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8 views

Can we add block reward contract in parity aura latter on

We know there is an option to add a block reward contract to incentivize authors of new block by using blockRewardContractAddress at chain engine specs. Is it possible to add this property in the ...
0
votes
1answer
32 views

web3 - web3.utils.toHex zeros length

I'm trying to send 12 integer as bytes to a contract function. If I use web3.utils.toHex(12) the variable will become 0xc The problem is that when contract function parses bytes, it reads uint256, ...
0
votes
1answer
22 views

Web3.py cannot connect to geth --dev node via IPC

I've launched a geth client over IPC: geth --dev --allow-insecure-unlock --ipcpath ipc://$HOME/Library/Ethereum/geth.ipc And trying to connect using a Web3 IPC provider: my_provider = Web3....
0
votes
0answers
26 views

web3 update monitoring

Inside a DAPP, I have been using web3.currentProvider.publicConfigStore.on('update',... to monitoring Metamask activity. But in the new metamask-mobile such method does not exists. There is a ...
1
vote
2answers
28 views

ERC20 not recognized by TokenTracker

I have deployed ERC20 with reference to // File: openzeppelin- zos/contracts/token/ERC20/DetailedMintableToken.sol I called the initialized function with owner, name, symbol and decimal value. ...
0
votes
1answer
15 views

Geth + Web3 | web3.eth.getAccounts() returns undefined

I have follow this SO answer for sending ERC20 tokens from 1 address to another. I am running into an issue where I am receiving an error that my from address is invalid Error: Error: ...
0
votes
1answer
23 views

Combine BytesX and BytesY to create BytesZ?

I am working on a Solidity Smart Contract (^0.5.10) where I want to return an array of Ratings elements. struct Ratings { address restaurant uint8 score }; Since returning Rating[], string[]...
1
vote
1answer
23 views

How to call a function with params and check them

I want to create a smart contract that users can send a number to and receive an amount of ether. function airdrop(uint val) public payable { require(airdrop == true); if (val == 0x31){ ...
0
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0answers
28 views

How to connect to MetaMask via web3js

I'm trying to recreate this site TenThousandSu And this is the smart contract I'm trying to call https://rinkeby.etherscan.io/address/0x7e338acfb7a5d7e99f4225cc12dc884f49c00f6a#code I'm using "1.0....
0
votes
0answers
16 views

What is the limit of IPC in Geth?

What is the maximum size of the IPC file in ethereum? Are there any way to increase its size?
0
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0answers
25 views

web3.utils.toHex but combined, hex concat?

I'm currently working with bytes in Remix. The goal I wanted to achieve was to put variables into bytes in one function, copy bytes, paste bytes to another function as a parameter and unpack these ...
0
votes
0answers
11 views

How to fix gas estimation failed error while getting random number from Provable Random DS?

I'm using Provable for getting a random number and I am using following code snippet from their github: https://github.com/provable-things/ethereum-examples/blob/master/solidity/random-datasource/...
0
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0answers
9 views

Web3.providers.WebsocketProvider — timeout and other network specific stuff

I'm looking here: https://web3js.readthedocs.io/en/v1.2.0/web3-eth-personal.html#providers This works fine for me, however I'm wondering how to specify things like timeout and other networks ...
0
votes
1answer
24 views

Has ERC20 mining been disrupted?

Do you know why a single address of type contract is mining 38% of 0xbtc? Does it mean that a single person has find a way to mine as much 0xbtc as a whole mining pool? Plus how come a contract is ...
1
vote
1answer
30 views

Possible to get enum length / count in solidity contract?

Is it possible to access the length of an enum in solidity? E.g. pragma solidity >=0.4.16 <0.6.0; contract test { enum ActionChoices { GoLeft, GoRight, GoStraight, SitStill } function ...
0
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0answers
28 views

web3 - Can I call a library function without a contract?

I have a library which contains a function concat - it can merge two bytes. I have deployed a contract which uses that library and it works. I would like to make a simple bytes builder on my website. ...
1
vote
1answer
38 views

Vyper mapping inside a struct

Is it possible to have a mapping inside a struct for vyper? For example: struct Teddy: id: uint256 year: uint256 component: map(uint256, uint256) teddies: private(map(uint256, Teddy)) ...
1
vote
0answers
38 views

Dapp with Authentication System

I know this question has been already asked many times, but I haven't got any satisfiable answer and so asking here. I want to create an Authentication system dApp using reactjs. The user is having ...
2
votes
3answers
105 views

How smart contract transactions work?

I read that smart contracts don’t have a private key, so they can’t sign a transaction. My question is: when a smart contract starts a transaction to an EOA, how are we sure that the smart contract ...
3
votes
1answer
43 views

What are remappings and how do they work in solidity?

How can they be used with solc?
4
votes
1answer
109 views

What is SMTChecker used for in Solidity?

From the solidity docs: If you use pragma experimental SMTChecker;, then you get additional safety warnings which are obtained by querying an SMT solver. The component does not yet support all ...
4
votes
2answers
47 views

Verifying a Token Contract with Interface

I managed to deploy a token contract with interface on Kovan Testnet. Now I wanted to verify the code. However this is a bigger problem than I thought. The contract got successfully deployed to: ...
5
votes
1answer
50 views

When should I use calldata and when should I use memory?

I have seen people use both memory and calldata keywords when writing Solidity. Specifically, they are used when declaring function parameters. When should I use memory and when should I use calldata?...
0
votes
1answer
32 views

How big is the Geth Fast Node Currently?

I am trying to embark on getting all the contract addresses pulled from the Ethereum blockchain. From what I read, a fast node is all that is required for this (getting blocks->txns->contractAddress ...
0
votes
1answer
22 views

How to extract or create a message with web3.js to sign with an external hardware device?

I'm using the Web3 library. I want to extract a signature hash from a Web3 transaction to send to an external hardware device, sign it there, then use the signature I get from there to broadcast my ...
0
votes
2answers
41 views

Am I Generating Random Numbers In A Non-Mallable Fashion?

Would this be a non-malleable way to generate numbers for my particular use case? Let me explain: I allow people to register for a lottery-type event. If a winning seed belongs to their ticket set, ...
0
votes
1answer
18 views

Setting methods permissions a quorum network

I have 3 solidity smart contracts that run in a quorum network with 7 nodes. At the moment i use the constructor to set the owner of the smart contract, that is the node that deployed it. ...
0
votes
2answers
19 views

Truffle migration script does not make transaction

Please look at my simple example below. Is migration script 3 being executed, such that it sets the value on the blockchain -- I think not, because there is no speak about a txHash or cost... How to ...
2
votes
0answers
18 views

Is the contract metadata automatically deployed to Swarm?

From the solidity docs on contract metadata: You have to publish the metadata file to Swarm (or another service) so that others can access it. You create the file by using the solc --metadata ...
2
votes
1answer
37 views

How to divide and allocate the amount to token holders without loops?

I have a smart contract that keeps record of the people holding the tokens in form of array of addresses. An owner of the smart contract, whenever, sends some ethers to the contract these ethers shall ...
0
votes
1answer
12 views

How to deploy a DAO on Ethereum?

Want to deploy and operate a Decentralized Autonomous Organization (DAO) on Ethereum. What are my options?
0
votes
3answers
55 views

How to build a decentralised Voting Website without using any 3rd party extensions like Metamask, or IDEs like Remix? [closed]

I've gone through various Blockchain Tutorials but everywhere it's one or the other same thing. Download truffle/ganache, from 10 free testrpc account, use one, use metamask, Remix IDE etc, and Voila!...
0
votes
1answer
28 views

How get private key or password from my keystore [duplicate]

I had wallet from 2016, but i'm forget password login by keystore. Current i just had keystore, how i can get private key or password keystore? Thank so much
0
votes
1answer
39 views

Filters object not working for web3.eth.contract getPastEvents() method

I have referred, Web3 Events, but filters object is not working for me, I've got the same result for events before and after applying filter object. Here's the code: instance.getPastEvents( "...
0
votes
1answer
26 views

Gas estimation errored using ERC20 in REMIX

I'm trying to test making some smart-contract that uses DAI ERC20 tokens on Kovan testnet (DAI contract on kovan is 0xc4375b7de8af5a38a93548eb8453a498222c4ff2). I developed this very simple contract ...
0
votes
1answer
46 views

How to connect with WebSocket with Web3?

Already referred web3 documentations and other Q-A for web socket connection. Currently using infura as provider.
-2
votes
2answers
23 views

ERC721 - How to create many ERC721 tokens at a time

Is it possible to create many ERC721 tokens at a time? I saw this link. ERC721 - Create 1000 tokens in one function call But I don't get it. Please help me.
0
votes
1answer
23 views

is it possible triggering a contract on specific date? [duplicate]

Can I trigger a smart contract on specific date? If I deploy a contract today and I want execute some function of that contract tomorrow without any exteral intervention. Is it possible?
0
votes
1answer
21 views

Not getting getPastEvents or once function using contract instance

I have followed Web3 documentation to subscribe an evnet, I have created Instance of web3 using infura url as argument. Created contract object using, const contract = web3.eth.contract(abi, ...
0
votes
3answers
42 views

How do I make a smart contract send a message to a user along with a transaction?

Smart contracts can obviously send transactions through the Ethereum network but can they also send a simple message along with the transaction? Usaully you would put the message into hex code in the ...
2
votes
2answers
36 views

Drizzle and Contract Instances

I am currently developing a dApp with Drizzle on top of ReactJS. My project consists of, basically, 8 .sol files. 4 of them are just abstract contracts that include the functions, structs etc. for ...
0
votes
1answer
20 views

EVM Stack - number of elements

The words in the stack are 256-bit, therefore 32 bytes in hexadecimal representation. The Ethereum Yellow Paper states “the stack as a size of 1024”, although it does not say what (bits/words). A ...
1
vote
1answer
18 views

Are there identifiers for smart contracts?

Say I want to reference another smart contract in my smart contract. Do smart contracts have an identifier (like a number 0xjdjdjdjdjjddj etc.)? And if they don't, how would you reference a ...
1
vote
2answers
42 views

Get All Contracts from Blockchain

I am developing a large database of exploitable contract addresses and creating a website to host such a database for users to use to see if contracts are safe. Is there a way to get all contract ...
0
votes
2answers
22 views

Does a transaction that consumes the block gas limit take an entire block by itself?

Does a transaction that requires the entire block gas limit to be executed (currently ~8M) take the entire block by itself? And if that's true, will that transaction take longer to get confirmed than ...
0
votes
0answers
28 views

Send ERC-20 token using Web3j

What is the best way to get balance and send ERC-20 token using web3j?
0
votes
2answers
30 views

truffle migrate fails silently

I'm trying to deploy a truffle project to testnet. When I run truffle migrate --reset --network rinkeby --verbose-rpc, this is output: You can improve web3's peformance when running Node.js versions ...
1
vote
3answers
29 views

Ethereum as a private network is possible? [closed]

can i deploy a private network like the way it does other private blockchains with Ethereum ? and the test networks in Ethereum only work for public right or can i deploy it there ?
2
votes
1answer
26 views

How to reach to one chain when hard fork is performed?

Assume that reward policy of Ethereum is changed from 3eth to 1eth. Hard fork is ongoing but, there are miners who don't consider updating their software. what happens? The miner who did update ...
1
vote
2answers
72 views

How to build the seamless bridge between two blockchain platform?

How to build the bridge between two different consensus blockchain platform? use case: 1.we need to ensure visibility of the transaction in both platforms to assure its integrity When a smart ...

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