未处理的拒绝错误:无效的JSON RPC响应:""

Question

我试图在我的ERC20令牌合同上调用一个方法.我正在连接到" https://rinkeby.infura.io/"httpProvider.我可以调用()常量方法,但是当我想通过调用send()函数来改变契约的状态时,我得到了这个提到的错误.如果您认为发布ABI JSON或Solidity合同有帮助,我也可以提供.我认为我的问题纯粹与web3有关.我想我需要签署交易(逻辑上),但web3文档没有提到任何内容.http://web3js.readthedocs.io/en/1.0/web3-eth-contract.html#methods-mymethod-send

这是我得到的错误:

Unhandled rejection Error: Invalid JSON RPC response: ""
at Object.InvalidResponse (/opt/backend/node_modules/web3-core-helpers/src/errors.js:42:16)
at XMLHttpRequest.request.onreadystatechange (/opt/backend/node_modules/web3-providers-http/src/index.js:60:32)
at XMLHttpRequestEventTarget.dispatchEvent (/opt/backend/node_modules/xhr2/lib/xhr2.js:64:18)
at XMLHttpRequest._setReadyState (/opt/backend/node_modules/xhr2/lib/xhr2.js:354:12)
at XMLHttpRequest._onHttpResponseEnd (/opt/backend/node_modules/xhr2/lib/xhr2.js:509:12)
at IncomingMessage.<anonymous> (/opt/backend/node_modules/xhr2/lib/xhr2.js:469:24)
at emitNone (events.js:111:20)
at IncomingMessage.emit (events.js:208:7)
at endReadableNT (_stream_readable.js:1055:12)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickCallback (internal/process/next_tick.js:180:9)
From previous event:
at PromiEvent (/opt/backend/node_modules/web3-core-promievent/src/index.js:35:24)
at send (/opt/backend/node_modules/web3-core-method/src/index.js:446:21)
at Object._executeMethod (/opt/backend/node_modules/web3-eth-contract/src/index.js:890:24)
at Object.currencyToken.sendSignUpBonousTokens (/opt/backend/server/common/token/currency-token.js:86:56)
at <anonymous>

从调用此方法:

const Web3 = require('web3');
const Tx = require('ethereumjs-tx');
const ABIjson = require('./ABI.json');

const web3 = new Web3(new Web3.providers.HttpProvider('https://rinkeby.infura.io/my_access_token_here'));
const contractAddress = '0x31cF32fa91286168B1A896Db4F99d106246932Bc';
const ownerAddress = '0x44Ba8c5a905D634c485dE6f8fD43df9682AfD342';

const token = new web3.eth.Contract(ABIjson, contractAddress);
try
{
    const gasAmount = await token.methods.transfer(company.walletAddress, 10000).estimateGas({from: ownerAddress});

    token.methods.transfer(company.walletAddress, 550).send(
      {
        from: ownerAddress,
        gasPrice: '20000000000',
        gas: gasAmount
      })
      .then(function(receipt)
      {
        console.log(receipt);
      });
}
catch (error)
{
    console.error(error);
}

以下是该方法的ABI代码段:

{  
"constant":false,
"inputs":[  
  {  
    "name":"_to",
    "type":"address"
  },
  {  
    "name":"_value",
    "type":"uint256"
  }
],
"name":"transfer",
"outputs":[  
  {  
    "name":"success",
    "type":"bool"
  }
],
"payable":true,
"stateMutability":"payable",
"type":"function"
},

Answer 1

@sam k，这是您可能正在寻找的更好、更全面的解决方案。我在您给定的代码片段中注意到一件重要的事情，您没有httpProvider在代码中包含一行，这可能就是原因（也可能还有其他原因）。因此，请添加下面提到的行。

let contractABI = <your contract ABI>;
let contractInstance = new web3.eth.Contract(contractABI, 
contractAddress);
/**The line below needs to be added, specifying the http provider*/
contractInstance.setProvider(new Web3.providers.HttpProvider(URL));

现在是您想要“签署”交易的部分，这些交易会对您的合约施加“状态”更改。因此，您可以按照以下代码结构来签署交易。

web3.eth.getTransactionCount(ownerAddress).then( (nonce) => {
    let encodedABI = 
contractInstance.methods.statechangingfunction(<arguments>).encodeABI();
/**Estimating the required gas automatically from the network itself*/
contractInstance.methods.statechangingfunction(<arguments>).estimateGas({ from: ownerAddress }, (error, gasEstimate) => {
      let tx = {
        to: contractAddress,
        gas: gasEstimate,
        data: encodedABI,
        nonce: nonce
      };
      /** Signing the transaction with the "privateKey" of the owner*/
      web3.eth.accounts.signTransaction(tx, privateKey, (err, resp) => {
        if (resp == null) {console.log("Error!");
        } else {
          let tran = web3.eth.sendSignedTransaction(resp.rawTransaction);
          tran.on('transactionHash', (txhash) => {console.log("Tx Hash: "+ txhash);});

如果您的其余代码没问题，则此解决方案应该有效。如果没有，我建议您评论您项目存储库的 github 链接，以便我可以查看并提供解决方案。让我知道这是否有帮助。您可以参考以下官方 web3 链接：signTransaction、sendSignedTransaction、getTransactionCount和estimateGas。