如何通过以太坊RPC显示令牌的平衡？

$id = 0;
$data = array();
$data['jsonrpc'] = '2.0';
$data['id'] = $id++;
$data['method'] = 'eth_call';
$data['params'] = [['from' => '0x0...', 'to' => '0x0...', 'data' => 'contract byte code here 0x0...'], 'latest'];

$ch = curl_init();
...

返回：

{"jsonrpc":"2.0","id":0,"result":"0x"}

接下来做什么？呼叫合同方法balanceOf？怎么做？

解决方法:

要使用eth_call获得令牌余额,您需要和data参数. to是合同地址,这里我们需要生成数据参数.正如文档eth_call所说,

data: DATA – (optional) Hash of the method signature and encoded
parameters. For details see 07001

以EOS token transaction为例.

合同地址：0x86fa049857e0209aa7d9e616f7eb3b3b78ecfdb0

令牌持有人地址：0x0b88516a6d22bf8e0d3657effbd41577c5fd4cb7

您可以看到合同代码here.

contract ERC20 {
    function totalSupply() constant returns (uint supply);
    function balanceOf( address who ) constant returns (uint value);
    function allowance( address owner, address spender ) constant returns (uint _allowance);

    function transfer( address to, uint value) returns (bool ok);
    function transferFrom( address from, address to, uint value) returns (bool ok);
    function approve( address spender, uint value ) returns (bool ok);

    event Transfer( address indexed from, address indexed to, uint value);
    event Approval( address indexed owner, address indexed spender, uint value);
}

Function Selector

>>> from web3 import Web3
>>> Web3.sha3("balanceOf(address)")
HexBytes('0x70a08231b98ef4ca268c9cc3f6b4590e4bfec28280db06bb5d45e689f2a360be')

取前四个字节70a08231

Argument Encoding

address: equivalent to uint160, except for the assumed interpretation
and language typing.

int: enc(X) is the big-endian two’s complement encoding of X,
padded on the higher-order (left) side with 0xff for negative X and
with zero bytes for positive X such that the length is a multiple of
32 bytes.

将20字节令牌地址填充为32字节,使用0填充令牌持有者地址：

0000000000000000000000000b88516a6d22bf8e0d3657effbd41577c5fd4cb7

然后连接函数选择器和编码参数,我们得到数据参数：

0x70a082310000000000000000000000000b88516a6d22bf8e0d3657effbd41577c5fd4cb7

提出请求：

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_call","params":[{"to": "0x86fa049857e0209aa7d9e616f7eb3b3b78ecfdb0", "data":"0x70a082310000000000000000000000000b88516a6d22bf8e0d3657effbd41577c5fd4cb7"}, "latest"],"id":67}' -H "Content-Type: application/json" http://127.0.0.1:8545/

这里是curl结果(你可能会在这里得到不同的答案,因为在我查询请求后可能会有一些事务与这个地址完成)

{"jsonrpc":"2.0","id":67,"result":"0x00000000000000000000000000000000000000000000014a314d9ff9b20b9800"}

您可以将十六进制格式转换为十进制

>>> 0x00000000000000000000000000000000000000000000014a314d9ff9b20b9800
6090978215900000000000

检查结果,