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Questions tagged [web3.py]

Web3.py helps you access your Ethereum node from Python. It is web3.js for Python.

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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 ...
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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 = ...
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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'...
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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?...
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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 ...
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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 ...
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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 ...
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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 ...
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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': '...
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1answer
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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')
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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 ...
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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 =&...
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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 ...
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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 ...
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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 ...
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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; ...
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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 ...
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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 ...
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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 ...
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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/...
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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 ...
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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( ...
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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: ...
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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,...
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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 ...
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2answers
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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-...
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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 ...
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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: ...
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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 ...
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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 ...
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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) ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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....
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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 ...
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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?
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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 ...
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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. ...
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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': ...
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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("...
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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'] ...
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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 ...