How can I retrieve the constructor arguments used during contract deployment

Question

I know how to extract the constructor arguments out of the transaction object returned from a contract-deployment operation.

It is explain in web3.js official documentation here.

But this is not an issue of course, because if I am the one deploying the contract, then I obviously know the constructor arguments beforehand.

I am interested in retrieving the constructor arguments of an already deployed contract, i.e., the constructor arguments used during the deployment of that contract (by someone else).

I have the following at my disposal:

• The address of the deployed contract
• The byte-code of the deployed contract
• The contract-deployment's transaction hash

Can any of the above help me retrieving the constructor arguments of an already deployed contract?

Thank you!

Answer 1

You can get them on Etherscan for any contract, see here for Example. It will take some research about RLP encoding to decode everything into readable text though.