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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);
});
}