随着区块链的发展，NFT也逐渐传入国内（数字藏品），大家都很好奇数藏APP是怎样开发出来的。今天就数藏APP开发过程中容易遇到的细节问题来简单说一下数藏APP开发过程中的注意点。　　The full name of the digital collection is Non-FungibleToken,abbreviated as NFT,which is a non-homogeneous token.The concept of NFT comes from foreign countries.It is a customized work using blockchain technology.The artwork forms a separate digital certificate.The authorization code is the information that protects copyright,and completes digital distribution,purchase,collection and use.The one-key digital collection of works is like a commodity,which is independent,indivisible,tamper-proof,verifiable and scarce.　　我们做的主要修改是增加一个Token ID到URL的映射。因为我们准备将NFT的图片和Metadata数据都放到IPFS上，所以增加一个Token ID到IPFS文件哈希的映射：　　contract ERC1155{　　mapping(uint256=>string)private _metadataHashes;　　string private _uriPrefix=“”;　　//返回”QmasWH…re2Ych?filename=metadata.json”　　//如果使用服务器API返回则可以固定uri为”{id}”　　function uri(uint256 id)public view returns(string memory){　　return _concat(_uriPrefix,_metadataHashes[id],“?filename=metadata.json”);　　}　　}　　第二个修改是增加一个mint()方法来铸造NFT：　　function mint(uint256 amount,string memory metadataHash)public returns(uint256){　　//如果只允许合约部署者铸造，加上判断:　　//require(msg.sender==owner,“Not contract owner”);　　nextTokenId++;　　uint256 tokenId=nextTokenId;　　_metadataHashes[tokenId]=metadataHash;　　_mint(msg.sender,tokenId,amount,“”);　　return tokenId;　　}　　最后一步是在isApprovedForAll()中判断下当前转移操作的发起者是不是OpenSea的代理合约：　　function isApprovedForAll(address account,address operator)public view returns(bool){　　//Whitelist OpenSea proxy contract for easy trading.　　ProxyRegistry proxyRegistry=ProxyRegistry(proxyRegistryAddress);　　if(address(proxyRegistry.proxies(account))==operator){　　return true;　　}　　return _operatorApprovals[account][operator];　　}　　这么做的目的是将来在OpenSea售卖的时候，不需要