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524 views

Implement Web3 and IPFS on server side (backend)

How do I implement Web3 and IPFS on the server side (backend)? I am able to implement on client-side (using web3.js and ipfs.js in HTML script tags) for localhost. However, it fails when I run the ...
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votes
1answer
53 views

Why does this smart contract compile? [duplicate]

Can someone please help me understand why this smart contract compiles in ReMix? What is the purpose of the word constant if it doesn't preclude the code from changing the state? I'm looking for a ...
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2answers
460 views

Ethereum wallet

Like many others I'm really struggling with setting up the ethereum wallet. I deleted the chaindata folder in order to make the download process quicker. Unfortunately I closed the ethereum wallet ...
0
votes
1answer
881 views

deployment of a functioning contract (testrpc) to ropsten with truffle/geth

I've developed a smart contract using truffle and testrpc, which can be found on GitHub here. At this point I want to deploy it to ropsten, but I can't figure out how to do that. After consulting ...
0
votes
1answer
283 views

Recent development tutorials for DApps?

Most of tutorials I found in the net were either too old or using old frameworks and development tools. I am talking specifically for building end to end DApps. Would you recommend some recent ...
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0answers
215 views

How to deploy smart contract using truffle , metamask with ropsten network [duplicate]

This question is an extension of Deploying to testnet using Truffle and Metamask Need to deploy smart contracts over ropsten testnet that connected through metamask . I am using truffle framework to ...
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votes
1answer
246 views

Can't launch mist wallet. Stuck after pressing 'launch application' in windows 10

Hi. I downloaded Mist wallet and then after some time when the 'launch application' button came up, I pressed that. However, now I only see the following image on my screen and the figures shown ...
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votes
2answers
397 views

Cannot assign value to a variable in truffle console and other problems

I'm trying to do very basic things with Truffle 3.4.6 console. I've been able to successfully compile and migrate a contract and access its contents using both: CoinCrowdsale.deployed() CoinCrowdsale....
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votes
1answer
335 views

truffle init webpack on Heroku

I'm having a hard time exporting the Truffle sample app on Heroku. I'd like to use it with Metamask. I tried simply pushing the code from my local machine (where the code is working) adding the ...
0
votes
1answer
849 views

API to get “total token left” of a custom token

If let say we launch a ICO using Ethereum blockchain, how can I check for total token left in the market? The typical workflow will be like: Investor send n ETH to my wallet System will verify the ...
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votes
0answers
471 views

returning struct in solidity

I have seen here that we can return struct for internal functions. Why can we return struct for non-internal function? Also, I can see in the same link "structs would have to be integrated into the ...
0
votes
2answers
675 views

I need help with a crowdfunding contract

This crowdfunding contract is far from complete, I'm still in the process of writing the code and testing each individual function. The approach that I have taken with the getRefund() function seems ...
0
votes
1answer
371 views

Ethereum private network - What is AWS minimum hardware requirement?

I have been setting up private blockchain network on two AWS EC2 instances for one of the demo setup. Initially, I chose t2.micro for both. However, miner.start(1) has been very unpredictable so far. ...
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votes
1answer
1k views

http: Accept error: accept tcp 127.0.0.1:8545: accept: too many open files; retrying in 5ms

I am running geth -rpc and node to directly interact with the blockchain. When executing a large amount of requests I noticed the following error: http: Accept error: accept tcp 127.0.0.1:8545: ...
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votes
2answers
231 views

filter: logs.blockNumber = undefined

I have the following code: var filter = web3.eth.filter({ fromBlock:4076955, toBlock:"latest", address:"0x0123456789012345678901234567890123456789" }); filter.get(function(error,logs){ ...
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votes
2answers
2k views

How much was BAT (Basic Attention Token) worth in eth / btc / usd during the 1 minute ICO?

What was the value of BAT (Basic Attention Token) during the 1 minute ICO in eth / usd / btc ? I can't seem to find this info anywhere. And what is the total supply?
0
votes
1answer
174 views

Out of Gas exception on testnet but on JVM it works

I am trying to withdraw a contracts balance to the owner of that contracts account. It works perfectly on the JVM in solidity browser. But on TestRPC it has an out of gas exception. The account has a ...
0
votes
1answer
427 views

Add Miners in open-ethereum-pool

I am using open-ethereum-pool for creating the ethereum mining pool over an private ethereum network . but it always give me no. of miners in pool are 0 . How do i add miners in the pool , I do not ...
0
votes
1answer
56 views

what information is provided to the miner with the transaction

I am wondering what information is provided to the miner with a transaction that needs to invoke a contract? I thought about Gas, GasPrice, name of function to invoke and input. But, whether the ...
0
votes
1answer
303 views

Cannot call function and send write-Transaction from geth-console

I have a contract which has this function: function registerSensor(bytes32 name, bytes32 unit, bytes32 location) returns (bool success) { sensors[msg.sender].exists = true; sensors[msg.sender]...
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votes
1answer
851 views

How to return the index value of an Enum?

I am trying to build a simple double escrow contract. I have an enum for the state: enum State { Created, Locked, Inactive } State public state; When I try to interact with the contract through the ...
0
votes
1answer
3k views

Proper way to stop the Geth console to turn off computer for maintenance?

After the synchronization of block chain is complete, what happens if you close the geth console while it continues to run the current block chain data? In the future, I would like to turn off ...
0
votes
1answer
224 views

Geth --rpc frozen after using geth --rpc --fast

For some reason it froze. Midway through the syncronization I stopped and re-entered geth rpc --fast Now for some reason it's super slow! At this rate it will be done in maybe a couple years or so. (...
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votes
0answers
662 views

How to fix Web3 syntax error (“Unexpected token {”)?

On line 33717 of Web3's app.js file (in the /build folder of a truffle project) there's the following line: })[0] || {}; However, somehow this turns into the following when app.js runs when my app ...
0
votes
1answer
133 views

The method db_putHex does not exsist/is not availabe

I am starting geth like the below command geth --testnet --rpc --rpccorsdomain http://localhost:8089 and get the error db_putHex does not exist/is not available on this line: web3.db.putHex(db, key,...
0
votes
2answers
222 views

EthereumJ connect to private node

I need to connect to private ethereum node with using ethereumj without ethereum.conf file. I need configure connect from code using Spring Framework.
0
votes
1answer
193 views

How can I transfer etherbase status to another account within mist?

After importing a wallet from JAXX to Mist, I wish to have the JAXX account having Etherbase status, instead of the default Geth one. However, I see no visual indications on how to do this within Mist....
0
votes
1answer
71 views

Time-Currency Tokens

How would you go about creating a token that has a value based on time? (Time-currency Tokens) What would be the solidity code be? I can't find much examples on this. Thanks.!
0
votes
1answer
298 views

ETh stuck in contract

I modified the example crowd sale contract from the Ethereum site slightly. First I sent 0.5 ETH from a wallet, it then sent the new tokens and I ran the safeWithdrawal function as the Beneficiary. ...
0
votes
1answer
471 views

Creating contract from another contract - remix issue

UPDATE: This works fine on the testnet/mainnet. For some reason the JavascriptVM in remix doesn't like it. If anyone from remix sees this and could lend a hand though! I wrote some a contract ...
0
votes
1answer
4k views

How much time will the Ethereum wallet take to sync for the first time

I downloaded and installed Ethereum wallet for windows 64 on my machine. When I tried to launch it for the first time, it started downloading the blocks .Already many hours have passed by but the ...
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votes
2answers
1k views

Motherboard Compatability

The amount of Video Cards a motherboard can support (if using powered risers) is only limited by the number of PCI-E slots, correct? I've found a board (MSI - B250 GAMING M3 ATX LGA1151 Motherboard) ...
0
votes
1answer
187 views

change gasLimit parameter into the genesis.json file on azure priavte blockchain

I am trying to deploy a smart contract to an azure blockchain. The contract is deployed without errors but i can't submit transaction to the blockchain through this contract. I guess this is an issue ...
0
votes
1answer
76 views

Downloading blocks problem and I can't see my transfer from Coinbase

Good afternoon to everyone! I have a big problem. I've downloaded the ethereum wallet and I made a tranferency from coinbase to my adress. I can't see it in my wallet. I red in the answers that I must ...
0
votes
1answer
36 views

HOW TO SPLIT OAX to ETH [duplicate]

I am not very technical. I want to know if there is an easier way to split eth from OAX tokens. I mistakenly brought OAX tokens from ETH using my exchange instead of wallet
0
votes
0answers
71 views

How to get contract adress when contract is deployed uisng other contract?

I have a smart contract with a function named, let's say, deployNewContract(..) this function takes some arguments and deployed a new contract based on the parameters. I am able to call the function ...
0
votes
1answer
2k views

web3 is not defined

I read other questions like this here but none solved my issue. I have a terminal window on which I ran geth --networkid=4 --rpc --rpcport 8545 --datadir=$HOME/.rinkeby --syncmode=light --ethstats='...
0
votes
1answer
416 views

How long does it take to reach consensus? [duplicate]

I know it takes about 10 minutes on Bitcoin? How long does it take to reach consensus on Ethereum so that I can start trusting a transaction? EDIT: I am not asking about pending transactions. ...
0
votes
0answers
531 views

“callback contain no result Error: Error: base fee exceeds gas limit” when call selfdestruct function (using Remix IDE)

I'm testing this simple contract. All the functions works well, but when I call the kill() function I'm getting this error: callback contain no result Error: Error: base fee exceeds gas limit I'm ...
0
votes
1answer
108 views

Sent ether to my wallet, been almost two months now and still downloading block chain. what do i do to speed this up? [duplicate]

i've downloaded geth but i don't know if it's doing anything. the terminal says "Fatal: Error starting protocol stack: resource temporarily unavailable" when i try to start it. i'm not really sure ...
0
votes
2answers
30 views

What's wrong in this mapping code?

Could someone please point out what is wrong in this code? It seems that when I call the registerClient() function, it succeeds and returns TRUE. But when I call the getRegisteredClients() method, it ...
0
votes
1answer
94 views

Question about how to have interacting contracts

Let's say I'm doing a crowdsale, but instead of selling a set amount of tokens I'm just giving tokens away at a pre-set price. In other words, my token has the following functoin: function give(...
0
votes
1answer
285 views

Modifiers misunderstanding

pragma solidity ^0.4.0; contract test { bool test_bool1 = false; bool test_bool2 = true; modifier test_modifier(bool _test_bool){ if (_test_bool == false) throw; _; } ...
0
votes
2answers
293 views

Contract not disbursing MetaCoin to parent account

I've combined MetaCoin and created an Ownable contract to allow for my Relay contract have access to MetaCoin methods and variables. Everything is successfully deployed using truffle. My assumption is ...
0
votes
0answers
187 views

EIP150 testBlockchain RangeError: Maximum call stack size exceeded

ethereumjs-vm > npm run testBlockchain TAP version 13 # BlockchainTests # file: ContractCreationSpam test: ContractCreationSpam_d0g0v0_EIP150 ok 1 correct pre stateRoot ok 2 correct genesis RLP ...
0
votes
2answers
132 views

Solidity opcode error when sending coin to an address

So I get the error below when attempting to send the coins to another address, and with the debugger, I can't figure out where's the problem. What am I doing wrong? (I just started learning solidity a ...
0
votes
1answer
253 views

How to get my private key?

I want to use the ecSign-function in the ethereumjs-util-library. But that needs a private key. So how and where do i get my private key for my wallet?
0
votes
1answer
567 views

How to assign ether value at deployment of contract

I am trying to run this buyer seller contract in truffle using testrpc. I am unable to assign the address and value for seller at the time of deploying contract. Here is my solidity code and deploy.js ...
0
votes
0answers
346 views

Ethereum mining problem - Receipt not found for transaction

I am using a private geth with a simple contract file SimpleContract.sol pragma solidity ^0.4.0; contract SimpleStorage { uint storedData; function set(uint x) { storedData = x; } ...
0
votes
1answer
1k views

Using Ethereum to buy Tezos

I would like to use my Ethereum to buy Tezos. Does anyone know if Coinbase pass transaction data along with the transaction? Thanks.

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