从实心度返回的数组，在Java脚本中被赋值为BigNumber [英] Array returned from Solidity assigned as bigNumber in Javascript

问题描述

我对固定性和Java脚本开发非常陌生，最近遇到了一些问题。

使用案例：

1. 将数据数组从Java脚本存储到Solidity。
2. 将存储的数组从实心返回到Java代码。

获取数组的脚本代码：

    async loadBlockchain() {
    const web3 = window.web3
    const accounts = await web3.eth.getAccounts()
    console.log("Eth account: " + accounts)
    this.setState({account: accounts[0]})
    const networkID = await web3.eth.net.getId()
    console.log("Eth network ID: " + networkID)
    const networkData = storeHash.networks[networkID]
    
    if(networkData) {
        //Fetch the smart contract from the address
        const abi = storeHash.abi
        const address = networkData.address
        const contract = new web3.eth.Contract(abi, address)
        this.setState({ contract })
        console.log(contract)

        var fileHashList = await contract.methods.get().call()
        console.log(fileHashList)
    } 
    else 
    {
        window.alert('Smart contract not deployed to detected network')
    }
}

返回数组的坚实代码：

pragma solidity 0.5.16;
pragma experimental ABIEncoderV2;

contract storeHash {
//Upload stored file hash in blockchain

string[] public fileHash;
//uint256 public fileCount = 0;

//Store hash value
function set(string memory _fileHash) public {
    
    fileHash.push(_fileHash);
}


//Retrieve hash value
function get() public view returns (string[] memory) {

    return fileHash;

}

问题：

1. 返回的数组似乎被读取为bigNumber，并显示以下错误：

   未处理的拒绝(空)：溢出(错误=溢出，操作=编号(&q；)， Value="；36830543755683898667443985212771609229556685323236234700674529361303541601398"；， CODE=NUMERIC_FAULT，VERSION=BIG NUMBER/5.3.0)

2. 控制台中的错误消息：

Uncaught (in promise) null: overflow (fault="overflow", operation="toNumber", value="36830543755683898667443985212771609229556685323236234700674529361303541601398", code=NUMERIC_FAULT, version=bignumber/5.3.0)
    at Logger.makeError (http://localhost:3000/static/js/vendors~main.chunk.js:6622:19)
    at Logger.throwError (http://localhost:3000/static/js/vendors~main.chunk.js:6633:18)
    at throwFault (http://localhost:3000/static/js/vendors~main.chunk.js:3782:17)
    at BigNumber.toNumber (http://localhost:3000/static/js/vendors~main.chunk.js:3584:9)
    at http://localhost:3000/static/js/vendors~main.chunk.js:666:54
    at Array.forEach (<anonymous>)
    at unpack (http://localhost:3000/static/js/vendors~main.chunk.js:661:10)
    at ArrayCoder.decode (http://localhost:3000/static/js/vendors~main.chunk.js:818:39)
    at http://localhost:3000/static/js/vendors~main.chunk.js:669:23
    at Array.forEach (<anonymous>)
    at unpack (http://localhost:3000/static/js/vendors~main.chunk.js:661:10)
    at TupleCoder.decode (http://localhost:3000/static/js/vendors~main.chunk.js:1275:92)
    at AbiCoder.decode (http://localhost:3000/static/js/vendors~main.chunk.js:185:20)
    at ABICoder.push../node_modules/web3-eth-abi/lib/index.js.ABICoder.decodeParametersWith (http://localhost:3000/static/js/vendors~main.chunk.js:308757:28)
    at ABICoder.push../node_modules/web3-eth-abi/lib/index.js.ABICoder.decodeParameters (http://localhost:3000/static/js/vendors~main.chunk.js:308739:15)
    at Contract.push../node_modules/web3-eth-contract/lib/index.js.Contract._decodeMethodReturn (http://localhost:3000/static/js/vendors~main.chunk.js:310221:20)
    at Method.outputFormatter (http://localhost:3000/static/js/vendors~main.chunk.js:310556:32)
    at Method.push../node_modules/web3-core-method/lib/index.js.Method.formatOutput (http://localhost:3000/static/js/vendors~main.chunk.js:306298:50)
    at sendTxCallback (http://localhost:3000/static/js/vendors~main.chunk.js:306848:25)
    at cb (http://localhost:3000/static/js/vendors~main.chunk.js:198169:22)
    at Item.push../node_modules/process/browser.js.Item.run (http://localhost:3000/static/js/vendors~main.chunk.js:242191:12)
    at drainQueue (http://localhost:3000/static/js/vendors~main.chunk.js:242155:34)

我可以知道如何解决此问题并在NodeJS应用程序中获得我想要的数组吗？ 提前感谢您！

推荐答案

您不能从Solidity返回数组，我认为这是因为它返回数组的地址，这就是您收到大数字错误的原因。

修改合同稳固性

• 编写返回数组长度的方法：

  function getLength() public view returns(uint){
      return fileHash.length
   }
  

• 编写按索引从数组中获取项的方法：

  function getFileHashByIndex(uint index) public view returns (string memory){
     return fileHash[index]
  }
  

修改Java脚本中的代码

let fileHashes,filesCount;
// dealing with contract is async. always use try/catch
try {
     filesCount = await contract.methods.getLength().call();
       
    fileHashes = await Promise.all(
      Array(parseInt(filesCount))
        .fill()
        .map((element, index) => {
          return contract.methods.getFileHashByIndex(index).call();
        })
    );
    
  } catch (e) {
    console.log("error in pulling file hashes", e);
  }

这篇关于从实心度返回的数组，在Java脚本中被赋值为BigNumber的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！