长安链Solidity智能合约调用原理分析

你的名字 2024-05-08 07:12 135阅读 0赞

目录

ERC20智能合约案例

JAVA-SDK调用案例

调用分析

JAVA-SDK生成地址

合约部署

合约调用

msg.sender

ERC20智能合约案例

  1. pragma solidity ^0.4.11;
  3. contract Token {
  5.     string public name = "token";      //  token name
  6.     string public symbol = "TK";           //  token symbol
  7.     uint256 public decimals = 6;            //  token digit
  9.     mapping (address => uint256) public balanceOf;
  10.     mapping (address => mapping (address => uint256)) public allowance;
  12.     uint256 public totalSupply = 0;
  13.     bool public stopped = false;
  15.     uint256 constant valueFounder = 100000000000000000;
  16.     address owner = 0x0;
  18.     modifier isOwner {
  19.         assert(owner == msg.sender);
  20.         _;
  21.     }
  23.     modifier isRunning {
  24.         assert (!stopped);
  25.         _;
  26.     }
  28.     modifier validAddress {
  29.         assert(0x0 != msg.sender);
  30.         _;
  31.     }
  33.     constructor (address _addressFounder) public {
  34.         owner = msg.sender;
  35.         totalSupply = valueFounder;
  36.         balanceOf[_addressFounder] = valueFounder;
  38.         emit Transfer(0x0, _addressFounder, valueFounder);
  39.     }
  41.     function transfer(address _to, uint256 _value) public isRunning validAddress returns (bool success) {
  42.         require(balanceOf[msg.sender] >= _value);
  43.         require(balanceOf[_to] + _value >= balanceOf[_to]);
  44.         balanceOf[msg.sender] -= _value;
  45.         balanceOf[_to] += _value;
  46.         emit Transfer(msg.sender, _to, _value);
  47.         return true;
  48.     }
  50.     function transferFrom(address _from, address _to, uint256 _value) public isRunning validAddress returns (bool success) {
  51.         require(balanceOf[_from] >= _value);
  52.         require(balanceOf[_to] + _value >= balanceOf[_to]);
  53.         require(allowance[_from][msg.sender] >= _value);
  54.         balanceOf[_to] += _value;
  55.         balanceOf[_from] -= _value;
  56.         allowance[_from][msg.sender] -= _value;
  57.         emit Transfer(_from, _to, _value);
  58.         return true;
  59.     }
  61.     function approve(address _spender, uint256 _value) public isRunning validAddress returns (bool success) {
  62.         require(_value == 0 || allowance[msg.sender][_spender] == 0);
  63.         allowance[msg.sender][_spender] = _value;
  64.         emit Approval(msg.sender, _spender, _value);
  65.         return true;
  66.     }
  68.     function stop() public isOwner {
  69.         stopped = true;
  70.     }
  72.     function start() public isOwner {
  73.         stopped = false;
  74.     }
  76.     function setName(string _name) public isOwner {
  77.         name = _name;
  78.     }
  80.     function burn(uint256 _value) public {
  81.         require(balanceOf[msg.sender] >= _value);
  82.         balanceOf[msg.sender] -= _value;
  83.         balanceOf[0x0] += _value;
  84.         emit Transfer(msg.sender, 0x0, _value);
  85.     }
  87.     event Transfer(address indexed _from, address indexed _to, uint256 _value);
  88.     event Approval(address indexed _owner, address indexed _spender, uint256 _value);
  89. }

JAVA-SDK调用案例

  1. public class TestEvmContract extends TestBase {
  3.     private static final String EVM_CONTRACT_FILE_PATH = "token.bin";
  4.     private static final String CONTRACT_NAME = "token";
  5.     private static final String CONTRACT_ARGS_EVM_PARAM = "data";
  6.     private static String ADDRESS = "";
  8.     private void makeAddrFromCert() {
  9.         try {
  10.             ADDRESS = CryptoUtils.makeAddrFromCert(chainClient.getClientUser().getCertificate());
  11.         } catch (UtilsException e) {
  12.             e.printStackTrace();
  13.         }
  14.     }
  16.     @Test
  17.     public void testCreateEvmContract() {
  19.         //address根据用户证书生成
  20.         makeAddrFromCert();
  21.         //创建合约构造参数扽RLP编码值
  22.         Function function = new Function( "" , Arrays.asList(new Address(ADDRESS)),
  23.                 Collections.emptyList());
  24.         String methodDataStr = FunctionEncoder.encode(function);
  26.         Map<String, String> paramMap = new HashMap<>();
  27.         paramMap.put(CONTRACT_ARGS_EVM_PARAM, methodDataStr.substring(10));
  30.         ResponseInfo responseInfo = null;
  31.         try {
  32.             byte[] byteCode = FileUtils.getResourceFileBytes(EVM_CONTRACT_FILE_PATH);
  33.             // 1. create payload
  34.             byte[] payload = chainClient.createPayloadOfContractCreation(CONTRACT_NAME,
  35.                     "1", ContractOuterClass.RuntimeType.EVM, paramMap, Hex.decode(new String(byteCode)));
  37.             // 2. create payloads with endorsement
  38.             byte[] payloadWithEndorsement1 = adminUser1.signPayloadOfContractMgmt(payload, chainClient.isEnabledCertHash());
  40.             // 3. merge endorsements using payloadsWithEndorsement
  41.             byte[][] payloadsWithEndorsement = new byte[1][];
  42.             payloadsWithEndorsement[0] = payloadWithEndorsement1;
  43.             byte[] payloadWithEndorsement = chainClient.mergeSignedPayloadsOfContractMgmt(payloadsWithEndorsement);
  45.             // 4. create contract
  46.             responseInfo = chainClient.createContract(payloadWithEndorsement, 10000, 10000);
  47.         } catch (SdkException e) {
  48.             e.printStackTrace();
  49.             Assert.fail(e.getMessage());
  50.         }
  51.         Assert.assertNotNull(responseInfo);
  52.     }
  54.     @Test
  55.     public void testInvokeTransferEvmContract() {
  56.         Map<String, String> params = new HashMap<>();
  57.         String add = "0x684a7b71376f6a28af5447516d2448dbe7d84460";
  58.         String toAddress ="0x06ffc656405700dd26aa1b2f2f38f55935f69661";
  59.         BigInteger amount = BigInteger.valueOf(600);
  60.         Function function = new Function( "transfer" , Arrays.asList(new Address(toAddress), new Uint256(amount)),
  61.                 Collections.emptyList());
  63.         String methodDataStr = FunctionEncoder.encode(function);
  65.         String method = methodDataStr.substring(0,10);
  67.         params.put(CONTRACT_ARGS_EVM_PARAM, methodDataStr);
  69.         ResponseInfo responseInfo = null;
  70.         try {
  71.             responseInfo = chainClient.invokeContract(CONTRACT_NAME, method, params, 10000, 10000);
  72.         } catch (SdkException e) {
  73.             e.printStackTrace();
  74.             Assert.fail(e.getMessage());
  75.         }
  76.         Assert.assertNotNull(Numeric.toBigInt(responseInfo.getSyncResultTxInfo().getTransaction().getResult().getContractResult().getResult().toByteArray()));
  77.         Assert.assertNotNull(responseInfo);
  78.     }
  80.     @Test
  81.     public void testInvokeBalanceOfEvmContract() {
  82.         Map<String, String> params = new HashMap<>();
  83.         makeAddrFromCert();
  85.         Function function = new Function( "balanceOf" , Arrays.asList(new Address(ADDRESS)),
  86.                 Collections.emptyList());
  88.         String methodDataStr = FunctionEncoder.encode(function);
  90.         String method = methodDataStr.substring(0,10);
  92.         params.put(CONTRACT_ARGS_EVM_PARAM, methodDataStr);
  94.         ResponseInfo responseInfo = null;
  95.         try {
  96.             responseInfo = chainClient.invokeContract(CONTRACT_NAME, method, params, 10000, 10000);
  97.         } catch (SdkException e) {
  98.             e.printStackTrace();
  99.             Assert.fail(e.getMessage());
  100.         }
  101.         Assert.assertNotNull(Numeric.toBigInt(responseInfo.getSyncResultTxInfo().getTransaction().getResult().getContractResult().getResult().toByteArray()));
  102.         Assert.assertNotNull(responseInfo);
  103.     }
  104. }

调用分析

JAVA-SDK生成地址

ChainMaker目前已支持的证书模型与以太坊的公钥模型不相同，为此ChainMaker在SDK中支持通过证书的SKI字段转换为EVM中所支持的地址格式。主要流程为：

  1. 通过证书获取其中的SKI信息
  2. 将SKI进行HASH(Keccak256)并截取，生成address

合约部署

1、合约部署需要先见token.sol编译成token.bin文件，编译方法详见官网：

5. 智能合约开发 — chainmaker-docs v2.2.1 documentation

2、调用合约部署的方法中会遇到两个web3j的类。

  1. Function function = new Function( "" , Arrays.asList(new Address(ADDRESS)),
  2.                 Collections.emptyList());
  3.         String methodDataStr = FunctionEncoder.encode(function);

Function里边主要构造的是合约方法名、合约请求参数（以集合形式传递）、合约响应参数（以集合形式传递）。

token.sol合约中的构造器方法需要一个初始化账户地址，并会在合约部署后给这个地址

  1. 100000000000000000的金额，故第二个参数即为此初始化账户。

FunctionEncoder当然就是编译abi码了。

3、部署合约与其他类型合约处理方法相同。

合约调用

合约调用时主要注意如下几个细节。

1、调用合约的参数

  1. Function function = new Function("transfer", Arrays.asList(new Address(toAddress), new Uint256(amount)),
  2.                 Collections.emptyList());

“transfer”为token.sol里边的转账方法名，第二个集合中所传递的toAddress和amount即为转账方法的两个参数，注意类型需要完全匹配。

2、合约方法名和合约名称的取值

相对于其他类型的合约可以直接传递合约方法的字符串，Solidity智能合约需要传编码后的值，这个是所有Solidity智能合约的通用规则。详见

Contract ABI Specification

  1. String method = methodDataStr.substring(0,10);

这里的10是一个固定值。

  1. Utils.calcContractName(CONTRACT_NAME)

3、params参数

  1. params.put(CONTRACT_ARGS_EVM_PARAM, methodDataStr.getBytes());

相对于其他合约params里边传的都是自定义合约的参数，但是在长安链中针对Solidity智能合约这里是一个“data”的常量（不可变更）。如果你没见过evm合约的调用示例，估计自己琢磨，这里将是你一个难以逾越的鸿沟（O(∩_∩)O）。要想找到这个data的出处还得去源码中找。长安链的evm有专门的开源项目。

chainmaker / vm-evm · ChainMaker

这个“data”的出处就在runtime.go的invoke方法里边

  1. func (r *RuntimeInstance) Invoke(contract *commonPb.Contract, method string, byteCode []byte,
  2.     parameters map[string][]byte, txSimContext protocol.TxSimContext, gasUsed uint64) (
  3.     contractResult *commonPb.ContractResult, specialTxType protocol.ExecOrderTxType)
  5. params := string(parameters[protocol.ContractEvmParamKey])

这个protocol.ContractEvmParamKey的背后藏的就是data。

msg.sender

了解完上边的好像差不多，合约也部署了，也能正常调用了。但是长安链还有一个比较坑的点就是这个msg.sender。这里处理不好很容易导致合约调用出现

  1. message: "OK"
  2. contract_result {
  3.   code: 1
  4.   message: "revert instruction was encountered during execution"
  5. }
  6. tx_id: "89ee744e75ad9066f339aa4f49942e09a0692f30e48e1e03257adb2cce26839e"

1、首先通过SDK源码找到sender的到底是谁

源码位置在JAVA SDK的ChainClient.java中，详细如下：

  1. private TxRequest createTxRequest(Payload payload, EndorsementEntry[] endorsementEntries) throws ChainMakerCryptoSuiteException {
  2.         Member sender;
  3.         org.chainmaker.pb.common.Request.EndorsementEntry.Builder endorsementEntryBuilder;
  4.         if (this.clientUser.getAuthType().equals(AuthType.PermissionedWithCert.getMsg())) {
  5.             if (this.isEnabledCertHash && this.clientUser.getCertHash() != null && this.clientUser.getCertHash().length > 0) {
  6.                 sender = Member.newBuilder().setOrgId(this.clientUser.getOrgId()).setMemberInfo(ByteString.copyFrom(this.clientUser.getCertHash())).setMemberType(MemberType.CERT_HASH).build();
  7.             } else if (this.isEnabledAlias && this.clientUser.getAlias() != null && this.clientUser.getAlias().length() > 0) {
  8.                 sender = Member.newBuilder().setOrgId(this.clientUser.getOrgId()).setMemberInfo(ByteString.copyFrom(this.clientUser.getAlias().getBytes())).setMemberType(MemberType.ALIAS).build();
  9.             } else {
  10.                 sender = Member.newBuilder().setOrgId(this.clientUser.getOrgId()).setMemberInfo(ByteString.copyFrom(this.clientUser.getCertBytes())).setMemberType(MemberType.CERT).build();
  11.             }
  13.             endorsementEntryBuilder = EndorsementEntry.newBuilder().setSigner(sender).setSignature(ByteString.copyFrom(this.clientUser.getCryptoSuite().sign(this.clientUser.getPrivateKey(), payload.toByteArray())));
  14.         } else {
  15.             sender = Member.newBuilder().setOrgId(this.clientUser.getOrgId()).setMemberInfo(ByteString.copyFrom(this.clientUser.getPukBytes())).setMemberType(MemberType.PUBLIC_KEY).build();
  16.             endorsementEntryBuilder = EndorsementEntry.newBuilder().setSigner(sender).setSignature(ByteString.copyFrom(this.clientUser.getCryptoSuite().rsaSign(this.clientUser.getPrivateKey(), payload.toByteArray())));
  17.         }
  19.         org.chainmaker.pb.common.Request.TxRequest.Builder txRequestBuilder = TxRequest.newBuilder().setPayload(payload).setSender(endorsementEntryBuilder);
  20.         if (endorsementEntries != null) {
  21.             txRequestBuilder.addAllEndorsers(Arrays.asList((Object[])endorsementEntries.clone()));
  22.         }
  24.         return txRequestBuilder.build();
  25.     }

2、里边有个this.clientUser他又是谁

是我们节点的client用户吗，这里很容易让人产生误解，答案是不一定。这里的clientUser实际就是代表ChainClient里边的一个用户，这个用户怎么创建的，又得网上找谁创建的ChainClient，此时就找到ChainManager.java，里边有个createChainClient方法，如下：

  1. public synchronized ChainClient createChainClient(SdkConfig sdkConfig) throws ChainClientException, RpcServiceClientException, UtilsException, ChainMakerCryptoSuiteException {
  2.         this.checkConfig(sdkConfig.getChainClient());
  3.         String chainId = sdkConfig.getChainClient().getChainId();
  4.         ChainClientConfig chainClientConfig = sdkConfig.getChainClient();
  5.         this.dealChainClientConfig(chainClientConfig);
  6.         User clientUser;
  7.         if (!chainClientConfig.getAuthType().equals(AuthType.PermissionedWithKey.getMsg()) && !chainClientConfig.getAuthType().equals(AuthType.Public.getMsg())) {
  8.             clientUser = new User(sdkConfig.getChainClient().getOrgId(), chainClientConfig.getUserSignKeyBytes(), chainClientConfig.getUserSignCrtBytes(), chainClientConfig.getUserKeyBytes(), chainClientConfig.getUserCrtBytes());
  9.             if (sdkConfig.getChainClient().getAlias() != null && sdkConfig.getChainClient().getAlias().length() > 0) {
  10.                 clientUser.setAlias(sdkConfig.getChainClient().getAlias());
  11.             }
  12.         } else {
  13.             clientUser = new User(sdkConfig.getChainClient().getOrgId());
  14.             clientUser.setPukBytes(CryptoUtils.getPemStrFromPublicKey(chainClientConfig.getPublicKey()).getBytes());
  15.             clientUser.setPublicKey(chainClientConfig.getPublicKey());
  16.             clientUser.setPrivateKey(CryptoUtils.getPrivateKeyFromBytes(FileUtils.getFileBytes(chainClientConfig.getUserSignKeyFilePath())));
  17.         }
  18. 。。。。未截全。。。。

到这里相当于知道了是哪个用户，但是一个用户有几个证书，此时还得再看看User的构造方法和前边sender的创建时取的哪一个证书，最终确认为用户的签名证书，也就是sdk_config.yaml配置的

  1. user_sign_crt_file_path

只有梳理清楚后，后续在调用比如transferFrom、approve方法时才不容易报错。

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