Build a smart contract oracle with Solidity, Node.js, and Replit

• openzeppelin-contracts

  234 24,109 9.5 JavaScript

  OpenZeppelin Contracts is a library for secure smart contract development.

  

OpenZeppelin's Ownable, an access control mix-in that allows us to implement functions that only the contract's owner (the address that deploys the contract) will be able to call.

• axios

  439 103,985 8.4 JavaScript

  Promise based HTTP client for the browser and node.js

  

Here we import hardhat and axios, which we'll need to request random numbers from the RANDOM.ORG API.

• SurveyJS

  surveyjs.io sponsored

  Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.

  

• metamask-extension

  1,137 11,467 10.0 JavaScript

  :globe_with_meridians: :electric_plug: The MetaMask browser extension enables browsing Ethereum blockchain enabled websites

  

We will need a browser-based Web3 wallet to interact with the Replit Testnet and our deployed contracts. MetaMask is a popular and feature-rich wallet implemented as a WebExtension. You can install it from MetaMask's download page. Make sure you're using a supported browser – Chrome, Firefox, Brave, or Edge.

• hardhat

  126 6,754 9.9 TypeScript

  Hardhat is a development environment to compile, deploy, test, and debug your Ethereum software.

  

We'll write our data provider as a simple Node.js application, using the Hardhat Ethereum development environment to help us interact with the blockchain. This environment provides a host of features for writing, testing, and deploying smart contracts, and for building applications that interface with the blockchain, such as this one. It includes a slightly modified version of the ethers library, which is the main component we'll be using.

• Express

  674 63,771 8.3 JavaScript

  Fast, unopinionated, minimalist web framework for node.

  

We'll also need to create a simple Node.js Express application to render the frontend. Create a file named frontend.js in your repl and add the following code to it:

• InfluxDB

  www.influxdata.com sponsored

  Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.

  

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