See also questions close to this topic

• Who i can create Developer and marketing fee with burn for my smart contract?

  I did a lot of research and looked at different classes but could not create anything similar. Is there a project property that I can use?
• Gas estimation failed: 'invalid opcode: INVALID'. This transaction will likely revert. If you wish to broadcast, you must set the gas limit manually

  I adapted the code from this tutorial for my needs. It works fine at rinkeby network, but I am getting an error when I try to run it on Mumbai network.

  AdvancedCollectible.sol >>

  pragma solidity 0.6.6;
  
  import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
  import "@chainlink/contracts/src/v0.6/VRFConsumerBase.sol";
  
  
  contract AdvancedCollectible is ERC721 {
  
      bytes32 internal keyHash;
      uint256 public fee;
      event requestedCollectible(address indexed senderAdd);
  
      uint256 public tokenCounter;
  
      struct Remedio { 
        string nome_medicamento;
        uint256 dosagem;
        string farmaceutica;
        string posologia;
     }   
  
  
      enum Breed{PUG, SHIBA_INU, ST_BERNARD}
      mapping(uint256 => address) public requestIdToSender;
      mapping(uint256 => Breed) public tokenIdToBreed;
      mapping(uint256 => Remedio) public tokenIdToRemedio;
      mapping(uint256 => uint256) public requestIdToTokenId;
  
      
  
      constructor() public
          ERC721("GeradorReceitasMedicas", "Receita")
      {
          
          tokenCounter = 0;
      }
  
      
  
      function createCollectible(string memory nomeMedicamento, uint256 dosagem, string memory farmaceutica, string memory posologia) 
      public returns (bytes32) {
          
          uint256 newItemId = tokenCounter;
  
          tokenCounter = tokenCounter + 1;
  
          Remedio memory newRemedio = Remedio({
             nome_medicamento: nomeMedicamento,
             dosagem: dosagem,
             farmaceutica: farmaceutica,
             posologia: 'posologia'
          });
  
          requestIdToSender[newItemId] = msg.sender;
          address receitaOwner = requestIdToSender[newItemId];
  
          _safeMint(receitaOwner, newItemId);
  
          tokenIdToRemedio[newItemId] = newRemedio;
  
          emit requestedCollectible(receitaOwner);
  
      }
      
      
  
  }
  

  LinkTokenInterface.sol:

  pragma solidity ^0.6.6;
  
  interface LinkTokenInterface {
    function allowance(address owner, address spender) external view returns (uint256 remaining);
    function approve(address spender, uint256 value) external returns (bool success);
    function balanceOf(address owner) external view returns (uint256 balance);
    function decimals() external view returns (uint8 decimalPlaces);
    function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
    function increaseApproval(address spender, uint256 subtractedValue) external;
    function name() external view returns (string memory tokenName);
    function symbol() external view returns (string memory tokenSymbol);
    function totalSupply() external view returns (uint256 totalTokensIssued);
    function transfer(address to, uint256 value) external returns (bool success);
    function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool success);
    function transferFrom(address from, address to, uint256 value) external returns (bool success);
  }
  

  DeployAdvanced.py:

  from brownie import AdvancedCollectible, accounts, network, config
  from scripts.helpful_scripts import fund_advanced_collectible
  
  def main():
      print(config['wallets']['from_key'])
      dev = accounts.add(config['wallets']['from_key'])
      print(network.show_active())
      #print(config['networks'][network.show_active()]['host'])
      publish_source = False
      print(config['wallets']['from_key'])
      advanced_collectible = AdvancedCollectible.deploy(
          {"from": dev},
          publish_source=publish_source,
      )
  
      fund_advanced_collectible(advanced_collectible)
  
      return advanced_collectible
  

  helpful_scripts.py:

  from brownie import AdvancedCollectible, accounts, config, interface, network
  
  
  
  def fund_advanced_collectible(nft_contract):
      dev = accounts.add(config['wallets']['from_key'])
      link_token = interface.LinkTokenInterface(
          config['networks'][network.show_active()]['link_token']
      )
      link_token.transfer(nft_contract, 1000000000000000000, {"from": dev})
  

  brownie-config.yaml:

  exclude SafeMath when calculating test coverage

  https://eth-brownie.readthedocs.io/en/v1.10.3/config.html#exclude_paths

  reports: exclude_contracts: - SafeMath dependencies:

  • smartcontractkit/chainlink-brownie-contracts@1.1.1
  • OpenZeppelin/openzeppelin-contracts@3.4.0 compiler: solc: remappings:
    • '@chainlink=smartcontractkit/chainlink-brownie-contracts@1.1.1'
    • '@openzeppelin=OpenZeppelin/openzeppelin-contracts@3.4.0'

  automatically fetch contract sources from Etherscan autofetch_sources: True dotenv: .env

  set a custom mnemonic for the development network networks: default: development kovan:

  vrf_coordinator: '0xdD3782915140c8f3b190B5D67eAc6dc5760C46E9'
  link_token: '0xa36085F69e2889c224210F603D836748e7dC0088'
  keyhash: '0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4'
  fee: 100000000000000000
  oracle: '0x2f90A6D021db21e1B2A077c5a37B3C7E75D15b7e'
  jobId: '29fa9aa13bf1468788b7cc4a500a45b8'
  eth_usd_price_feed: '0x9326BFA02ADD2366b30bacB125260Af641031331'   rinkeby:
  vrf_coordinator: '0xb3dCcb4Cf7a26f6cf6B120Cf5A73875B7BBc655B'
  link_token: '0x01be23585060835e02b77ef475b0cc51aa1e0709'
  keyhash: '0x2ed0feb3e7fd2022120aa84fab1945545a9f2ffc9076fd6156fa96eaff4c1311'
  fee: 100000000000000000
  oracle: '0x7AFe1118Ea78C1eae84ca8feE5C65Bc76CcF879e'
  jobId: '6d1bfe27e7034b1d87b5270556b17277'
  eth_usd_price_feed: '0x8A753747A1Fa494EC906cE90E9f37563A8AF630e'
  host: 'https://rinkeby.infura.io/v3/${WEB3_INFURA_PROJECT_ID}'   mumbai:
  link_token: '0x326C977E6efc84E512bB9C30f76E30c160eD06FB'
  eth_usd_price_feed: '0x0715A7794a1dc8e42615F059dD6e406A6594651A'   polygon-test:
  link_token: '0x326C977E6efc84E512bB9C30f76E30c160eD06FB'
  eth_usd_price_feed: '0x0715A7794a1dc8e42615F059dD6e406A6594651A'   binance:
  # link_token: ??
  eth_usd_price_feed: '0x9ef1B8c0E4F7dc8bF5719Ea496883DC6401d5b2e'   binance-fork:
  eth_usd_price_feed: '0x9ef1B8c0E4F7dc8bF5719Ea496883DC6401d5b2e'   mainnet-fork:
  eth_usd_price_feed: '0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419'   matic-fork:
  eth_usd_price_feed: '0xF9680D99D6C9589e2a93a78A04A279e509205945' wallets:   from_key: ${PRIVATE_KEY}   from_mnemonic: ${MNEMONIC}
  

  settings: gas_limit: "100000000000"

  When I run it on Rinkeby, I get (run command brownie run .\scripts\advancedCollectible\deploy_advanced.py --network rinkeby):

  INFORMAÇÕES: não foi possível localizar arquivos para o(s) padrão(ões) especificado(s). Brownie v1.18.1 - Python development framework for Ethereum

  ContratoNftProject is the active project.

  Running 'scripts\advancedCollectible\deploy_advanced.py::main'... fdb0ee33d87a414d57235c1eb5df7b3cd15a69c3041214584e4eb2d2b220e2ef rinkeby fdb0ee33d87a414d57235c1eb5df7b3cd15a69c3041214584e4eb2d2b220e2ef Transaction sent: 0xf3cbcf650ab9b4408f8e795469ffa60a61f5943ab485ec133e3650fece7545db
  Gas price: 1.499999222 gwei Gas limit: 2377218 Nonce: 67
  AdvancedCollectible deployed at: 0x5D37fc76D54880F878a395755df5101B644B655a

  C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\network\contract.py:1180: BrownieCompilerWarning: 0x5D37fc76D54880F878a395755df5101B644B655a: Locally compiled and on-chain bytecode do not match! warnings.warn( Transaction sent: 0x74a64ac1449a597584bbca8dc0947e80a6ad042ca68453da6e550a0dbbfe67da
  Gas price: 1.499999221 gwei Gas limit: 56992 Nonce: 68
  LinkToken.transfer confirmed Block: 10631644 Gas used: 51811 (90.91%)

  When I run it on Mumbai, I get (run command brownie run .\scripts\advancedCollectible\deploy_advanced.py --network polygon-test):

  INFORMAÇÕES: não foi possível localizar arquivos para o(s) padrão(ões) especificado(s). Brownie v1.18.1 - Python development framework for Ethereum

  ContratoNftProject is the active project.

  Running 'scripts\advancedCollectible\deploy_advanced.py::main'... fdb0ee33d87a414d57235c1eb5df7b3cd15a69c3041214584e4eb2d2b220e2ef polygon-test fdb0ee33d87a414d57235c1eb5df7b3cd15a69c3041214584e4eb2d2b220e2ef Transaction sent: 0x6915605b9dfb985b8ef078e3268a6b6e6e2e0b95d3d25ce8e5912c7a71db84d7
  Gas price: 1.759579396 gwei Gas limit: 2377218 Nonce: 13
  AdvancedCollectible.constructor confirmed Block: 26234140 Gas used: 2161108 (90.91%) AdvancedCollectible deployed at: 0xdbae4544699a953f2b28AFfBA77008Fd9eb1B4Cf

  File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie_cli\run.py", line 51, in main return_value, frame = run( File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\project\scripts.py", line 103, in run return_value = f_locals[method_name](*args, **kwargs) File ".\scripts\advancedCollectible\deploy_advanced.py", line 16, in main fund_advanced_collectible(advanced_collectible) File ".\scripts\helpful_scripts.py", line 10, in fund_advanced_collectible link_token.transfer(nft_contract, 1000000000000000000, {"from": dev}) File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\network\contract.py", line 1710, in call return self.transact(*args) File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\network\contract.py", line 1583, in transact return tx["from"].transfer( File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\network\account.py", line 644, in transfer receipt, exc = self._make_transaction( File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\network\account.py", line 727, in _make_transaction
  raise VirtualMachineError(e) from None File "C:\Users\p\AppData\Roaming\Python\Python39\site-packages\brownie\exceptions.py", line 93, in init raise ValueError(str(exc)) from None ValueError: Gas estimation failed: 'invalid opcode: INVALID'. This transaction will likely revert. If you wish to broadcast, you must set the gas limit manually.

  Why am I getting this error on Mumbai Network? Is it possible to fix the error above?
• Sending ether from Contract A to Contract B

  I'm trying to send ether from contract A to Contract B but it's currently not connecting to Metamask. I'm not sure if I need to add something else in order to inherit from another contract or if the problem is with the function. I want to send ether to the owner in Contract A and have tried looking at all solutions online but not having any luck. I wanted to do this all in one contract and although the transaction went through, it wasn't sent to the owner so I am now trying to send from another contract instead.

  Any help on how to fix this so I can send ether to the owner would be appreciated.

  Contract A:

  struct Building {
          string name;
          address owner;
          int256 posX;
          int256 posY;
          int256 posZ;
          uint256 sizeX;
          uint256 sizeY;
          uint256 sizeZ;
          address tenant;
      }
  
      Building[] public buildings;
  
  buildings.push(
              Building('Plot 1', address(0x0), 0, 0, 0, 10, 10, 10, address(0x0))
          );
  

  Contract B:

  contract B {
  
      uint public amount = 1 ether;
  
      function sendRentalPayment(address payable owner) payable public {
          require(msg.value >= amount);
          owner.transfer(msg.value);
      }
  
  }
  

  App.js

  await senderContract.methods.sendRentalPayment().send({from: account, value: '1000000000000000000' })
  
• How can be a NFT contract can be sold on multiple markets?

  I'm trying to build an NFT marketplace. When I inspect the ERC721 protocol I see that we can set only one operator that can call safe transfer. That means if an NFT contract is listed on A market, then after B market. A market loses its privilege to call safe transfer. What happens if my marketplace contract loses the operator position for that contract?
• Metamask mainnet error: MetaMask - RPC Error: Internal JSON-RPC error. {code: -32603, message: 'Internal JSON-RPC error

  React app working well with metamask on testnet, but not able to buy nfts on mainnet. Am using ERC721.

  This is the error data :

  inpage.js:1 MetaMask - RPC Error: Internal JSON-RPC error. {code: -32603, message: 'Internal JSON-RPC error.', data: {…}}code: -32603data: {code: 3, data: '0x08c379a00000000000000000000000000000000000000000…0746f20636f6d706c65746520707572636861736500000000', message: 'execution reverted: Please submit the asking price in order to complete purchase'}message: "Internal JSON-RPC error."[[Prototype]]: Object (anonymous) @ inpage.js:1 (anonymous) @ inpage.js:17
• IPFS uri format: https://ipfs.io/ipfs/<CID> vs. ipfs://<CID>?

  Here is my test tokenURI.json file w/ the imageURI I pass to my token contract.setTokenURI():

  {
   "attributes": [
      {
        "trait_type": "location",
        "value": "West Awesomeville"
      },
      {
        "display_type": "date",
        "trait_type": "created",
        "value": 1535250800
      }
    ],
    "description": "My awesome NFT.",
    "image": "https://ipfs.io/ipfs/QmaUXii41ESnUMxLJUoVcrEeXowz7RHcdTiumvrBmUvcwG?filename=test4.png",
    "name": "NFT 1"
  }
  

  Which is the best IPFS uri form to use esp. if I want to load this NFT into Opensea?

  The docs in IPFS recommend:

  https://ipfs.io/ipfs/<CID>
  

  but the docs in Opensea recommend:

  ipfs://<CID>
  

  Which form is better and why?

  In the above json I'm using the first form recommended by IPFS. It works but loading into Opensea is slow/somewhat unpredictable.

  The form Opensea recommends is shorter, no gateway. Would the image load faster in Opensea if I used the 2nd form?

  IPFS docs: Address IPFS on the Web

  Opensea docs:
  If you use IPFS to host your metadata, your URL should be in the format ipfs://CID. For example, ipfs://QmTy8w65yBXgyfG2ZBg5TrfB2hPjrDQH3RCQFJGkARStJb.