I have a contract method which emits events but ganache seems not to catch any events. I say this because when I deploy my contract on ropsten the events are being caught fine but only in ganache I have this problem. Also I am using web3 js to watch for the events.

This is my solidity contract which emits events:

pragma solidity ^0.5.0;

contract Marketplace {
    string public name;
    address owner;
    uint public fileCount = 0;
    mapping(uint => File) public files; 

    struct File
        uint id;
        string name;
        address owner;
        address sharedWith;

    event FileViewed(
        uint id,
        string name,
        address owner,
        address sharedWith

    constructor() public {
        name = "File Sharing System";
        owner = msg.sender;

    function viewFile(uint _id) public 
        File memory _file = files[_id];
        require(msg.sender==_file.sharedWith || msg.sender==owner ,"Not shared with you!!");
        emit FileViewed(fileCount, _file.name, owner, _file.sharedWith);

This is my App.js in which I am watching for events:

import React, { Component } from 'react';
import Web3 from 'web3';
import './App.css';
import Navbar from './Navbar';
import Main from './Main';
import Marketplace from '../abis/Marketplace.json';

class App extends Component {
  //const marketplace 

  async componentWillMount()
    await this.loadWeb3()
    await this.loadBlockChainData()

  async loadWeb3()
      window.web3 = new Web3(window.ethereum);
      await window.ethereum.enable();
    else if (window.web3)
      window.web3 = new Web3(window.web3.currentProvider);
      await window.ethereum.enable();
      window.alert("Non ethereum browser detected!!!!");

  async loadBlockChainData()
    const web3 = window.web3;
    //load Account
    const accounts = await web3.eth.getAccounts();
    this.setState({account: accounts[0]});
    const networkId = await web3.eth.net.getId();
    const networkData = Marketplace.networks[networkId];
      const marketplace = web3.eth.Contract(Marketplace.abi, networkData.address);

      const fileCount = await marketplace.methods.fileCount().call();
      for(var i=1;i<=fileCount;i++)
        const file = await marketplace.methods.files(i).call();
          files: [...this.state.files, file]
      window.alert('Marketplace contract not deployed to detected network.');


    this.state =
      account: '',
      fileCount: 0,
      files: [], 
      loading: false

    this.viewFile = this.viewFile.bind(this);

    this.setState({loading: true});
    this.state.marketplace.methods.viewFile(id).send({from: this.state.account})

      fromBlock: 0
    }, function(error, event)
        window.alert("Error: ", error);


Note: I don't want to use ropsten network because it takes time to record my transactions.

Help would be appreciated and new here any suggestions would be appreciated.

  • Sharing the relevant code and specifying where you are having issues will make it easier for someone to help you. Commented Oct 23, 2019 at 12:58
  • Added the code now, Please take a look if you can
    – vteja711
    Commented Oct 23, 2019 at 17:22
  • From the code provided i am not sure why you need to emit an event here. Rather just return the values from the viewFile() function. Commented Oct 23, 2019 at 18:15
  • Actually I want to create an event whenever the file is viewed. So that I can create alerts with my js. but my problem is that the event is not getting emitted when I am working with ganache and they are being emittied when I use Ropsten test network. I just want to know why
    – vteja711
    Commented Oct 24, 2019 at 3:36
  • I coundn't find any issue with Ganache. here is my App.js Commented Oct 24, 2019 at 5:20

1 Answer 1


It looks like you have to add a Truffle project.


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