web3.eth¶
The web3-eth package allows you to interact with an Ethereum blockchain and Ethereum smart contracts.
Note on checksum addresses¶
All 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.
Example¶
subscribe¶
For web3.eth.subscribe see the Subscribe reference documentation
Contract¶
For web3.eth.Contract see the Contract reference documentation
Iban¶
For web3.eth.Iban see the Iban reference documentation
personal¶
For web3.eth.personal see the personal reference documentation
accounts¶
For web3.eth.accounts see the accounts reference documentation
ens¶
For web3.eth.ens see the ENS reference documentation
abi¶
For web3.eth.abi see the ABI reference documentation
net¶
For web3.eth.net see the net reference documentation
setProvider¶
Will change the provider for its module.
Note
When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.
Parameters¶
- Object - myProvider: a valid provider.
Returns¶
Boolean
Example¶
providers¶
Contains the current available providers.
Value¶
Object with the following providers:
- Object - HttpProvider: The HTTP provider is deprecated, as it wont work for subscriptions.
- Object - WebsocketProvider: The Websocket provider is the standard for usage in legacy browsers.
- Object - IpcProvider: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.
Example¶
givenProvider¶
When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the [browser] environment, otherwise null.
Returns¶
Object: The given provider set or null;
Example¶
currentProvider¶
Will return the current provider, otherwise null.
Returns¶
Object: The current provider set or null;
Example¶
BatchRequest¶
Class to create and execute batch requests.
Parameters¶
none
Returns¶
Object: With the following methods:
- add[request]: To add a request object to the batch call.
- execute[]: Will execute the batch request.
Example¶
extend¶
Allows extending the web3 modules.
Note
You also have *.extend.formatters as additional formatter functions to be used for in and output formatting. Please see the source file for function details.
Parameters¶
- methods - Object: Extension object with array of methods description objects as follows:
- property - String: [optional] The name of the property to add to the module. If no property is set it will be added to the module directly.
- methods - Array: The array of method descriptions:
- name - String: Name of the method to add.
- call - String: The RPC method name.
- params - Number: [optional] The number of parameters for that function. Default 0.
- inputFormatter - Array: [optional] Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a null instead.
- outputFormatter - ``Function: [optional] Can be used to format the output of the method.
Returns¶
Object: The extended module.
Example¶
defaultAccount¶
This default address is used as the default "from" property, if no "from" property is specified in for the following methods:
- web3.eth.sendTransaction[]
- web3.eth.call[]
- new web3.eth.Contract[] -> myContract.methods.myMethod[].call[]
- new web3.eth.Contract[] -> myContract.methods.myMethod[].send[]
Property¶
String - 20 Bytes: Any ethereum address. You should have the private key for that address in your node or keystore. [Default is undefined]
Example¶
defaultBlock¶
The default block is used for certain methods. You can override it by passing in the defaultBlock as last parameter. The default value is latest.
- web3.eth.getBalance[]
- web3.eth.getCode[]
- web3.eth.getTransactionCount[]
- web3.eth.getStorageAt[]
- web3.eth.call[]
- new web3.eth.Contract[] -> myContract.methods.myMethod[].call[]
Property¶
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"
Example¶
defaultHardfork¶
The default hardfork property is used for signing transactions locally.
Property¶
The default hardfork property can be one of the following:
- "chainstart" - String
- "homestead" - String
- "dao" - String
- "tangerineWhistle" - String
- "spuriousDragon" - String
- "byzantium" - String
- "constantinople" - String
- "petersburg" - String
- "istanbul" - String
Default is "petersburg"
Example¶
defaultChain¶
The default chain property is used for signing transactions locally.
Property¶
The default chain property can be one of the following:
- "mainnet" - String
- "goerli" - String
- "kovan" - String
- "rinkeby" - String
- "ropsten" - String
Default is "mainnet"
Example¶
defaultCommon¶
The default common property is used for signing transactions locally.
Property¶
The default common property does contain the following Common object:
- customChain - Object: The custom chain properties
- name - string: [optional] The name of the chain
- networkId - number: Network ID of the custom chain
- chainId - number: Chain ID of the custom chain
- baseChain - string: [optional] mainnet, goerli, kovan, rinkeby, or ropsten
- hardfork - string: [optional] chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul
Default is undefined.
Example¶
transactionBlockTimeout¶
The transactionBlockTimeout will be used over a socket based connection. This option does define the amount of new blocks it should wait until the first confirmation happens. This means the PromiEvent rejects with a timeout error when the timeout got exceeded.
Returns¶
number: The current value of transactionBlockTimeout [default: 50]
transactionConfirmationBlocks¶
This defines the number of blocks it requires until a transaction will be handled as confirmed.
Returns¶
number: The current value of transactionConfirmationBlocks [default: 24]
transactionPollingTimeout¶
The transactionPollingTimeout will be used over a HTTP connection. This option defines the number of seconds Web3 will wait for a receipt which confirms that a transaction was mined by the network. NB: If this method times out, the transaction may still be pending.
Returns¶
number: The current value of transactionPollingTimeout [default: 750]
getProtocolVersion¶
Returns the ethereum protocol version of the node.
Returns¶
Promise returns String: the protocol version.
Example¶
isSyncing¶
Checks if the node is currently syncing and returns either a syncing object, or false.
Returns¶
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 download
- pulledStates - Number: The already downloaded states
Example¶
getCoinbase¶
Returns the coinbase address to which mining rewards will go.
Returns¶
Promise returns String - bytes 20: The coinbase address set in the node for mining rewards.
Example¶
isMining¶
Checks whether the node is mining or not.
Returns¶
Promise returns Boolean: true if the node is mining, otherwise false.
Example¶
getHashrate¶
Returns the number of hashes per second that the node is mining with.
Returns¶
Promise returns Number: Number of hashes per second.
Example¶
getGasPrice¶
Returns the current gas price oracle. The gas price is determined by the last few blocks median gas price.
Returns¶
Promise returns String - Number string of the current gas price in wei.
See the A note on dealing with big numbers in JavaScript.
Example¶
getAccounts¶
Returns a list of accounts the node controls.
Returns¶
Promise returns Array - An array of addresses controlled by node.
Example¶
getBlockNumber¶
Returns the current block number.
Returns¶
Promise returns Number - The number of the most recent block.
Example¶
getBalance¶
Get the balance of an address at a given block.
Parameters¶
- 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 web3.eth.defaultBlock.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns String - The current balance for the given address in wei.
See the A note on dealing with big numbers in JavaScript.
Example¶
getStorageAt¶
Get the storage at a specific position of an address.
Parameters¶
- 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 web3.eth.defaultBlock.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns String - The value in storage at the given position.
Example¶
getCode¶
Get the code at a specific address.
Parameters¶
- 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 web3.eth.defaultBlock.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns String - The data at given address address.
Example¶
getBlock¶
Returns a block matching the block number or block hash.
Parameters¶
- String|Number - The block number or block hash. Or the string "genesis", "latest" or "pending" as in the default block parameter.
- Boolean - [optional, default false] If true, the returned block will contain all transactions as objects, if false it will only contains the transaction hashes.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Object - The block object:
- number - Number: The block number. null when its pending block.
- hash 32 Bytes - String: Hash of the block. null when its pending block.
- parentHash 32 Bytes - String: Hash of the parent block.
- nonce 8 Bytes - String: Hash of the generated proof-of-work. null when its pending block.
- sha3Uncles 32 Bytes - String: SHA3 of the uncles data in the block.
- logsBloom 256 Bytes - String: The bloom filter for the logs of the block. null when its pending block.
- transactionsRoot 32 Bytes - String: The root of the transaction trie of the block
- stateRoot 32 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 the returnTransactionObjects parameter.
- uncles - Array: Array of uncle hashes.
Example¶
getBlockTransactionCount¶
Returns the number of transaction in a given block.
Parameters¶
- String|Number - The block number or hash. Or the string "genesis", "latest" or "pending" as in the default block parameter.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Number - The number of transactions in the given block.
Example¶
getUncle¶
Returns a blocks uncle by a given uncle index position.
Parameters¶
- String|Number - The block number or hash. Or the string "genesis", "latest" or "pending" as in the default block parameter.
- Number - The index position of the uncle.
- Boolean - [optional, default false] If true, the returned block will contain all transactions as objects, if false it will only contains the transaction hashes.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Object - the returned uncle. For a return value see web3.eth.getBlock[].
Note
An uncle doesnt contain individual transactions.
Example¶
getTransaction¶
Returns a transaction matching the given transaction hash.
Parameters¶
- String - The transaction hash.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Object - A transaction object its hash transactionHash:
- hash 32 Bytes - String: Hash of the transaction.
- nonce - Number: The number of transactions made by the sender prior to this one.
- blockHash 32 Bytes - String: Hash of the block where this transaction was in. null when its pending.
- blockNumber - Number: Block number where this transaction was in. null when its pending.
- transactionIndex - Number: Integer of the transactions index position in the block. null when its pending.
- from - String: Address of the sender.
- to - String: Address of the receiver. null when its a contract creation transaction.
- value - String: Value transferred in wei.
- gasPrice - String: Gas price provided by the sender in wei.
- gas - Number: Gas provided by the sender.
- input - String: The data sent along with the transaction.
Example¶
getTransactionFromBlock¶
Returns a transaction based on a block hash or number and the transactions index position.
Parameters¶
- String - A block number or hash. Or the string "genesis", "latest" or "pending" as in the default block parameter.
- Number - The transactions index position.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Object - A transaction object, see web3.eth.getTransaction:
Example¶
getTransactionReceipt¶
Returns the receipt of a transaction by transaction hash.
Note
The receipt is not available for pending transactions and returns null.
Parameters¶
- String - The transaction hash.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Object - A transaction receipt object, or null when no receipt was found:
- status - Boolean: TRUE if the transaction was successful, FALSE, if the EVM reverted the transaction.
- blockHash 32 Bytes - String: Hash of the block where this transaction was in.
- blockNumber - Number: Block number where this transaction was in.
- transactionHash 32 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. null when its a contract creation transaction.
- contractAddress - String: The contract address created, if the transaction was a contract creation, otherwise null.
- 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.
Example¶
getTransactionCount¶
Get the numbers of transactions sent from this address.
Parameters¶
- 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 web3.eth.defaultBlock.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Number - The number of transactions sent from the given address.
Example¶
sendTransaction¶
Sends a transaction to the network.
Parameters¶
- Object - The transaction object to send:
- from - String|Number: The address for the sending account. Uses the web3.eth.defaultAccount property, if not specified. Or an address or index of a local wallet in web3.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 wei, also the endowment if its 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 wei, defaults to web3.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.
- chain - String: [optional] Defaults to mainnet.
- hardfork - String: [optional] Defaults to petersburg.
- common - Object: [optional] The common object
- customChain - Object: The custom chain properties
- name - string: [optional] The name of the chain
- networkId - number: Network ID of the custom chain
- chainId - number: Chain ID of the custom chain
- baseChain - string: [optional] mainnet, goerli, kovan, rinkeby, or ropsten
- hardfork - string: [optional] chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul
- customChain - Object: The custom chain properties
- 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 web3.eth.accounts.wallet. It will then sign locally using the private key of that account, and send the transaction via web3.eth.sendSignedTransaction[]. If the properties chain and hardfork or common are not set, Web3 will try to set appropriate values by
querying the network for its chainId and networkId.
Returns¶
The callback will return the 32 bytes transaction hash.
PromiEvent: A promise combined event emitter. Will be resolved when the transaction receipt is available. Additionally the following events are available:
- "transactionHash" returns String: Is fired right after the transaction is sent and a transaction hash is available.
- "receipt" returns Object: Is fired when the transaction receipt is available.
- "confirmation" returns Number, Object: Is fired for every confirmation up to the 12th confirmation. Receives the confirmation number as the first and the receipt as the second argument. Fired from confirmation 0 on, which is the block where its minded.
"error" returns Error and Object|undefined: Is fired if an error occurs during sending. If the transaction was rejected by the network with a receipt, the second parameter will be the receipt.
Example¶
sendSignedTransaction¶
Sends an already signed transaction, generated for example using web3.eth.accounts.signTransaction.
Parameters¶
- String - Signed transaction data in HEX format
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
PromiEvent: A promise combined event emitter. Will be resolved when the transaction receipt is available.
Please see the return values for web3.eth.sendTransaction for details.
Example¶
Note
When use the package ethereumjs-tx at the version of 2.0.0, if we dont specify the parameter chain, it will use mainnet, so if you wan to use at the other network, you should add this parameter chain to specify.
sign¶
Signs data using a specific account. This account needs to be unlocked.
Parameters¶
- String - Data to sign. If String it will be converted using web3.utils.utf8ToHex.
- String|Number - Address to sign data with. Or an address or index of a local wallet in web3.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 web3.eth.accounts.wallet. It will then sign locally using the private key of this account.
Returns¶
Promise returns String - The signature.
Example¶
signTransaction¶
Signs a transaction. This account needs to be unlocked.
Parameters¶
- Object - The transaction data to sign web3.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.
Returns¶
Promise returns Object - The RLP encoded transaction. The raw property can be used to send the transaction using web3.eth.sendSignedTransaction.
Example¶
call¶
Executes a message call transaction, which is directly executed in the VM of the node, but never mined into the blockchain.
Parameters¶
- Object - A transaction object see web3.eth.sendTransaction, with the difference that for calls the from property is optional as well.
- Number|String - [optional] If you pass this parameter it will not use the default block set with web3.eth.defaultBlock.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns String: The returned data of the call, e.g. a smart contract functions return value.
Example¶
estimateGas¶
Executes a message call or transaction and returns the amount of the gas used.
Parameters¶
- Object - A transaction object see web3.eth.sendTransaction, with the difference that for calls the from property is optional as well.
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Number - the used gas for the simulated call/transaction.
Example¶
getPastLogs¶
Gets past logs, matching the given options.
Parameters¶
- 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 use null, e.g. [null, '0x12...']. You can also pass an array for each topic with options for that topic e.g. [null, ['option1', 'option2']]
Returns¶
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 transactions index position, the event was created in.
- transactionHash 32 Bytes - String: Hash of the transaction this event was created in.
- blockHash 32 Bytes - String: Hash of the block where this event was created in. null when its still pending.
- blockNumber - Number: The block number where this log was created in. null when still pending.
Example¶
getWork¶
Gets work for miners to mine on. Returns the hash of the current block, the seedHash, and the boundary condition to be met [target].
Parameters¶
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Array - the mining work with the following structure:
- String 32 Bytes - at index 0: current block header pow-hash
- String 32 Bytes - at index 1: the seed hash used for the DAG.
- String 32 Bytes - at index 2: the boundary condition [target], 2^256 / difficulty.
Example¶
submitWork¶
Used for submitting a proof-of-work solution.
Parameters¶
- String 8 Bytes: The nonce found [64 bits]
- String 32 Bytes: The headers pow-hash [256 bits]
- String 32 Bytes: The mix digest [256 bits]
- Function - [optional] Optional callback, returns an error object as first parameter and the result as second.
Returns¶
Promise returns Boolean - Returns TRUE if the provided solution is valid, otherwise false.
Example¶
getChainId¶
Returns the chain ID of the current connected node as described in the EIP-695.
Returns¶
Promise - Returns chain ID.
Example¶
getNodeInfo¶
Returns¶
Promise - The current client version.