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2
votes
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26 views

Full Node Bigger Than Online Reports?

I am running a full node and I noticed that the amount of disk space it takes is larger than reports online. I use the command ./geth --syncmode full --rpcapi eth,web3,personal --rpc --rpcaddr 127.0....
0
votes
1answer
319 views

How increase mining speed in AWS instance?

I have setup a private blockchain in AWS micro instance using go-ethereum. In that when I start the mining process it was taking nearly 2-3 hours to mine a new block.Whereas on my local machine it was ...
48
votes
3answers
33k views

<address>.send vs <address>.transfer best practice usage?

I noticed that address's offer two member functions that perform the transfer of ether to the specified address. send returns false upon failure and transfer raises an exception. In the Solidity ...
-1
votes
0answers
23 views

Can we take input of an address and pass it on the function to send ether using web3 and truffle? [closed]

Actually i am trying to create a betting application so when i get the result that Home team has won Before this i will be taking both address as input (betting do two address whoever wins gets the ...
0
votes
0answers
17 views

Efficient way to save and retrieve hash in blockchain

I am learning Ethereum using Geth. I have a private blockchain and I am saving hashes through a REST API (python web service). I have readed I can save hash values using maps (mapping data type) and ...
0
votes
1answer
27 views

How can i use Token from an ERC20 Contract in my own contract?

I have following contract here on ropsten https://ropsten.etherscan.io/address/0x813870feba76f27ec1afcf79432e065a4839f7ab#code I want to use tokens from a different erc20 contract(...
0
votes
1answer
25 views

metamask fails to be enable on the ethjs examples

I enabled the metamask by uncommenting the section regarding metamask on ethjs examples from Github but they were no connection and examples seem not been deployed. I am wondering if there is ...
0
votes
0answers
23 views

Using web3.py to send a 0 price gas erc20 transaction

Sorry about the formatting, I’m on mobile I'm trying to push an ERC20 Token transaction with 0 gas price using web3.py. Although when I set the gas price to 0, I receive the following error: {'code':...
2
votes
3answers
358 views

Balance may be outdated, Metamask

Metamask is showing an asterisk near the account balance, and the message "Balance may be outdated". Indeed the balance is outdated. This is true an all networks (Main, Ropsten, etc.) and different ...
1
vote
1answer
38 views

What is the best (cheapest) method to store RGB/RGBA pixel data in a smart contract (on ethereum-classic blockchain) with python?

I would to implement a method to store pixel (RGB/RGBA) in a Smart contract (on ethereum-classic blockchain) from python and with the cheapest method ( when storing and updating pixel data) I try to ...
0
votes
0answers
31 views

0 gas transaction underpriced in pushtx? [closed]

I want to do a pushtx with 0 gas but when I do I get the 'transaction underpriced' error. I've seen transactions with 0 gas before. Why can I not do it?
4
votes
1answer
2k views

Mist, transaction “couldn't be successfully executed”

For some reason I can't send transactions from my Mist wallet. I'm running the newest version (0.8.7). When I send a transaction, after a couple of minutes I get the message that the transaction "...
0
votes
1answer
22 views

Sharing an verifiable secret message in a contract

I would like to hear your opinion on my idea to share a proof of a secret message in a contract, that users can verify later in a second phase when the message will be revealed. If the message is a ...
1
vote
0answers
19 views

Migration from PoW to PoA Clique on geth

After reading chapter "Repurposing header fields for signing and voting" at https://eips.ethereum.org/EIPS/eip-225 I've understood the nonce field of blocks in PoW consensus blockchain is reused for ...
2
votes
1answer
358 views

How to Import an Online Wallet to Parity?

I wanted to Import my Ethereum Online Wallet (ether.li) to Parity. I created 2 Accounts with the private keys and 1 Wallet with the Wallet Address. How can I transfer my funds to another Wallet (...
0
votes
0answers
18 views

How to lock token certain amount of time [closed]

lock token certain amount of time and then automatically unlock the token and transfer to other user.. suppose owner send some token to user and the lock certain amount of time i.e 10 mins now then ...
0
votes
1answer
519 views

Deploying Solidity Contract Using Web GUI and web3

Any guide or step by step Tutorial for deploying a solidity smart using a GUI and accessing the meta mask account ? Please Help
3
votes
1answer
592 views

Is Geth's Clique PoA Consensus Algorithm production ready?

Is it recommended to use geth's Clique PoA in a production setup or is it for test-net only? Does someone know of productive deployments of Clique PoA?
0
votes
0answers
17 views

How to Convert address from String to byte[] for EthereumJ?

How can I convert an ETH address represented as string, like 0xECF16255e690a608ABaB5329DEAF3B11a65Fa12B to obtain a corresponding byte[] to use in EthereumJ raw transaction builder? I need the ...
0
votes
1answer
31 views

Getting stuck in truffle testing

I am trying to run a test and I am getting the following message; I have tried the following; npm install scrypt npm install web3 as to solve the yellow message and when running truffle test ...
5
votes
3answers
4k views

How to create a smart contract to send an ETH tx on time?

For a specific purpose, I would like to create a smart contract in ETH blockchain and its job is to send a specific amount of ETH to a defined address when the time comes (unix time or specific block ...
0
votes
1answer
243 views

Nethereum: CallAsync return a wrong msg.sender

I write this simple contract: contract greeter { event LogSender(address sender); function getSender() constant returns (address) { LogSender(msg.sender); return msg.sender; }...
4
votes
3answers
151 views

Getting Addresses using a Path causes the error: Could not derive hardened child key

I am using ethereumjs-wallet npm package to generate a unique wallet address for each user. However instead of using the mnemonic/seed, a public extended key xpub will be used instead to keep the ...
3
votes
1answer
37 views

Why are blocks imported so slowly? - Geth node

I'm running a geth node on AWS and it's fully synced, but looking at the logs and the blocks mined I see that it takes a lot of time to import a new block. For example: Geth log INFO [01-14|18:15:...
0
votes
1answer
99 views

How to unlock account to deploy contract without using personal.unlockAccount()?

When I have account keystore file on geth node http://192.168.43.201:8545 , I can deploy a contract like below: const web3 = new Web3('http://192.168.43.201:8545'); ... const contract = new web3.eth....
1
vote
1answer
267 views

why does it not work if I don't handle the return value of call/callcode/delegatecall?

This is my Contract code : pragma solidity ^0.4.15; contract D { uint public n; address public sender; event CallStatus(bool); function callSetN(address _e, uint _n) { if (!_e.call.gas(...
3
votes
1answer
464 views

Cannot make subscribe newBlockHeaders work

I'm doing this to get all blocks from the network: var web3 = new Web3(); web3.setProvider(new Web3.providers.IpcProvider("...", net)); web3.eth.subscribe('newBlockHeaders', function (err, result) { ...
1
vote
2answers
3k views

How To Connect Web3 With MetaMask?

No tutorial can help me, I have watched almost every major tutorial on Youtube and read a ton of results from Google... I have on my HTML file imported the web3.min.js (copied from Truffle pet-shop ...
0
votes
1answer
16 views

Storing name values off-chain in events and web3.js

Somewhere I read the advice to store name (title, geographical name, people name, etc.) value off-chain in events. But if a value is stored in an event, is there an efficient way to retrieve its ...
1
vote
1answer
599 views

Geth settings for watching Events?

what are the optimal geth settings if you just want to listen to some events that are fired by smart contracts? I'm having a bit trouble to setup geth properly. Thanks a lot. PS: That is my ...
1
vote
2answers
521 views

Is there a step by step tutorial on how to use EtherDelta exchange?

Totally new to using the etherdelta exchange. Is there a well written up step by step tutorial on how to use etherdelta exchange to make a trade?
1
vote
2answers
397 views

Automatic transaction

I would like to know if it was possible to automatically send any ETH amout to an address "B" just after receiving them on an address "A"? Maybe via a script? I need help
1
vote
1answer
529 views

Managing ERC20 tokens with a multisignature address

Say I have the following: Address A belongs to me and holds 10 ERC20 tokens, but does not hold any ETH Address B belongs to somebody else and I need to send 10 ERC20 tokens there from address A ...
1
vote
1answer
47 views

Solidity: Smart Contract, always get wrong result

I'm writing a token locker contract, code as following: pragma solidity ^0.4.24; import "./SafeMath.sol"; import "./ERC20.sol"; contract TokenLocker { using SafeMath for uint256; address ...
2
votes
1answer
955 views

Time Lock and vesting smart contract

I would like to create a smart contract that will take care of locking and/or vesting funds to several beneficiaries (inputted by the owner of the smart contract). The funds that it will vest and lock ...
0
votes
1answer
275 views

How to download the whole transfer records of a token

I want download the whole transfer records of a token. https://etherscan.io/token/0xB8c77482e45F1F44dE1745F52C74426C631bDD52?a=0xd551234ae421e3bcba99a0da6d736074f22192ff. But the default setting is ...
1
vote
3answers
425 views

How to manage keystore in private blockchain?

Ethereum Setup : I have created the private blockchain using two nodes (node1, node2). I have mounted a share drive between these two node to store keystore values so that both nodes can have same ...
0
votes
0answers
23 views

How can I approve and buy for another contract? [closed]

Im having this contract here https://ropsten.etherscan.io/address/0x813870feba76f27ec1afcf79432e065a4839f7ab#code This contract "TOKEN"(agi.sol) first needs to approve an transaction amount from a ...
5
votes
2answers
1k views

Sign data with private key inside a truffle test file

I've got a contract method that checks the signer of a message using the solidity ecrecover function. In my truffle test file I now want to check if this is done correctly. Therefore I need to sign a ...
1
vote
1answer
880 views

Can't connect to local rinkeby node from web3.js

I'm developing a Dapp using truffle and I need to connect to a contract that I uploaded on rinkeby using truffle migrate --network rinkeby. Problem is that I'm unable to connect to the rinkeby network ...
1
vote
1answer
42 views

Public variable getter shows as transaction in Remix

As of Solidity 0.6.0+ compiler, my remix shows getter functions, built by public variables, as transactions and, therefore, do not return the value. I searched the solidity 0.6.0 breaking changes but ...
0
votes
2answers
30 views

Making contract compatible with newer solidity compiler

I have a simple timelock contract however it doesn't work with modern solidity compilers, Could anyone make my contract compatible with solidity newer than 0.5.16? Thanks. Here is the code, it only ...
0
votes
1answer
31 views

Is it possible to get contract payload/data of a smart contract created via instance?

I am trying to get contract instance payload created via instance but don't seem to know how. I don't want to save just the contract address. Kindly help. See my code below. contract LandRegistry { //...
0
votes
1answer
258 views

call smartcontract functions using geth

I created a POA chain using this tutorial, I created a network of 5 nodes and 3 are mining on the network. I tried to deploy token contract to the network from one account using truffle and it was ...
1
vote
2answers
97 views

Why does ecrecover() take signature parameters (v,r,s) instead of the full signature?

Is there any reason ecrecover() takes the (v, r, s) signature parameters instead of the full signature, given that these can be easily computed inside the function itself? I am asking because ...
7
votes
5answers
3k views

address.transfer not working

pragma solidity ^0.4.23; contract ApprovalContract { address public sender; address public receiver; address public constant approver = 0x5AEDA56215b167893e80B4fE645BA6d5Bab767DE; constructor() ...
1
vote
2answers
24 views

How to read data returned by a function? [duplicate]

Counter.sol: pragma solidity >=0.5.0 <0.7.0; contract Counter { uint public _counter = 0; function GenNextID() public returns (uint) { return _counter++; } } I use ...
1
vote
2answers
540 views

Out of gas when calling smart contract function from web3/Meteor Dapp

The following smart contract function works when called in the Remix-Solidity IDE and connected to testrpc. function submitAsset(string ownerName, string assetName, string assetDesc, string barcode, ...
1
vote
1answer
30 views

Metamask Signing gives different signature than web3.js

I have successfully been using metamask to sign EIP712 data. I am currently trying to write truffle tests and need to replicate the signing process outside the browser. The issue I am facing is that ...
0
votes
1answer
58 views

Getting error for creating a contract for not enough gas? [closed]

Forkdelta.sol pragma solidity 0.4.19; import "./IToken.sol"; import "./LSafeMath.sol"; /** * @title ForkDelta * @dev This is the main contract for the ForkDelta exchange. */ contract ForkDelta { ...

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