元类（Meta-Classes）的概念有些令人困惑，因此我们将介绍一个简短的例子。
元类是在运行时（run-time）定义的类。合约是由应用程序二进制接口(ABI)指定的，它描述了它所拥有的方法和事件。 这些描述是合约（Contract）对象处于run-time时传入的，它创建一个新的Class，在run-time时添加了ABI中定义的所有方法。
大多数情况下，您需要与之交互的任何合约都已经部署到区块链上，但对于本例需要先部署合约。
new ethers.ContractFactory( abi , bytecode , signer )
创建一个新的ContractFactory，它可以将合约部署到区块链。
const bytecode = "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";
// 一个人类可读（Human-Readable）的ABI;我们只需要指定相关的部分内容，在这里我们用到了构造函数
const abi = [
"constructor(uint totalSupply)"
];
const factory = new ethers.ContractFactory(abi, bytecode, signer)
// 部署，设置token的total supply为100，分配给部署人（deployer）
const contract = await factory.deploy(parseUnits("100"));
//链上现在虽然我们还没有这个合约，但是这个合约地址我们是预先经过计算后得到的
contract.address
// '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC'
// 在交易被挖出来之前(即合约被部署)等待（Wait）
// - 部署后，交易会返回receipt
await contract.deployTransaction.wait();
// {
// blockHash: '0xe9b244958d066490c46a826a9733c1a43210316777185353b3ecbc2ec362ea87',
// blockNumber: 22,
// byzantium: true,
// confirmations: 1,
// contractAddress: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// cumulativeGasUsed: { BigNumber: "250842" },
// effectiveGasPrice: { BigNumber: "1553830469" },
// events: [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// blockHash: '0xe9b244958d066490c46a826a9733c1a43210316777185353b3ecbc2ec362ea87',
// blockNumber: 22,
// data: '0x0000000000000000000000000000000000000000000000056bc75e2d63100000',
// getBlock: [Function],
// getTransaction: [Function],
// getTransactionReceipt: [Function],
// logIndex: 0,
// removeListener: [Function],
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x0000000000000000000000000000000000000000000000000000000000000000',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759'
// ],
// transactionHash: '0x03164a2299c8334178d5a2c731149910d5c21db0309bfbc8aae89a34c8069ad4',
// transactionIndex: 0
// }
// ],
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// gasUsed: { BigNumber: "250842" },
// logs: [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// blockHash: '0xe9b244958d066490c46a826a9733c1a43210316777185353b3ecbc2ec362ea87',
// blockNumber: 22,
// data: '0x0000000000000000000000000000000000000000000000056bc75e2d63100000',
// logIndex: 0,
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x0000000000000000000000000000000000000000000000000000000000000000',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759'
// ],
// transactionHash: '0x03164a2299c8334178d5a2c731149910d5c21db0309bfbc8aae89a34c8069ad4',
// transactionIndex: 0
// }
// ],
// logsBloom: '0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000008000000080000000000000000000000000000000000000000020000000000000000000800000000000000000002000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020000002000000000000000000000000000000000000000000000000000020000000800008000000000000000000000000000000200000000000000000000000',
// status: 1,
// to: null,
// transactionHash: '0x03164a2299c8334178d5a2c731149910d5c21db0309bfbc8aae89a34c8069ad4',
// transactionIndex: 0,
// type: 2
// }
ERC20Contract inherits 合约（Contract）
new ethers.Contract( address , abi , providerOrSigner )
// 一个人类可读（Human-Readable）的ABI;用来与合约交互，必须要包含我们要具体使用的函数内容
const abi = [
// Read-Only Functions
"function balanceOf(address owner) view returns (uint256)",
"function decimals() view returns (uint8)",
"function symbol() view returns (string)",
// Authenticated Functions
"function transfer(address to, uint amount) returns (bool)",
// Events
"event Transfer(address indexed from, address indexed to, uint amount)"
];
// 可以是 address 也可以是 一个 ENS name
const address = "0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC";
// 只读; 通过 Provider连接，允许以下操作:
// - 访问常量函数 constant function
// - 查询过滤器
// - 对于 non-constant methods 填充未签名的交易
// - 对于non-constant估算Gas(作为匿名发送者)
// - 对于non-constant methods静态调用 (作为匿名发送者)
const erc20 = new ethers.Contract(address, abi, provider);
// 可读写; 通过Signer连接，允许以下操作:
// - 任何只读的操作 (作为Signer而非匿名者)
// - 为non-constant functions发送交易
const erc20_rw = new ethers.Contract(address, abi, signer);
属性(inheritted from 合约（Contract）)
合约被创建的 地址address (或 ENS name)
这是一个解析到合约对象的地址的promise。 如果是地址(Address)提供给构造函数，结果就是这个地址(Address); 如果提供的是ENS name，结果就是解析后地址。
如果Contract对象是ContractFactory部署的得到的，在这里的返回的结果就是用于部署合约的交易。
如果一个provider被提供给构造函数，这条语句的结果就是provider； 如果提供了的Provider是一个signer，结果就是signer。
如果是一个signer提供给构造函数，结果就是signer。
Methods(inheritted from 合约（Contract）)
返回一个附在新地址的合约的新实例。 如果网络上有多个类似或相同的合约副本，并且您希望与它们中的每一个进行交互，那么这是非常有用的。
erc20.deployed( ) ⇒ Promise< Contract >
Contract.isIndexed( value ) ⇒ boolean
事件（Events）(inheritted from 合约（Contract）)
关于使用事件的例子请参考Meta-Class Filters。
返回匹配event参数的事件。
erc20.listenerCount( [ event ] ) ⇒ number
返回订阅该event的监听器数量。如果没有提供event，则返回所有事件的总数。
erc20.listeners( event ) ⇒ Array< Listener >
返回订阅该event的监听器列表。
erc20.off( event , listener ) ⇒ this
返回订阅该event的监听器列表。
erc20.on( event , listener ) ⇒ this
监听event事件，当事件发生时，会调用listener函数。
erc20.once( event , listener ) ⇒ this
监听event事件，当事件发生时，仅调用一次listener函数。
erc20.removeAllListeners( [ event ] ) ⇒ this
取消所有订阅event事件的监听器。如果未提供event事件，则取消订阅所有事件的监听。
因为合约是元类，这里面可用的方法取决于传入合约的ABI。
erc20.decimals( [ overrides ] ) ⇒ Promise< number >
返回此ERC-20 token所使用的小数位数。在前端界面，当从用户获取输入时，可以使用parseUnits转化后传入合约； 从合约获得token后可以通过[formatUnits](utils-formatunits]转化后再显示给用户。
await erc20.decimals();
// 18
返回持有这个ERC-20 token的持有者(owner)的余额。
await erc20.balanceOf(signer.getAddress())
// { BigNumber: "100000000000000000000" }
erc20.symbol( [ overrides ] ) ⇒ Promise< string >
返回token的symbol。
await erc20.symbol();
// 'MyToken'
从当前的signer将数量为amount的tokens转给接收者target。 在交易处于写入操作时，返回值(布尔类型)是得不到的。 如果需要这个值，则需要其他方法(如事件)。链上合约调用transfer函数可以得到这个结果。
// 在这之前先转化格式
formatUnits(await erc20_rw.balanceOf(signer.getAddress()));
// '100.0'
// 转 1.23 tokens 到 ENS name 为 "ricmoo.eth" 的地址
tx = await erc20_rw.transfer("ricmoo.eth", parseUnits("1.23"));
// {
// accessList: [],
// chainId: 31337,
// confirmations: 0,
// data: '0xa9059cbb0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// gasLimit: { BigNumber: "51558" },
// gasPrice: null,
// hash: '0xceb49c9db1d35d18db9b3c56d285e691f006d62529dec397eec004337206e600',
// maxFeePerGas: { BigNumber: "1607660938" },
// maxPriorityFeePerGas: { BigNumber: "1500000000" },
// nonce: 2,
// r: '0x33284b92f1197507d7bd48aee7ccf4f7386527e72b6bf3fe23245026cf0a7eac',
// s: '0x64eb0ca43292a98695f702ed0d59ec1d97618905c3366ac1d4ff50841f4cd0fb',
// to: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// type: 2,
// v: 1,
// value: { BigNumber: "0" },
// wait: [Function]
// }
// 等待交易所在的区块被挖出打包
await tx.wait();
// {
// blockHash: '0x95ac5d8669e6c73c1784296c0ad09c3ccf3e06055c78361056d971c6498171f1',
// blockNumber: 23,
// byzantium: true,
// confirmations: 1,
// contractAddress: null,
// cumulativeGasUsed: { BigNumber: "51558" },
// effectiveGasPrice: { BigNumber: "1547214185" },
// events: [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// args: [
// '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// '0x5555763613a12D8F3e73be831DFf8598089d3dCa',
// { BigNumber: "1230000000000000000" },
// amount: { BigNumber: "1230000000000000000" },
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// to: '0x5555763613a12D8F3e73be831DFf8598089d3dCa'
// ],
// blockHash: '0x95ac5d8669e6c73c1784296c0ad09c3ccf3e06055c78361056d971c6498171f1',
// blockNumber: 23,
// data: '0x0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// decode: [Function],
// event: 'Transfer',
// eventSignature: 'Transfer(address,address,uint256)',
// getBlock: [Function],
// getTransaction: [Function],
// getTransactionReceipt: [Function],
// logIndex: 0,
// removeListener: [Function],
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759',
// '0x0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca'
// ],
// transactionHash: '0xceb49c9db1d35d18db9b3c56d285e691f006d62529dec397eec004337206e600',
// transactionIndex: 0
// }
// ],
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// gasUsed: { BigNumber: "51558" },
// logs: [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// blockHash: '0x95ac5d8669e6c73c1784296c0ad09c3ccf3e06055c78361056d971c6498171f1',
// blockNumber: 23,
// data: '0x0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// logIndex: 0,
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759',
// '0x0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca'
// ],
// transactionHash: '0xceb49c9db1d35d18db9b3c56d285e691f006d62529dec397eec004337206e600',
// transactionIndex: 0
// }
// ],
// logsBloom: '0x00000000000000000800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000008000000080000000000000000000000000000000000000000000000000000000000000000000000000000000002000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020000002000000000000000000000000000000000000000000000000000000000000800008000001000000000200000000000000200000000000000000000000',
// status: 1,
// to: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// transactionHash: '0xceb49c9db1d35d18db9b3c56d285e691f006d62529dec397eec004337206e600',
// transactionIndex: 0,
// type: 2
// }
// 成功后转化格式
formatUnits(await erc20_rw.balanceOf(signer.getAddress()));
// '98.77'
formatUnits(await erc20_rw.balanceOf("ricmoo.eth"));
// '1.23'
erc20.callStatic.transfer( target , amount [ , overrides ] ) ⇒ Promise< boolean >
执行一次从当前signer向target地址转移amount数量的token的演练，而不实际签名或发送交易。
这可以用于检查真实的转账前，交易是否能成功。
// signer有足够的tokens发送的话，结果会返回true
await erc20_rw.callStatic.transfer("ricmoo.eth", parseUnits("1.23"));
// true
// 一个随机的地址不会有足够的tokens用于发送，在这个例子里会抛出错误
erc20_random = erc20_rw.connect(randomWallet);
await erc20_random.callStatic.transfer("ricmoo.eth", parseUnits("1.23"));
// [Error: call revert exception; VM Exception while processing transaction: reverted with reason string "insufficient token balance" [ See: https://links.ethers.org/v5-errors-CALL_EXCEPTION ]] {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// args: [
// 'ricmoo.eth',
// { BigNumber: "1230000000000000000" }
// ],
// code: 'CALL_EXCEPTION',
// data: '0x08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000001a696e73756666696369656e7420746f6b656e2062616c616e6365000000000000',
// errorArgs: [
// 'insufficient token balance'
// ],
// errorName: 'Error',
// errorSignature: 'Error(string)',
// method: 'transfer(address,uint256)',
// reason: 'insufficient token balance',
// transaction: {
// data: '0xa9059cbb0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// from: '0x3744A6A188e46e3f2A10f918126d13F73E3C58D9',
// to: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC'
// }
// }
返回估计的“将amount数量的tokens发送target地址”所需的多少gas值。
await erc20_rw.estimateGas.transfer("ricmoo.eth", parseUnits("1.23"));
// { BigNumber: "34458" }
返回一个未签名交易(UnsignedTransaction)，它可以被签名并提交给网络，达成“将amount数量的tokens发送target地址”的目的。
await erc20_rw.populateTransaction.transfer("ricmoo.eth", parseUnits("1.23"));
// {
// data: '0xa9059cbb0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// to: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC'
// }
关于估算和静态调用的注意事项
当你执行一个静态调用时，以太坊会尽可能地考虑当前状态。 在许多情况下，这可能会提供假阳性和假阴性。 The eventually consistent model of the blockchain also means there are certain consistency modes that cannot be known until an actual transaction is attempted.
因为合约是元类，这里面可用的方法取决于传入合约的ABI。
erc20.filters.Transfer( [ fromAddress [ , toAddress ] ] ) ⇒ Filter
返回一个新的Filter用于查询或者去subscribe/unsubscribe to events。
如果fromAddress 是空的或者没有填写，将匹配任何发送人的地址。 如果 toAddress是空的或者没有填写，将匹配任何接受人的地址。
query filter *from* events
filterFrom = erc20.filters.Transfer(signer.address);
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759'
// ]
// }
// 在最新的10个区块内查询我发送的交易
logsFrom = await erc20.queryFilter(filterFrom, -10, "latest");
// [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// args: [
// '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// '0x5555763613a12D8F3e73be831DFf8598089d3dCa',
// { BigNumber: "1230000000000000000" },
// amount: { BigNumber: "1230000000000000000" },
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// to: '0x5555763613a12D8F3e73be831DFf8598089d3dCa'
// ],
// blockHash: '0x95ac5d8669e6c73c1784296c0ad09c3ccf3e06055c78361056d971c6498171f1',
// blockNumber: 23,
// data: '0x0000000000000000000000000000000000000000000000001111d67bb1bb0000',
// decode: [Function],
// event: 'Transfer',
// eventSignature: 'Transfer(address,address,uint256)',
// getBlock: [Function],
// getTransaction: [Function],
// getTransactionReceipt: [Function],
// logIndex: 0,
// removeListener: [Function],
// removed: false,
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759',
// '0x0000000000000000000000005555763613a12d8f3e73be831dff8598089d3dca'
// ],
// transactionHash: '0xceb49c9db1d35d18db9b3c56d285e691f006d62529dec397eec004337206e600',
// transactionIndex: 0
// }
// ]
// 请注意，args提供了事件的详细信息，每个参数都是可用的，这是因为我们的ABI包含了所有参数的名称
logsFrom[0].args
// [
// '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// '0x5555763613a12D8F3e73be831DFf8598089d3dCa',
// { BigNumber: "1230000000000000000" },
// amount: { BigNumber: "1230000000000000000" },
// from: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// to: '0x5555763613a12D8F3e73be831DFf8598089d3dCa'
// ]
query filter with *to* events
filterTo = erc20.filters.Transfer(null, signer.address);
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// null,
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759'
// ]
// }
// 在最新的10个区块内查询发送给我的交易
// 注意: 这是因为合约在部署时，构造函数写了将totalSupply tokens转给我
logsTo = await erc20.queryFilter(filterTo, -10, "latest");
// [
// {
// address: '0xa22aB6748282B3125dC26dAFb79e38B7eb24EAcC',
// args: [
// '0x0000000000000000000000000000000000000000',
// '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// { BigNumber: "100000000000000000000" },
// amount: { BigNumber: "100000000000000000000" },
// from: '0x0000000000000000000000000000000000000000',
// to: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759'
// ],
// blockHash: '0xe9b244958d066490c46a826a9733c1a43210316777185353b3ecbc2ec362ea87',
// blockNumber: 22,
// data: '0x0000000000000000000000000000000000000000000000056bc75e2d63100000',
// decode: [Function],
// event: 'Transfer',
// eventSignature: 'Transfer(address,address,uint256)',
// getBlock: [Function],
// getTransaction: [Function],
// getTransactionReceipt: [Function],
// logIndex: 0,
// removeListener: [Function],
// removed: false,
// topics: [
// '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
// '0x0000000000000000000000000000000000000000000000000000000000000000',
// '0x000000000000000000000000894ed91b666facce5a4d2ff8261924b4754a5759'
// ],
// transactionHash: '0x03164a2299c8334178d5a2c731149910d5c21db0309bfbc8aae89a34c8069ad4',
// transactionIndex: 0
// }
// ]
// 请注意，args提供了事件的详细信息，每个参数都是可用的，这是因为我们的ABI包含了所有参数的名称
logsTo[0].args
// [
// '0x0000000000000000000000000000000000000000',
// '0x894ed91B666FacCe5a4D2FF8261924b4754A5759',
// { BigNumber: "100000000000000000000" },
// amount: { BigNumber: "100000000000000000000" },
// from: '0x0000000000000000000000000000000000000000',
// to: '0x894ed91B666FacCe5a4D2FF8261924b4754A5759'
// ]
listen for events
// 监听signer的发送的event事件:
erc20.on(filterFrom, (from, to, amount, event) => {
// The `from` will always be the signer address
});
// 监听signer的接受转账的event事件:
erc20.on(filterTo, (from, to, amount, event) => {
// The `to` will always be the signer address
});
// 监听所有的转账交易event事件:
erc20.on("Transfer", (from, to, amount, event) => {
// ...
});
The content of this site is licensed under the Creative Commons License. Generated on January 11, 2023, 9:24pm.