.then() 函数从不 运行 调用区块链

Question

请在下面找到我的代码片段。这里 credentialHash 没有在 .then() 调用中设置。 “In then”或“Callback rejected”都没有被打印出来，所以我知道它不是 运行 但我不明白为什么。我还在我的智能合约中包含了 setHash 函数的代码。

let hash;
    await ipfs.add(JSON.stringify(this.state.credential)).then((result, error) => {
      hash = result.path;
      if (error) {
        console.error(error)
        return;
      }
      // Store hash on blockchain
      console.log("Hash before BC:" + hash);
      this.state.contract.methods.setHash(hash).send({from: this.state.account}).then((resolve) => {
    console.log("In then")
    this.setState({credentialHash: hash});
  }, (rejected) => {
    console.log("Callback rejected");
  });
      console.log("After setting:" + this.state.credentialHash);
    });

function setHash(string memory _CredentialHash) public returns(string memory) { credentialHash = _CredentialHash; return _CredentialHash; }

从console.log(this.state.contract.methods.setHash(hash).send({from: this.state.account}))返回的结果是：

Proxy {promise: Promise, eventEmitter: EventEmitter, resolve: ƒ, reject: ƒ}
[[Handler]]: Object
get: ƒ proxyHandler(target, name)
[[Prototype]]: Object
[[Target]]: PromiEvent
eventEmitter: EventEmitter
_events: Events
[[Prototype]]: Object
_eventsCount: 0
[[Prototype]]: Object
promise: Promise
[[Prototype]]: Promise
[[PromiseState]]: "pending"
[[PromiseResult]]: undefined
reject: ƒ ()
resolve: ƒ ()
[[Prototype]]: Object
[[IsRevoked]]: false

Answer 1

尝试完全删除 .then() 语法并仅使用 async/await 样式。下面的代码给出了什么？

let hash, result;

try {
  result = await ipfs.add(JSON.stringify(this.state.credential))
  hash = result.path;
} catch (error) {
  console.error(error)
  return;
}

// Store hash on blockchain
console.log("Hash before BC:" + hash);

try {
  await this.state.contract.methods.setHash(hash).send({
    from: this.state.account
  })
} catch(error) {
  console.log("Callback rejected");
  return
}

this.setState({
  credentialHash: hash
});

console.log("After setting:" + this.state.credentialHash);

Answer 2

对于遇到此问题的其他人，我终于找到了答案。 transactionConfirmationBlocks 的默认数量是 24，这需要很长时间才能完成。如下所示将其设置为 1 解决了我的问题。

this.setState({contract: new web3.eth.Contract(
      credentialArtifact.abi,
      deployedNetworkCred.address,
        {transactionConfirmationBlocks: 1}
  )});