ERC1155 - Problem NFT Unidentified contract

Question

I'm trying to create an ERC1155 NFT but when I deploy the contract and try to see it on Opensea testnet, it always show "Unidentified contract" whereas I didn't have any problem with ERC721.

Here is the difference : When you create an ERC721 you can add the name of the ERC721 token with its symbol like this :

contract MyNFT is ERC721URIStorage {
  using Counters for Counters.Counter;
  Counters.Counter private _tokenIds;

  constructor() ERC721 ("NAME", "SYMBOL") {
  }

However, this is completely different for ERC1155 tokens, this is my code :

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract MyNFT is ERC1155, Ownable {
    constructor() ERC1155("JSON FILE WITH METADATA") {
        _mint(msg.sender,1,1,"");
    }

And this is what I have on my json file metadatas

{
   "name":"Sword",
   "description":"Sword from GameItems",
   "image":"link_picture"
}

By looking at this https://eips.ethereum.org/EIPS/eip-1155#rationale It seems that in order to put a name for the collection I have to insert it on the metadata itself, but I don't know which designation I have to use. I tried this:

{
   "title":"GameItems",
   "name":"Sword",
   "description":"Sword from GameItems",
   "image":"link_picture"
}

But it's not working. Did anyone succed in applying a name for the collection on Opensea ? It would be very helpful to have some advice

Thanks

Answer 1

If you just want to add a name and a symbol you can do the following:

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract MyNFT is ERC1155, Ownable {
    
    string public name;
    string public symbol;
    
    constructor() ERC1155("JSON FILE WITH METADATA") {
        name = "Hello World 4321";
        symbol = "HELO";
        _mint(msg.sender,1,1,"");
    }
}

However if you want to define even more details about your collection and you only care about what people see on OpenSea. You could do something like this:

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract MyNFT is ERC1155, Ownable {
    
    constructor() ERC1155("JSON FILE WITH METADATA") {
        _mint(msg.sender,1,1,"");
    }
    
    function contractURI() public view returns (string memory) {
        return "https://LINK-TO-COLLECTION-METADATA";
    }
}

And then upload another metadata file. NOTE this metadata file is not about the NFT its a seperate file about the collection.

{
  "name": "Hello World 4321",
  "description": "Welcome to my collection about Hello World 4321",
  "image": "https://link-to-image",
  "external_link": "https://link-to-website",
  "seller_fee_basis_points": 100, # Indicates a 1% seller fee.
  "fee_recipient": "YOUR_ADDRESS_TO_COLLECT_ROYALTIES" 
}

I got this from here. You can also combine the code from both examples and do both :) Hope this helps!

P.S you didn't ask about it so maybe you have it covered. But I just want you to know that you might have an issue visualising your NFTs on OpenSea if you dont override the uri() function. Like in this example I created for EatTheBlocks.