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62 votes
Accepted

What is the relationship between Mist and Ethereum Wallet?

Mist DApp Browser Mist is the browser for decentralized web apps. What Mozilla Firefox or Google Chrome are for the Web 2.0, the Mist Browser will be for the Web 3.0 (which will be decentralized). ...
q9f's user avatar
  • 32.9k
27 votes

How can I find my `chaindata` folder?

geth (used in the Ethereum Wallet) saves its internal states for the main network in the chaindata directory. You can find it in the: ~/.ethereum on Linux ~/Library/Ethereum on OS X ~/AppData/Roaming/...
Ellis's user avatar
  • 2,354
24 votes
Accepted

How to pass constructor parameters to a contract using Truffle?

In Truffle, constructor params go in /migrations. So, something like: deployer.deploy(User, "foo"); User.deployed() will be a User contract that was deployed with _name="foo"
Rob Hitchens's user avatar
  • 55.3k
24 votes

How to get private key from account address and password?

I used this code to recover the private key from account address and password. firstly, install Keythereum: npm install keythereum Keythereum is a JavaScript tool to generate, import and export ...
Mounir Atouil's user avatar
21 votes
Accepted

In Mist browser how can I move the data (blockchain) to another drive on Mac OSX?

The default subdirectory where your Ethereum data files are stored on a Mac is ~/Library/Ethereum . Within this subdirectory, your blockchain data is stored in the subdirectory chaindata, i.e., ~/...
BokkyPooBah's user avatar
  • 40.3k
19 votes

What is the cause of the error: Expected import directive or contract definition

Not true in the OP's case, but a cause of this problem is missing a semi-colon from the first line specifiying compiler version, e.g.: pragma solidity ^0.4.6;
Lee's user avatar
  • 8,558
18 votes

CryptoCurrency NODE.js Web3 Ethereum - Can't connect to TESTRPC

If you are using the new web3.js 1.0.0-beta, then try this (all the syntax has changed, sigh). Tested with testrpc -d. > var Web3 = require('web3'); > var web3 = new Web3('http://localhost:8545'...
benjaminion's user avatar
  • 9,297
17 votes

address.transfer not working

Use address payable public receiver; in declaration for the addresses you are looking to transfer Ether in contract. As per the solidity documentation: The address type comes in two flavours, ...
Aniket's user avatar
  • 3,545
16 votes

Best way to test a smart contract

Truffle is a development environment, testing framework and asset pipeline for Ethereum, aiming to make life as an Ethereum developer easier. With Truffle, you get: Built-in smart contract ...
Herman Junge's user avatar
  • 2,381
13 votes
Accepted

How to remove The DAO contract from Ethereum Wallet (Mist) watch list as it is freezing?

Trashcan Click on the contract you want to delete. On the contract page, hover over the name. You see a trashcan. Click on this to remove the contract. EDIT: As noted by @Vesa, you may not be able ...
BokkyPooBah's user avatar
  • 40.3k
13 votes
Accepted

How to set a different datadir in Mist?

Ethereum-Wallet comes packaged with geth.exe which is the Ethereum blockchain node software. Here is the listing from the Ethereum-Wallet-win64-0-5-2.zip file downloaded from https://github.com/...
BokkyPooBah's user avatar
  • 40.3k
13 votes

Transfer from contract address

If the ether is already in the contract and you do not have the functionality to transfer ether already implemented in it, the ether will be forever in the contract. A simple contract that receives ...
Jaime's user avatar
  • 8,350
12 votes

How to get private key from account address and password?

Private key is often required to import your account in a different wallet. Even Metamask needs a private key to import the account. This is how I was able to extract the private key from the node ...
Koshik Raj's user avatar
11 votes

How do Ethereum clients generate unique addresses?

I think the most important phrase in your question is 'what is the likelihood'. The other answers are correct in determining that there is a 1 in 2^160 likelihood of finding a collision with 100% ...
bekah's user avatar
  • 1,099
10 votes
Accepted

How to generate Private key, public key and address

I have extracted this code from HD Wallet Provider const bip39 = require('bip39'); const hdkey = require('ethereumjs-wallet/hdkey'); const mnemonic = '..'; const hdwallet = hdkey.fromMasterSeed(...
Ismael's user avatar
  • 30.5k
10 votes

Free and public Ethereum JSON-RPC API nodes

Please see Ethereum Nodes for available options. https://ethereumnodes.com/ Multiple options might be cheaper than Infura. For example, CloudFlare is free. However they offer limited history and might ...
Mikko Ohtamaa's user avatar
9 votes

Can we modify a deployed contract in ethereum-wallet?

You can deploy a modified contract, but it will be deployed to a new address. Basically, it will be another contract. As an analogy, you can think of your deployed contract like a program that you ...
eth's user avatar
  • 85.9k
9 votes
Accepted

Connect Mist with testrpc on a Mac

This one worked straight away for me: $ /Applications/Mist.app/Contents/MacOS/Mist --rpc http://localhost:8545
Xavier Leprêtre B9lab's user avatar
9 votes

How to get private key from account address and password?

How to get private key from account address and password? One of the founding notions of public/private key cryptography is that what you are describing should be impossible. No cryptographic system ...
Samuel Hawksby-Robinson's user avatar
9 votes

Could somebody please explain in detail what this Ethereum contract is doing?

approve(address _spender, uint _value) returns (bool success) {...} This function is just being used to make an entry to the allowance array when another contract want to spend some tokens. _ spender ...
Aniket's user avatar
  • 3,545
9 votes
Accepted

Will it ever be possible to group multiple ERC20 tokens into a single transaction?

You can do this by creating a contract and having the contract interact with the various token contracts. One method would be to create your contract, then transfer ownership of your balance on each ...
Edmund Edgar's user avatar
  • 16.9k
9 votes

Error creating contracts on Ethereum wallet

throw was deprecated in solidity version 0.4.13. You need to replace each line that says if(condition) throw; with require(opposite of condition);. For example: if (_to == 0x0) throw; becomes ...
Joe's user avatar
  • 1,173
8 votes
Accepted

How to troubleshoot a white screen in Mist browser?

Missing dependencies? First of all try installing meteorjs and electron. These dependencies should be included in the binaries but some operating systems behave weird. Is your GPU blacklisted? Try ...
q9f's user avatar
  • 32.9k
8 votes

I am having trouble doing the initial sync of Ethereum-Wallet, what can I do to troubleshoot?

New versions of Ethereum-Wallet (aka: Mist) will do a fast sync the first time they startup. However, if you quit Ethereum-Wallet before it is done syncing it will switch to slow-sync from then on ...
Micah Zoltu's user avatar
8 votes

how to connect to geth from two local machines ethereum

Since you're running two nodes on two different machines, you need to mention the IP address of the node while connecting through addPeer(enodeURI). Detailed walkthrough: You need to have the same ...
galahad's user avatar
  • 3,920
8 votes
Accepted

Best way to test a smart contract

Ropsten (or Görli/Kovan etc) test network is the right choice for you, when you are still testing. I simply install the Chrome Metamask plugin. It communicates with nodes on a remote server (so no ...
simonDos's user avatar
  • 366
8 votes
Accepted

How to withdraw Ether from a contract

The function would be something like this: pragma solidity >=0.8.0; function withdraw() { payable(msg.sender).transfer(address(this).balance); } Just make sure you only allow yourself to ...
thefett's user avatar
  • 3,890
8 votes

How to create a local account from an external private key in Web3.py?

That's because the attribute of the function w3.eth.account.create(...) is not the private key. To generate an account from an external private key you must use the function w3.eth.account....
alberto's user avatar
  • 3,343
8 votes
Accepted

How to export mnemonics for a specific account in MetaMask

I'm curious why metaMask doesn't offer to generate seed words for a specific account Seed words are used as a seed to the master key of a BIP39-compliant deterministic wallet. BIP39 added the ...
Richard Horrocks's user avatar
7 votes

Why is it that the Mist client can not display the transactions?

TL;DR: it's computational too expensive to monitor incoming transactions for accounts on the Ethereum blockchain. linagee asked the developer of Mist: Its because you'd need to traverse the entire ...
q9f's user avatar
  • 32.9k

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