

@@ -0,0 +1,208 @@
+---
+sidebar_position: 1
+title: Retrieve Price
+description: Learn how to Use Pyth Oracle on Conflux eSpace to Retrieve CFX Price
+keywords:
+  - Hardhat
+  - Smart Contracts
+  - Oracle
+  - Pyth
+  - CFX Price
+displayed_sidebar: eSpaceSidebar
+---
+
+# Retrieve Price
+
+This tutorial will guide you through building a project on Conflux eSpace using Hardhat and retrieving the CFX price through the Pyth oracle.
+
+## Prerequisites
+
+Before starting, ensure you have the following software installed:
+
+1. Node.js and npm
+2. Hardhat
+3. Conflux wallet extension
+
+## Step 1: Create a Hardhat Project
+
+First, create a new Hardhat project:
+
+```bash
+mkdir conflux-pyth-cfx-price
+cd conflux-pyth-cfx-price
+npx hardhat
+```
+
+Follow the prompts to create a basic JavaScript project.
+
+## Step 2: Install Necessary Dependencies
+
+Install the Pyth SDK and other required dependencies:
+
+```bash
+npm install @pythnetwork/pyth-sdk-solidity @pythnetwork/pyth-evm-js dotenv
+```
+
+## Step 3: Configure Hardhat
+
+Update `hardhat.config.js` to include the Conflux eSpace Testnet:
+
+```javascript
+require("@nomicfoundation/hardhat-toolbox");
+
+/** @type import('hardhat/config').HardhatUserConfig */
+module.exports = {
+  solidity: "0.8.24",
+  networks: {
+    confluxTestnet: {
+      url: "https://evmtestnet.confluxrpc.com",
+      accounts: [process.env.PRIVATE_KEY], // Your private key here
+    },
+  },
+};
+```
+
+Make sure to set your private key as an environment variable for security.
+
+## Step 4: Write the Smart Contract
+
+Create `CFXPrice.sol` in the `contracts` directory:
+
+```solidity
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.18;
+
+import "@pythnetwork/pyth-sdk-solidity/IPyth.sol";
+import "@pythnetwork/pyth-sdk-solidity/PythStructs.sol";
+
+contract CFXPrice {
+    IPyth pyth;
+    bytes32 constant CFX_USD_PRICE_ID = 0x8879170230c9603342f3837cf9a8e76c61791198fb1271bb2552c9af7b33c933;
+
+    constructor(address pythContract) {
+        pyth = IPyth(pythContract);
+    }
+
+    function getCFXPrice(bytes[] calldata priceUpdateData) public payable returns (int64, uint) {
+        uint fee = pyth.getUpdateFee(priceUpdateData);
+        pyth.updatePriceFeeds{value: fee}(priceUpdateData);
+
+        PythStructs.Price memory price = pyth.getPrice(CFX_USD_PRICE_ID);
+        return (price.price, price.conf);
+    }
+}
+```
+
+## Step 5: Deploy the Smart Contract
+
+Create `deploy.js` in the `scripts` directory:
+
+```javascript
+const hre = require("hardhat");
+
+async function main() {
+  const pythContractAddress = "0xDd24F84d36BF92C65F92307595335bdFab5Bbd21"; // Pyth contract address on Conflux eSpace Testnet
+
+  const CFXPrice = await hre.ethers.getContractFactory("CFXPrice");
+  const cfxPrice = await CFXPrice.deploy(pythContractAddress);
+
+  await cfxPrice.waitForDeployment();
+
+  console.log("CFXPrice deployed to:", await cfxPrice.getAddress());
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});
+```
+
+## Step 6: Run the Deployment Script
+
+Deploy the contract using:
+
+```bash
+npx hardhat run scripts/deploy.js --network confluxTestnet
+```
+
+## Step 7: Interact with the Contract
+
+Create `interact.js` in the `scripts` directory:
+
+```javascript
+const hre = require("hardhat");
+const { EvmPriceServiceConnection } = require("@pythnetwork/pyth-evm-js");
+
+async function main() {
+  const CFXPrice = await hre.ethers.getContractFactory("CFXPrice");
+  const cfxPrice = await CFXPrice.attach("YOUR_DEPLOYED_CONTRACT_ADDRESS"); // Replace with your actual deployed address
+
+  const connection = new EvmPriceServiceConnection(
+    "https://hermes.pyth.network" // Use Hermes price service
+  );
+
+  const priceIds = [
+    "0x8879170230c9603342f3837cf9a8e76c61791198fb1271bb2552c9af7b33c933", // CFX/USD price feed ID
+  ];
+
+  try {
+    const priceUpdateData = await connection.getPriceFeedsUpdateData(priceIds);
+
+    // Estimate gas
+    const gasEstimate = await cfxPrice.getCFXPrice.estimateGas(priceUpdateData, {
+      value: hre.ethers.parseEther("0.01"), // Send some CFX to pay for the update fee, adjust as needed
+    });
+
+    console.log("Estimated gas:", gasEstimate.toString());
+
+    // Call getCFXPrice function
+    const tx = await cfxPrice.getCFXPrice(priceUpdateData, {
+      value: hre.ethers.parseEther("0.01"), // Send some CFX to pay for the update fee, adjust as needed
+    });
+
+    console.log("Transaction sent:", tx.hash);
+
+    // Wait for transaction confirmation
+    const receipt = await tx.wait();
+
+    console.log("Transaction confirmed in block:", receipt.blockNumber);
+
+    // Get the price directly using staticCall
+    const [price, confidence] = await cfxPrice.getCFXPrice.staticCall(priceUpdateData, {
+      value: hre.ethers.parseEther("0.01"),
+    });
+
+    console.log("CFX/USD Price:", hre.ethers.formatUnits(price, 8)); // Pyth prices are usually in 8 decimals
+    console.log("Confidence:", hre.ethers.formatUnits(confidence, 8));
+
+  } catch (error) {
+    console.error("Error occurred:", error);
+  }
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});
+```
+
+Run the interaction script:
+
+```bash
+npx hardhat run scripts/interact.js --network confluxTestnet
+```
+
+![Get CFX Price Success](../../img/get-cfx-price-success.png)
+
+## Summary
+
+This tutorial demonstrates how to deploy a smart contract on Conflux eSpace Testnet that fetches the CFX/USD price using Pyth Network. Key points:
+
+1. We use the correct CFX/USD price feed ID for Pyth.
+2. The contract is deployed on Conflux eSpace Testnet.
+3. We use the Hermes price service for fetching update data.
+4. The interaction script estimates gas, sends a transaction to update the price, and then retrieves the latest price.
+
+Remember to always use testnet tokens and addresses when testing. For production use, you'd switch to mainnet addresses and endpoints.
+
+For more information, refer to the [Pyth Network documentation](https://docs.pyth.network/)

docs/espace/tutorials/oracle/_category_.json

@@ -0,0 +1,9 @@
+{
+    "label": "How to use Oracle",
+    "position": 1,
+    "link": {
+      "type": "generated-index",
+      "description": "Tutorial on how to use Oracle on Conflux eSpace"
+    }
+  }
+

docs/espace/tutorials/scaffoldCfx/_category_.json

@@ -5,5 +5,4 @@
       "type": "generated-index",
       "description": "Tutorial on how to use a Scaffold for Developing Conflux Apps and Testing Contracts"
     }
-  }
-
+  }