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AttributeError: 'Web3' object has no attribute 'middleware_stack

web3.py version: 5.0.1 , Python: 3.6.3 Following code was working on web3==4.9.2, which does not work for the web3==5.0.1. I am getting following error: web3.middleware_stack.inject(...
0
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1answer
11 views

Is it possible to send erc20 token when I have 0$ ether but $1000 in the token?

Long story short I have $1000 in one erc20 token contract but 0$ in ETH. Can I at least transfer these $1000 from the token to another address without ethereum asking for gas? That is: just change ...
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0answers
4 views

Transaction always failing - Vyper

I've been trying to teach myself how to program smart contracts in Vyper and I was trying out a toy problem where the contract transfers USDC to itself and then mints some Compound USDC on Compound ...
1
vote
0answers
8 views

How is the length of the message counted when calling eth_sign?

According to https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign The sign method calculates an Ethereum specific signature with: sign(keccak256("\x19Ethereum Signed Message:\n" + len(message) +...
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0answers
9 views

Truffle deploying smart contracts to a private blockchain on a virtual machine (digital ocean)

I tried truffle deploying smart contracts to local geth private blockchain with success, but I cannot deploy the same contract to private blockchain(with the same genesis) on Digital Ocean droplet. ...
0
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0answers
7 views

How to connect to Rinkeby without using Geth / Parity?

First let me explain my development environment. I am using Jupyter Notebook to play around with the Web3.py front-end code and Remix for the Solidity smart contract code. I am using the Metamask ...
0
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1answer
7 views

Load Smartcontract in Nodejs

I created the server based on golang. This server can load smart contract that is deployed using its address. It works on my local machine, but it does not work on EC2 instance. So I decided to ...
0
votes
1answer
18 views

“onlyOwner” Function restrict the call from child contract

I have a basic knowledge of solidity. I am trying to create an upgradable ERC20 Token. For that, I create TokenStorage contract and Logic contract and trying to write the Proxy contract. In the Logic ...
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0answers
7 views

EIP712 implementation for web3 1.0

I tried replicating the instructions in this article to implement EIP712 signing, however, it doesn't appear to work for web3 1.0 versions. https://medium.com/metamask/eip712-is-coming-what-to-expect-...
2
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0answers
8 views

What is an SSZ partial?

What is an SSZ partial? What are its benefits and are there any existing similar concepts that would help in understanding it? Some references: https://github.com/ethereum/eth2.0-specs/pull/1184/...
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0answers
16 views

invalid JSON RPC when using custom domain name

geth --testnet --networkid 3 --syncmode "fast" --datadir "." --cache=2048 --rpc --rpcport 8545 --rpcaddr example.ropsten.hk --rpcvhosts example.ropsten.hk --rpccorsdomain "*" --rpcapi="web3,miner,...
2
votes
2answers
28 views

Why can't I use a contract method in my Chrome console?

I am attempting to call a method from a smart contract from my chrome console. My dApps index.html file is deployed locally at http://127.0.0.1:5500. I set up web3 and instantiate a smart contract ...
0
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1answer
21 views

Function should return all objects stored in the mapping array

Here's my solidity code. And I want all the objects to be returned stored in mapping array contracts in the getContract method by giving address as a parameter to the getContract function. pragma ...
0
votes
1answer
14 views

When calling a contract from an other contract, what happends if the value of callgas argument is above availaible gas?

In such case, the value is replaced with available gas right ? Or Does an out of gas exception is thrown ?
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2answers
26 views

How to get response from Solidity Smart contract by Web3 client?

Here is the Smart contract code. I want to get the result of function of UserRegister by using web3. function UserRegister(string memory userName,uint feiyong ) public payable returns(string ...
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0answers
10 views

Truffle migrations - get deployed contracts list

I have the following problem: migrations no. 7: (deploy proxies) await deployer.deploy(TestProxy); await ExportUtils.addDeployed(await TestProxy.deployed(), true, { privileges: [ { ...
0
votes
1answer
17 views

Decentralized database for ethereum?

I'm looking for a way to store data in a decentralized way such that I can access any record from within the smart contract, probably through oracles I guess? I've been looking into gundb but not ...
2
votes
0answers
16 views

What is SSZ SimpleSerialize and why was it developed?

We were looking at the latest spec and it didn't have much background information or explanation on what SSZ is trying to achieve. What are the key goals of SSZ? Examples of its serialization and ...
0
votes
1answer
26 views

Solidity: extract data from signed message?

In an effort to reduce gas costs for users, I'm looking for a way to delegate certain transactions to a contract owner so that the owner makes a transactions that would have been otherwise sent by the ...
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0answers
23 views

How can I use bitcoin block stamp as seed for random number generation?

I am trying to create an ethereum based smart contract that shall generate random number. After searching around, I get to know that ethereum block stamp is vulnerable to miners hacks and false ...
0
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0answers
7 views

How can I find the block where a user enacted a certain event on a contract?

I'm trying to build a web3.py program to take in a given user's address, and return the amount of ETH traded since they added liquidity to a Uniswap exchange. Uniswap is a smart contract on the ...
-2
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0answers
14 views

How do I get people to interact with my DApp? [on hold]

I am making a password recovery DApp on the Ethereum blockchain: https://cracknet.io It enables people to pay a reward to crackers for cracking cryptographic hashes via Ethereum smart contracts. The ...
0
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2answers
22 views

Remix Deploy Error encoding arguments

I'm building a simple fund raising smart contract and having problems deploying this through Remix. I'm wanting to set the "goal" and "minimum contribution" values (in wei) during the contract ...
0
votes
1answer
17 views

Is it possible to deploy the ERC721 token on private network for free?

I created a private network with 3 instances (one controller, 2 nodes) based on PoA on AWS. And I checked if my custom ERC721token is deployable by using Ropspan test network. so I have a working-...
0
votes
1answer
24 views

What is meant by a “non one time use EOA”

Could someone explain what is meant by a non-one-time-use externally owned account and what is used (or misused) for?
0
votes
1answer
22 views

TypeError: Cannot read property 'nodes' of undefined

I'm new to ethereum, and I'm trying to test the depositToken function of etherdelta on linux, which version is 0.4.9, and the token I use is vixcore which version is 0.4.24, and I got this error when ...
1
vote
1answer
36 views

Off-chain authorization system

I'm working on a dapp and am running into a dilemma regarding how to balance trustlessness with the cost of transactions for users. In order to reduce gas usage by users, I want to be able to able to ...
3
votes
2answers
33 views

Alternatives to metamask [on hold]

What are existing alternatives to metamask with that works online inside existing browsers, that don't require installing a browser extension? What are some of the tradeoffs between them?
1
vote
1answer
11 views

Uncaught (in promise) Error: Contract has not been deployed to detected network (network/artifact mismatch)

The client side application always throws the above error. I have connected the ganache account(by copying the private key)also with the correct port number in Metamask extension as well as in the ...
0
votes
1answer
16 views

Quorum Nodes not syncing

I have 5 nodes with quite different block numbers( one is stuck at 201504, another at 280432 and so on) , they don't seem to be syncing. No particular error in Quorum Logs as well. Any transaction ...
0
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0answers
10 views

How to filter by string parameter , web3 2.0.0-alpha.1 Solidity events?

I'm trying to filter some events , and I noticed since I updated the web3 to version 2.0.0-alpha 1 the event catch is a little bit different. I have a Smart Contract with this event : event ...
3
votes
0answers
20 views

account unlock with HTTP access is forbidden [duplicate]

I am using in the geth console and there is a similar error. Do I add "--allow-insecure-unlock" when I "init a node"? personal.unlockAccount(eth.accounts1) Any suggestion would be helpful. Thank ...
1
vote
0answers
7 views

How to get events on android with infura?

I am developing an app on Android, but Web3j does not support events on infura ( Should I use Infura with Web3j for Event filter? ) . What are the options, I did not find any alternative library?
1
vote
0answers
24 views

VM error: revert. revert The transaction has been reverted to the initial state. Note: The called function should be payable if

Hi Guys 👋 I have two contacts first one is SubToken and second one is MainContract. First I deploy MainContract after that I use createNewContract function and I create new SubToken. and then I ...
0
votes
1answer
19 views

Cannot Find Module Error for Truffle-contract

Error:- Uncaught Error: Cannot find module './truffle-contract.min.js' at c (web3.min.js:1) at c (web3.min.js:1) at index.html:27 <!DOCTYPE html> <html lang="en"> <head&...
0
votes
2answers
29 views

gas required exceeds allowance when deploying ERC721token

I am trying to deploy Smart-contract(ERC721) on my private ethereum network. But I have this issue. Here is my genesis. { "config": { "chainId": 3333, "homesteadBlock": 1, ...
0
votes
2answers
21 views

ParserError: Expected pragma, import directive or contract /interface/library definition

In an attempt to compile my ABI and verify my contract, I am getting the following warning: "ParserError: Expected pragma, import directive or contract /interface/library definition" on the first line ...
1
vote
1answer
17 views

Trouble accessing an array inside a struct inside a mapping via web3

Here are a few relevant code snippets from my smart contract struct Constituency{ uint16 id; string name; uint64[] cans; } mapping(uint => Constituency) public constituencies; ...
1
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0answers
17 views

Strange points of Casper algorithm

Currently, Ethereum developers are developing Casper Algorithm for Ethereum 2.0. According to their proposal, some validator are chosen randomly but validators has permanently authority to verify ...
2
votes
1answer
22 views

TypeError: Indexed expression has to be a type, mapping or array (is function (address) view external returns (string memory,string memory…)

I have 2 contracts first one is sub second one is main . First i deploy main and create a new subtoken. Then I want to access my maincontract in subToken contract but I cant :( When I compile this ...
0
votes
0answers
39 views

How to make password with mnemonic words?

i'm new on blockchain development and i'm trying to make a login like metamask in vuejs. Can someone teach me how to make 13 mnemonics word, where the last mnemonic is the password value get from an ...
1
vote
1answer
21 views

How can I reduce the gas price for the fallback function?

Below is my fallback function for ethereum. It currently require 91000 gaslimit which is way more than 21000. Metamask always starts the transaction with 21000 gas stipend due to which transaction ...
1
vote
0answers
11 views

How exactly theᴅᴀᴏ reentrancy hack was performed without having weiGiven>0 nor IsAllowed(WithdrawAddress)?

The well known ᴅᴀᴏ hack didn’t affect ether balances of theᴅᴀᴏ but balances of rewardAccount. That’s why I’m talking about the hack version which affected contract balances of theᴅᴀᴏ itself. With ...
0
votes
0answers
11 views

Cannot get returned signature

I have met a problem when I am developing a Metamask installed Dapp. I am using web3.personal.sign()to get the signature of accounts. However, I could not get the returned signature string from this ...
0
votes
0answers
17 views

What does mean $(sai tub) and $(sai tap) in SAI readme.md

I try to deploy and use https://github.com/makerdao/sai/( SAI ) on my private blockchain. I deployed SAI with scripts (bin/deploy-fab && bin/deploy) without any mistake. In https://github....
3
votes
0answers
26 views

Process address deposit from contract

Our service handles thousands (currently 10000+) of users and each user has his own Ethereum deposit address. To detect a new deposit we: Scan each block to get a list of transactions Get a list of ...
1
vote
0answers
10 views

Changing from Filter to Subscribe with the current code im using

i'm having difficulties to change this line of code to web3.eth.subscribe anyone know how to write in subcribe for this since i want to change from old ver to new beta ver. const filter2 = web3....
-1
votes
1answer
16 views

Where is web3.eth.abi with the version of web3.js given with Metamask

Seems the docs doesn’t contain the answer. Looks like that part was moved elsewhere with latest transaction. The aim is to access encodeFunctionSignature() for knowing to which function name the ...
0
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0answers
35 views

Transactions go to an older contract address rather than the present deployed one

Though I have deployed a new contract but the transactions go to a previously deployed contract in my application. I'm attaching the screenshot of my Remix-ide code and the code for the front end ...
0
votes
0answers
19 views

Ether.js - Sending transaction with metamask

Problem: Cannot send transaction to contract with metamask when using Ether.js I can get a result when calling a public view function as shown below. However, when calling a normal function, ...

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