Limit NFT minting by month

Smart Contracts
1

Hi,

So I want to mint only 100 NFTs per month, and I want to deploy just one contract how would I go about it? I though of having an ownerOnly manual flag, that can be set:

if (secondMonth)
maximumSupply = 200

if (thirdMonth)
maximumSupply = 300

And so on? Any flaws?,
Thanks!

2

Are these 100 NFTs evenly spaced in minting time or not? Is there an absolute maximum supply? Who is able to mint the NFTs?

3

100 per month, if the 100 are minted in a single day is fine.
Yes there is a maximum supply, after a year the max supply should be reached (1200).
Anybody should be able to call the mint function, plus a fee.

4

If the timeline is not strictly required, then a timelock can be implemented, i.e., there is a strict relationship between tokenIds and timestamps or time elapsed since deployment. Then when mint function is called, check if this condition is met or not.

5

Ok. It is almost the same check-wise, the main difference is that is automatic and not manual?

uint public constant november = 11 days;
uint public constant december= 41 days;

if (block.timestamp >= november)
maximumSupply = 200
if (block.timestamp >= december)
maximumSupply = 300

1 Like
6

yes, in the world of blockchain, the spirit is to code the rules in smart contracts instead of executing rules by people. A lot more transparent and thus trustworthy

1 Like
7

is that the code that would be used? im trying to do the same thing with my collection

8

Not sure if you figured this out but I was trying to do the same thing and figured out you have to add whatever time interval you want to the initial block.timestamp of your contracts creation. I attached the code below that worked for me.

uint256 deployDate;

constructor() ERC721("Name Of Collection", "NOC") {
        deployDate = block.timestamp;
}

function safeMint(address to, string memory uri) public payable {
        if(block.timestamp >= deployDate + 1 days){
            maxSupply = 1;
        }
        if(block.timestamp >= deployDate + 2 days){
            maxSupply = 2;
        }
        if(block.timestamp >= deployDate + 3 days){
            maxSupply = 3;
        }
        if(block.timestamp >= deployDate + 4 days){
            maxSupply = 4;
        }
        if(block.timestamp >= deployDate + 5 days){
            maxSupply = 5;
        }

        require(totalSupply() < maxSupply, "max supply reached for now");
        ... (rest of safeMint code)...
}

I will probably move to safemath to prevent overflow errors and i recommend you do the same but I left it as normal signs to keep understanding simple. If you want to learn more about time in solidity this article was super helpful.
https://soliditytips.com/articles/solidity-dates-time-operations/

if you want month intervals just do deployDate + 4 weeks or however many days are within each month you are releasing

Hope this helped :slight_smile:

9

Hi Zergucci,

Thank you for the response. I have a question regarding monthly payements (fees, rents, etc).
You recommend using 4 weeks... but what if I'm trying to have exact monthly installments?

I saw OpenZeppelin is implementing a Datetime utils, which is great (https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3255), but I wonder if it's worth the cost to calculate the different month to seconds periods, which vary greatly.

By the way, I don't understand how Solidity can infer seconds from year since there are years that are longer than others...

Thanks in advance,

Antoine