第二十八篇墨客区块链(MOAC BlockChain) 智能合约event调用实例

event调用过程：首先需要在合约中定义event，并在某个函数中去触发它。当我们调用该函数的时候就会触发event，然后，可以通过在该次调用智能合约产生的block上建立filter来捕获event。

环境：

墨客区块链版本：nuwa1.0.5.win.zip；

操作系统：64位Windows 10家庭版。

1.部署标准erc20合约

1.1 启动本地节点

D:\nuwa1.0.5.win\win\vnode>moac --rpc  --rpcaddr 0.0.0.0 --rpccorsdomain "*" --rpcapi="db,mc,net,chain3,personal,vnode,debug,scs"

1.2 按照《第四篇墨客区块链(MOAC BlockChain) 部署ERC-20合约》部署智能合约。

2.监测智能合约事件

代码如下：

#!/usr/bin/env node
/*
   Test the ERC20 contract interface on MOAC network.
   This test requires a running MOAC node with RPC http port open at 8545
   and the contract address and abi.
1. Connect to a local MOAC node.
2. Load the contract address and abi.
3. Setup a filter of the contract and watch the event, such as transfer.
*/

var Chain3 = require('chain3');
var chain3 = new Chain3(new Chain3.providers.HttpProvider('http://localhost:8545'));

var tokenabi='[ { "constant": true, "inputs": [], "name": "name", ............, { "indexed": false, "name": "_value", "type": "uint256" } ], "name": "Approval", "type": "event" } ]';

//Load the contract ABI
var tokenContract=chain3.mc.contract(JSON.parse(tokenabi));
var myContractInstance = tokenContract.at('0xA2580D58A58998ca06e6f5b2A96A95D8d48f1679');  //智能合约地址

chain3.setProvider(new chain3.providers.HttpProvider('http://localhost:8545'));

if ( chain3.isConnected() ){

    console.log("RPC connected, check token balance");
    // watch for an event with {some: 'args'}
    var events = myContractInstance.allEvents({fromBlock: 0, toBlock: 'latest'});
    events.watch(function(error, result){
        if( !error )
        {
            var msg = result.blockNumber;
            console.log( msg + ":" + JSON.stringify(result.TxData))
        }
        else{
            console.log("err:" + error);
        }  
    });

}else{
      console.log("RPC not connected!");
}
return;

运行后处于侦听状态：

3.操作合约的transfer，查看监测

在http://wallet.moac.io/对erc20合约进行一次transfer操作。

打包后，检测程序显示与浏览器内容一致：

附录：对合约的调用操作

#!/usr/bin/env node
/*
   Test the ERC20 contract interface on MOAC network.
   This test requires a running MOAC node with RPC http port open at 8545
   and the contract address and abi.
1. Connect to a local MOAC node.
2. Load the contract address and abi.
*/

var Chain3 = require('chain3');
var chain3 = new Chain3(new Chain3.providers.HttpProvider('http://localhost:8545'));

//Set the contract ABI and address to use
//The ABI info can be obtained using REMIX
//The address is the contract HASH after deploying the contract. 
var tokenabi='[ { "constant": true, "inputs": [], "name": "name",............, "name": "Approval", "type": "event" } ]';

//Load the contract ABI
var tokenContract=chain3.mc.contract(JSON.parse(tokenabi));

//Testnetwork token, networkid = 101
var tokenaddress='0xA2580D58A58998ca06e6f5b2A96A95XXXXXXXXXX';

//Load the contract methods 
var tcalls=tokenContract.at(tokenaddress);

//check the balance
var totalBal = 0;

//test accounts
//Need to add the addr and private key for your own ERC20 tokens
var taccts = [{
    "addr": "0x68986c1BCD54Ae5dAe69310fC64Ea5XXXXXXXXXX", 
    "key": "9a863cb325ba30b5f41bd285e80c14c2d96f86b21e90XXXXXXXXXXXXXXXXXXXX"
},{
    "addr": "0x745c57ca5318093115D61Bbca3687cXXXXXXXXXX", 
    "key": ""
}];

//Connect the local MOAC node through HTTP 
chain3.setProvider(new chain3.providers.HttpProvider('http://localhost:8545'));

if ( chain3.isConnected() ){

    console.log("RPC connected, check token balance");

    // console.log("code len:", chain3.mc.getCode(tokenaddress));
    var contractCode = chain3.mc.getCode(tokenaddress);
  
    if (contractCode == '0x') {
        console.log("Contract address has no data!");
        return;
    }

    //Get token Info
    console.log("Token Info\nfull name:", tcalls.name());
    console.log("   symbol:", tcalls.symbol());

        var src = taccts[0].addr;
        var des = "0x745c57ca5318093115D61Bbca3687cXXXXXXXXXX";//taccts[1].addr;
        console.log("src bal:", src, ":",tcalls.balanceOf(src).toString(10));
        console.log("des bal:", des, ":",tcalls.balanceOf(des).toString(10));

        //var strData = '';
        var srcVal = tcalls.balanceOf(src);
        var desVal = tcalls.balanceOf(des);

        var amt = 123;//amout in erc20 token "m02"

        console.log(" Transfer from:\n", src, "\n to \n", des);
        var tcalldata = tcalls.transfer.getData(des, amt);
        console.log("\n Tcalldata:", tcalldata);

        let gasEstimate = chain3.mc.estimateGas({data: tcalldata});

        gasEstimate = 4000000;

        //The sign of the transaction requires the correct network id
        var networkid = chain3.version.network;
        console.log("On network:", networkid);

        //Add some more gas on the estimate to ensure the call can be processed
        callContractMethod(taccts[0], tokenaddress, gasEstimate+100, networkid, tcalldata);


  }else
      console.log("RPC not connected!");

/*
 * Call a contract with the input byteCode
 * 
*/
function callContractMethod(src, contractAddress, gasValue, inchainID, inByteCode){

    var txcount = chain3.mc.getTransactionCount(src["addr"]);
    console.log("Get tx account", txcount)
    //Build the raw tx obj
    //note the transaction
    var rawTx = {
        from: src.addr,
        to: contractAddress, 
        nonce: chain3.intToHex(txcount),
        gasPrice: chain3.intToHex(30000000000),
        gasLimit: chain3.intToHex(gasValue),
        value: '0x', 
        data: inByteCode,
        chainId: chain3.intToHex(inchainID)
    }

    console.log(rawTx);

    var cmd1 = chain3.signTransaction(rawTx, src["key"]);    

    console.log("\nSend signed TX:\n", cmd1);

    chain3.mc.sendRawTransaction(cmd1, function(err, hash) {
        if (!err){
            
            console.log("Succeed!: ", hash);
            return hash;
        }else{
            console.log("Chain3 error:", err.message);
            return err.message;
        }

    console.log("Get response from MOAC node in the feedback function!")
        // res.send(response);
    });
}

第二十八篇 墨客区块链(MOAC BlockChain) 智能合约event调用实例

猜你喜欢

第二十八篇墨客区块链(MOAC BlockChain) 智能合约event调用实例