Questions tagged [python]

Python is a dynamic and strongly typed programming language designed to emphasize usability.

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Inconsistent responses with 'eth_getTransactionByHash' through RPC API. Can anyone help?

I have been using the requests library with python to query the geth/rpc api in order to get ETH transaction data. I connected to geth via "geth --rpc --unlock TESTINGADDRESSWITHNOVALUE --allow-...
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31 views

Sign Message using passphrase only

I'm creating an authentication system using python and web3.py. I'm trying to authenticate a user using from web3.auto import w3 msg = 'sdb41554xcb4xc548cxd84dxcb' message = encode_defunct(text=...
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8 views

fail for read ethereum node base on leveldb.py

I installed leveldb base on python3.6.but when I using leveldb.LevelDB import path for files to be read. a error occered "leveldb.LevelDBError: Corruption: 3 missing files; e.g.: D:/downloads_by_geth/...
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14 views

Can't install `eth-tester` Python Package

I am trying to install [eth-tester][1] Python Package so that I can use it to load test ethereum in my account by using its get_balance() function. First when i installed this package using; pip ...
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1answer
102 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 ...
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28 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, ...
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17 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 ...
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1answer
52 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 ...
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1answer
58 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 ...
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1answer
50 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'))...
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1answer
84 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 ...
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53 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(...
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85 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 : /...
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1answer
128 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; } ...
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51 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 ...
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1answer
106 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 ...
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32 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-...
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1answer
230 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 ...
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2answers
103 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 ...
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2answers
35 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
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1answer
38 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')
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0answers
111 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 ...
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0answers
40 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 ...
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1answer
67 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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1answer
679 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
291 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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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.
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1answer
190 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 ...
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0answers
365 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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0answers
185 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
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1answer
101 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
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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 ...
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1answer
207 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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1answer
100 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
28 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
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1answer
178 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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1answer
141 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 ...
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1answer
241 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....
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1answer
25 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' ....
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2answers
89 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['...
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1answer
42 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
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1answer
330 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
271 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
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1answer
104 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 ...
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2answers
41 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 ...
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1answer
98 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 ...
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0answers
127 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
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2answers
298 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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0answers
133 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 ...
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1answer
314 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 ...