IPFS_with_Solidity

A decentralized file storage system built using Solidity, IPFS, and MetaMask. This DApp allows users to securely upload files to IPFS and store the corresponding hash on the blockchain. Later, users can retrieve their files using the hash, ensuring security, decentralization, and immutability.

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🚀 Features

• 🔐 Connect MetaMask wallet to interact with the blockchain
• 📤 Upload files and store them on IPFS using web3.storage
• 🧾 Record IPFS hash on Ethereum-compatible blockchain via a smart contract
• 📥 Retrieve files using stored hashes
• 🎨 User-friendly frontend built with HTML, CSS, and JavaScript

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🗂️ Project Structure

IPFS_with_Solidity/
├── client/                       # Frontend UI
│   ├── index.html
│   ├── style.css
│   └── wallet.js
│
├── server/                       # Backend server (optional usage)
│   └── server.js
│
├── smart-contract/
│   └── contracts/               # Solidity smart contracts
│       └── FileStorage.sol
│
├── ignition/modules/            # Hardhat deployment module
│   └── Lock.js
│
├── scripts/                     # Hardhat scripts (e.g., deploy)
│
├── test/                        # Contract test cases
│
├── uploads/                     # Temporary file storage
│
├── hardhat.config.js            # Hardhat config
├── package.json
├── package-lock.json
├── .gitignore
└── README.md                    # You’re reading it!

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🛠️ Installation & Setup

1. Clone the repository

   git clone https://github.com/your-username/IPFS_with_Solidity.git
   cd IPFS_with_Solidity

2. Install dependencies

   npm install

3. Compile the smart contract

   npx hardhat compile

4. Run a local blockchain (optional)

   npx hardhat node

5. Deploy the contract

   npx hardhat ignition deploy ./ignition/modules/Lock.js

6. Start the frontend Open client/index.html in your browser.

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🧪 Usage Instructions

1. 🦊 Connect MetaMask
   Make sure MetaMask is installed and connected to the correct network (e.g., local or Goerli testnet).

2. 📤 Upload a file

   • Click on "Choose File"
   • Click "Upload"
   • The file is sent to IPFS, and the hash is saved to the blockchain

3. 🔗 Retrieve file
   Use the saved IPFS hash to retrieve the file anytime using a public IPFS gateway

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🧱 Tech Stack

• Smart Contracts: Solidity, Hardhat
• Frontend: HTML, CSS, JavaScript
• Wallet Integration: MetaMask + Ethers.js
• File Storage: IPFS via web3.storage
• Local Blockchain: Hardhat

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🧰 Scripts & Commands

npx hardhat help                       # List all available Hardhat tasks
npx hardhat compile                   # Compile contracts
npx hardhat test                      # Run tests
npx hardhat node                      # Start local Hardhat blockchain
npx hardhat ignition deploy ./ignition/modules/Lock.js  # Deploy contract

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⚠️ Troubleshooting

• ethers is not defined
  ➤ Ensure you include the ethers.js CDN in your index.html before any custom JS:

  <script src="https://cdn.jsdelivr.net/npm/ethers@5.7.2/dist/ethers.umd.min.js"></script>

• MetaMask not connecting
  ➤ Make sure MetaMask is unlocked and connected to the correct network. Refresh the page after approving.

• Unexpected token 'export'
  ➤ Use <script type="module"> only if you’re writing ES6 imports/exports.

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please make sure you have pinita ipfs key and secret. --> create an .env file and paste your pinita ipfs key and secret like this

PINATA_API_KEY=xxxxxxxxxxxxxxxxxx // this should be an alpha numeric character PINATA_SECRET_API_KEY=xxxxxxxxxxxxxxxxxxxxx // this should also be a alpha numeric charecter

🙌 Acknowledgments

Thanks to:

• MetaMask
• Ethers.js
• web3.storage
• Hardhat