Challenge 4

Here is the next challenge for dev to dive into Polymer Labs with Universal Channel

The challenge will get you to find out to mint NFT Challenge 4

Prepare

Clone the Polymer's helper source code

git clone https://github.com/polymerdevs/testnet-challenge-3-template.git
cd testnet-challenge-3-template
cp .env.example .env

Then, you need to change the keys like the challenge 1

Doing

Run install

just install

In config.json file, please change the address of Optimism portAddr to 0x691B9bB9f262f997263FBF47F968d2B08bb5a6B8

In Justfile, add the script

run-challenge-4:
    echo "Running the challenge 4 flow..."
    just deploy base base
    just sanity-check
    just send-packet optimism
    echo "Thank you for participating in Challenge!"
    echo "Submit your evidence in the #proof channel in our Discord Server!"

Open your editor with the project you just cloned above, try to edit your contracts/CCQueryUC.sol

In function onRecvUniversalPacket try to write the code in side

recvedPackets.push(UcPacketWithChannel(channelId, packet));

(address sender, string memory query) = abi.decode(packet.appData, (address, string));

bytes memory payload = abi.encode(sender, "mint");

return AckPacket(true, payload);

Just do it

Run the command

just run-challenge-4

Results

You should see somethings in the end of your command

Go the explorer of Optimism

Check your wallet which you add secret key

Check your Token transfer, if you see Challenge 4 NFT with ID, you are done, please don't run the script again

Proof

You go to OP Sepolia Explorer to find your wallet address

Find your first tx sendUniversalPacket then click on it

Copy that TxHash, then go Polymer Packet Zone, Paste it

Click on row, you just filtered, you will see somethings like below picture, screenshot it

You go to OP Sepolia Explorer to find your wallet address

Click on Tab Token transfer to get NFT Challenge 4 Token, then copy the url. It should be like https://optimism-sepolia.blockscout.com/token/0x691B9bB9f262f997263FBF47F968d2B08bb5a6B8/instance/1

Proof will go

Wallet: {your wallet}
QueryMint: Your full url for txhash above
NFT: your full url NFT 

And the screenshot you took above, send to Proof channel

End here, Good Luck!