Synchronous requests are not supported when deploying smart contract using web3

Question

I'm trying to deploy a smart contract locally using Web3, Truffle, and Testrpc. I used Truffle to compile a smart contract and have the following code to extract the ABI and bytecode. In the same script, I'm trying to deploy the contract using web3.eth.contract.deploy (given in this documentation: https://web3js.readthedocs.io/en/1.0/web3-eth-contract.html#deploy) but have been getting this error:

Error: Synchronous requests are not supported

What should I do to get around this?

Here is the script for reference:

let fs = require("fs");
let Web3 = require('web3'); // https://www.npmjs.com/package/web3
var TestRPC = require("ethereumjs-testrpc");

let web3 = new Web3();
web3.setProvider(TestRPC.provider());

let source = fs.readFileSync("../SmartContracts/build/contracts/TheContract.json");
let JSONObject = JSON.parse(source);

// ABI and bytecode description as JSON structure
let abi = JSONObject.abi
let bytecode = JSONObject.unlinked_binary;

// Create Contract proxy class
let contractSettings = {
  from: addr, 
  gas: 1000000, 
  data: bytecode
}
let SampleContract = new web3.eth.Contract(abi, contractSettings);

let deploySettings = {
  data: bytecode,
  from: addr
}

SampleContract.deploy(deploySettings)
  .send({
    from: addr,
    gas: 1500000,
    gasPrice: '30000000000000'
  })
  .on('error', function(error){ 
    console.log("error");
  })
  .on('transactionHash', function(transactionHash){ 
    console.log("transaction hash");
  })
  .on('receipt', function(receipt){
    console.log("receipt") // contains the new contract address
  })
  .on('confirmation', function(confirmationNumber, receipt){ 
    console.log("confirmation");
  })
  .then(function(newContractInstance){
    console.log(newContractInstance.options.address) // instance with the new contract address
  });

console.log("finished");

Did you end up finding a solution to this? I have the same problem. — Leopold Joy

Bill Chen Bill Chen · Accepted Answer · 2017-09-10T21:52:11

I believe that this is an issue with using TestRPC as the web3 provider. Switching to a local geth instance seemed to have solved the problem.

Synchronous requests are not supported when deploying smart contract using web3

1 Answers