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尝试使用以太坊围绕区块链工作时，我在尝试与已部署的合约交互时遇到了问题。我将尝试实现的是调用一种方法来显示添加到使用 Geth 本地部署的私有区块链的信息。

我无法从我的智能合约中调用任何函数，我一直在想我是否做错了什么......有人可以告诉我如何从这个合约中实现对其中一个方法的简单调用吗？假设显示现有机构，或用户所属的机构名称。

我的合同：agent.sol

pragma solidity ^0.4.18;
// We have to specify what version of compiler this code will compile with

contract Agency {

  event NewAgency(uint agencyId, string name, uint dna);

  uint dnaDigits = 16;
  uint dnaModulus = 10 ** dnaDigits;

  //agency structure
  struct Agency {
    string name;
    uint dna;
  }

  Agency[] public agencies;

  mapping (uint => address) public agencyToOwner;
  mapping (address => uint) ownerAgencyCount;

  function _createAgency(string _name, uint _dna) private {
    uint id = agencies.push(Agency(_name, _dna)) - 1;
    agencyToOwner[id] = msg.sender;
    ownerAgencyCount[msg.sender]++;
    NewAgency(id, _name, _dna);
  } 

  function _generateRandomDna(string _str) private view returns (uint) {
    uint rand = uint(keccak256(_str));
    return rand % dnaModulus;
  }

  function createRandomAgency(string _name) public {
    //make sure contract can only execute if user is not part of an agency
    require(ownerAgencyCount[msg.sender] == 0);
    uint randDna = _generateRandomDna(_name);
    _createAgency(_name, randDna);
  }
}

abi定义

> abiDefinition
[ { constant: true,
    inputs: [ [Object] ],
    name: 'agencies',
    outputs: [ [Object], [Object] ],
    payable: false,
    stateMutability: 'view',
    type: 'function' },
  { constant: true,
    inputs: [ [Object] ],
    name: 'agencyToOwner',
    outputs: [ [Object] ],
    payable: false,
    stateMutability: 'view',
    type: 'function' },
  { constant: false,
    inputs: [ [Object] ],
    name: 'createRandomAgency',
    outputs: [],
    payable: false,
    stateMutability: 'nonpayable',
    type: 'function' },
  { anonymous: false,
    inputs: [ [Object], [Object], [Object] ],
    name: 'NewAgency',
    type: 'event' } ]

成功部署：

INFO [01-09|19:09:14] Submitted contract creation              fullhash=0x7c43e896329138a6778938ca30d2f5f17f9a63062b359a4fccbd1a1be439f385 contract=0x65175d22C56E1Bad976A331A8B6B448cd4B3995d

最后contractInstance：

> contractInstance = AgencyContract.at(0x65175d22C56E1Bad976A331A8B6B448cd4B3995d)
Contract {
  _eth: 
   Eth {
     _requestManager: RequestManager { provider: [Object], polls: {}, timeout: null },
     getBalance: { [Function: send] request: [Function: bound ], call: 'eth_getBalance' },
     getStorageAt: { [Function: send] request: [Function: bound ], call: 'eth_getStorageAt' },
     getCode: { [Function: send] request: [Function: bound ], call: 'eth_getCode' },
     getBlock: { [Function: send] request: [Function: bound ], call: [Function: blockCall] },
     getUncle: { [Function: send] request: [Function: bound ], call: [Function: uncleCall] },
     getCompilers: { [Function: send] request: [Function: bound ], call: 'eth_getCompilers' },
     getBlockTransactionCount: 
      { [Function: send]
        request: [Function: bound ],
        call: [Function: getBlockTransactionCountCall] },
     getBlockUncleCount: 
      { [Function: send]
        request: [Function: bound ],
        call: [Function: uncleCountCall] },
     getTransaction: 
      { [Function: send]
        request: [Function: bound ],
        call: 'eth_getTransactionByHash' },
     getTransactionFromBlock: 
      { [Function: send]
        request: [Function: bound ],
        call: [Function: transactionFromBlockCall] },
     getTransactionReceipt: 
      { [Function: send]
        request: [Function: bound ],
        call: 'eth_getTransactionReceipt' },
     getTransactionCount: { [Function: send] request: [Function: bound ], call: 'eth_getTransactionCount' },
     call: { [Function: send] request: [Function: bound ], call: 'eth_call' },
     estimateGas: { [Function: send] request: [Function: bound ], call: 'eth_estimateGas' },
     sendRawTransaction: { [Function: send] request: [Function: bound ], call: 'eth_sendRawTransaction' },
     signTransaction: { [Function: send] request: [Function: bound ], call: 'eth_signTransaction' },
     sendTransaction: { [Function: send] request: [Function: bound ], call: 'eth_sendTransaction' },
     sign: { [Function: send] request: [Function: bound ], call: 'eth_sign' },
     compile: { solidity: [Object], lll: [Object], serpent: [Object] },
     submitWork: { [Function: send] request: [Function: bound ], call: 'eth_submitWork' },
     getWork: { [Function: send] request: [Function: bound ], call: 'eth_getWork' },
     coinbase: [Getter],
     getCoinbase: { [Function: get] request: [Function: bound ] },
     mining: [Getter],
     getMining: { [Function: get] request: [Function: bound ] },
     hashrate: [Getter],
     getHashrate: { [Function: get] request: [Function: bound ] },
     syncing: [Getter],
     getSyncing: { [Function: get] request: [Function: bound ] },
     gasPrice: [Getter],
     getGasPrice: { [Function: get] request: [Function: bound ] },
     accounts: [Getter],
     getAccounts: { [Function: get] request: [Function: bound ] },
     blockNumber: [Getter],
     getBlockNumber: { [Function: get] request: [Function: bound ] },
     protocolVersion: [Getter],
     getProtocolVersion: { [Function: get] request: [Function: bound ] },
     iban: 
      { [Function: Iban]
        fromAddress: [Function],
        fromBban: [Function],
        createIndirect: [Function],
        isValid: [Function] },
     sendIBANTransaction: [Function: bound transfer] },
  transactionHash: null,
  address: 5.771290982673958e+47,
  abi: 
   [ { constant: true,
       inputs: [Array],
       name: 'agencies',
       outputs: [Array],
       payable: false,
       stateMutability: 'view',
       type: 'function' },
     { constant: true,
       inputs: [Array],
       name: 'agencyToOwner',
       outputs: [Array],
       payable: false,
       stateMutability: 'view',
       type: 'function' },
     { constant: false,
       inputs: [Array],
       name: 'createRandomAgency',
       outputs: [],
       payable: false,
       stateMutability: 'nonpayable',
       type: 'function' },
     { anonymous: false,
       inputs: [Array],
       name: 'NewAgency',
       type: 'event' } ],
  agencies: 
   { [Function: bound ]
     request: [Function: bound ],
     call: [Function: bound ],
     sendTransaction: [Function: bound ],
     estimateGas: [Function: bound ],
     getData: [Function: bound ],
     uint256: [Circular] },
  agencyToOwner: 
   { [Function: bound ]
     request: [Function: bound ],
     call: [Function: bound ],
     sendTransaction: [Function: bound ],
     estimateGas: [Function: bound ],
     getData: [Function: bound ],
     uint256: [Circular] },
  createRandomAgency: 
   { [Function: bound ]
     request: [Function: bound ],
     call: [Function: bound ],
     sendTransaction: [Function: bound ],
     estimateGas: [Function: bound ],
     getData: [Function: bound ],
     string: [Circular] },
  allEvents: [Function: bound ],
  NewAgency: { [Function: bound ] 'uint256,string,uint256': [Function: bound ] } }

我试过了：

contractInstance.agencies()
contractInstance.agencies.call()
contractInstance.agencies.call({from:ak})

结果是Error: Invalid number of arguments to Solidity function

contractInstance.agencies.call("name" {from:ak})

结果Error: invalid address 我也试过打电话agencyToOwner，createRandomAgency但没有任何效果。

任何帮助都会很高兴收到！谢谢，

4

3 回答 3

20

您可以使用 、 或 方法调用contract.methodName.call()合约contract.methodName.sendTransaction()函数contract.methodName()。最后一个版本根据方法类型（即，如果它是 a constant）简单地委托给前两个中的一个。请参阅文档中的合同方法部分。

参数列表以函数本身的参数（如果有）开始，然后是可选的事务对象，然后是回调。要调用您的createRandomAgency()方法，您可以这样做：

const contract = web3.eth.contract(contractAbi);
const contractInstance = contract.at(contractAddress);

const transactionObject = {
  from: fromAccount,
  gas: gasLimit
  gasPrice: gasPriceInWei
};

contractInstance.createRandomAgency.sendTransaction('name', transactionObject, (error, result) => { // do something with error checking/result here });

可以在此处找到事务对象的可用选项列表。

要调用您的公共agencies数组，它看起来像

contractInstance.agencies.call(0, (error, result) => {
  if (!error) {
    console.log(result.name);
    console.log(result.dna);
  }
}); // transaction object not needed
于 2018-01-10T18:07:28.797 回答
2

我认为您应该尝试这样的事情-：

 var contractAbi= "" //here put your contract abi in json string
 var deployedContract = web3.eth.contract(abi).at("contract address");
 //now you should be able to access contract methods
 deployedContract.agencies.call({from:address}, function(err,data){
 console.log(data);
 });

测试一次。

于 2018-01-10T10:59:51.850 回答
0

尝试使用回调或承诺。当我想从合同的一种方法中获取返回值时，以下代码对我有用：

const contract = web3.eth.contract(contractABI);
const contractInstance = contract.at(this.contractAddress);

return new Promise((resolve, reject) => {
  contractInstance.**yourMethod**.call(function (error, result) {
    if (error) {
      console.log(error);
    } else {
      resolve(result);
    }
  });
}) as Promise<number>;

另请查看：https ://github.com/ethereum/wiki/wiki/JavaScript-API#using-callbacks

于 2018-07-22T16:51:21.037 回答