Web3 学习日记 - Web3 Android 原生库测试 (二)
web3j 的版本管理问题
web3j 不知道为什么，在 maven 上有一个目前为止版本号最高的 5.0.0, 发布于 2020 年 5 月 而真正最新的版本是 4.12.0
参见如下链接
https://github.com/hyperledger/web3j/issues/1976#issuecomment-1809820843 https://mvnrepository.com/artifact/org.web3j/core
而 Android Studio 会根据版本号字符串的比较规则来提示升级，注意不要错误的”升级”到 5.0.0 版本了。
web3j 和测试代码 repo
https://github.com/hyperledger/web3j
https://github.com/yushihang/web3j.test
Android 项目配置
参见 web3j 文档和 测试代码 repo
ganache 配置
参见 https://yushihang.github.io/did/web3/smartcontracts/2024/05/10/debug-solidity-contracts-locally.html
各测试用例
参见测试代码 https://github.com/yushihang/web3j.test/blob/main/app/src/main/java/com/web3jtest/ViewModel.kt
合约函数调用
合约函数的调用有两种方式
- 通过 abi 导出对应的 java 函数定义
- 通过函数名和动态参数/返回值调用
通过 abi 导出对应的 java 函数
web3j-cli 安装
curl -L get.web3j.io | sh && source ~/.web3j/source.sh
java 环境
java 需要升级到 17 或以上
导出 abi.json
参考 https://yushihang.github.io/did/web3/smartcontracts/2024/05/10/debug-solidity-contracts-locally.html 导出
通过 abi.json 生成合约对应的 java 代码
web3j generate solidity -st -jt -a abi.json -o . -p com.web3jtest
注意: abi.json 中如果有 uint256[64]之类的类型定义， 需要修改为非固定长度的 uint256[], 否则 java 文件导入项目后会遇到调用时的 exception 问题 (“Array types must be wrapped in a TypeReference”)
(这个可能是 web3j-cli 的版本问题导致，期待后续版本可以解决)
java 文件修改(1)
导出后的 java 文件有些时候可能编译会失败，可以尝试 Android Studio 的自动修复。
例如
public RemoteFunctionCall<List> getGISTRootHistory(Uint256 start, Uint256 length) {
final Function function = new Function(FUNC_GETGISTROOTHISTORY,
Arrays.<Type>asList(start, length),
Arrays.<TypeReference<?>>asList(new TypeReference<DynamicArray<GistRootInfo>>() {}));
return executeRemoteCallSingleValueReturn(function);
修改为
public RemoteFunctionCall<Type> getGISTRootHistory(Uint256 start, Uint256 length) {
final Function function = new Function(FUNC_GETGISTROOTHISTORY,
Arrays.<Type>asList(start, length),
Arrays.<TypeReference<?>>asList(new TypeReference<DynamicArray<GistRootInfo>>() {}));
return executeRemoteCallSingleValueReturn(function);
java 文件修改(2)
如果调用函数时遇到 “parameter can not be null, try to use annotation @Parameterized to specify the parameter type” 这种 exception, 可以在对应的构造函数的参数前加上@Parameterized
例如如下代码中的@Parameterized(type = Uint256.class)
public static class GistProof extends DynamicStruct {
public Uint256 root;
public Bool existence;
public DynamicArray<Uint256> siblings;
public Uint256 index;
public Uint256 value;
public Bool auxExistence;
public Uint256 auxIndex;
public Uint256 auxValue;
public GistProof(Uint256 root, Bool existence, @Parameterized(type = Uint256.class) DynamicArray<Uint256> siblings,
Uint256 index, Uint256 value, Bool auxExistence, Uint256 auxIndex,
Uint256 auxValue) {
super(root, existence, siblings, index, value, auxExistence, auxIndex, auxValue);
this.root = root;
this.existence = existence;
this.siblings = siblings;
this.index = index;
this.value = value;
this.auxExistence = auxExistence;
this.auxIndex = auxIndex;
this.auxValue = auxValue;
}
}
通过 abi 导出的 java 代码调用合约函数
公共函数
private suspend fun <T> handleContractCall(
remoteFunctionCall: RemoteFunctionCall<T>
): T = suspendCancellableCoroutine { continuation ->
val future = remoteFunctionCall.sendAsync()
future.thenAccept { result ->
continuation.resume(result)
}.exceptionally { ex ->
continuation.resumeWithException(ex)
null
}
continuation.invokeOnCancellation {
future.cancel(true)
}
}
view 函数
fun callContractViewFunction() {
viewModelScope.launch {
try {
val gistProof = handleContractCall(stateContract.getGISTProof(Uint256(123)))
val gistProofStr = gistProof.toPrettyString()
println("response: $gistProofStr")
(state.contractViewFunctionResponse as MutableStateFlow).value = gistProofStr
} catch (e: Exception) {
e.printStackTrace()
}
}
}
涉及状态修改的函数
fun callContractStateModifyFunction() {
viewModelScope.launch {
try {
val txHash = handleContractCall(
stateContract.transitStateGeneric(
Uint256(generateRandomBigInteger(200)),
Uint256(0),
Uint256(2),
Bool(true),
Uint256(1),
DynamicBytes.DEFAULT
)
).transactionHash
println("txHash: $txHash")
(state.contractStateModifyFunctionTxHash as MutableStateFlow).value = txHash
} catch (e: Exception) {
e.printStackTrace()
}
}
}
动态构造调用合约函数
公共代码
private suspend fun <T : Response<*>> handleWeb3jRequest(
request: Request<*, T>
): T = suspendCancellableCoroutine { continuation ->
val future: CompletableFuture<T> = request.sendAsync()
future.thenAccept { result ->
continuation.resume(result)
}.exceptionally { ex ->
ex.printStackTrace()
continuation.resumeWithException(ex)
null
}
view 函数
fun callContractViewFunction2() {
viewModelScope.launch {
try {
val id = Uint256(BigInteger.valueOf(123))
val function = Function(
"getGISTProof",
listOf(id),
listOf(
object : TypeReference<Uint256>() {},
object : TypeReference<Bool>() {},
object : TypeReference<DynamicArray<Uint256>>() {},
object : TypeReference<Uint256>() {},
object : TypeReference<Uint256>() {},
object : TypeReference<Bool>() {},
object : TypeReference<Uint256>() {},
object : TypeReference<Uint256>() {}
)
)
val encodedFunction = FunctionEncoder.encode(function)
val transaction = Transaction.createEthCallTransaction(credentials.address, contractAddressHex, encodedFunction)
val ethCall = handleWeb3jRequest(web3j.ethCall(transaction, DefaultBlockParameterName.LATEST))
val result = ethCall.result
val decodedResult = FunctionReturnDecoder.decode(result, function.outputParameters)
// 解析返回值
val root = decodedResult[0].value as BigInteger
val existence = decodedResult[1].value as Boolean
val siblings = (decodedResult[2].value as List<*>).map { it as BigInteger }
val index = decodedResult[3].value as BigInteger
val value = decodedResult[4].value as BigInteger
val auxExistence = decodedResult[5].value as Boolean
val auxIndex = decodedResult[6].value as BigInteger
val auxValue = decodedResult[7].value as BigInteger
// 创建 JSON 对象
val json = JSONObject()
json.put("root", root.toString())
json.put("existence", existence)
json.put("siblings", JSONArray(siblings.map { it.toString() }))
json.put("index", index.toString())
json.put("value", value.toString())
json.put("auxExistence", auxExistence)
json.put("auxIndex", auxIndex.toString())
json.put("auxValue", auxValue.toString())
val gistProofStr = json.toString(4)
println("response: $gistProofStr")
(state.contractViewFunctionResponse2 as MutableStateFlow).value = gistProofStr
} catch (e: Exception) {
e.printStackTrace()
}
}
}
涉及状态修改的函数
fun callContractStateModifyFunction() {
viewModelScope.launch {
try {
val func = Function("transitStateGeneric",
listOf(
Uint256(generateRandomBigInteger(200)),
Uint256(0),
Uint256(2),
Bool(true),
Uint256(1),
DynamicBytes.DEFAULT
),
emptyList()
)
val encodedFunc = FunctionEncoder.encode(func)
val nonce = handleWeb3jRequest(web3j.ethGetTransactionCount(credentials.address, DefaultBlockParameterName.LATEST)).transactionCount
println("nonce: $nonce")
val gasPrice = handleWeb3jRequest(web3j.ethGasPrice()).gasPrice
println("gasPrice: $gasPrice")
val gasLimit = BigInteger.valueOf(210000)
val value = BigInteger.ZERO //we just call contract function, not sending ETH
val rawTransaction = RawTransaction.createTransaction(
nonce, gasPrice, gasLimit, contractAddressHex, value, encodedFunc
)
val signedMessage = TransactionEncoder.signMessage(rawTransaction, credentials)
val hexValue = Numeric.toHexString(signedMessage)
val transactionHash = handleWeb3jRequest(web3j.ethSendRawTransaction(hexValue)).transactionHash
(state.txHash as MutableStateFlow).value = transactionHash
(state.contractStateModifyFunctionTxHash as MutableStateFlow).value = transactionHash
updateContractStateModifyFunctionTxHashReceipt()
} catch (e: Exception) {
e.printStackTrace()
}
}
}