Web3 API¶

Providers
Attributes
Encoding and Decoding Helpers
Currency Conversions
Addresses
Cryptographic Hashing
Check Encodability
RPC APIS

class web3.Web3(provider)¶

Each web3 instance exposes the following APIs.

Providers ¶

Web3.HTTPProvider¶: Convenience API to access web3.providers.rpc.HTTPProvider

Web3.IPCProvider¶: Convenience API to access web3.providers.ipc.IPCProvider

Attributes ¶

Web3.api¶

Returns the current Web3 version.

>>> web3.api
"4.7.0"

Web3.clientVersion¶

Delegates to web3_clientVersion RPC Method

Returns the current client version.

>>> web3.clientVersion
'Geth/v1.4.11-stable-fed692f6/darwin/go1.7'

Encoding and Decoding Helpers ¶

Web3.toHex(primitive=None, hexstr=None, text=None)¶

Takes a variety of inputs and returns it in its hexadecimal representation. It follows the rules for converting to hex in the JSON-RPC spec

>>> Web3.toHex(0)
'0x0'
>>> Web3.toHex(1)
'0x1'
>>> Web3.toHex(0x0)
'0x0'
>>> Web3.toHex(0x000F)
'0xf'
>>> Web3.toHex(b'')
'0x'
>>> Web3.toHex(b'\x00\x0F')
'0x000f'
>>> Web3.toHex(False)
'0x0'
>>> Web3.toHex(True)
'0x1'
>>> Web3.toHex(hexstr='0x000F')
'0x000f'
>>> Web3.toHex(hexstr='000F')
'0x000f'
>>> Web3.toHex(text='')
'0x'
>>> Web3.toHex(text='cowmö')
'0x636f776dc3b6'

Web3.toText(primitive=None, hexstr=None, text=None)¶

Takes a variety of inputs and returns its string equivalent. Text gets decoded as UTF-8.

>>> Web3.toText(0x636f776dc3b6)
'cowmö'
>>> Web3.toText(b'cowm\xc3\xb6')
'cowmö'
>>> Web3.toText(hexstr='0x636f776dc3b6')
'cowmö'
>>> Web3.toText(hexstr='636f776dc3b6')
'cowmö'
>>> Web3.toText(text='cowmö')
'cowmö'

Web3.toBytes(primitive=None, hexstr=None, text=None)¶

Takes a variety of inputs and returns its bytes equivalent. Text gets encoded as UTF-8.

>>> Web3.toBytes(0)
b'\x00'
>>> Web3.toBytes(0x000F)
b'\x0f'
>>> Web3.toBytes(b'')
b''
>>> Web3.toBytes(b'\x00\x0F')
b'\x00\x0f'
>>> Web3.toBytes(False)
b'\x00'
>>> Web3.toBytes(True)
b'\x01'
>>> Web3.toBytes(hexstr='0x000F')
b'\x00\x0f'
>>> Web3.toBytes(hexstr='000F')
b'\x00\x0f'
>>> Web3.toBytes(text='')
b''
>>> Web3.toBytes(text='cowmö')
b'cowm\xc3\xb6'

Web3.toInt(primitive=None, hexstr=None, text=None)¶

Takes a variety of inputs and returns its integer equivalent.

>>> Web3.toInt(0)
0
>>> Web3.toInt(0x000F)
15
>>> Web3.toInt(b'\x00\x0F')
15
>>> Web3.toInt(False)
0
>>> Web3.toInt(True)
1
>>> Web3.toInt(hexstr='0x000F')
15
>>> Web3.toInt(hexstr='000F')
15

Web3.toJSON(obj)¶

Takes a variety of inputs and returns its JSON equivalent.

>>> Web3.toJSON(3)
'3'
>>> Web3.toJSON({'one': 1})
'{"one": 1}'

Currency Conversions ¶

Web3.toWei(value, currency)¶

Returns the value in the denomination specified by the currency argument converted to wei.

>>> Web3.toWei(1, 'ether')
1000000000000000000

Web3.fromWei(value, currency)¶

Returns the value in wei converted to the given currency. The value is returned as a Decimal to ensure precision down to the wei.

>>> Web3.fromWei(1000000000000000000, 'ether')
Decimal('1')

Addresses ¶

Web3.isAddress(value)¶

Returns True if the value is one of the recognized address formats.

Allows for both 0x prefixed and non-prefixed values.
If the address contains mixed upper and lower cased characters this function also checks if the address checksum is valid according to EIP55

>>> Web3.isAddress('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True

Web3.isChecksumAddress(value)¶

Returns True if the value is a valid EIP55 checksummed address

>>> Web3.isChecksumAddress('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> Web3.isChecksumAddress('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False

Web3.toChecksumAddress(value)¶

Returns the given address with an EIP55 checksum.

>>> Web3.toChecksumAddress('0xd3cda913deb6f67967b99d67acdfa1712c293601')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'

Cryptographic Hashing ¶

classmethod Web3.keccak(primitive=None, hexstr=None, text=None)¶

Returns the Keccak-256 of the given value. Text is encoded to UTF-8 before computing the hash, just like Solidity. Any of the following are valid and equivalent:

>>> Web3.keccak(0x747874)
>>> Web3.keccak(b'\x74\x78\x74')
>>> Web3.keccak(hexstr='0x747874')
>>> Web3.keccak(hexstr='747874')
>>> Web3.keccak(text='txt')
HexBytes('0xd7278090a36507640ea6b7a0034b69b0d240766fa3f98e3722be93c613b29d2e')

classmethod Web3.solidityKeccak(abi_types, value)¶

Returns the Keccak-256 as it would be computed by the solidity keccak function on a packed ABI encoding of the value list contents. The abi_types argument should be a list of solidity type strings which correspond to each of the provided values.

>>> Web3.solidityKeccak(['bool'], [True])
HexBytes("0x5fe7f977e71dba2ea1a68e21057beebb9be2ac30c6410aa38d4f3fbe41dcffd2")

>>> Web3.solidityKeccak(['uint8', 'uint8', 'uint8'], [97, 98, 99])
HexBytes("0x4e03657aea45a94fc7d47ba826c8d667c0d1e6e33a64a036ec44f58fa12d6c45")

>>> Web3.solidityKeccak(['uint8[]'], [[97, 98, 99]])
HexBytes("0x233002c671295529bcc50b76a2ef2b0de2dac2d93945fca745255de1a9e4017e")

>>> Web3.solidityKeccak(['address'], ["0x49EdDD3769c0712032808D86597B84ac5c2F5614"])
HexBytes("0x2ff37b5607484cd4eecf6d13292e22bd6e5401eaffcc07e279583bc742c68882")

>>> Web3.solidityKeccak(['address'], ["ethereumfoundation.eth"])
HexBytes("0x913c99ea930c78868f1535d34cd705ab85929b2eaaf70fcd09677ecd6e5d75e9")

Comparable solidity usage:

bytes32 data1 = keccak256(abi.encodePacked(true));
assert(data1 == hex"5fe7f977e71dba2ea1a68e21057beebb9be2ac30c6410aa38d4f3fbe41dcffd2");
bytes32 data2 = keccak256(abi.encodePacked(uint8(97), uint8(98), uint8(99)));
assert(data2 == hex"4e03657aea45a94fc7d47ba826c8d667c0d1e6e33a64a036ec44f58fa12d6c45");

classmethod Web3.sha3(primitive=None, hexstr=None, text=None)¶

Warning

This method has been deprecated for keccak()

Returns the Keccak SHA256 of the given value. Text is encoded to UTF-8 before computing the hash, just like Solidity. Any of the following are valid and equivalent:

>>> Web3.sha3(0x747874)
>>> Web3.sha3(b'\x74\x78\x74')
>>> Web3.sha3(hexstr='0x747874')
>>> Web3.sha3(hexstr='747874')
>>> Web3.sha3(text='txt')
HexBytes('0xd7278090a36507640ea6b7a0034b69b0d240766fa3f98e3722be93c613b29d2e')

classmethod Web3.soliditySha3(abi_types, value)¶

Warning

This method has been deprecated for solidityKeccak()

Returns the sha3 as it would be computed by the solidity sha3 function on the provided value and abi_types. The abi_types value should be a list of solidity type strings which correspond to each of the provided values.

>>> Web3.soliditySha3(['bool'], [True])
HexBytes("0x5fe7f977e71dba2ea1a68e21057beebb9be2ac30c6410aa38d4f3fbe41dcffd2")

>>> Web3.soliditySha3(['uint8', 'uint8', 'uint8'], [97, 98, 99])
HexBytes("0x4e03657aea45a94fc7d47ba826c8d667c0d1e6e33a64a036ec44f58fa12d6c45")

>>> Web3.soliditySha3(['uint8[]'], [[97, 98, 99]])
HexBytes("0x233002c671295529bcc50b76a2ef2b0de2dac2d93945fca745255de1a9e4017e")

>>> Web3.soliditySha3(['address'], ["0x49EdDD3769c0712032808D86597B84ac5c2F5614"])
HexBytes("0x2ff37b5607484cd4eecf6d13292e22bd6e5401eaffcc07e279583bc742c68882")

>>> Web3.soliditySha3(['address'], ["ethereumfoundation.eth"])
HexBytes("0x913c99ea930c78868f1535d34cd705ab85929b2eaaf70fcd09677ecd6e5d75e9")

Check Encodability ¶

w3.is_encodable(_type, value)¶

Returns True if a value can be encoded as the given type. Otherwise returns False.

>>> from web3.auto.gethdev import w3
>>> w3.is_encodable('bytes2', b'12')
True
>>> w3.is_encodable('bytes2', b'1')
True
>>> w3.is_encodable('bytes2', '0x1234')
True
>>> w3.is_encodable('bytes2', b'123')
False

w3.enable_strict_bytes_type_checking()¶

Enables stricter bytes type checking. For more examples see Enabling Strict Checks for Bytes Types

>>> from web3.auto.gethdev import w3
>>> w3.enable_strict_bytes_type_checking()
>>> w3.is_encodable('bytes2', b'12')
True
>>> w3.is_encodable('bytes2', b'1')
False

RPC APIS ¶

Each web3 instance also exposes these namespaced APIs.

Web3.eth¶: See web3.eth API

Web3.miner¶: See Miner API

Web3.pm¶: See Package Manager API

Web3.geth¶: See Geth API

Web3.parity¶: See Parity API