🚀 Day 2 of 30 Days of Solidity Challenge – Building Enhanced User Profiles

#blockchain #solidity #web3 #smartcontract

Hello developers 👋

This is Day 2 of my 30 Days of Solidity Challenge where I share my learning journey while building small but useful smart contracts.

📌 Task for Today

Yesterday, we built a simple contract that stored just a user’s name and bio.
Today, I enhanced that contract to make it feel more like a real user profile system.

We added extra fields like:

Username
Bio
Age
Location
Profile Picture (can be an IPFS hash or URL)
JoinedOn (timestamp when profile was created/updated)

📝 Smart Contract – Enhanced Profile

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract EnhancedProfile {
    struct Profile {
        string username;
        string bio;
        uint256 age;
        string location;
        string profilePic;  // could store IPFS hash or URL
        uint256 joinedOn;
    }

    mapping(address => Profile) private profiles;

    event ProfileUpdated(
        address indexed user,
        string username,
        string bio,
        uint256 age,
        string location,
        string profilePic
    );

    function setProfile(
        string memory _username,
        string memory _bio,
        uint256 _age,
        string memory _location,
        string memory _profilePic
    ) public {
        profiles[msg.sender] = Profile({
            username: _username,
            bio: _bio,
            age: _age,
            location: _location,
            profilePic: _profilePic,
            joinedOn: block.timestamp
        });

        emit ProfileUpdated(msg.sender, _username, _bio, _age, _location, _profilePic);
    }

    function getProfile(address _user)
        public
        view
        returns (
            string memory username,
            string memory bio,
            uint256 age,
            string memory location,
            string memory profilePic,
            uint256 joinedOn
        )
    {
        Profile memory profile = profiles[_user];
        return (
            profile.username,
            profile.bio,
            profile.age,
            profile.location,
            profile.profilePic,
            profile.joinedOn
        );
    }
}

🔎 How It Works

Struct Profile → Stores all user details.
Mapping (address => Profile) → Each wallet address is linked to its profile.
setProfile() → Users can create or update their profile.
getProfile() → Anyone can fetch a profile by providing the wallet address.
Event ProfileUpdated → Logs every update, useful for dApp frontends.

⚡ Example Usage

A user saves their profile:

setProfile("Alice", "I build dApps", 25, "Bangalore, India", "ipfs://QmHashOfPic");

Anyone can retrieve Alice’s profile:

getProfile(aliceAddress);

➡️ Returns all details including the timestamp.

🎯 Learning Outcome

With this task, I learned how to:
✅ Store multiple user details on-chain.
✅ Use structs + mappings effectively.
✅ Add events for tracking profile changes.
✅ Design a basic identity system for future dApps.

This is a small but important step towards understanding data storage & retrieval in Solidity. Tomorrow, I’ll move to the next challenge and keep building!

👉 You can also check out Day 1 blog here: Day 1 of Solidity Challenge – Click Counter

Stay tuned for Day 3 🚀

✨ Thanks for reading! If you’re also learning Solidity, let’s connect and build together.