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352 views

web3 detect/listen to events if someone send ether to addresses

I need to constantly keep running some code to detect if someone has in the past minute sent some ether/token to a lot of addresses, is there better way to do than https://ethereum.stackexchange.com/a/...
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votes
1answer
501 views

About Abi Encoder V2

I came across the following code and found the term "pragma experimental ABIEncoderV2". Can anybody be specific in telling what this actually means? //pragma solidity ^0.5.2; pragma experimental ...
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votes
1answer
52 views

How can I decode transaction input to know what method was called and what arguments were passed in (and arguments types)?

following to the approach explained here to use etherscan api from Python to get transactions info such as input How to retrieve transactions' info such as gaslimit and gasprice from Etherscan? ...
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2answers
686 views

create ethereum wallet in Api

I want to create an Ethereum wallet, and I need an address and a private key, but I am unable to generate both. Please suggest a way to generate key pairs.
0
votes
1answer
250 views

Can't set gas limit for oraclize callback function higher than the default 200000

Could you please help me with the following. I am using OraclizeIt (https://github.com/oraclize/ethereum-api) to retrieve a JSON from some other service via REST. Basically the smart contract method ...
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votes
1answer
164 views

How to get all the contracts deployed by a specific ethereum address?

It is anyhow possible to get all the contracts deployed by a specific ethereum address in lifetime? If yes, is it possible to get ABI details of the contract by their address?
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votes
1answer
704 views

Is it possible to deploy smart contract source code using remix? [duplicate]

I use remix ide. I want the source code of my contact to be published and visible in Etherscan. I do next things: Write some sample Smart Contract Open "Compile" tab, check that there are no errors ...
0
votes
1answer
97 views

Is there any way to return multiple structs (or the fields from them) in Solidity when one of the struct fields is of type `bytes`?

I would like to return structs keys from my contract to display on the frontend, ideally 10 at a time. I understand that if I make keyByOwner public I can return a single key at a time with the getter ...
0
votes
1answer
785 views

how to check if my testnet geth node has mined some ether?

As per the instructions detailed in this post, I've created an account: and started running my geth node: how can I check if it's mined any ether yet? the answer of @lungj resulted in this:
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0answers
45 views

Why incorrect number of tokens are sent according to the current rate to the contributor.?

Token Contract https://ropsten.etherscan.io/address/0x6f5c43f62b4b18aa8ed37b42f2804f7049cbe0e9#code CrowdSale Contract https://ropsten.etherscan.io/address/0x9b94e1894abe2051e6e96bf1b57fe5d3adbbc5aa#...
0
votes
1answer
642 views

Out of gas on truffle test

I am following the tutorial on http://truffleframework.com/tutorials/pet-shop I am using Ganache for testing, where i am also deploying the tutorial contract. 1) TestAdoption "before all" hook: ...
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votes
1answer
116 views

How to get decrypted transaction data in quorum?

On Quorum_Node1 I am sending a transaction with privateFor: parameter as follows: eth.sendTransaction({from: eth.accounts[0], to: "0xca84356...9a3d0ccf92b8e", data: web3.toHex('sample message for ...
0
votes
1answer
536 views

geth mining on 32bits host (raspberry pi) memory error

My objective is to create a private testnet, and mining it on a 32bits hardware (RPi3). The memory error I keep getting during DAG generation, if Im not mistaken, is excepted if I am running it on a ...
0
votes
1answer
276 views

Why do exchanges maintain their own wallet?

On a crypto exchange, I transferred 1 ether from my account with let's say wallet A to my friend's wallet B. When I searched for my friend's wallet B on etherscan.io to see the transaction, the sender ...
0
votes
1answer
124 views

Synchronous call of external contract function in Solidity

I have two Solidity contracts, where contract Caller depends on a second contract Callee. Contract Callee provides a public view function which checks the validity of a string (e.g. an password), ...
0
votes
1answer
388 views

How do you estimate the gas cost of any arbitrary function in Remix IDE?

I've found plenty of information on how to do this using Truffle and Web3, but nothing regarding how to achieve this in the Remix IDE. Examples would be very much appreciated.
0
votes
1answer
276 views

How to add peers to a private blockchain network without using IP address?

I have created a private blockchain network and added peers to that network using the admin.addPeers() command. But the problem is, in that method I have to give the local IP address of the system ...
0
votes
1answer
3k views

How to upgrade geth to version 1.7.3? [closed]

I am trying to update geth. I have followed this guide: https://ethereum.stackexchange.com/a/2088/4575 When I do: git pull: I have face with following error. From https://github.com/ethereum/go-...
0
votes
1answer
841 views

GETH ~ why do i get ERROR: no space left on device

While downloading blockchain im getting this error Fatal: Error starting protocol stack: write /root/.ethereum/geth/chaindata/230944.ldb: no space left on device how this can be resolved? Im ...
0
votes
1answer
549 views

Cannot connect to testrpc

I have a testrpc running on a virtual machine (Ubuntu 16.04) and it works properly when I interact with it using the truffle console. My only goal is to call a smart contract that simply sends ether ...
0
votes
1answer
79 views

Unable to input address[] parameter in remix

I need help for deploy below smart contract on remix IDE. I have facing a problem as I need to input to 'setgrantaddress' as address[], How to input data in it? There is two file name owned.sol and ...
0
votes
1answer
195 views

What exactly is Ether currency in Ethereum? [duplicate]

What is exactly Ether currency in Ethereum? Is it a token or a set of some functions that generate some tokens? If so, how many of those functions exist and what do they do? Are they hardcoded in the ...
0
votes
2answers
1k views

How add accounts to web3.js

I'm using web3.jp 1.0 How to connect (log in) my existing account (for example, created through myetherwallet) to make a transaction or call contract? As I understand it, the list of accounts is ...
0
votes
0answers
519 views

“callback contain no result Error: Error: base fee exceeds gas limit” when call selfdestruct function (using Remix IDE)

I'm testing this simple contract. All the functions works well, but when I call the kill() function I'm getting this error: callback contain no result Error: Error: base fee exceeds gas limit I'm ...
0
votes
1answer
17 views

Define “difficultyHardforkTransition” parameter?

I have looked through all of the glossaries I know of for genesis/chain spec files but I don't see this one. Can anyone tell me what "difficultyHardforkTransition" means?
0
votes
0answers
36 views

Web3 & Solidity - Automatically read ABI and Create Contract

Is there a way to automatically create a new Solidity Contract - from within a web3 JS file using the .json file created in a project's build folder after each compile? I have already figured out how ...
0
votes
1answer
165 views

Getting TypeError: Operator == not compatible with types int_const 1000000000000000000 and address payable

I am trying to use external modifier however I getting error as below code. { require(block.timestamp < start + buyPeriod); require(1 ether == msg.sender);<--- error got here ...
0
votes
2answers
49 views

Where the Smart Contract deployment charges goes?

I'm newbie to Ethereum, and finding answers of some questions that I have. I have learned about SC deployment that deploying the contract cost 0.01072934 ether, or about $3.21 USD So, where that cost ...
0
votes
2answers
26 views

Oraclize: Mismatching queryId and myid

I have the following contract that uses Oraclize: contract Test is usingOraclize { bytes32 public query; mapping (bytes32=> address) senderAddress; address public resultAddress; function ...
0
votes
0answers
24 views

how I can add a new account to the web3 object to run contract functions? (from specific sender)

** this is my previous post : web3.eth.accounts.wallet.add(account) not working what I have tried? -1: web3 = new Web3(new Web3.providers.HttpProvider(connectionString)); const account = await ...
0
votes
2answers
493 views

Why is string getter returning an empty response?

This is a sequence of another question I asked. I have the following contract contract User { string publicKey; function setPublicKey(string _publicKey) onlyOwner { ...
0
votes
2answers
315 views

truffle-contract error: Number can only safely store up to 53 bits

I am using truffle-contract with a local quorum node and try to execute a smart contract method, but getting this error: Error: Number can only safely store up to 53 bits That's the way I do it: ...
0
votes
2answers
527 views

Public struct array variable getter

I create a struct array and map it to an address: contract MyContract { struct something { bytes32 test1; bytes32 test2; bytes32 test3; } mapping (address => ...
0
votes
1answer
234 views

How do I export ethereum blocks with quickblocks to a JSON file?

I am looking for how to export or save data from ethereum blocks in a json file using quickblocks.
0
votes
1answer
32 views

Error: Member “func” not found or not visible after argument-dependent lookup in address

I am trying replicate the program given at the following link: What is a function Selector However, I am not using the function selector. I am using the name of the function explicitly to invoke it ...
0
votes
1answer
936 views

Hash of the transaction VS Transaction Hash or Transaction ID

I just want to be sure I understood well how each of them are generated. I'm a bit confused because of the similarity of the names and because I couldn't find in the yellow paper how the transaction ...
0
votes
0answers
51 views

Problem in creating genesis

Which folder to save the genesis specs into? (default = current) Will create puptest.json, puptest-aleth.json, puptest-harmony.json, puptest-parity.json puptest.json INFO [06-07|15:00:08.253] ...
0
votes
1answer
2k views

getting error nonce too low , but nonce is proper stuck since one day

I am working with web3.js since sometime now , but now i am stuck with nonce too low error , the nonce is proper also i have checked private key and other addresses , they also seem to proper , ...
0
votes
1answer
399 views

Ethereum light node: Light vs Cache vs fastsync

There are many different options when running a Ethereum node. I want to make sure I pick the right options before I start downloading the blockchain... can someone explain the advantages of using: —...
0
votes
2answers
1k views

Returning dynamic array not works

I'm trying to build a function that, when called, returns a mapping as two different array. The problem that I have a mapping (address => uint) content2view and I have to get this value outside ...
0
votes
0answers
31 views

Web3 Websocket Connection To Infura Rinkeby Ropsten

This is my Javascript code. I keep getting an error that states (node:30062) UnhandledPromiseRejectionWarning: TypeError: privateKey.startsWith is not a function I am using node 12.1.0 & ...
0
votes
1answer
45 views

How to connect with Metamask and Smart contract?

I am ready with my frontend design. I have only 3 files HTML, CSS, and JAVASCRIPT. So, I didn't create any project or DAPP to have other files. Now next step is to connect with metamask and smart ...
0
votes
1answer
681 views

Unlock remote account

I have smart contract deployed that accepts funds (via fallback function function() payable { ... }). Also I have frontend using web3 to send funds. When I tested it with local node (and JSON wallets ...
0
votes
1answer
228 views

Comparison of Metamask vs Ganache [closed]

I watched some videos about Metamask but I am so confused by it Metamask: To use the final application like the end user would. Based on that, what is the purpose of React then? What are the ...
0
votes
1answer
453 views

I don't see “Start Mining” option?

I just installed Ethereum wallet, but I do not see the Start Mining option in the menu. What am I missing?
0
votes
1answer
357 views

Create a faucet for Ethereum Private network to get Ethers

I have came up with a private ethereum network. I was able to do the transactions and contract deployments. The funds for all the nodes were specified in genesis. But I need to get a way to send any ...
0
votes
1answer
213 views

Deploying and calling a contract works only with Ganache (not with Geth)

I deployed a HelloWorld contract using web3j and it worked awesome with Ganache. I was able to call my only function from the contract and it returns the desired result all the time. When I deploy ...
0
votes
1answer
303 views

Truffle will not compile contract written in VS code. Pragma error

I'm trying to run example from https://truffleframework.com/tutorials/pet-shop, but when I run truffle compile I get error saying Error parsing C:/WINDOWS/system32/TruffleTest/pet-shop-tutorial/...
0
votes
1answer
114 views

Mist hash Identicon

Upon finding this thread How are the account "pictures" used in Mist generated? I tried to use this version of blockies to generate the identicon based on a wallet/contract hash Although i ...
0
votes
1answer
2k views

How to quickly check Ethereum Hashing Speed?

I have 4-5 different GPUs with me. What would be the easiest way to quickly run a Hashing Speed Test on those cards assuming I already have the Drivers for them installed?

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