ethereum Questions

2

Currently reading solidity documentation: https://solidity.readthedocs.io/en/develop/types.html#function-types By default, function types are internal, so the internal keyword can be omitted. ...
Celeski asked 3/12, 2017 at 19:19

4

Please tell me how can I get transactionHash in avance? // I have these tx opts: var txOpts = { "to":"0x345cA3e014Aaf5dcA488057592ee47305D9B3e10", "nonce":"0x8", "gasPrice":1, "gas":250000, "...
Suited asked 12/1, 2018 at 20:40

1

import json from web3 import Web3 infura_url = "https://mainnet.infura.io/v3/5b314a9b373442fc8ed0c9cd184e838f" web3 = Web3(Web3.HTTPProvider(infura_url)) abi=json.loads('[{"constant&...
Perrotta asked 3/8, 2019 at 6:28

1

Solved

I want to get all events emitted by a Solidity contract using web3, however the .getPastEvents() method is for a contract. This returns all events for contractInstance, however, my contract calls ...
Worriment asked 14/7, 2019 at 12:24

1

I am getting error while connecting with ethereum node. this line ==> print(client.getBlockNumber()); returns error E/flutter (22015): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled ...
Induna asked 28/3, 2019 at 8:40

1

I'm currently trying to implement an ethereum Node Connection to my Typescript/ Node Project. I'm connection to the "Infura" node server where i need to sign my transaction locally. Well, anyway. ...
Wellspoken asked 26/6, 2017 at 16:0

3

I have a node js process that creates a web3 websocket connection, like so: web3 = new Web3('ws://localhost:7545') When the process completes (I send it a SIGTERM), it does not exit, but rather ...
Carvalho asked 31/5, 2018 at 20:15

1

Solved

In the backend of a Web application I have to communicate with the public Ethereum Blockchain. On local development machine, I run ganache as testrpc and connect with such a line of code: web3 = ...
Berri asked 13/5, 2019 at 15:2

3

I have been experimenting with truffle recently and followed the following tutorial: http://truffleframework.com/tutorials/pet-shop Whenever I try to setup a transaction I keep getting the same er...
Whitecollar asked 9/8, 2017 at 8:43

0

I am using golang to listen to the smart contract events. I deployed my contracts to ganache ui and ganache-cli ports. But I get the below error: ➜ sc_events go run main.go 2019/04/17 14:25:04 wr...
Faun asked 17/4, 2019 at 9:4

5

struct buyer { uint amount; Status status; } mapping(address=>buyer) public buyers; mapping(uint=>address) buyerIndex; uint public buyerNum; // Order a product. function() { uint doubleV...
Schellens asked 16/6, 2016 at 7:34

3

Solved

I'm actually using truffle with Ganache to do some development. I would like to know where does Ganache store it's blockchain to see how much data is used by my test. Is it stored somewhere access...
Glassy asked 4/1, 2018 at 14:18

4

Solved

I am installing Ethereum on Ubuntu 17.10 following the steps in this article: https://medium.com/@mvmurthy/full-stack-hello-world-voting-ethereum-dapp-tutorial-part-2-30b3d335aa1f But when executi...
Sydel asked 13/11, 2017 at 5:47

1

Solved

I would assume comparing strings would be as easy as doing: function withStrs(string memory a, string memory b) internal { if (a == b) { // do something } } But doing so gives me an error Ope...
Cluff asked 3/2, 2019 at 1:23

2

Solved

How to return string in 0.5.0 solidity compiler version? contract Test { string public text = 'show me'; function test() public view returns (string) { return text; } } I got error message: ...
Caprification asked 23/11, 2018 at 13:26

1

Solved

Im trying to run my first HelloWorld smart contract on the Enthereum network. This is my HelloWorld.sol contract. pragma solidity ^0.5.0; contract HelloWorld { bytes32 message; constructor (byt...
Solubilize asked 24/11, 2018 at 18:10

1

Solved

I must store JSON formatted data in my Solidity contract. I don't need to do any operations on the data. I simply need to store it, update it, and return it. Let's say I have JSON formatted data s...
Sonics asked 16/11, 2018 at 3:43

6

Solved

I have a contract's function which emit events on each call. I would like to have an event emitted on each test which are passing, here are some tests : it("should emit Error event when sending 5...
Chromatic asked 14/4, 2016 at 15:34

1

Solved

Windows 10 Home x64 bignumber.js@^7.2.1 [email protected] [email protected] [email protected] [email protected] [email protected] Full version reference: https://github.com...
Incessant asked 15/11, 2018 at 5:13

1

I am just starting with IPFS and Ethereum. We are building a dApp (mobile) and planning to replace the standard API & DB layer with IPFS and Ethereum. So, after lots of reading I have the follo...
Jennifer asked 30/10, 2018 at 17:33

2

Solved

i have some script using to sending Ethers from address to addres. Im using Parity, and Python 3.6. It is using Flask looks like: from flask import Flask, render_template, json, request import url...
Irreversible asked 24/1, 2018 at 22:38

9

As the developers are constantly using different network protocols of blockchain such as Hyperledger, multichain, Ethereum, Corda, and others. Community will appreciate if the developers &amp...
Yolandayolande asked 17/1, 2017 at 7:11

5

I have a function on a Solidity contract that does a throw. Eg. function do(x,y) { if ( msg.sender != owner ) throw; // ... } In the Truffle environment I have a test js something like: //...
Arlin asked 13/4, 2016 at 10:26

2

> w3.eth.syncing AttributeDict({ 'currentBlock': 5787386, 'highestBlock': 5787491, 'knownStates': 138355583, 'pulledStates': 138341120, 'startingBlock': 5787335, }) > w3.eth.blockNumber...
Azaria asked 14/6, 2018 at 13:19

1

I'm trying to explore Ethereum and creating a app which let user sign message and validate the message. I'm using web3swift framework for this and what I have tried so far is as follows - let web...
Keyway asked 22/9, 2018 at 9:11

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