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2answers
52 views

Block Numbers Different

I have a Ropsten test node up and running. When I check the block height on etherscan.io, it's different from the block number on my node. How is this possible? Please help.
1
vote
2answers
419 views

This contract object doesn't have address set yet, please set an address first

I am in the final stages of developing an application that is similar to https://www.ethereum.org/crowdsale, however, when I click on the create button, my Metamask modal is not popping up to ask me ...
0
votes
1answer
5 views

'ALERT: Trying to call a function on a non-contract address' Why Do I Keeping This Error?

This is the error from metamask directly: This is the error I get once after I submit the information to IPFS: My Smart Contract: pragma solidity 0.5.3; //Imports for safe math operations import "...
0
votes
0answers
8 views

Address Transaction Listener (Python)

I have a couple of eth addresses and want to create a script that fires hooks whenever a transaction is detected on either address. I have seen subscription to addresses in web3.js but I want to do ...
1
vote
1answer
24 views

Metamask Web3js Synchronous Method Error

Okay guys, I'm a complete newbie to Ethereum and Web3.js and going through the Crypto Zombies tutorial and have done okay so far. But, when I use this function in my index.html file as they show it I ...
1
vote
1answer
11 views

Does it align with the base concept of blockchain, if one stores the hash value generated from IPFS network in a database?

A friend of mine utilized IPFS to store data files regarding some user info.But for an android application of the same, he retrieved all hash values(same user but different files) and stored it in a ...
0
votes
1answer
29 views

How to withdraw from multiple contracts?

Thank you for watching this topic. I'm not sure how I can withdraw my balance from multiple contracts. The situation is like this. 1)People have rights to withdraw each fund. 2)funds are stored at ...
0
votes
1answer
9 views

ERC20 token contract address changes

I'm making a mobile wallet to send and receive ERC20 tokens, I finished with the code to Send and Receive, but I don't know what to do if a Token Contract Address changes, what happen if somebody have ...
0
votes
2answers
300 views

Solidity ,Member“transfer”Not found or not visible after argument dependent lookup in address

pragma solidity ^0.4.11; /** * @title Ownable * @dev The Ownable contract has an owner address, and provides basic authorization control * functions, this simplifies the implementation of "user ...
1
vote
0answers
9 views

Erc20 token prices

I am new to erc20 contracts and I deploy a contract to etherscan,it's price is $0.00. so my question is that, how does the token start to gain value,or is there a way of setting an initial price that ...
0
votes
0answers
11 views

I can't execute transaction from Dapp: Nounce too low

I'am trying to use go-ethereum on my local network: I have configured a 5-node quorum network on my local machine and I'am building Dapp. I created smart contract and generated go bindings. When I ...
0
votes
0answers
5 views

Eth.getTransactionReceipt sometimes shows 'root' value in response instead of 'status'. why?

I am using Geth 1.9.0. While fetching the value for eth.getTransactionreceipt, I am not getting 'status' in response. Instead i am getting 'Root' field in response. Why status is not getting ...
0
votes
1answer
48 views

Ethereum classic wallet is zero

I logged onto my ethereum classic wallet and the balance is zero. This is absolutely wrong. What do I need to do.
1
vote
1answer
19 views

How to get transaction status (programatically, not etherscan)?

I have a problem when I interact with an Smart Contract, from a javascript webapp. I can execute the transaction correctly when the status is confirmed, but I cannot get any error response when it ...
6
votes
2answers
8k views

How to fork my own version of ETH?

I would like to understand the basics of Ethereum and i would like to clone it and make my own local currency based on Ethereum to experiment at most its capabilities. Is there anyone that can give me ...
0
votes
0answers
5 views

how to add my custom token to 0x protocol in testnet/mainnet

I am new to the 0x protocol. Is it possible to add custom token using 0x Portal DApp?. Share any example or document. I have deployed my own exchange medium. it is running in http://localhost:3001 I ...
0
votes
1answer
25 views

Why I can't deploy a smart contract to a specific public key if i just generated and own this publickey/private key?

I am writing an explorative article about the actors/assets model for Ethereum 2.0 (https://ethresear.ch/t/ethereum-2-0-data-model-actors-and-assets/4117). Are there some reasons why is it not ...
13
votes
5answers
3k views

How to experiment with Ethereum without downloading the entire blockchain?

I want to experiment with Ethereum without having to download the entire blockchain. My ISP limits my bandwidth to 50GB and downloading the ETH chain would consume a lot of that, not to mention the ...
1
vote
1answer
21 views

What happened to the official documentation of web3.js v1.0?

It should be at https://web3js.readthedocs.io/en/1.0/, but now I'm getting this: Does anybody happen to know why this wonderful tool has been taken off line?
1
vote
1answer
60 views

Truffle migrate ERC820Registry

I use Truffle and Ganache and I want to test some contracts that use the ERC820 Registry. I'm new to Truffle (and JavaScript in general) and I'm struggling to follow the instructions described in EIP-...
0
votes
1answer
7 views

TypeError: Trying to create an instance of an abstract contract

pragma solidity ^0.5.0; import 'https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/SafeMath.sol'; contract SubToken{ function totalSupply() public view returns (...
29
votes
8answers
13k views

What are the development tools for Ethereum?

Could someone make a list with development tools for Ethereum together with a short description what they are good for?
1
vote
1answer
70 views

How to call a contract function that alters blockchain state on geth console

It should be easy, but I'm having a hard time using a simple smart contract described in the Solidity language reference called SimpleStorage. It only as one attribute, a setter and a getter, and I'm ...
10
votes
2answers
8k views

TypeError: Data location must be “storage” or “memory” for parameter in function, but none was given

/// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet. /// @param destination Transaction target address. /// @param value Transaction ether value. /// @param ...
0
votes
1answer
22 views

create ERC-20 token from a contract function

I would like to do a function create contract with ERC-20 interface. But I have a few problems. If anyone help me I’ll be appreciated. Here’s the code : pragma solidity ^0.5.0; import 'https://...
0
votes
0answers
11 views

Split smart-contract

We are developing a decentralized application on Ethereum that manages surveys. We have a main smart-contract that contains survey information (i.e. hashes) as well as 2 main functions: one to create ...
0
votes
0answers
12 views

How to create a node.js multisig wallet? [on hold]

I was reading about multisig wallet and found out that it is simple smart contract based. multi-sig wallet github However, someone told me about node.js based multisig wallet. Is it possible to ...
2
votes
1answer
19 views

Mining a private transaction in quorum

I was going through the quorum docs and got stuck on how private transactions are mined? When two nodes, say Node A and Node B do a private transaction between themselves. Which node then mines the ...
0
votes
1answer
37 views

Design of contract that mediates a transaction between a seller and a buyer

I'm working on designing an application that requires a contract to mediate a transaction between a seller and a buyer. The buyer will initiate the game by paying the contract, the contract will then ...
0
votes
1answer
13 views

Smart Contract Deployment issue

I am making a smart contract with a Transfer function. function transfer(address _to, uint256 _value) public returns(bool success) { //checking whether sender has enough number of tokens ...
1
vote
2answers
33 views

Calling a smart contract function with an unsigned transaction

I'm new to working with Ethereum smart contracts and would appreciate some guidance by the community on a task that I'm trying to solve. This is the contract I want to use - https://github.com/chatch/...
1
vote
1answer
48 views
1
vote
2answers
893 views

Monitor and restart web3 connection if disconnected

Is there a way to listen for web3 connection to node continuously and restart if it fails. I am expecting some similar to this. It is something very common but i can't find this in documentation. If ...
0
votes
1answer
38 views

HTML interaction with blockchain

I'm collecting temperature data from user on-chain. However, since cant get exact (live) time through my html code connected via testrpc to the blockchain I do so. Where post click a button, html ...
0
votes
1answer
25 views

Deploy contract to Parity dev chain using Remix

I'm trying to deploy a contract via remix to my local development chain. However, the transaction never gets mined and is pending forever. When I use a node script it works (at least I receive the ...
0
votes
1answer
15 views

what will happen to transactions on smaller length chain when peered with longer length chain in private ethereum

what will happen to transactions on smaller length chain when peered with longer length chain in private ethereum? Below is the scenario Step 1: I have started Ethreum private chain in 2 different ...
0
votes
1answer
32 views

Sending funds to a possible smart-contract

When sending funds to an Ethereum address, Should my wallet check in the blockchain whether the address is associated with a smart contract? In order to choose the gas limit automatically. If someone ...
0
votes
1answer
20 views

Deposit event is not call while contract get token

My contract pragma solidity ^0.5.0; contract Transfereventaction { event Deposit( address indexed _from, bytes32 indexed _id, uint _value ); function deposit(...
1
vote
1answer
35 views

Can transaction hash be used to get v, r, s parameters using web3js?

I am trying to create a function which can be used to get the v, r, s parameters (ECDSA) of the signature. So i am thinking to pass a random tx hash from etherscan and it will return v,r,s parameters ...
1
vote
1answer
60 views

What are the anticipated economics of moving from PoW to PoS?

As the move to PoS gets closer, I'm trying to get more details on how the PoS validators will get compensated. In PoW, it is based on formulas and the awards are transparent. Not so for staking ...
0
votes
2answers
59 views

Can not install Ganache GUI on Ubuntu?

I am trying to install Ganache GUI on my ubuntu 18.04. I downloaded the Ganache-2.0.1.AppImage from the site. On the site it says that the package installs automatically when double clicked. But it is ...
0
votes
2answers
29 views

Automating user data storage on a blockchain

I have a smart contract that contains a function to store data onto the blockchain. The function stores two integer variables to the blockchain. Now, I can manually store the values from the remix-ide ...
0
votes
1answer
10 views

How to request tokens from msg.sender within contract function

transferring ethereum from the user of your smart contract is simple enough, you simply use msg.value and can use this within your contract's functions. But doing the same thing with tokens is a bit ...
0
votes
0answers
24 views

Why am I getting an out of gas error on transactions that should instead revert due to a require statement?

I've thoroughly tested a contract using Ganache, and when calling a method with a value that would trigger one of its require statements, it reverted as expected and returned the error message I ...
2
votes
2answers
26 views

Ethereum adoption in Enterprise without tokens/Ethers

from an enterprise perspective, we may not need to deal with tokens/ethers. Can an enterprise use ethereum at the same time decide not to use tokens/ethers (for example not supplying gas for every ...
0
votes
1answer
51 views

can not find specific events and list events of the past the last 1day

I'm wrote this sample but I want to filter specific events 'unsealBid' and list events of the past (e.g. the last 1 or 2 days). const Web3 = require('web3'); const web3 = new Web3('https://mainnet....
12
votes
8answers
14k views

Invalid Address Error when interacting with a smart contract with metamask

I want to call the methods with metamask of this simple contract: contract AssetPrices { mapping (uint => uint) public prices; uint public data; function EnterPrice(uint _time, uint _price){...
0
votes
2answers
85 views

Code Example from “Mastering Ethereum: Building Smart Contracts and DApps” doesn't work

I'm reading the Ethereum book of Gavin Wood right know and the following code example gives an error message when I try to compile it with truffle: pragma solidity ^0.4.22; contract calledContract { ...
1
vote
0answers
11 views

Using AWS CloudHSM to sign transactions

Does somebody knows how to properly use AWS CloudHSM to sign ethereum transactions (Keccak256)?
5
votes
1answer
27 views

Will block numbers be sequential on a sharded blockchain

When Ethereum shards (assuming it does) will the block numbers across the multiple shards be unique? I doubt it (I don't think the shards can have sequential block numbers and be independent of the ...

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