Questions tagged [python]
Python is a dynamic and strongly typed programming language designed to emphasize usability.
1
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1answer
51 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
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0answers
15 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
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0answers
19 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
45 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
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0answers
20 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
37 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
16 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
78 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
43 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
24 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
20 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
57 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
34 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
46 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
440 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
126 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
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0answers
14 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
141 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
277 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
127 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
76 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
65 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
155 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
58 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
140 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
107 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
165 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
72 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
35 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 ...
2
votes
1answer
220 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
200 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
84 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
33 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
63 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
105 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
203 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
107 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
280 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
202 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
196 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
219 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
151 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?
1
vote
1answer
53 views
Are Solidity modifiers functionally equivalent to Python decorators?
I understand that in Solidity if a function has a modifier, this modifier runs first, prior the the logic within the function running. This is done for checks of ownership, checks of state, etc.
In ...
2
votes
1answer
402 views
Using Python to invoke smart contract [duplicate]
I'm currently writing a thesis on a simulation of a peer to peer electricity market. The payments between the agents of the simulation would be settled through an Eth smart contract. I would like to ...
1
vote
1answer
41 views
Argument encoding: list of uints (uint[48])
Using python web3 module, attempting to call a contract function that takes one argument, a list of 48 uints:
function checkOrderBatch(uint[48] input) external view returns(uint16[16] status, uint[...
0
votes
1answer
69 views
How to determine using web3.py when this contract's tokens are unlocked? (contract code attached)
Currently the tokens of this contract are locked. I want to be able to figure out when the tokens of this contract have become transferrable in my python script. I'm using web3.py for this work.
Link ...
1
vote
1answer
138 views
Decoding Contract Log's “Data” field With eth-abi Throws Error: “Padding bytes were not empty: b'0x0000000000'”
I used this guide to create the code below. I suspect the error is somewhat related to the encoding processes I do to the strings, as that is the only place where I deviate from the guide. Here is my ...
0
votes
1answer
297 views
Transaction done, but nonce does not update and call to a function returns zero
I've used web3py to deploy a contract and send some transactions to it.
I calculate the nonce this way: nonce = web3.eth.getTransactionCount(account, "pending")
When I deploy the contract, ...
