Assignment

• Create API that returns the completion of NFT(ERC721) transfer
• The provided NFT has multiple transfer transactions (See https://mumbai.polygonscan.com/address/0x51a1B628d9a2CFb76306FDccb39E56382A64482B)
• Return the transaction result by checking Transfer Event using a transaction hash (e.g. 0x4a58bb65402fe0f24147f83e005de65ae02c92f9902d2767f58aec2121e6784c)
• This NFT is on the polygon mumbai network. Use any provider to access the blockchain

Expected request and response

// Transaction is completed
$ curl "http://localhost:8080/nft_result?tx=0x4a58bb65402fe0f24147f83e005de65ae02c92f9902d2767f58aec2121e6784c"
{"message":"tokenId: 24, to: 0x70997970C51812dc3A010C7d01b50e0d17dc79C8"}

// Transaction hash is invalid

$ curl "http://localhost:8080/nft_result?tx=0x4a58bb65402fe0f24147f83e005de65ae02c92f9902d2767f58aecbad0000000"
Bad Request%                           

// Transaction hash is not from this Smart Contract
$ curl "http://localhost:8080/nft_result?tx=0x2e901329ae6e554937d2eef332f233329448dac91a4b0d283979de29fda841a7"
{"message":"not ERC721 transaction"}% 

Hint

• Ethers.js provides a way to get a transaction receipt which holds the event data.
• Since events are in hex format on the blockchain, the result should be parsed using abi file under src/abi/nftabi.json
• Ethers.js is one recommended way to implement this but you can use any tools or library to achieve this API

How to share the result

1. Clone this project locally
2. Remove .git by rm -rf .git
3. Run git init
4. Create your private repository on github
5. Push this project to your private reposity
6. Make a branch and add your update, then push your code
7. Invite https://github.com/tomo-noxx to your private project