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EIP 170, Ethereum Contract Size Limitation - Ints, Strings, Etc

Already figured out comments do NOT affect contract size, here. What else can be done to decrease a contract size without changing the standard. If I reduce the int types from 256 to 16, will that ...
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0answers
2 views

Geth sync at 99.99%, Latest block is 0, Importing state entries for a long time

I know its a common issue but I wanted to post to see if there is an updated solution. I am running: geth --rinkeby --rpc --rpcapi="personal,eth,network,web3,net" geth attach http://localhost:8545 ...
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0answers
4 views

I want to create a account on blockchain using web3swift in IOS app, but I am new on blockchain don't know how to do. Please can anyone help me out?

I want to create an account on the blockchain using web3swift in the IOS app, but I am new on blockchain don't know how to do it. Please, can anyone help me out?
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1answer
22 views

Stack too deep problem

I try to add more property to the scenario struct but when I run the compile the same error appear: struct Scenario { uint id; address payable author; address editor; ...
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1answer
18 views

giving users ETH addresses to deposit to

So I want to allow users to deposit ETH to their accounts in my website. How could i go about giving a user an ETH address to deposit to that address and then detect it and add the funds to user's ...
0
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1answer
14 views

Smart Contract Transfer Event Log Data & transfer _value [Rust]

I'd like to have a better understanding of events and logs data, more specifically when it comes to interacting with ERC20 tokens smart contracts and their Transfer events. I'm looking for a way to ...
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0answers
10 views

Advice on tools, Git hosting, and CI for smart contracts

I am writing a software system, consisting of: a simple smart contract another Aragon-based smart contract Aragon-based Web UI First, should I have one, two, or three separate Git repos for these ...
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2answers
20 views

safe way to allow users to deposit ETH to an address

I'm new to this and I want to simply allow users to deposit ETH to an address (not a contract). I was wondering what is a safe way to do this? for example using the code below on client side i can ...
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0answers
13 views

Could this work? Proof of Consistency?

So, I have been doing some research on Blockchain , for my dissertation, recently and had spent a lot of time researching consensus protocols. This had led me to wondering if there is any other ways ...
0
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1answer
18 views

Do comments affect the contract size limit?

I ran into the eip-170 contract code size limitation. I need to trim it down. Do comments affect the size of the contract as I have a lot of them and don't mind getting rid of them.
0
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1answer
9 views

ethers.js - How to derive child addresses + private keys from HD private key

I have a HD private key which I have derived from my mnemonic using the ethers library. I would now like to derive child addresses and corresponding private keys from it. Does anybody know how I can ...
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1answer
8 views

is it possible to get address and private key from mnemonic code?

I have question Is it possible to get address and private key from mnemonic code?? For example) I created address (0x12345) and I receive mnemonic code such as apple bed bad rice If i know mnemonic ...
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1answer
16 views

Does transaction hash in Ropsten ( testnet) deprecate ever?

I want to know whether transaction hash created in testnet stay forever or after sometime it gets deleted? Like in IPFS garbage collector deletes unpinned files after two weeks. IPFS is also ...
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1answer
17 views

Can I use the data returned by web3.eth.getTransaction() to determine if the transaction created a smart contract?

I am attempting to create a smart contract counter. Can I use the data returned by web3.eth.getTransaction() to determine if the transaction created a smart contract?
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0answers
9 views

How do you inspect the properties and methods of a web3 object in web3.py?

How do you inspect the properties and methods of a web3 object in web3.py? In Node.js, if I type in the name of my web3 instance and press enter, the object is printed in the console. I am able to ...
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0answers
13 views

Can you verify transaction data by matching it to the transaction hash

TlDr; Can you use the transaction hash to confirm the integrity of the data components of a transaction (post data, addresses, nonce, etc). In my application, I have a connection to the Ethereum ...
0
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1answer
18 views

How can I implement redactable chain for ETH?

I am trying to research about Redactable blockchain so my question is how can I implement a Redactable chain in Eth if someone has some idea about it I will be thankful
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2answers
34 views

onlyOwner check fails using Proxy Contract

I was testing delegate calls with the proxy pattern for the upgradable contract. Things were going good till the time I added onlyOwner modifier. My Contracts pragma solidity 0.5.8; contract ...
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1answer
9 views

Using delegatecall for multiple parameters fuction in solidity

Does someone have a exemple of solidity delegatecall for multiple parameters function?
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1answer
17 views

Metamask TestRPC shows 0 Ether while connecting to Ganache- CLI

I've gone through various Q/A(s) of the problem of ganache-cli and metamask not linking but after trying all the solutions, still doesn't work for me. As soon as I type ganache-cli in windows cmd ...
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0answers
21 views

About transaction higher nonce than current nonce

I'm working with concurrent Ethereum transaction (old discussed thread). Sometimes, invalid nonce can be occured, I'm using Redis and physical DB to storage nonce, actually higher nonce than current ...
0
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1answer
24 views

How to choose wallet with web3

I have MEW and Metamask installed. When I am trying to send a transaction using: web3.eth.sendTransaction() It always uses Metamask. May I know how can I specify I want to use MEW instead?
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0answers
20 views

Truffle - Get ETH Balance with Web3JS - two different errors

Using Gnache and Truffle unit tests, I have tried two helper routines to get Eth balance for an address. URL to source of the code in comments inline below: const Web3 = require('web3') const ...
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1answer
11 views

Checking for no duplicate values in an array

I have an uint256[] array. I need to check that no value is repeated in the array more than once. What is an efficient way to do this?
0
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3answers
17 views

Using a Non-Fungible token to gain access to a file

Please excuse me, I'm a layperson, not a programmer. At this time is there a way to issue NFT's to be used as a 'key' to gain access to a file on the internet? For example you create and sell an NFT ...
0
votes
1answer
17 views

Need to enumerate keys of a mapping

I have a directed multigraph of courts "trusting" each other: struct TrustedCourt { uint256 courtId; mapping (uint256 => uint256) limits; // intercourt token => amount } ...
2
votes
2answers
18 views

How to generate a new token address?

Developing an ERC1155 contract, how to generate an address for a new token? I need to create an API function like function createToken() returns (address). How? Should I just use an incrementing-by-...
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1answer
12 views

Truffle returning balances from a function

This maybe just a simple Javascript issue, but it's in the context of running under Truffle. I can't seem to access my object variables coming back from my function; thus the tests are failing with ...
0
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0answers
10 views

Why are there non-batch transfers in ERC-1155?

Why are there non-batch transfers in ERC-1155? Why not the API only for batch transfers? It would make contract codes shorter and thus simplified contract development and saved gas.
0
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2answers
21 views

Why use nodepools or backends?

I have a fundamental question about eth/blockchain infrastructure. I see several posts talking about the need for backend node infrastructure when launching a dapp/ smart contract. This infrastructure ...
0
votes
1answer
11 views

How to swap BTC to WBTC

Wrapped Bitcoin (WBTC) is the first ERC20 token backed 1:1 with Bitcoin. So there must be a mechanism to lock BTC in the Bitcoin network and mint WBTC in Ethereum. I read about custodians and ...
0
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0answers
12 views

How to deploy contract using ropsten infural url and web3.py? [duplicate]

# web3.py instance >>> w3 = Web3(Web3.EthereumTesterProvider()) # set pre-funded account as sender >>> w3.eth.defaultAccount = w3.eth.accounts[0] # get bytecode >>> ...
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1answer
10 views

Correct terminology for minting?

I am creating a contract such that for every wallet owner there is a "special" set of tokens that he can send to other wallets in unlimited quantifies (even if having zero or little of this token on ...
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0answers
8 views

Where to specify the spent limit?

I am creating a contract representing a court. A court can add an arbitrary amount of crypto to any account of its choice. (This is what a court is intended for.) It looks reasonable to assign a ...
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0answers
5 views

Whats the use of utility token if you don't want ICOs for your dapps?

You can mint coins and do your ico to get money. But what if I want an app without any ICO, will utility tokens still useful. Can't all transactions be made with already existing ether or dia stable ...
0
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0answers
8 views

What is operator approval in context of ERC-1155?

https://github.com/enjin/erc-1155/blob/master/contracts/ERC1155.sol says something about "operator approval". What is an operator and what is operator approval?
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0answers
5 views

How to use metamask wallet address and private key with ropsten and web3.py

I have used ganache RPC server and account address to compile and deploy contract, i want to use rospten account and metamask account for the same. I dont want metamask plugin to pop up everytime ...
0
votes
2answers
15 views

One or multiple owners?

My contract is controlled by owner(s) who can decide to discharge the money from it. The owner also can assign another owner, set spending limits, etc. Should the contract have one or several owners? ...
-2
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0answers
18 views

How to get length of a structure? [on hold]

I have structure candidate and I wanna get the length of candidate structure. struct Candidate { string name; uint voteCount; uint candidateslength; } Candidate[] public candidates; ...
0
votes
1answer
20 views

What Would Be The Reward For Smart Contract Miners In Ethereum POS?

I have seen this: What’s the block reward for smart contract miners? Which addresses it for the POW period of Ethereum, but what about POS? They just earn a sort of "interest" for their stake as ...
1
vote
2answers
16 views

Where are Geth's “fast” and “light” syncing options officially documented?

Go Ethereum's documentation for running the command line program is at https://geth.ethereum.org/docs/interface/command-line-options There it specifies the --syncmode option with the explanation: ...
0
votes
1answer
19 views

In MetaMask, I have my seed phrase but I didn't export my private keys. How do I recover my wallet?

So, I've been using MetaMask to try app.compound.finance and everything went well. I've deposited a small sum and connected the app to the wallet. But a few weeks later I decided to deleted the chrome ...
1
vote
1answer
24 views

I want the full list of ethereum smart‑contracts whose balances increased by 1000 Ethers above the past week

How to make this kind of query using my 200kb/s second Internet connection speed ? With such speed, there’s no possibility to run an archival node (except maybe with a service allowing to download ...
0
votes
0answers
19 views

Blocktime zero (period:0) with clique in permissioned blockchain

I am considering to set the blocktime to zero (clique.period:0) in a permissioned private blockchain with known but untrusted nodes. The reason to do this is having a minimum transaction process ...
0
votes
2answers
39 views

Sign message with web3 and verify with openzeppelin-solidity ECDSA.sol

I'm trying to get a little example working with ECDSA.sol here: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/cryptography/ECDSA.sol This contract: Generate a random(...
0
votes
0answers
25 views

Why use Chrome Extensions for Hardware Wallets?

Is there any way for a remote webserver to connect to a USB device using serial? If so, why did major hardware wallets use a Chrome Extension as opposed to a backend server for connection? Ledger used ...
2
votes
1answer
17 views

If external function declarations are saving gas, why aren't we using it for the transfer functions?

All the source code I could find (to date) has declared transfer, transferFrom, approve, approveAndCall as public and not external. Although external can be used, what is the reason behind not using ...
0
votes
1answer
21 views

Not able to successfully send Transactions via MetaMask on Firefox Browser

Does anybody help me figuring out why I am getting failed transaction here?What does this error means? Few days back,with the same line of code,I was able to successfully send transactions. An update:...
-1
votes
0answers
13 views

After Creation Contcact and receive ETH it answer messagem ERRO and Block Owner [on hold]

After Creation Contcact and receive ETH it answer messagem ERRO and Block Owner It was made with CODE Pattern when Eth was watched like Model to ERC 20 How to cancel or erase contract and Get Back ...
0
votes
1answer
31 views

Error Handling on Contract Calls to Other Contracts

I'm trying to call a function from another contract and need a way to accommodate errors. Say contract A has the method getBalance: function getBalance(address x) public view ...

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