kandi X-RAY | BlockChain Summary
kandi X-RAY | BlockChain Summary
Dark Horse Programmer 120-day full-stack blockchain development open source tutorial
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I am new to blockchain app development, I saw a project where ganache accounts are imported into Metamask, then web3.js is used to access and print those accounts and balances on Frontend (user interface).
If web3.js can directly access ganache blockchain accounts and balances, why do we need Metamask in between?...
ANSWERAnswered 2022-Feb-08 at 09:11
If web3.js can directly acccess ganache blockchain accounts and balances, why we need metamask in between?
In this case, you don't need MetaMask to sign the transaction, as the node (Ganache) holds your private key.
But in a public environment (testnets and mainnet), the node doesn't hold your private key, so you'd need to sign the transaction using MetaMask (or any other tool that holds the private key).
so I'am trying to learn dart and flutter and everything went well so far. But now I'am stuck at an error which I cannot handle. I coded a function which is supposed to asynchronously return the actual BTC price from https://blockchain.info/ticker.
Only thing it returns is errors:...
ANSWERAnswered 2022-Mar-29 at 00:29
To get rid of that error you need to use the bang operator to tell the compiler that
snapshot.data won't be null.
I am creating a DApp that connects to a smart contract deployed on a local test RSK blockchain (regtest) run by RSKj Java app. I intend to send transactions via Web3 connected to Metamask. In DApp I am getting the accounts list by sending a Web3 request:...
ANSWERAnswered 2022-Mar-25 at 10:34
The first account from the list is referred as a “cow” seed in this file in RSKj. You can take the corresponding private key from there.
Do the following:
- copy the private key
- open your Metamask browser plugin
- import the account
- Account icon in the upper right corner
- Import account
- ‘Paste your private key string here:’
- Set the just imported account as an active one
- Enjoy sending your transactions
I would like to convert my bytes array into a u64.
b"00" should return 0u64
b"0a" should return 10u64
I am working on blockchain, so I must find something efficient.
For example, my current function is not efficient at all.
ANSWERAnswered 2022-Mar-16 at 20:21
I am trying to deploy my SimpleStorage.sol contract to a ganache local chain by making a transaction using python. It seems to have trouble connecting to the chain....
ANSWERAnswered 2022-Jan-17 at 18:17
Had this issue myself, apparently it's some sort of Ganache CLI error but the simplest fix I could find was to change the network id in Ganache through settings>server to 1337. It restarts the session so you'd then need to change the address and private key variable.
If it's the same tutorial I'm doing, you're likely to come unstuck after this... the code for transaction should be:
While trying to set up a basic self-hosted unit testing environment (and CI) that tests this Chainlink VRF random number contract, I am experiencing slight difficulties in how to simulate any relevant blockchains/testnets locally.
For example, I found this repository that tests Chainlinks VRF. However, for default deployment it suggests/requires a free
KOVAN_RPC_URL e.g. from Infura's site and even for "local deployment" it suggests/requires a free
MAINNET_RPC_URL from e.g. Alchemy's site.
I adopted a unit test environment from the waffle framework which is described as:Filestructure ...
ANSWERAnswered 2021-Sep-09 at 04:35
to test locally you need to make use of mocks which can simulate having an oracle network. Because you're working locally, a Chainlink node doesn't know about your local blockchain, so you can't actually do proper VRF requests. Note you can try deploy a local Chainlink node and a local blockchain and have them talk, but it isn't fully supported yet so you may get mixed results. Anyway, as per the hardhat starter kit that you linked, you can set the defaultNetwork to be 'hardhat' in the hardhat.config.js file, then when you deploy and run the integration tests (yarn test-integration), it will use mocks to mock up the VRF node, and to test the requesting of a random number. See the test here, and the mock contracts and linktoken get deployed here
I am very new to blockchain programming and programming in general. I want to generate my SOL address using the mnemonic seed phrase with the derivation path "m/44'/501'/0'/0". I can't find a proper BIP44 module for python where you can specify the derivation path....
ANSWERAnswered 2022-Feb-23 at 00:41
After a long search through the internet, I have finally found a way of solving my problem that I want to share with you.
I am trying to sign a message in
go generated via hd wallet's private key using cosmos sdk. Below is the equivalent implementation in python which generates the signed message / signature as expected when submitted/verified is working properly but unable to get it working wtih
Go implementation. Any inputs for equivalent golang version of the python implementation is much appreciated. Thank you.
Python version uses sha256 , ecdsa but when using the equivalent cyrpto/ecdsa doesn't return valid signature.
ANSWERAnswered 2022-Feb-20 at 14:48
Both codes return hex encoded as private key
Am starting off in blockchain development using the book Mastering Blockchain - A deep dive into distributed ledgers, consensus protocols, smart contracts, DApps, cryptocurrencies, Ethereum,
Am using WSL with geth version 1.10.9....
ANSWERAnswered 2021-Oct-11 at 23:20
It appears 1.10.9-stable version has a problem and is returning a -rpc error. GETH 1.10.8-stable version works fine when running the geth command with --rpc
I tried all that you mentioned in the discussion here (in other questions) and at https://github.com/smartcontractkit/full-blockchain-solidity-course-py/discussions/522 , however it is not solving the issue for me, I also noticed that the current compiler version remains (current compiler is 0.6.12+commit.27d51765.Windows.msvc). But when I right click and select Solidty:Compiler information, it shows 0.8.0.
ANSWERAnswered 2022-Jan-02 at 03:09
i had the same issue. i had this compiler setting:
No vulnerabilities reported
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