node.js - 如何获得 BEP20 代币的价格？

Question

我想在 BNB 中计算 BEP20 代币的价格。
我检查了 poocoin 和 pancakeswap 他们如何计算价格。正如我所见，他们通过 web3.js 不断调用 bsc-dataseed，但我还没有找到解决方案。
我的调查现状:

他们不断调用数据种子(webrpc)来获取最新的区块号:

// Request params
{
    "jsonrp": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
}

在他们收到最新的区块后，他们立即使用以下参数开始另一个调用

{
  "jsonrpc": "2.0",
  "id": 53,
  "method": "eth_call",
  "params": [
    {
      "to": "0x1ee38d535d541c55c9dae27b12edf090c608e6fb",
      "data": "0x252dba420000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000001c00000000000000000000000000000000000000000000000000000000000003800000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000048000000000000000000000000000000000000000000000000000000000000005000000000000000000000000000000000000000000000000000000000000000580000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000006800000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000078000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000880000000000000000000000000000000000000000000000000000000000000090000000000000000000000000000000000000000000000000000000000000009800000000000000000000000000000000000000000000000000000000000000a000000000000000000000000000000000000000000000000000000000000000a800000000000000000000000000000000000000000000000000000000000000b000000000000000000000000000000000000000000000000000000000000000b800000000000000000000000000000000000000000000000000000000000000c000000000000000000000000000000000000000000000000000000000000000c800000000000000000000000000000000000000000000000000000000000000d000000000000000000000000000000000000000000000000000000000000000d800000000000000000000000000000000000000000000000000000000000000e000000000000000000000000000000000000000000000000000000000000000e800000000000000000000000000000000000000000000000000000000000000f000000000000000000000000000000000000000000000000000000000000000f8000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001080000000000000000000000000000000000000000000000000000000000000110000000000000000000000000003ff6c83226cdb10c7a42a2c54c67d63a135ab69000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000003fc20bdafdac6b2ae8f7f5f885f0819c2b968f0000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000008b018585d4949ae4714f057b66b8b033408bfa6000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000012c8db147721ac1e3e54e9ff73d99ef0ee4b1725000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000001b96b92314c44b159149f7e0303511fb2fc4774f000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000020bcc3b8a0091ddac2d0bc30f68e6cbb97de59cd000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000002c5d712cf39eaebc1ef2d1281eb48a70dcd34d49000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000003ab77e40340ab084c3e23be8e5a6f7afed9d41dc000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000003b872e6b1633f060680cf9c277b43dd1e254e564000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000056c77d59e82f33c712f919d09fceddf49660a829000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000006f656513f6e8eae19b6dc30cd372dd6ba4b5543a000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000070d8929d04b60af4fb9b58713ebcf18765ade422000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000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    },
    "latest"
  ]
}

据我所知 0x1ee38d535d541c55c9dae27b12edf090c608e6fb是一个包含 multicall 的合约方法。数据的前 10 个字符 (0x252dba42) 是 aggregate方法。但是数据的剩余部分是什么？
这是 aggregate 的合约 ABI方法:

{
    "constant": true,
    "inputs": [
      {
        "components": [
            {"name": "target","type": "address"},
            {"name": "callData","type": "bytes"}
        ],
        "name": "calls",
        "type": "tuple[]"
      }
    ],
    "name": "aggregate",
    "outputs": [
      {
        "name": "blockNumber",
        "type": "uint256"
      },
      {
        "name": "returnData",
        "type": "bytes[]"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  }

问题:
需要第二次通话吗？
如何根据这些数据计算价格？
你知道更简单的方法吗？

Answer 1

关于是否可以从 web3 计算代币价格的问题的答案在这里:https://ethereum.stackexchange.com/questions/98302/how-can-we-get-the-current-spot-price-for-a-bep20-token-used-web3
但是:部分回答您的问题。eth_blockNumber用于获取在最新块中传递的交易并在此处显示值:
eth_call使用方法 sha3 0x252dba42 调用对应于 aggregator你提到的功能。代码如下:

contract Multicall {
struct Call {
    address target;
    bytes callData;
}
function aggregate(Call[] memory calls) public returns (uint256 blockNumber, bytes[] memory returnData) {
    blockNumber = block.number;
    returnData = new bytes[](calls.length);
    for(uint256 i = 0; i < calls.length; i++) {
        (bool success, bytes memory ret) = calls[i].target.call(calls[i].callData);
        require(success);
        returnData[i] = ret;
    }
}

如您所见，这只是执行多个 eth_call calls[i].target.call(calls[i].callData); 的一种方式这意味着它是做很多事情的有效方式 eth_call通过只调用 Web3 一次，因此是为了大幅增加执行时间。
然后进入细节，你将不得不解析不同的 eth_call包含在更大的结构中。
例如，给定以下查询 (eth_call) :

0x252dba42
0000000000000000000000000000000000000000000000000000000000000020
000000000000000000000000000000000000000000000000000000000000000d
00000000000000000000000000000000000000000000000000000000000001a0
0000000000000000000000000000000000000000000000000000000000000220
00000000000000000000000000000000000000000000000000000000000002a0
0000000000000000000000000000000000000000000000000000000000000320
00000000000000000000000000000000000000000000000000000000000003a0
0000000000000000000000000000000000000000000000000000000000000420
00000000000000000000000000000000000000000000000000000000000004a0
0000000000000000000000000000000000000000000000000000000000000520
00000000000000000000000000000000000000000000000000000000000005c0
0000000000000000000000000000000000000000000000000000000000000660
0000000000000000000000000000000000000000000000000000000000000700
0000000000000000000000000000000000000000000000000000000000000780
0000000000000000000000000000000000000000000000000000000000000800
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
0902f1ac > getReserves() -> pancake
00000000000000000000000000000000000000000000000000000000
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
d21220a7 > token1 -> pancake
00000000000000000000000000000000000000000000000000000000
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
18160ddd > totalSupply -> swole
00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
313ce567 > decimals > swole
00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
18160ddd > totalSupply > swole
00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
95d89b41 > symbol > swole
00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
06fdde03 > name > swole 
00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000024
70a08231 > balanceOf > swole
00000000000000000000000000000000000000000000000000000000
0000dead00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000024
70a08231 > balanceOf > swole
00000000000000000000000000000000000000000000000000000000
00000ded00000000000000000000000000000000000000000000000000000000
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000024
70a08231 > balanceOf > pancake
00000000000000000000000000000000000000000000000000000000
0000000100000000000000000000000000000000000000000000000000000000
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
0902f1ac > getReserves > pancake
00000000000000000000000000000000000000000000000000000000
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
d21220a7 > Token1 (pancake)
00000000000000000000000000000000000000000000000000000000
000000000000000000000000b443d19e5448c8a58916ca8e0a33c41212668ad3
0000000000000000000000000000000000000000000000000000000000000040
0000000000000000000000000000000000000000000000000000000000000004
18160ddd > TotalSupply 
00000000000000000000000000000000000000000000000000000000

如果你想找到sha3所涉及的方法的名称，你可以引用这个网站: https://pkg.go.dev/github.com/y2labs-0sh/dada-api/contractabi
由于给定的 eth_call它会给你:

0x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 > decimals
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000001431e0fae6d7217caa0000000
0000000000000000000000000000000000000000000000000000000000000060
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000004
534f474500000000000000000000000000000000000000000000000000000000 > SOGE
0000000000000000000000000000000000000000000000000000000000000060
0000000000000000000000000000000000000000000000000000000000000020
000000000000000000000000000000000000000000000000000000000000000a
53776f6c6520446f676500000000000000000000000000000000000000000000 > Swole Doge
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000020
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000060
0000000000000000000000000000000000000000000000000d04526e1cee610a
0000000000000000000000000000000000000000096f9d05ebe63c03e58cc07a
0000000000000000000000000000000000000000000000000000000060a16f16
0000000000000000000000000000000000000000000000000000000000000020
000000000000000000000000f5318b3941b3f1239dd910c941bbe2259f32311b
0000000000000000000000000000000000000000000000000000000000000020
000000000000000000000000000000000000000000000a968163f0a57b400000

另请注意，poocoin 每次都使用不同的 token 地址进行多个 eth_call。
poocoin 如何利用这些数据来获取价格？我不知道，现在甚至确定这些 eth_call用于确定代币价格。不过如果你发现了，我会很感兴趣的。
干杯，