Questions tagged [python]
Python is a dynamic and strongly typed programming language designed to emphasize usability.
199
questions
2
votes
1answer
60 views
Convert BIP-39 mnemonic to Ethereum private key in Python
How do I convert a BIP-39 mnemonic to an Ethereum private key in Python (via BIP-44 key derivation)? All the libraries I found that gave me the intended result depend on the two1 package, which ...
0
votes
0answers
27 views
compile_files gives errror for given path of the contract [duplicate]
pragma solidity ^0.5.1;
import "./Owned.sol";
contract Greeter is Owned {
bytes32 public greeting;
event GreetingChange (
address indexed changer,
bytes32 indexed _from,
...
0
votes
0answers
13 views
how to write smart contract in django python?
I am trying to create a daap website in django. In django use apps to write views and urls to mvc pattern. I tried to create an app and wrote smartcontract there but i am not able to access it. I have ...
0
votes
1answer
45 views
Getting Error:VM Exception while processing transaction: revert', 'code': -32000. when deploying to Ganache using Web3.py
I get the following error message:
Getting Error:VM Exception while processing transaction: revert', 'code': -32000
I am connected to Ganache. Here is my code:
import json
from web3 import Web3
...
0
votes
1answer
50 views
solcx compile_files Key error
I am using python package py-solc-x for compiling the smart contract.
os.path.abspath("D:/new.sol")
Gives path where my test contract exits. 'D:\\new.sol'
Then i use compile_files to compile the ...
1
vote
1answer
40 views
How to access Parity node's mempool with web3.py?
I'm running a Parity node with parity --jsonrpc-api all, then connecting to it in python3 with w3 = web3.Web3(web3.HTTPProvider('http://localhost:8545')).
I can call print(w3.eth.getBlock('latest'))...
1
vote
1answer
83 views
How to build a simple transaction?
Where is the information on the tx package build protocol? Bitcoin as an example, Bitcoin Wiki - Protocol Documentation: tx
Is there an example of serialization for python like this answer to How to ...
0
votes
0answers
46 views
How to listen contract event in Python
The test contract is
pragma solidity ^0.5.0;
contract Test{
event Here(uint256 indexed a);
uint256 public a;
function add() public returns (uint256){
a += 1;
emit Here(...
0
votes
0answers
65 views
Web3py AttributeError: 'HTTPProvider' object has no attribute 'manager'
I am trying to use web3 in a Django based web application in a task which is run using celery and kafka. However while trying to use web3.eth module, I am getting the following error :
/...
2
votes
1answer
117 views
How pass a struct as an argument in call from python code
How call this contract functions from python code?
pragma solidity ^0.4.24;
pragma experimental ABIEncoderV2;
contract MY_PERSONS {
struct Person{
string name;
uint age;
}
...
0
votes
0answers
42 views
How to make ECDSA signature of (value_1, value_2) with web3 on Python?
I want to call function with four parameters. I know how to create two of them, but the last two is the r and s components of ECDSA signature of (param_1, param_2).
I tried this (and a lot of ...
0
votes
1answer
98 views
Is it possible to deploy a contract from python web3 if I have the ABI and bytecode from Remix?
Question says it all. I have a contract that I've written and compiled via Remix. I've dumped the ABI and Bytecode into local files, and I'm reading them into my python application. I'm following the ...
0
votes
0answers
29 views
call() returning BadFunctionCallOutput in web3.py
Have a very basic ERC721 contract based on OpenZeppelin-Solidity, as follows:
pragma solidity ^0.5.7;
import 'openzeppelin-solidity/contracts/token/ERC721/ERC721Mintable.sol';
import 'openzeppelin-...
1
vote
1answer
181 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
2answers
92 views
No such file or directory: 'solc': 'solc'
I have been trying to follow the following tutorial
[https://github.com/adamyala/Your_First_Decentralized_Application_Python]
But the following error occurs:
I have followed all the steps in ...
1
vote
2answers
34 views
How can I read/write ethereum as a database by python code? [closed]
I am a startup in this domain. I see some article about Ethereum could save data as a contract. But they are too complex to me. If I already have an Ethereum account with some ETH. Is there some ...
2
votes
1answer
30 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
97 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
39 views
How can I create transaction via BlockCypher Ethereum API?(missing trie node)
I am created two ETH addresses, BUT I dont have any wei on it, if I will try create transaction, what response should I get, error that I dont have any wei or something like this
{'error': 'Error ...
0
votes
1answer
61 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 ...
0
votes
1answer
629 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 ...
2
votes
1answer
263 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
0answers
20 views
How to get live mempool transactions whitout full blokchain
I just want to analyse all mempool txs in realtime.
I cant use an api because after several requests my ip gets blocked for some minutes, so I dont get the txs in this time.
Thank you for help.
1
vote
1answer
185 views
Error whilst running solidity with python(py-solc)
I have been running my code which involves deployment of smart contract to Ethereum Ropsten network. I ran this successfully for some time but last week did installed another software after which ...
1
vote
0answers
351 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
175 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,...
1
vote
1answer
95 views
Hash functions soldity to python
In Solidity, I run the following code:
function hashTest() public returns(bytes32,bytes32,bytes32) {
bytes32 _solution = 0xbc756c25d68ea2f260ea5f15e1e1c734c019cbc014270dd386eacca4699f60f6;
bytes32 v ...
1
vote
1answer
76 views
Bit manipulation (python vs solidity)
I am working on translating code from Python to Solidity and everything has worked up until this last loop. Cannot figure out where the difference is in the code (besides the bytes being in decimal ...
0
votes
1answer
200 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
1answer
94 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
27 views
What is the best (cheapest) method to store RGB/RGBA pixel data in a smart contract (on ethereum-classic blockchain) with python?
I would to implement a method to store pixel (RGB/RGBA) in a Smart contract (on ethereum-classic blockchain) from python and with the cheapest method ( when storing and updating pixel data)
I try to ...
1
vote
1answer
171 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
1answer
135 views
Problem installing Web3
I am getting a python version error while installing web3js from npm
gyp ERR! stack Error: Python executable "/anaconda3/bin/python" is v3.6.4, which is not supported by gyp.
gyp ERR! stack You can ...
0
votes
1answer
231 views
How to calculate ethash in python?
I am trying to use ethash(hash(blockHeader),nonce) < TARGET to prove that the block was mined with at least a minimum difficulty.
Is the formula above correct?
When I try to use ehtereum.pow....
2
votes
1answer
17 views
How to recreate a HexaryTrie from a saved database
I am trying to create a HexaryTrie from the database that the trie writes to.
Here is my Code:
from trie import (
HexaryTrie,
)
db = {}
trie1 = HexaryTrie(db)
trie1[b'deadbeef'] = b'deadbeef'
....
0
votes
2answers
84 views
Different Values for v, r, s? What am I doing wrong?
lets assume I have this private key (test account on ropsten, no need to worry):
785cdcd731a1b2438ec4511a25d04efbdc499ed350df612364af1aa6f4fd6abd
When I use Pyethereum to run
v, r, s = ecsign(tx['...
1
vote
1answer
39 views
Hashing header “offline” python
I am trying to prove that the TransactionsRoot and the ReceiptsRoot do belong to a specific block. So that I can verify without web3 that all the transactions and receipts actually belong to this ...
3
votes
1answer
311 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
259 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
101 views
Web3 (python) - confirming transaction hash format
Due to the fact, that I am storing txId obtained from the user, before determining whether transaction has been ended or not, I want to make sure that the transaction hash, which will be stored in my ...
0
votes
2answers
37 views
Using Python trie to build transactionsTrie. Why is my Transactionsroot wrong?
I am trying to build a TransactionsTrie with python. I am using this [trie][1]-Library. I followed the Instructions.
Edit: Removed the original question because it was stupid.
@carver
Thank you ...
0
votes
1answer
90 views
Python: How make Ethereum tx without web3.py?
make a simple eth raw tx and self sign without web3
I only need generate a eth raw transaction and self sign , web3.py is bloated.
I generate lots of eth address using python like this:
def ...
1
vote
0answers
121 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
278 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
128 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 ...
1
vote
1answer
308 views
Unable to load Solidity contract using `compile_files` function with web3.py
I am new to ethereum block-chain. I created a ERC20 smart-contract with help of open-zeppelin framework. I used py-solc package for solidity compilation with python. I imported compile_files function ...
0
votes
1answer
229 views
Converting web3.sha3() bytes to string (Python)?
The code I am having trouble with:
new_address = Web3.sha3(rlp.encode([normalize_address(accountAddress), nonce]))[-40:]
return '0x'+new_address
new_adress remains in bytes and I can't join it with ...
1
vote
1answer
226 views
How to access a deployed smart contract attributes using web3.eth.contract(abi,address) in python
web3 = Web3(provider=HTTPProvider(http://ropsten.infura.io/v4/API_KEY)
abi = '[{"constant":false,"inputs":[{"name":"_utxoPos","type":"uint256"},{"name":"_txBytes","type":"bytes"},{"name":"_proof","...
2
votes
1answer
272 views
What is pyethereum?
I have seen a definition here saying: "This is the Python core library of the Ethereum project"
So what is it's use? To develop dapps using python on the ethereum network?
2
votes
1answer
189 views
What advantages does Trinity have over Geth or Parity? What differences does it have?
With the exception of the language it is being written in, what are the main differences that Trinity has over Geth or Parity (if any). What advantages does it have? Disadvantages?
