Questions tagged [erc-721]
Relating to ERC-721, the standard for Non-Fungible Tokens (also known as Deeds)
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1answer
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How do you add miner address so that it can mint tokens?
I have ERC721 that I'm making.
function mint(address to, uint256 tokenId) public onlyMinter returns (bool) {
_mint(to, tokenId);
return true;
}
How can I add an address so that it is able ...
0
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1answer
12 views
What does the single line “_;” in OpenZeppelin's onlyMinter() function do?
In onlyMinter(), there is a line with only _;. I'm having troubles adding a minter address, so I'm just checking the various contracts that go into ERC721. The function is
modifier onlyMinter() {
...
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0answers
10 views
No events were emitted - Exchanging ERC721 Tokens
Function to exchange ERC721 Tokens between two addresses. I am implementing this on truffle and openzeppelin 2.10. Two different tokens should be exchanged between two addresses.
Here's my contract ...
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0answers
11 views
Write a Function to Exchange ERC721 Tokens
How can we exchange Exchange ERC721 Tokens between two addresses? What would be contract function to write with oppenzeppelin 2.0 and truffle.
Implemented exchangeStars() function in contract:
...
1
vote
1answer
15 views
How do I transfer an arbitrary erc 721 asset from a smart contract?
I'm trying to work with ERC 721 tokens in such a way that my contract freezes and unfreezes them (based on some conditions) but I'm having trouble wrapping function calls to the ERC 721 token contract ...
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0answers
18 views
ERC721 Default Implementation
I’m working on a card game. Right now it is really simple. There are orcs and cards. Both should be implemented as ERC 721.
What would be the most natural way to make the orc an ERC-721 token?
...
2
votes
1answer
20 views
How to integrate ERC 721 and 20 to create semi-fungible tokens?
ERC 721 defines non-fungible tokens where each token is unique. But if one needs to create a token where there is a limited supply of various types, is there a an effective way to accomplish this by ...
1
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1answer
16 views
How to ERC721 token using external contract to msg.sender?
I have Caller and ERC721 contract just like this :
contract SampleToken is ERC721MetadataMintable {
string private name;
string private symbol;
constructor (address _creator, string _name,...
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2answers
23 views
ERC721 Error: invalid number value arg=“_tokenId”, coderType=“uint256”, value=
MyERC721:
pragma solidity ^0.5.0;
import "openzeppelin-solidity/contracts/ownership/Ownable.sol";
import "openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol";
import "openzeppelin-solidity/...
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0answers
21 views
Member “transfer” not found or not visible after argument-dependent [duplicate]
I am writing ERC721 contract with truffle. I have recently upgrade solc to 0.5.0 due to openzepplin compiler version. Read about the changes to the 0.5.0 version unfortunately I am unable to resolve ...
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2answers
22 views
How to estimate ERC721 mint transaction?
My contract;
contract My721 is ERC721Full, ERC721Mintable, Ownable {
constructor() ERC721Full("My721", "MY721") public {}
function mintUniqueTokenTo (address _to, uint256 _tokenId, string ...
0
votes
2answers
22 views
Deploy ERC721 tokens to many addresses
How to I transfer many of my ERC721 tokens to many addresses?
MyERC721:
function mintUniqueTokenTo (
address _to,
uint256 _tokenId,
string _tokenURI // Store, receipient'...
3
votes
3answers
29 views
Function that returns address if is passed or msg.sender
I'm implementing an ERC721 contract and I want to execute the following logic.
This is what I want:
If the user pass to a method an address, return that address, if not, return the user's address.
I ...
1
vote
2answers
61 views
How to check Balance & send ERC721 Tokens
I have SPH ERC721 Tokens.
How can I check balance like ERC20 and send ERC721 tokens token to Exchange or in other wallet ?
0
votes
1answer
32 views
what is the equivalent of encodeFunctionSignature for web3.js version ^0.20.6
I want to check if a specific contract deployed at an address is an erc721 contract. I found out that most of the erc721 contracts should have safeTransferFrom function implemented. (except ...
3
votes
1answer
36 views
ERC721 Metadata Creation (Newbie Question) [closed]
Complete newbie here so thanks in advance for tolerating the ignorance that follows.
Working on creating a little card game to learn solidity and have reached the part where I need to assign metadata ...
1
vote
0answers
22 views
Distinguishing erc721 transactions from the response of txlist on etherscan
I am making some erc721 transactions. I can retrieve those transactions using the etherscan api like this
https://api.etherscan.io/api?module=contract&action=txlist&address=...
1
vote
2answers
56 views
Should My ERC721 Show In A Wallet?
We've created and deployed a contract to mint and issue an ERC721 token. I've gone to our admin page in our dapp and "sent" 3 of them to my personal address.
When I check my address in etherscan I ...
1
vote
2answers
57 views
What is the difference between the transfer and transferFrom function in an ERC721 contract
Using web.js, I am trying to transfer erc721 tokens across different addresses.
In case of cryptokitties, I can do the transfer using transfer function only while in case of cryptoheroes, I can use ...
1
vote
1answer
47 views
Error: Invalid number of arguments to Solidity function when calling safeTransferFrom function
I want to call the safeTransferFrom function to transfer ERC721 tokens. I am using the following code:
var contract = this.web3.eth.contract(JSON.parse(contractabierc721)).at(contractAddress);
// ...
2
votes
1answer
28 views
Is it possible to check the Thrid party token ( USDT ) within my ERC223 contracts?
I want to check how many tokens are received in my contracts, so that I am able to allocate MY TOKENS to the TOKEN Sender.
I tried several ways like approveAndCall, but its not working.
I don't ...
-1
votes
0answers
86 views
ERC-20 Token Transfer Error (Unable to locate Corresponding Transfer Event Logs), Check with Sender when trying to send ERC721 tokens
I am trying to transfer ERC721 tokens from one account to another on Ropsten network. I do this by creating raw transaction, signing and broadcasting transactions
I created the transaction this way
{...
1
vote
1answer
44 views
ERC 721 card game
The general concept of ERC 721 is clear to me. My question is more about the contract deployment. I want to have 100 unique cards, So I thought of these two implementations:
Having an initial supply(...
0
votes
1answer
42 views
how to get Token_Id from ERC721 smart contract
How do I retriever Token_Id of cryptokitties from ERC721 Smart contract
Smart contract address : https://etherscan.io/address/0x06012c8cf97bead5deae237070f9587f8e7a266d#code
1
vote
1answer
130 views
Get ERC721 token total supply using web3.js
I created a simple contract which basically does nothing but mints new ERC721 tokens. The solidity code for it is as follows:
struct Monster {
string name;
uint level;
uint ...
1
vote
0answers
79 views
List holders and tokens for an ERC-721 contract
Given a contract, I want to map the holders to their token ids.
For example, the contract 0xFBeef911Dc5821886e1dda71586d90eD28174B7d is an ERC-721 contract for KnownOriginDigitalAsset. Etherscan ...
3
votes
2answers
76 views
Ethereum implementation of a non-fungible but divisible token? (ERC721 seems not to work for that)
I am struggling currently with finding the right implementation possibility for a token with the following properties:
Asset-backed token based on a non-fungible asset (like a piece of art)
More than ...
1
vote
1answer
34 views
Can we create a token with some data inside it?
I wane to write some data (like a link to some file etc) in a token, and once someone sends it from one address to another, that data should be sent as well. Is there anyway we can do now? or you this ...
5
votes
1answer
209 views
How etherscan.io is able to track ERC721 tokens on the blockchain
My question can be rephrased as: how does https://etherscan.io/tokens-nft work?
Does they analyze every transaction data?
The NFT tokens listed there doesn't implement the exact same ABI, is there ...
1
vote
1answer
50 views
How ERC20 and ERC721 deals with confirmation level
a smart contract store the internal balance per owner.
when we transfer tokens from Owner A to Owner B, we update the internal balance sheet.
but the internal balance sheet is a most recent snap shot.
...
1
vote
1answer
164 views
Two ERC721 tokens that refer to the same metadata
This is a question about the ERC721 interface. I understand that the tokens are non-fungible and guaranteed to be unique to a specific account (owner).
One possible way to use ERC721 tokens would be ...
2
votes
1answer
194 views
mint method usage in ERC721 token implementation
What does the internal method call _mint(msg.sender, tokenId) really do in the background when used with ERC721 token implementation?
3
votes
1answer
72 views
How can there be a balance for an ERC721 contract?
Look at this implementation, I can see that ERC721 contracts keep track of an owner (identified by its address) for each single token (identified by its token ID, a 256 bit number):
mapping (uint256 =...
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0answers
33 views
Should I checkAndCallSafeTransfer while creating NFT?
As per erc721 a good practice during transfer of an NFT is to use 'safeTransfer()' which calls:
checkAndCallSafeTransfer
of the
IERC721Receiver
interface.
My question is, when creating a new ...
3
votes
1answer
69 views
Is it a good practice to create a new ERC721 NFT as needed?
I'm prototyping an asset management system using private blockchain and one of the main event is adding a new asset to the system. I was thinking about creating a new token when the asset is added to ...
1
vote
1answer
73 views
ERC725 adopting/extending ERC721 non fungibility attribute for unique decentralized identifier (DIDs) [closed]
Like the ERC20 standards, which is a great standard, I am imagining a future where there will be full of erc725 based token/identities. For decentralized identities to be unique, is there some way to ...
3
votes
1answer
151 views
ERC721 Metadata
Regarding the metadata URI extension - I don't think it should be required that each token ID has an individual metadata URI. I think there should be a globalTokenURI state variable that can be ...
1
vote
1answer
179 views
How do ERC721 tokens get created on private blockchain?
I'm creating a prototype using solidity for asset tracking where I need to create a new token for new items that are being added to the tracking system. I have gone through all possible tutorial on ...
2
votes
2answers
418 views
Proper way to implement “buyable” ERC721 tokens
I have a contract that implements the ERC721 interface, and I want to allow token owners to set their tokens as "buyable", so that any other address can buy their token without any action on the part ...
0
votes
1answer
401 views
“Error: sender account not recognized” when calling transferFrom() on an ERC721 contract
I am having an issue transferring ownership of an ERC721 token to a deployed Holding contract.
The error I’m getting when running truffle test is the following - Error: sender account not recognized ...
0
votes
2answers
107 views
Is ERC721 an appropriate standard for managing licenses?
In my example scenario, I have an e-commerce dApp where e-books are sold. I originally thought that I could represent licenses to access these books using non-fungible tokens (NFTs) through the ERC721 ...
0
votes
1answer
189 views
DeclarationError: Identifier already declared. Two imports import the same ERC721 contract
Im building a contract that uses two contracts that both use the ERC721 zeppelin contract, when I import the two as such:
import nonFungableWidthAddedFunctionality1.sol;
import ...
0
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1answer
27 views
When extending a contract how to call the external constructor and pass parameters?
I have the following contract
import "zeppelin-solidity/contracts/token/ERC721/ERC721Token.sol";
contract Contract is ERC721Token {
function Contract(string _name, string _symbol) public {
...
1
vote
1answer
44 views
erc-721 erc-20 solidity code check effects interaction pattern
Where can one locate a formally verified ERC20/ERC721 solidity code/template that adheres to security design patterns such as check effects interaction patterns?
1
vote
1answer
68 views
Use of the “indexed” keyword and token standards
Long story short, while making a blockchain crawler that would extract all ERC20 transactions I learned the hard way that ERC721 has the same "signature" as ERC20 (and probably many others that I ...
3
votes
0answers
72 views
How are ERC-721 protocol tokens different from Ardor assets? Is there a pro/con data sheet?
ERC-721 protocol is used to create unique tokens like crypto kitties, but I'm curious has anyone compared it to the Ardor Ignis singleton assets as it seems like it does something similar. Is there a ...
0
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0answers
365 views
Transfer an ERC721 Token from another contract
I'm getting a revert when trying to transfer a token from another contract, I'm calling the function from an Auctions contract, for example, when the max bidder claims the reward they get the token ...
1
vote
1answer
20 views
Truffle test failing due to different data type than expected
I am using truffle and ganache to make a token demo for myself. I'm following this guide then making my own changes according to my project.
When I try running tests to verify that my contract is ...
0
votes
1answer
327 views
List ERC721 tokens owned by a user on a web page
Let's say that I have an ERC721 (NFT) contract that represents a set of playing cards.
Is there sample code out there that shows listing all of the tokens of that ERC721 contract that a user owns on ...
1
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1answer
33 views
Does ERC-20 or ERC-721 compliance mean anything of consequence? Are these standards necessary to use
Why do we have to use these standards? Is complying with these standards a necessity if we want our token to be listed anywhere? If our token doesn't fit within the listed standard, can we still have ...
