Questions tagged [blockchain]

The Ethereum blockchain is a distributed database based on the Ethereum whitepaper specification and stores both the full transaction list and the most recent state.

Filter by
Sorted by
Tagged with
0
votes
0answers
7 views

Run dapp in mobile metamask browser

I am having a dapp which is working perfectly in web browser using metamask wallet.Now I want to test my dapp in mobile browser using metamask mobile wallet. I tried to make transactions in BC using ...
3
votes
0answers
17 views

Difference between Ethereum Web APIs and Ethereum API as a service

I am approaching ethereum for the first time and I am reading the documentation. Can anyone explain the difference between Ethereum Web APIs (BlockCypher) and The Ethereum API as a service (infura)? ...
1
vote
1answer
60 views

How Do Sniper Bots Really Work?

If you ever traded in defi, you probably have seen coins getting sniped at the very second of their launch and drastically inflating the prices. I assume these bots are written in js, ad using web3 ...
0
votes
0answers
25 views

What is the theoretical average latency of data transmission?

I concluded a pretty simple test to measure some latencies. I connected to two providers (Infura and Quiknode) with Web3.js and subscribed to new block headers. Then I compared the time of arrival and ...
0
votes
0answers
22 views

differences in terms of api supported by full node vs light node

Are there any differences on the API supported by full node vs light node in Ethereum?
0
votes
0answers
18 views

Solidity Ethereum Errors

I am new to solidity and I have been spending hours trying to figure out what was wrong but I still can't find it. Any help would be appreciated. pragma solidity ^0.5.10; contract ...
0
votes
1answer
19 views

When all the BitCoins are mined, how the next transactions can be done? [closed]

I know that the BitCoin miners are trying to solve the POW puzzle to get rewarded. They are rewarded since they introduce new blocks to the blockchain and as a result, they can pack new transactions ...
2
votes
1answer
28 views

What kind of node use for Ethereum development?

I am working with ethereum and to connect my backend to the blockchain I use an ethereum node: full node or a light node. I was asked a question but I didn't quite understand how to answer. The ...
0
votes
0answers
19 views

Architecture of an oracle

I am building the architecture of an oracle-based blockchain (ethereum) system. Is it correct to represent the oracle in this way?
0
votes
1answer
18 views

In a dapp application who listens to events?

In a dapp application who listens to events? the geth node or my node.js component (backend component? How can I implement the listen function in web3.js?
0
votes
0answers
12 views

How to solve this error: “Cannot read property 'address' of undefined”?

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'address' of undefined TypeError: Cannot read property 'address' of undefined This is my code that uses web3.js: public getContract(...
1
vote
1answer
43 views

Which component sends a transaction and which component subscribes to an event?

I am working on an ethereum project but I have some doubts. I have a backend that connects to the blockchain via web3.js. To connect to the blockchain I use a geth node. I understand that the sequence ...
1
vote
0answers
24 views

How can i update the status of the blockchian?

How can I update the status of the blockchian? I issue a transaction and pass an id to the smart contract. Smart contract A retrieves data from smart contract B and uses it to check whether a ...
0
votes
0answers
12 views

smart contract transaction error [closed]

so in my earlier question asked, i stated i had accidentally sent some funds (674.2 VRS) well someone hacked me i guess.... but anyways some how "I" sent these funds to an unkown address and ...
0
votes
1answer
14 views

How can I create a similar application to YouTube on Blockchain? What is the cost of it?

How can I create a similar application to YouTube on Blockchain or as a smart contract? What is the cost of it?. I am keen on picking it up as a project. Thank you!
1
vote
0answers
6 views

Regarding orderer container [closed]

I am trying to setup multi channel network, every thing was working fine except my Orderer was getting exited immediately. As there is no Orderer I could not proceed further. My setup consists of 3 ...
0
votes
0answers
6 views

How do I use in3 (Incubed) for Bash to view ethereum records for a given address?

I want to be able to query an ethereum contract address that I know is valid with the in3 module in bash. I have installed Incubed (in3) for bash), and I have used this documentation to try to query ...
0
votes
1answer
27 views

I would like to become a blockchain developer [closed]

I would like some advice before deciding to become a blockchain developer. Any comment would be really appreciated, thank you in advance.
0
votes
2answers
17 views

can we create our own cryptography system and use it with ethereum or hyperledger fabric frameworks?

i have a project where we have to build a fuzzy encryption for biomedical data like DNA and use it on blockchain for storage. So is it possible to create our own cryptography scheme on Ethereum and ...
0
votes
0answers
30 views

Uniswap fork: remove liquidity error

I am trying to fork uniswap. And I have a problem when liquidity is removed. Problem in UniswapERC20. I don't know what's wrong. Step by step (repeatedly for Rinkeby and Ropsten): Copy Uniswap ...
0
votes
0answers
11 views

“Getting AGE/TIMESTAMP of a Pending Transaction from a Transaction Checker”

Can I get TIMESTAMP of a pending transaction as soon as it's added to etherscan.io recent transactions list? I'm using GETH and WEB3 for a transaction checker and it's fetching me recent pending ...
1
vote
1answer
20 views

Solidity - Proper way to Import Contracts

When importing one Solidity contract into another, what’s the difference between importing it and accessing it using the is keyword, vs. importing it and just instantiating an object of it? Here’s ...
0
votes
0answers
13 views

Fork Ethereum (geth source code)

I wanted to Fork geth source code to create my own currency like ethereum but changing the currency name. I want it to be able to carry smart contracts also that's why I am not forking bitcoin. Is ...
0
votes
0answers
19 views

Is it possible to have many users and one EOA? [closed]

I'm working on an ethereum blockchain project where people want to make reservations in a city. Is it possible to have many users who want to make a reservation but a single EOA that collects all the ...
0
votes
0answers
17 views

When is the transaction mined?

I'm working on an ethereum blockchain project where people want to make reservations in a city. My backend sends a transaction to the smart contract with the user id, city and other data. The smart ...
1
vote
1answer
11 views

Is it important to save the transaction ID in ethereum?

In Bitcoin, the data that you want to keep in the blockchain resides in the transactions so it is important to keep the transaction ID. Is it the same in Ethereum? Or is the data saved in smart ...
0
votes
0answers
34 views

I have a problem with the transfer of ownership by a smart contract

I have a smart contract. I own, it belongs to my wallet. I am trying to implement a function to transfer the OWNERSHIP of this smart contract to another wallet. I have two solutions, but for some ...
0
votes
0answers
14 views

Issue with Solidity Payable function?

I get error when I try to call this function AvailableEnergyAdvert with energy_produced greater value > 1. pragma solidity ^0.6.0; import "https://github.com/OpenZeppelin/openzeppelin-...
0
votes
0answers
7 views

How do I pass a dictionary for the in3_registry value for the Incubed Python API?

I am using Python 3. I have installed the in3 (Incubed) Python module. I want to invoke the ClientConfig of the in3 Python API in a specific way. There is an in3_registry argument that is part of ...
0
votes
0answers
14 views

How to get all transactions in ganache-cli that have not been mined yet?

Considering a scenario in ganache where a block is mined every 200 seconds ganache-cli --blockTime 200 how can I get the all the transactions that have been sent but not yet mined?
0
votes
0answers
12 views

Will OmiseGO (OMG) become redundant when Ethereum migrates to Proof of Stake?

When Ethereum migrates to "Proof of Stake" to validate the transactions. Will OmiseGO (OMG) lose its value ? as scalability issues in Ethereum would be resolved after the migration and I am ...
1
vote
0answers
32 views

What does sendSignedTransaction return?

I want to call a method in the smart contract (UpdateWeather) that goes through several steps before returning the result (an integer). I use sendSingendTransaction but I have doubts. Is the ...
1
vote
1answer
88 views

THETA token sent to contract address instead of correct wallet address

By mistake, I sent my THETA token to the contract address instead of my correct wallet address. This is the transaction link on Etherscan https://etherscan.io/tx/...
0
votes
0answers
18 views

Trying to be a validator in blockchain but I have got the error : Mining aborted due to sync

I try to run blockchain in local to be a validator with this command : geth --config ./config.toml --datadir ./node -unlock {your-validator-address} --password password.txt --mine --allow-insecure-...
3
votes
2answers
105 views

What economic incentive does anyone have to mine Ropsten and other networks?

Ethereum 1.0 has a basic limitation, as all global blockchains do: each block can only hold so many transactions. Due to this scarcity, every time even one application gets too popular on the main ...
0
votes
1answer
23 views

Storing multiple values in one key mapping dynamically

I am making a blockchain project using solidity which requires storing various objectIDs corresponding to a personId. The person can add and remove objects and we cannot hard-code the number of ...
0
votes
1answer
31 views

Is it Possible to Prove Who Sent Funds to Particular ETH Address?

I’m building a cryptocurrency marketplace where users mainly buy and sell small ticket items (worth $10 - $50) using cryptocurrency. Typically, the average user will deposit $100 at a time into a ...
0
votes
1answer
39 views

Solidity Contract Invalid Opcode RPC Errors

I have a pretty straight-forward contract that let's you buy ERC721 Tokens. My issue is that my "buyToken" function works half the time - and fails the other half of the time with the ...
0
votes
1answer
16 views

Smart Contract Shared Ownership

Can A smart contract ownership be shared. If No!, is the restriction imposed at the EVM level Otherwise how can shared ownership be achieved.
0
votes
1answer
11 views

Why don't blockchains use simple voting based consensus algorithms?

Suppose we have an malicious agent Bob with account balance of 100 units trying to double spend a coin by broadcasting two messages simultaneously: A: Bob sends Alice 100 units B: Bob sends Emily 100 ...
0
votes
1answer
26 views

My metamask extension is not getting connected to ganache local block chain

This is my Html code : <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> ...
0
votes
0answers
10 views

Does everyone who invested in Pre-ICO get the same rate, once the ICO is over?

I would like to know if all the people who invested in a coin (any coin) during Pre-ICO are all buying at the same rate or at the same price. For instance, during Pre-ICO, A buys today and B buys a ...
0
votes
1answer
24 views

How can I make an asynchronous interaction between two contracts?

How can I make an asynchronous interaction between two contracts? I have contract A and contract B. contract A calls contract B contract B obtains data from an external source contract B returns the ...
0
votes
1answer
32 views

Get ETH Wallet address list (holder list) given a smart contract address (erc20)

I would like to fetch the list of all ETH wallet addresses by an API(?), given a smart contract address (erc20 token address). Similar feature that we see on etherscan.io under the erc20 Holder list. ...
0
votes
1answer
23 views

Smart contract and Oracle contract

I have 2 contracts: my contract and an oracle contract. I make a request to my smart contract and send some data that needs to be processed. I use mySmartContract.methods.availability(value1,value2)....
0
votes
1answer
32 views

How to disable/kill and get funds from a smart contract that I'm the owner?

I have a smart contract that is not being used anymore and still have funds. I would like to withdraw them and destruct or disable it. I didn't write the code but I'm the owner and the programmer ...
3
votes
1answer
17 views

What is the maximum size of string which we can store on solidity?

Is there a limit to the size of a string that we can store on the Ethereum blockchain?
0
votes
1answer
47 views

how can I pass data to my smart contract?

I have a threshold and some data that must be passed to the smart contract. The smart contract uses this data to make decisions. I'm using web3js. how do I pass this data to the smart contract?
0
votes
2answers
245 views

Could not fetch chain ID. Is your RPC URL correct?

I want to connect local ethereum network to metamask , it says that it need chain id but when i entered the chain id for local node it shows the error "Could not fetch chain ID. Is your RPC URL ...
2
votes
0answers
39 views

events and relationships between smart contracts and oracle smart contracts [closed]

How to subscribe a web3j client node to a smart Oracle contract event? Do I need the Oracle contract address?

1
2 3 4 5
39