All Questions

1
vote
1answer
27 views

How to compile Solidity ^0.5.5 contract with Node.js?

I am terribly new in Solidity and now I try to learn how to compile a contract in Solidity ^0.5.5 (No versions below). I have the contract as follow (UsersContract.sol) pragma solidity ^0.5.5; ...
2
votes
0answers
39 views

Solidity get return variable from a send method in React

I'm trying to call a method that pushes data to my Blockchain and then returns back the ID of the new struct I created. This is how I'm calling the method in my React code: const documentId = await ...
0
votes
0answers
23 views

Solidity and mongodb

Hello I have to create dapp, and more specific I want to create something like store where people can create items and sell them. The problem is I want to keep information about the items offchain (...
1
vote
1answer
25 views

Ethereum wallet Vs Ethereum account?

I created an Ethereum node (geth) and this automatically created an Ethereum account. Is this account an Ethereum wallet? I then created 2 other accounts using personal.newAccount() command. Are these ...
0
votes
0answers
29 views

Release / Debug build generated json-rpc calls are different

I'm trying to make simple web3 calls in React Native with web3.js, but generated json-rpc calls are different between release / debug builds - IOS/Xcode. Expected behavior const web3 = new Web3(`...
0
votes
1answer
10 views

does the transaction trie include the contract internal transactions?

Does the transaction trie include the contract internal transactions besides the transactions collected from the network? if not, how the contract internal transactions are handled in the EVM and ...
0
votes
0answers
14 views

Inconsistency after restarting EthereumMiner, using AWS Blockchain Template for Ethereum

I have deployed the AWS Blockchain Template for Ethereum stack (the ECS version). There is 1 miner and 2 clients (default stack). I realized that I don't have access to the default accounts set in the ...
1
vote
1answer
23 views

Solidity Vs Vyper

What is the key differences between Solidity and Vyper? In present and future which one can more acceptable for making smart contracts and why?
1
vote
1answer
14 views

Augur, publicBuyCompleteSets reverts

I'm building a contract function that purchases and distributes complete sets of AugurShares for a specific market. (Testing on Rinkeby). Version of Augur-core (node_modules/augur) used: https://...
0
votes
0answers
13 views

Verify transaction was included in certain block within smart contract

Is there a good resource for proving that a particular transaction was included in block x?
1
vote
1answer
20 views

Method to verify an address nonce within a contract?

Hey I'm looking for a simple way to verify that a certain address has executed x number of transactions? I noticed that this can be accomplished by having them deploy some contract and verifying ...
2
votes
1answer
15 views

Second price auctions for more stable transaction fees

Why does Ethereum not use a second price auction for setting transaction fees? This would protect users from paying too much by mistake and lead to more stable and predictable fees for everyone. ...
1
vote
0answers
18 views

What are the drawbacks of layer 2?

The scalability trilemma states that a blockchain can only have two out the following three properties: decentralization, scalability, and security. Layer 2 protocols aim to make Ethereum more ...
0
votes
0answers
11 views

How can I better set up automatic sending of ethereum from the first address to the second address when I receive any amount for the first one?

I use Node.js. Every 5 seconds I check the address balance using the function eth.getBalance. When I receive funds to the first address, the function of transferring funds to the second address is ...
-1
votes
0answers
16 views

Flask - Smart Contract Example [closed]

I am new to blockchain technology and I am looking for a smart contract implementation example using flask. Any leads will be much appreciated.
1
vote
1answer
35 views

Deploying Contract with Quorum Web3j response: Non-200 status code

SCENARIO: I have the following code: final String hostUrl = this.deployerProperties.getProperty("quorum.host.url"); final String hostPort = this.deployerProperties.getProperty("quorum.host.port"); ...
1
vote
2answers
19 views

How are transactions stored in a block?

In State, use Merkle Patricia Trie for storing data. "key value" is account address(hash value). And also, Ethereum block uses MPT for storing transactions. However, Additionally Ethereum Block use ...
0
votes
1answer
24 views

Is there any Reentrancy attack in given code snippet? If yes then how can I fix it?

function withdrawForeignTokens(address _tokenContract) onlyOwner IsAuthenticate public returns (bool) { ERC223Interface token = ERC223Interface(_tokenContract); return token.transfer(...
0
votes
0answers
6 views

Can we compare some of decentralized exchanges? [closed]

among the top decentralized exchanges, I almost use KyberSwap and Bancor. I would like to hear your options when you choose the exchange to trade. Many thanks!
0
votes
0answers
31 views

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

Contract fail to compile in IDE Remix.due to the following error: TypeError: Data location must be "storage" or "memory" for parameter in function, but none was given. version:0.5.6+commit....
0
votes
0answers
12 views

How to completely empty an Ethereum wallet using W3.py

I have an ethereum wallet, I need to calculate the amount to completely empty the wallet. So currently i calculate the needed gas like this, needed_gas = w3.eth.gasprice * 210000 amount_to_send = ...
-2
votes
0answers
21 views

Error: Type “mapping(string => string)” not supported for state variable.\n\tmapping (string => string) dataLink; [closed]

My work is in terminal. First i install the solidity compiler by $ sudo npm install solc@0.4.11 $ node ...
0
votes
0answers
5 views

geth implementation [closed]

Can anyone tell me how do I know about geth implementation or can someone give me pointers to how do I start learning about the project I do know how to use it but now want to actually dig deeper ...
0
votes
1answer
22 views

how can we know the address of the peers in Private ethereum block chain to send the transactions

Hi iam new to private ethereum block chain and geth. Can anybody suggest me how can we know the receivers address to send the transaction using geth console on sender side?
1
vote
1answer
49 views

Is it possible for a smart contract to relay raw signed transaction

I am rethinking the flow for token transfer and confirmation on the network (ERC20,ERC721...). I am unaware of a way presently to: 1- transfer tokens and 2- trigger a call in different contract, ...
0
votes
0answers
28 views

I am having the following error while testing my Newcontract using truffle test command. I am using the latest version of solidity and truffle

C:\Users\Dreams\Newcontract>truffle test Using network 'development'. Compiling your contracts... =========================== > Everything is up to date, there is nothing to compile. C:\Users\...
0
votes
0answers
20 views

Not storing Item in variable

I am working on making a game where users can collect items. I have chosen to store the ERC721 tokens that represent the items in this way: Item struct: User struct and map that maps account-...
0
votes
0answers
19 views

Calling an API from truffle [closed]

Is it possible to call an api from a truffle test file? I have developed a nodejs app with koa that directly interacts with my SC. I now want to test this API. I have built a test for a usecase of ...
0
votes
0answers
26 views

Import Ethereum Privatekey

can we able to use ethereum balance using its privatekey.? is there any android application ( except trust wallet ) or a website on which we can inport our ethereum privatekeys and use balance ? I ...
0
votes
1answer
28 views

If one gains 51% of network resources can he force drain the biggest wallet? [duplicate]

If one gains 51% of the network compute resources can he force drain the biggest wallet? How could he do it if he can keep that 51% advantage?
0
votes
0answers
25 views

Help learning contract testing [closed]

Hi im new to the smart contract space and i would appreciate it greatly if anyone could refer me any good materials which i could use to learn smart contract auditing and testing. Thanks.
0
votes
1answer
23 views

What DSAuthority(0) and eos.owner() means and does?

In ERC20 EOS crowdsale contract, what these three lines(469-471) does? function initialize(DSToken eos) auth { assert(address(EOS) == address(0)); //[Someone explained this line here][...
2
votes
1answer
21 views

Would a 51% attack be easier if an attacker can DoS certain nodes?

I am wondering whether a 51% attack would be simplified by being able to remotely crash miner nodes. Consider the following scenario: Malicious mining pool A controls 16% percent of the mining power ...
0
votes
1answer
37 views

Difference between window.ethereum and window.web3?

If I log the two functions, I get two objects, that both contain for example selectedAddress, but the structure of the objects seem different. I couldn't find a comparison in the documentation. I ...
0
votes
0answers
23 views

Metamask not connected with web3.js

if (typeof window.web3 !== 'undefined') { web3 = new Web3(web3.currentProvider); } else { // set the provider you want from Web3.providers window.web3 = new Web3(new Web3....
0
votes
1answer
15 views

truffle test get different results between ganache-cli and local geth

When I run truffle test on ganache-cli, it will pass the test but when I run the same truffle test commnad on local geth node, it will fail with error saying invalid address at the method which takes ...
1
vote
1answer
15 views

Parity: if I don't include --no-ancient-blocks will it download blocks all the way back to genesis (after the initial sync)?

In other words, if I have less than 1.5TB to play with, is --no-ancient-blocks essential?
0
votes
2answers
22 views

Getting error in truffle migrate

I am trying to compile a sample solidity contract,sampleapp.sol. The code is given below: pragma solidity >=0.4.21 <0.6.0; contract SimpleStorage { uint storedData; function set(uint ...
1
vote
2answers
17 views

How can I read/write ethereum as a database by python code? [on hold]

I am a startup in this domain. I see some article about Ethereum could save data as a contract. But they are too complex to me. If I already have an Ethereum account with some ETH. Is there some ...
0
votes
1answer
27 views

Metamask not connecting to localhost “7545”

After following the pet shop tutorial i cant connect my localhost to the metamask wallet i'm still get 0eth in my wallet whereas it should be 99eth after connecting. The metamask is not showing it as ...
0
votes
0answers
16 views

Private Chain Gas Zero [duplicate]

Is there a way to make transactions costless on a private Ethereum network? I am already limiting who can interact with the deployed smart contracts and who is a member of the network with code. I ...
0
votes
0answers
20 views

Anonymous Coinbase Transaction

Is there any solution to have anonymous coinbase transaction in ethereum or other Cryptocurrency? Something like using coinjoin for coinbase transactions or something else.
0
votes
1answer
14 views

Different synchronization types

What are the different synchronization types for an Ethereum node? Which of them are client-specific (Geth, Parity)?
0
votes
1answer
25 views

How are new users authenticated into Quorum network

I could find from online readings that Quorum has a Network Manager component that controls nodes access to network to created permissioned network of nodes. But, I couldn't see explanation on how ...
1
vote
1answer
20 views

Check Augur market validity in solidity contract

I'm trying to validate my market created through my node on Rinkeby Testnet. I created some markets on Rinkeby Testnet (using Augur.js) running my own Rinkeby Augur node. When I get the markets ...
0
votes
1answer
17 views

Cannot read property 'hexToAscii' of undefined

deployedContract.deploy({ data: bytecode, arguments: [listOfCandidates.map(name => web3.utils.hexToAscii(Rama))] }).send({ from: '0xfb9286cde20bbd5ed60ee3bb156f9d9938c5b151', gas: 1500000, ...
1
vote
1answer
14 views

Full node disconnected in a whole country

Why is it important to have at least a few full nodes running in a specific country? Does e.g. Spain have any advantage to run ETH full nodes? Thank you.
0
votes
0answers
17 views

Api do not return response with promise handling, works without it

I have already deployed ethereum private blockchain network on linux and on windows 10, but api's do not return response. For example contract.methods.freezeAccount(address,tempStatus).send({from:'...
0
votes
0answers
19 views

Quorum issue calling external function [closed]

Some incidence is known in Quorum that make not able to call function from external contracts?? I mean, having a contract A with a function. The A contract is imported inside the B contract, there a ...
1
vote
0answers
9 views

Synchronisation failed, dropping peer valid and Impossible reorg

I'm working on a project called Rubykube Workbench. But the "ethereum/client-go:Stable" container gives error. System information Geth version: 1.8.23-stable-c9427004 (docker container) OS & ...

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