Questions tagged [web3.py]
Web3.py helps you access your Ethereum node from Python. It is web3.js for Python.
1
vote
1answer
25 views
How to get the value of the transaction?
I am using web3.py but I need help to know the value of the transaction sent.
I know that the information is stored in the input but how do I parse the string. I know nothing about ABI.
Here is the ...
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 = ...
0
votes
0answers
13 views
Genearte error 'invalid sender' when doing send transaction using infura or roopsten
I am using following code to perform transaction
web3 = Web3(HTTPProvider('https://ropsten.infura.io/{}'.format('XXXXXXXXXXXXXXXXX')))
print('https://ropsten.infura.io/{}'.format('XXXXXXXXXXXXXXXXXXX'...
1
vote
0answers
20 views
How to send transaction using web3py using infura.io
I have connected to mainnet via
infura.io
and have used http provider for connections now
i want to generate address
and
send transaction
And i wand to send real eth
so how can i do this?...
1
vote
0answers
58 views
How to transfer transaction and send balance on public blockchain using web3py api?
I have followed tutorial and setup private Blockchain using geth:
https://medium.com/infrageth/practical-steps-for-go-ethereum-setup-27b8d64903fc
I have used
web3py
python library for creating ...
1
vote
1answer
16 views
Ethereum with Rails
I am much familiar with Rails but new in the Ethereum. But base on my understanding, if I am going to build a Dapp.
The web stack should not include the back-end system like Rails.
But why there's so ...
1
vote
1answer
27 views
web3.py multiple argument
I have created a "get_all" function that reads all variables in Solidity and a "set_all" function that writes all variables.
And I did a test in remix,
1, "0", 123123, "hash", "map", "eul"
I gave ...
2
votes
0answers
19 views
Accessing the network through light node
I've been trying, unsuccessfully, to make a web3.py app that needs to catch events, with the use of filters. After hours and hours of testing it appeared the problem was that Infura, which is the ...
1
vote
0answers
23 views
Strange result for w3.eth.filter({'fromBlock': 2500000, 'toBlock': 'latest'})?
I use
Parity:
Parity-Ethereum//v2.2.7-stable-b00a21f-20190115/x86_64-linux-gnu/rustc1.31.1
I tried code to see new entries for block range.
l = w3.eth.filter({'fromBlock': 2500000, 'toBlock': '...
2
votes
1answer
18 views
What's the difference between two params of web3.eth.filter?
I read official manual
What the difference between this
web3.eth.filter({'fromBlock': 'pending', 'toBlock': 'latest'})
and this?
web3.eth.filter('latest')
2
votes
0answers
34 views
How w3.eth.filter('latest').get_new_entries() works exactly?
I try to monitor new transactions.
from web3.auto import w3
import time
l = w3.eth.filter('latest')
while True:
ts = time.time()
ll = l.get_new_entries()
for i in ll:
print('===== Block ...
0
votes
0answers
21 views
Get the entries of an event by an event filter in web3.py
here is my Solidity Contract:
# Solidity source code
contract_source_code = '''
pragma solidity ^0.4.1;
contract Identities {
event ExistProduction(bool);
address private owner;
mapping(address =&...
0
votes
1answer
26 views
How to use soliditySha3 in web3py
I have tested soliditySha3 function with web3js.
var msg = web3Infura.utils.soliditySha3("transferPreSigned", mainContractAddress, recepientAddress, tokenAmountWei, transferFee, randomNounce);
I ...
0
votes
3answers
57 views
Use function return variable of smart contract in web3.py
since im new to solidity programming i have some problem with executing my Contract.
My Contract looks like this:
# Solidity source code
contract_source_code = '''
pragma solidity ^0.4.1;
contract ...
0
votes
1answer
22 views
Interacting with Already deployed Ethereum Contract and recording response
I understand this topic has been discussed before, but my question is specific to web3.py. How can I interact with function of already deployed ethereum contracts on Ropsten TestNet. my code runs with ...
1
vote
3answers
78 views
How can I call a function in deployed contract on Ropsten Testnet when I don't have ABI and source code?
For some testing I deployed several contracts on Ropsten Testnet using web3.py but now if I want to execute them or call any function from them, how can I do this? I don't have ABI as I did several ...
0
votes
0answers
25 views
How to generate Ethereum accounts using Web3 Python on Ropsten?
Just wanted to know how to use web3.py to generate Ethereum accounts. I tried using ropsten.infura.io/v3/<KEY> as an HTTPProvider, but it does not allows to create me account
0
votes
1answer
29 views
Match web3py hashing function to solidity hashing function
If I am using web3py to hash some data, like so,
msgHash = w3.soliditySha3(['bytes32','bytes32'], [dataBytes, saltBytes]);
What would be the correct way to hash inside of a Solidity contract and ...
1
vote
0answers
45 views
web3py encode method call parameters
I want to encode the parameters needed to call a contract method.
In web3js I would use web3.eth.abi.encodeParameters(types, values);
I need to do the same in python I found a function called ...
1
vote
1answer
88 views
ValueError: {'code': -32000, 'message': 'invalid sender'}
I'm trying to transfer some test ether from one Metamask address to another
using the private key that I exported from it. But it always return a error code of -32000 with a message of 'Invalid ...
0
votes
0answers
50 views
Invalid opcode on estimateGas 'code': -32000
this is my contract :
pragma solidity >=0.4.21 <0.6.0;
contract CloudProject {
uint public nbCandidates = 0;
uint public nbBureau = 0;
uint public nPartiPouvoir = 0;
...
0
votes
1answer
44 views
web3.py locally signed transaction rejected because of invalid nonce
I'm trying to sign locally a transaction to a smart contract method using web3.py.
I'm using ganache and there is one interesting issue when I send a transaction as the contract deployer everything ...
0
votes
1answer
286 views
Downloading a specific version of solc within a Docker image
I am working with the release of Solidity v0.4.25 for it works well with py-solc. When running on a local machine the codebase works quite well with 0.4.25. My issue currently is to get the codebase ...
1
vote
1answer
79 views
web3 python installation failes lately. What am I doing wrong?
I was trying to setup a new virtual environment for my project. I did not have any issues the last 5 Months installing web3, but today I just cant get it to work :(
pip install web3==4.1.0
...
1
vote
1answer
101 views
How do I verify and query my transaction? (Web3.py + Infura + Remix)
I've used buildTransaction() (which works at Contract.transact()) and I can see my transaction has taken place.
(https://ropsten.etherscan.io/tx/...
1
vote
0answers
58 views
Unable to call setter function in solidity using Infura
Solidity code
contract Greeter {
string public greeting;
function Greeter() public {
greeting = 'Hello';
}
function setGreeting(string _greeting) public {
greeting = _greeting;
}
function ...
1
vote
1answer
126 views
Estimate Gas For Smart Contract Always Fails
I have deployed a very simple contract to the Ethereum blockchain to be able to split a payment across two different outputs.
pragma solidity ^0.5.0;
contract MoonTrade
{
function multiSendETH( ...
1
vote
0answers
221 views
How to fix a web3.py HTTPConnectionPool read timeout error
I have a web3.py program running and everything was seemingly working. I was connecting to my local server via the automatic connection offered in web3.py.
I am now getting the following error:
...
1
vote
0answers
78 views
Using web3.py, I get a key error when connecting to a remote server with 3 nodes running (autoconnect works fine)
I have a web3.py project that is successfully performing basic tasks (read from blockchain, send tx, process data, etc.). It is connected to a remote server that is running an ETH node, a Rinkeby node,...
0
votes
1answer
100 views
How to deploy contract with local private key?
I am trying to deploy my contract onto the blockchain in my private network with local private key (no wallet: I used web3.auto.w3.account.create()).
I know how to send normal transaction with local ...
0
votes
2answers
89 views
How to use a metamask Wallet from web3,py?
I deployed contracts to Ropsten test net using truffle and a metamask wallet to pay for the transactions and Infura as a Hosted ethereum node.
To do that in Truffle, I have to use the truffle-...
0
votes
1answer
45 views
Problem with running web3.py code
I am trying to run this code
from web3 import Web3, HTTPProvider
import json
import pprint
import requests
from random import randint
# Debug flags
debug_transaction = False
debug_CALL_transactions ...
1
vote
1answer
43 views
How can I increase EVM time in web3.py?
When working with web3.js, Truffle and Ganache, I can do this:
web3.currentProvider.send({method: "evm_increaseTime", params: [numOfSeconds]});
How can I do the equivalent in web3.py?
When I do:
...
1
vote
1answer
102 views
Is there any way to know why a contract call cannot work through web3.py?
I have a deployed smart contract and attempt to write codes to call it through web3.py. I'm getting the following error when I call estimateGas().
ValueError: {'code': -32000, 'message': 'gas ...
0
votes
0answers
66 views
how to return transaction receipt in JSON format web3.py
I am trying to return transaction receipt in a JSON from my flask API (python). in JS this is absolutely easy but I can't get the receipt or the transaction hash to pass.
All I get is Object of type ...
1
vote
1answer
60 views
Transaction Hash after deploying contract with Web3.py too long
I managed to successfully deploy a contract using Web3.py to the Ethereum Ropsten network using this bit of code
def deploy(self):
instance = self.w3.eth.contract(abi=self.abi, bytecode=self.bin)
...
1
vote
1answer
95 views
web3py: get public key from transaction
I'm trying to retrieve the public key of an address from a transaction. I'm getting the transaction via tx = web3.eth.getTransaction('xxx')
According to the docs the public key should be retrievable ...
1
vote
1answer
145 views
How to integrate rinkeby test network with centralised server?
I am new to ethereum blockchain. I want to create ICO platform based website. I have created smart contract and deployed on rinkeby test network. I used python web3.py library to integrate python with ...
2
votes
1answer
173 views
web3 python sendTransaction error
from web3 import *
etherscan_provider = Web3.HTTPProvider( 'https://api.etherscan.io/api')
w3 = Web3(etherscan_provider)
signed_txn = w3.eth.account.signTransaction(dict(
gas = 2000000,
...
2
votes
3answers
143 views
How to make a Docker container talk to geth.ipc on local host
from web3 import Web3
web3 = Web3(Web3.IPCProvider("/Ethereum/geth.ipc"))
print(f'IPC connected: {web3.isConnected()}') # want to return True
I have the above script Dockerized and I'm trying to ...
1
vote
1answer
100 views
web3.py manually derive address from public key string [for dummies]
Let's say I need to derive the address from a public key string.
0xbb8250cc01a0afa7dcaee987b2adda8d1b0a0bb2f7cc427bd942a98c7837364d62e6ea4728a99db39fd55a6f7474a159ca88a96b40279044a1349a2280c8cd43
...
1
vote
1answer
26 views
web3.py equivalent to geth console command eth.pendingTransactions
I'm currently running a geth server and use the geth console for sysadmin stuff, while using web3.py for interfacing with geth programmatically. From the geth console, there is a handy command eth....
1
vote
1answer
196 views
web3py: get public key from private key (without prior transaction)
Is there a way to get the public key from a private key with web3.py? I know I could get it by checking a transaction signed by that key but that's not working for me in this example.
It should be ...
1
vote
1answer
152 views
Ethereum how to create account on parity hosted on Kovan network?
I have a parity node hosted on kovan network.
How to create account using web3py?
I used web3.personal.newAccount()=>which is giving error as no method found.
What are the api's available for parity?
1
vote
1answer
316 views
How can I retrieve the transaction hash / block hash of a contract that has already been deployed?
If you use Web3.py to deploy a Solidity contract to the blockchain, you can retrieve a transaction hash, like this:
tx_hash = w3.eth.sendRawTransaction(signed.rawTransaction)
Once you have that ...
-1
votes
1answer
109 views
How to call Sell event and buy token function with help of web3.py?
I am new to ethereum block-chain. I created a ERC20 token and crow-sale smart contract in solidity. I also deployed these smart contract with the help of web3.py. I created a contract instance.
...
0
votes
1answer
20 views
Creating an Ethereum id Hash
I'm trying to understand how to convert my transaction data into the id hash before signing the transaction.
Let's say I have this data:
transaction = {
'to': to_address,
'from': ...
1
vote
0answers
89 views
Transaction hash using web3.py received but variable state not changed
Trying to send a value to function and set it to a variable.
Making transaction using
txn = contractInstact.transact({
'from':
Web3.toChecksumAddress("...
2
votes
2answers
149 views
How to send a python bytearray into solidity function by web3.py?
I have a solidity function declared as:
function setUnitData(bytes32[10] my_input_array) public payable {...}
When I run this code:
contract = self.contract_instance['../contracts/test.sol:test']
...
1
vote
0answers
88 views
eventFilter web3.py in python to get events of locally deployed smart contracts using geth
I have tried ganache and geth too for contracts deployment locally hosted port # 8545. A function of deployed contract is called from another smart contract (deployed locally on same port)
So its ...
