The web3-eth package allows you to interact with an Ethereum blockchain and Ethereum smart contracts.
var Eth = require('web3-eth');
// "Eth.providers.givenProvider" will be set if in an Ethereum supported browser.
var eth = new Eth(Eth.givenProvider || 'ws://some.local-or-remote.node:8546');
// or using the web3 umbrella package
var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');
// -> web3.ethAll Ethereum addresses returned by functions of this package are returned as checksum addresses. This means some letters are uppercase and some are lowercase. Based on that it will calculate a checksum for the address and prove its correctness. Incorrect checksum addresses will throw an error when passed into functions. If you want to circumvent the checksum check you can make an address all lower- or uppercase.
web3.eth.getAccounts(console.log);
> ["0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe" ,"0x85F43D8a49eeB85d32Cf465507DD71d507100C1d"]For web3.eth.subscribe see the :ref:`Subscribe reference documentation <eth-subscribe>`
For web3.eth.Contract see the :ref:`Contract reference documentation <eth-contract>`
For web3.eth.Iban see the :ref:`Iban reference documentation <eth-iban>`
For web3.eth.personal see the :ref:`personal reference documentation <eth-personal>`
For web3.eth.accounts see the :ref:`accounts reference documentation <eth-accounts>`
For web3.eth.abi see the :ref:`abi reference documentation <eth-abi>`
For web3.eth.net see the :ref:`net reference documentation <eth-net>`
web3.eth.defaultAccountThis default address is used as the default "from" property, if no "from" property is specified in for the following methods:
- :ref:`web3.eth.sendTransaction() <eth-sendtransaction>`
- :ref:`web3.eth.call() <eth-call>`
- :ref:`new web3.eth.Contract() -> myContract.methods.myMethod().call() <eth-contract-call>`
- :ref:`new web3.eth.Contract() -> myContract.methods.myMethod().send() <eth-contract-send>`
String - 20 Bytes: Any ethereum address. You should have the private key for that address in your node or keystore. (Default is undefined)
web3.eth.defaultAccount;
> undefined
// set the default account
web3.eth.defaultAccount = '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe';web3.eth.defaultBlockThe default block is used for certain methods. You can override it by passing in the defaultBlock as last parameter. The default value is "latest".
- :ref:`web3.eth.getBalance() <eth-getbalance>`
- :ref:`web3.eth.getCode() <eth-getcode>`
- :ref:`web3.eth.getTransactionCount() <eth-gettransactioncount>`
- :ref:`web3.eth.getStorageAt() <eth-getstorageat>`
- :ref:`web3.eth.call() <eth-call>`
- :ref:`new web3.eth.Contract() -> myContract.methods.myMethod().call() <eth-contract-call>`
Default block parameters can be one of the following:
Number: A block number"genesis"-String: The genesis block"latest"-String: The latest block (current head of the blockchain)"pending"-String: The currently mined block (including pending transactions)
Default is "latest"
web3.eth.defaultBlock;
> "latest"
// set the default block
web3.eth.defaultBlock = 231;web3.eth.getProtocolVersion([callback])Returns the ethereum protocol version of the node.
Promise returns String: the protocol version.
web3.eth.getProtocolVersion()
.then(console.log);
> "63"web3.eth.isSyncing([callback])Checks if the node is currently syncing and returns either a syncing object, or false.
Promise returns Object|Boolean - A sync object when the node is currently syncing or false:
startingBlock-Number: The block number where the sync started.currentBlock-Number: The block number where at which block the node currently synced to already.highestBlock-Number: The estimated block number to sync to.knownStates-Number: The estimated states to downloadpulledStates-Number: The already downloaded states
web3.eth.isSyncing()
.then(console.log);
> {
startingBlock: 100,
currentBlock: 312,
highestBlock: 512,
knownStates: 234566,
pulledStates: 123455
}getCoinbase([callback])Returns the coinbase address to which mining rewards will go.
Promise returns String - bytes 20: The coinbase address set in the node for mining rewards.
web3.eth.getCoinbase()
.then(console.log);
> "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe"web3.eth.isMining([callback])Checks whether the node is mining or not.
Promise returns Boolean: true if the node is mining, otherwise false.
web3.eth.isMining()
.then(console.log);
> trueweb3.eth.getHashrate([callback])Returns the number of hashes per second that the node is mining with.
Promise returns Number: Number of hashes per second.
web3.eth.getHashrate()
.then(console.log);
> 493736web3.eth.getGasPrice([callback])Returns the current gas price oracle. The gas price is determined by the last few blocks median gas price.
Promise returns String - Number string of the current gas price in :ref:`wei <what-is-wei>`.
See the :ref:`A note on dealing with big numbers in JavaScript <big-numbers-in-javascript>`.
web3.eth.getGasPrice()
.then(console.log);
> "20000000000"web3.eth.getAccounts([callback])Returns a list of accounts the node controls.
Promise returns Array - An array of addresses controlled by node.
web3.eth.getAccounts()
.then(console.log);
> ["0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "0xDCc6960376d6C6dEa93647383FfB245CfCed97Cf"]web3.eth.getBlockNumber([callback])Returns the current block number.
Promise returns Number - The number of the most recent block.
web3.eth.getBlockNumber()
.then(console.log);
> 2744web3.eth.getBalance(address [, defaultBlock] [, callback])Get the balance of an address at a given block.
String- The address to get the balance of.Number|String- (optional) If you pass this parameter it will not use the default block set with :ref:`web3.eth.defaultBlock <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns String - The current balance for the given address in :ref:`wei <what-is-wei>`.
See the :ref:`A note on dealing with big numbers in JavaScript <big-numbers-in-javascript>`.
web3.eth.getBalance("0x407d73d8a49eeb85d32cf465507dd71d507100c1")
.then(console.log);
> "1000000000000"web3.eth.getStorageAt(address, position [, defaultBlock] [, callback])Get the storage at a specific position of an address.
String- The address to get the storage from.Number- The index position of the storage.Number|String- (optional) If you pass this parameter it will not use the default block set with :ref:`web3.eth.defaultBlock <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns String - The value in storage at the given position.
web3.eth.getStorageAt("0x407d73d8a49eeb85d32cf465507dd71d507100c1", 0)
.then(console.log);
> "0x033456732123ffff2342342dd12342434324234234fd234fd23fd4f23d4234"web3.eth.getCode(address [, defaultBlock] [, callback])Get the code at a specific address.
String- The address to get the code from.Number|String- (optional) If you pass this parameter it will not use the default block set with :ref:`web3.eth.defaultBlock <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns String - The data at given address address.
web3.eth.getCode("0xd5677cf67b5aa051bb40496e68ad359eb97cfbf8")
.then(console.log);
> "0x600160008035811a818181146012578301005b601b6001356025565b8060005260206000f25b600060078202905091905056"web3.eth.getBlock(blockHashOrBlockNumber [, returnTransactionObjects] [, callback])Returns a block matching the block number or block hash.
String|Number- The block number or block hash. Or the string"genesis","latest"or"pending"as in the :ref:`default block parameter <eth-defaultblock>`.Boolean- (optional, defaultfalse) Iftrue, the returned block will contain all transactions as objects, iffalseit will only contains the transaction hashes.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - The block object:
number-Number: The block number.nullwhen its pending block.hash32 Bytes -String: Hash of the block.nullwhen its pending block.parentHash32 Bytes -String: Hash of the parent block.nonce8 Bytes -String: Hash of the generated proof-of-work.nullwhen its pending block.sha3Uncles32 Bytes -String: SHA3 of the uncles data in the block.logsBloom256 Bytes -String: The bloom filter for the logs of the block.nullwhen its pending block.transactionsRoot32 Bytes -String: The root of the transaction trie of the blockstateRoot32 Bytes -String: The root of the final state trie of the block.miner-String: The address of the beneficiary to whom the mining rewards were given.difficulty-String: Integer of the difficulty for this block.totalDifficulty-String: Integer of the total difficulty of the chain until this block.extraData-String: The "extra data" field of this block.size-Number: Integer the size of this block in bytes.gasLimit-Number: The maximum gas allowed in this block.gasUsed-Number: The total used gas by all transactions in this block.timestamp-Number: The unix timestamp for when the block was collated.transactions-Array: Array of transaction objects, or 32 Bytes transaction hashes depending on thereturnTransactionObjectsparameter.uncles-Array: Array of uncle hashes.
web3.eth.getBlock(3150)
.then(console.log);
> {
"number": 3,
"hash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
"parentHash": "0x2302e1c0b972d00932deb5dab9eb2982f570597d9d42504c05d9c2147eaf9c88",
"nonce": "0xfb6e1a62d119228b",
"sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"transactionsRoot": "0x3a1b03875115b79539e5bd33fb00d8f7b7cd61929d5a3c574f507b8acf415bee",
"stateRoot": "0xf1133199d44695dfa8fd1bcfe424d82854b5cebef75bddd7e40ea94cda515bcb",
"miner": "0x8888f1f195afa192cfee860698584c030f4c9db1",
"difficulty": '21345678965432',
"totalDifficulty": '324567845321',
"size": 616,
"extraData": "0x",
"gasLimit": 3141592,
"gasUsed": 21662,
"timestamp": 1429287689,
"transactions": [
"0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b"
],
"uncles": []
}web3.eth.getBlockTransactionCount(blockHashOrBlockNumber [, callback])Returns the number of transaction in a given block.
String|Number- The block number or hash. Or the string"genesis","latest"or"pending"as in the :ref:`default block parameter <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Number - The number of transactions in the given block.
web3.eth.getBlockTransactionCount("0x407d73d8a49eeb85d32cf465507dd71d507100c1")
.then(console.log);
> 1web3.eth.getUncle(blockHashOrBlockNumber, uncleIndex [, returnTransactionObjects] [, callback])Returns a blocks uncle by a given uncle index position.
String|Number- The block number or hash. Or the string"genesis","latest"or"pending"as in the :ref:`default block parameter <eth-defaultblock>`.Number- The index position of the uncle.Boolean- (optional, defaultfalse) Iftrue, the returned block will contain all transactions as objects, iffalseit will only contains the transaction hashes.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - the returned uncle. For a return value see :ref:`web3.eth.getBlock() <eth-getblock>`.
Note
An uncle doesn't contain individual transactions.
web3.eth.getUncle(500, 0)
.then(console.log);
> // see web3.eth.getBlockweb3.eth.getTransaction(transactionHash [, callback])Returns a transaction matching the given transaction hash.
String- The transaction hash.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - A transaction object its hash transactionHash:
hash32 Bytes -String: Hash of the transaction.nonce-Number: The number of transactions made by the sender prior to this one.blockHash32 Bytes -String: Hash of the block where this transaction was in.nullwhen its pending.blockNumber-Number: Block number where this transaction was in.nullwhen its pending.transactionIndex-Number: Integer of the transactions index position in the block.nullwhen its pending.from-String: Address of the sender.to-String: Address of the receiver.nullwhen its a contract creation transaction.value-String: Value transferred in :ref:`wei <what-is-wei>`.gasPrice-String: Gas price provided by the sender in :ref:`wei <what-is-wei>`.gas-Number: Gas provided by the sender.input-String: The data sent along with the transaction.
web3.eth.getTransaction('0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b§234')
.then(console.log);
> {
"hash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
"nonce": 2,
"blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
"blockNumber": 3,
"transactionIndex": 0,
"from": "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b",
"to": "0x6295ee1b4f6dd65047762f924ecd367c17eabf8f",
"value": '123450000000000000',
"gas": 314159,
"gasPrice": '2000000000000',
"input": "0x57cb2fc4"
}getTransactionFromBlock(hashStringOrNumber, indexNumber [, callback])Returns a transaction based on a block hash or number and the transactions index position.
String- A block number or hash. Or the string"genesis","latest"or"pending"as in the :ref:`default block parameter <eth-defaultblock>`.Number- The transactions index position.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - A transaction object, see :ref:`web3.eth.getTransaction <eth-gettransaction-return>`:
var transaction = web3.eth.getTransactionFromBlock('0x4534534534', 2)
.then(console.log);
> // see web3.eth.getTransactionweb3.eth.getTransactionReceipt(hash [, callback])Returns the receipt of a transaction by transaction hash.
Note
The receipt is not available for pending transactions and returns null.
String- The transaction hash.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - A transaction receipt object, or null when no receipt was found:
status-Boolean:TRUEif the transaction was successful,FALSE, if the EVM reverted the transaction.blockHash32 Bytes -String: Hash of the block where this transaction was in.blockNumber-Number: Block number where this transaction was in.transactionHash32 Bytes -String: Hash of the transaction.transactionIndex-Number: Integer of the transactions index position in the block.from-String: Address of the sender.to-String: Address of the receiver.nullwhen its a contract creation transaction.contractAddress-String: The contract address created, if the transaction was a contract creation, otherwisenull.cumulativeGasUsed-Number: The total amount of gas used when this transaction was executed in the block.gasUsed-Number: The amount of gas used by this specific transaction alone.logs-Array: Array of log objects, which this transaction generated.
var receipt = web3.eth.getTransactionReceipt('0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b')
.then(console.log);
> {
"status": true,
"transactionHash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
"transactionIndex": 0,
"blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
"blockNumber": 3,
"contractAddress": "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
"cumulativeGasUsed": 314159,
"gasUsed": 30234,
"logs": [{
// logs as returned by getPastLogs, etc.
}, ...]
}web3.eth.getTransactionCount(address [, defaultBlock] [, callback])Get the numbers of transactions sent from this address.
String- The address to get the numbers of transactions from.Number|String- (optional) If you pass this parameter it will not use the default block set with :ref:`web3.eth.defaultBlock <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Number - The number of transactions sent from the given address.
web3.eth.getTransactionCount("0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> 1web3.eth.sendTransaction(transactionObject [, callback])Sends a transaction to the network.
Object- The transaction object to send:
from-String|Number: The address for the sending account. Uses the :ref:`web3.eth.defaultAccount <eth-defaultaccount>` property, if not specified. Or an address or index of a local wallet in :ref:`web3.eth.accounts.wallet <eth_accounts_wallet>`.to-String: (optional) The destination address of the message, left undefined for a contract-creation transaction.value-Number|String|BN|BigNumber: (optional) The value transferred for the transaction in :ref:`wei <what-is-wei>`, also the endowment if it's a contract-creation transaction.gas-Number: (optional, default: To-Be-Determined) The amount of gas to use for the transaction (unused gas is refunded).gasPrice-Number|String|BN|BigNumber: (optional) The price of gas for this transaction in :ref:`wei <what-is-wei>`, defaults to :ref:`web3.eth.gasPrice <eth-gasprice>`.data-String: (optional) Either a ABI byte string containing the data of the function call on a contract, or in the case of a contract-creation transaction the initialisation code.nonce-Number: (optional) Integer of a nonce. This allows to overwrite your own pending transactions that use the same nonce.
callback-Function: (optional) Optional callback, returns an error object as first parameter and the result as second.
Note
The from property can also be an address or index from the :ref:`web3.eth.accounts.wallet <eth_accounts_wallet>`. It will then sign locally using the private key of that account, and send the transaction via :ref:`web3.eth.sendSignedTransaction() <eth-sendsignedtransaction>`.
The callback will return the 32 bytes transaction hash.
PromiEvent: A :ref:`promise combined event emitter <promiEvent>`. Will be resolved when the transaction :ref:`receipt <eth-gettransactionreceipt-return>` is available. Additionally the following events are available:
"transactionHash"returnsString: Is fired right after the transaction is sent and a transaction hash is available."receipt"returnsObject: Is fired when the transaction receipt is available."confirmation"returnsNumber,Object: Is fired for every confirmation up to the 12th confirmation. Receives the confirmation number as the first and the :ref:`receipt <eth-gettransactionreceipt-return>` as the second argument. Fired from confirmation 0 on, which is the block where its minded."error"returnsError: Is fired if an error occurs during sending. If a out of gas error, the second parameter is the receipt.
// compiled solidity source code using https://remix.ethereum.org
var code = "603d80600c6000396000f3007c01000000000000000000000000000000000000000000000000000000006000350463c6888fa18114602d57005b6007600435028060005260206000f3";
// using the callback
web3.eth.sendTransaction({
from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
data: code // deploying a contracrt
}, function(error, hash){
...
});
// using the promise
web3.eth.sendTransaction({
from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
value: '1000000000000000'
})
.then(function(receipt){
...
});
// using the event emitter
web3.eth.sendTransaction({
from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
value: '1000000000000000'
})
.on('transactionHash', function(hash){
...
})
.on('receipt', function(receipt){
...
})
.on('confirmation', function(confirmationNumber, receipt){ ... })
.on('error', console.error); // If a out of gas error, the second parameter is the receipt.web3.eth.sendSignedTransaction(signedTransactionData [, callback])Sends an already signed transaction, generated for example using :ref:`web3.eth.accounts.signTransaction <eth-accounts-signtransaction>`.
String- Signed transaction data in HEX formatFunction- (optional) Optional callback, returns an error object as first parameter and the result as second.
PromiEvent: A :ref:`promise combined event emitter <promiEvent>`. Will be resolved when the transaction :ref:`receipt <eth-gettransactionreceipt-return>` is available.
Please see the return values for :ref:`web3.eth.sendTransaction <eth-sendtransaction-return>` for details.
var Tx = require('ethereumjs-tx');
var privateKey = new Buffer('e331b6d69882b4cb4ea581d88e0b604039a3de5967688d3dcffdd2270c0fd109', 'hex')
var rawTx = {
nonce: '0x00',
gasPrice: '0x09184e72a000',
gasLimit: '0x2710',
to: '0x0000000000000000000000000000000000000000',
value: '0x00',
data: '0x7f7465737432000000000000000000000000000000000000000000000000000000600057'
}
var tx = new Tx(rawTx);
tx.sign(privateKey);
var serializedTx = tx.serialize();
// console.log(serializedTx.toString('hex'));
// 0xf889808609184e72a00082271094000000000000000000000000000000000000000080a47f74657374320000000000000000000000000000000000000000000000000000006000571ca08a8bbf888cfa37bbf0bb965423625641fc956967b81d12e23709cead01446075a01ce999b56a8a88504be365442ea61239198e23d1fce7d00fcfc5cd3b44b7215f
web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'))
.on('receipt', console.log);
> // see eth.getTransactionReceipt() for detailsweb3.eth.sign(dataToSign, address [, callback])Signs data using a specific account. This account needs to be unlocked.
String- Data to sign. If String it will be converted using :ref:`web3.utils.utf8ToHex <utils-utf8tohex>`.String|Number- Address to sign data with. Or an address or index of a local wallet in :ref:`web3.eth.accounts.wallet <eth_accounts_wallet>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Note
The 2. address parameter can also be an address or index from the :ref:`web3.eth.accounts.wallet <eth_accounts_wallet>`. It will then sign locally using the private key of this account.
Promise returns String - The signature.
web3.eth.sign("Hello world", "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"
// the below is the same
web3.eth.sign(web3.utils.utf8ToHex("Hello world"), "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"web3.eth.signTransaction(transactionObject, address [, callback])Signs a transaction. This account needs to be unlocked.
Object- The transaction data to sign :ref:`web3.eth.sendTransaction() <eth-sendtransaction>` for more.String- Address to sign transaction with.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Object - The RLP encoded transaction. The raw property can be used to send the transaction using :ref:`web3.eth.sendSignedTransaction <eth-sendsignedtransaction>`.
web3.eth.signTransaction({
from: "0xEB014f8c8B418Db6b45774c326A0E64C78914dC0",
gasPrice: "20000000000",
gas: "21000",
to: '0x3535353535353535353535353535353535353535',
value: "1000000000000000000",
data: ""
}).then(console.log);
> {
raw: '0xf86c808504a817c800825208943535353535353535353535353535353535353535880de0b6b3a76400008025a04f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88da07e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
tx: {
nonce: '0x0',
gasPrice: '0x4a817c800',
gas: '0x5208',
to: '0x3535353535353535353535353535353535353535',
value: '0xde0b6b3a7640000',
input: '0x',
v: '0x25',
r: '0x4f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88d',
s: '0x7e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
hash: '0xda3be87732110de6c1354c83770aae630ede9ac308d9f7b399ecfba23d923384'
}
}web3.eth.call(callObject [, defaultBlock] [, callback])Executes a message call transaction, which is directly executed in the VM of the node, but never mined into the blockchain.
Object- A transaction object see :ref:`web3.eth.sendTransaction <eth-sendtransaction-return>`, with the difference that for calls thefromproperty is optional as well.Number|String- (optional) If you pass this parameter it will not use the default block set with :ref:`web3.eth.defaultBlock <eth-defaultblock>`.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns String: The returned data of the call, e.g. a smart contract functions return value.
web3.eth.call({
to: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", // contract address
data: "0xc6888fa10000000000000000000000000000000000000000000000000000000000000003"
})
.then(console.log);
> "0x000000000000000000000000000000000000000000000000000000000000000a"web3.eth.estimateGas(callObject [, callback])Executes a message call or transaction and returns the amount of the gas used.
Object- A transaction object see :ref:`web3.eth.sendTransaction <eth-sendtransaction-return>`, with the difference that for calls thefromproperty is optional as well.Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Number - the used gas for the simulated call/transaction.
web3.eth.estimateGas({
to: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
data: "0xc6888fa10000000000000000000000000000000000000000000000000000000000000003"
})
.then(console.log);
> "0x0000000000000000000000000000000000000000000000000000000000000015"web3.eth.getPastLogs(options [, callback])Gets past logs, matching the given options.
Object- The filter options as follows:
fromBlock-Number|String: The number of the earliest block ("latest"may be given to mean the most recent and"pending"currently mining, block). By default"latest".toBlock-Number|String: The number of the latest block ("latest"may be given to mean the most recent and"pending"currently mining, block). By default"latest".address-String|Array: An address or a list of addresses to only get logs from particular account(s).topics-Array: An array of values which must each appear in the log entries. The order is important, if you want to leave topics out usenull, e.g.[null, '0x12...']. You can also pass an array for each topic with options for that topic e.g.[null, ['option1', 'option2']]
Promise returns Array - Array of log objects.
The structure of the returned event Object in the Array looks as follows:
address-String: From which this event originated from.data-String: The data containing non-indexed log parameter.topics-Array: An array with max 4 32 Byte topics, topic 1-3 contains indexed parameters of the log.logIndex-Number: Integer of the event index position in the block.transactionIndex-Number: Integer of the transaction's index position, the event was created in.transactionHash32 Bytes -String: Hash of the transaction this event was created in.blockHash32 Bytes -String: Hash of the block where this event was created in.nullwhen its still pending.blockNumber-Number: The block number where this log was created in.nullwhen still pending.
web3.eth.getPastLogs({
address: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
topics: ["0x033456732123ffff2342342dd12342434324234234fd234fd23fd4f23d4234"]
})
.then(console.log);
> [{
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blockNumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{...}]web3.eth.getWork([callback])Gets work for miners to mine on. Returns the hash of the current block, the seedHash, and the boundary condition to be met ("target").
Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Array - the mining work with the following structure:
String32 Bytes - at index 0: current block header pow-hashString32 Bytes - at index 1: the seed hash used for the DAG.String32 Bytes - at index 2: the boundary condition ("target"), 2^256 / difficulty.
web3.eth.getWork()
.then(console.log);
> [
"0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
"0x5EED00000000000000000000000000005EED0000000000000000000000000000",
"0xd1ff1c01710000000000000000000000d1ff1c01710000000000000000000000"
]web3.eth.submitWork(nonce, powHash, digest, [callback])Used for submitting a proof-of-work solution.
String8 Bytes: The nonce found (64 bits)String32 Bytes: The header's pow-hash (256 bits)String32 Bytes: The mix digest (256 bits)Function- (optional) Optional callback, returns an error object as first parameter and the result as second.
Promise returns Boolean - Returns TRUE if the provided solution is valid, otherwise false.
web3.eth.submitWork([
"0x0000000000000001",
"0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
"0xD1FE5700000000000000000000000000D1FE5700000000000000000000000000"
])
.then(console.log);
> true