.. py:module:: web3
.. py:currentmodule:: web3
.. py:class:: Web3(provider)
Each Web3 instance exposes the following APIs.
.. py:attribute:: Web3.HTTPProvider
Convenience API to access :py:class:`web3.providers.rpc.HTTPProvider`
.. py:attribute:: Web3.IPCProvider
Convenience API to access :py:class:`web3.providers.ipc.IPCProvider`
.. py:attribute:: Web3.api
Returns the current Web3 version.
.. code-block:: python
>>> web3.api
"4.7.0"
.. py:attribute:: Web3.clientVersion
* Delegates to ``web3_clientVersion`` RPC Method
Returns the current client version.
.. code-block:: python
>>> web3.clientVersion
'Geth/v1.4.11-stable-fed692f6/darwin/go1.7'
.. py:method:: 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`_
.. code-block:: python
>>> 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'
.. py:method:: Web3.toText(primitive=None, hexstr=None, text=None)
Takes a variety of inputs and returns its string equivalent.
Text gets decoded as UTF-8.
.. code-block:: python
>>> 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'
.. py:method:: Web3.toBytes(primitive=None, hexstr=None, text=None)
Takes a variety of inputs and returns its bytes equivalent.
Text gets encoded as UTF-8.
.. code-block:: python
>>> 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'
.. py:method:: Web3.toInt(primitive=None, hexstr=None, text=None)
Takes a variety of inputs and returns its integer equivalent.
.. code-block:: python
>>> 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
.. py:method:: Web3.toJSON(obj)
Takes a variety of inputs and returns its JSON equivalent.
.. code-block:: python
>>> Web3.toJSON(3)
'3'
>>> Web3.toJSON({'one': 1})
'{"one": 1}'
.. py:method:: Web3.toWei(value, currency)
Returns the value in the denomination specified by the ``currency`` argument
converted to wei.
.. code-block:: python
>>> Web3.toWei(1, 'ether')
1000000000000000000
.. py:method:: 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.
.. code-block:: python
>>> Web3.fromWei(1000000000000000000, 'ether')
Decimal('1')
.. py:method:: 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`_
.. code-block:: python
>>> Web3.isAddress('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
.. py:method:: Web3.isChecksumAddress(value)
Returns ``True`` if the value is a valid `EIP55`_ checksummed address
.. code-block:: python
>>> Web3.isChecksumAddress('0xd3CdA913deB6f67967B99D67aCDFa1712C293601')
True
>>> Web3.isChecksumAddress('0xd3cda913deb6f67967b99d67acdfa1712c293601')
False
.. py:method:: Web3.toChecksumAddress(value)
Returns the given address with an `EIP55`_ checksum.
.. code-block:: python
>>> Web3.toChecksumAddress('0xd3cda913deb6f67967b99d67acdfa1712c293601')
'0xd3CdA913deB6f67967B99D67aCDFa1712C293601'
.. py: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:
.. code-block:: python
>>> Web3.keccak(0x747874)
>>> Web3.keccak(b'\x74\x78\x74')
>>> Web3.keccak(hexstr='0x747874')
>>> Web3.keccak(hexstr='747874')
>>> Web3.keccak(text='txt')
HexBytes('0xd7278090a36507640ea6b7a0034b69b0d240766fa3f98e3722be93c613b29d2e')
.. py: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.
.. code-block:: python
>>> 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:
.. code-block:: solidity
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");
.. py:classmethod:: Web3.sha3(primitive=None, hexstr=None, text=None)
.. WARNING::
This method has been deprecated for :meth:`~Web3.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:
.. code-block:: python
>>> Web3.sha3(0x747874)
>>> Web3.sha3(b'\x74\x78\x74')
>>> Web3.sha3(hexstr='0x747874')
>>> Web3.sha3(hexstr='747874')
>>> Web3.sha3(text='txt')
HexBytes('0xd7278090a36507640ea6b7a0034b69b0d240766fa3f98e3722be93c613b29d2e')
.. py:classmethod:: Web3.soliditySha3(abi_types, value)
.. WARNING::
This method has been deprecated for :meth:`~Web3.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.
.. code-block:: python
>>> 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")
.. py:method:: w3.is_encodable(_type, value)
Returns ``True`` if a value can be encoded as the given type. Otherwise returns ``False``.
.. code-block:: python
>>> 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
.. py:method:: w3.enable_strict_bytes_type_checking()
Enables stricter bytes type checking. For more examples see :ref:`enable-strict-byte-check`
.. doctest::
>>> 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
Each Web3 instance also exposes these namespaced APIs.
.. py:attribute:: Web3.eth
See :doc:`./web3.eth`
.. py:attribute:: Web3.miner
See :doc:`./web3.miner`
.. py:attribute:: Web3.pm
See :doc:`./web3.pm`
.. py:attribute:: Web3.geth
See :doc:`./web3.geth`
.. py:attribute:: Web3.parity
See :doc:`./web3.parity`
Modules that inherit from the web3.module.Module class may be attached to the Web3 instance either at
instantiation or by making use of the attach_modules() method.
To instantiate the Web3 instance with external modules:
>>> from web3 import Web3, EthereumTesterProvider
>>> w3 = Web3(
... EthereumTesterProvider(),
... external_modules={
... # ModuleClass objects in this example inherit from the `web3.module.Module` class
... 'module1': ModuleClass1,
... 'module2': (ModuleClass2, {
... 'submodule1': ModuleClass3,
... 'submodule2': (ModuleClass4, {
... 'submodule2a': ModuleClass5, # submodule children may be nested further if necessary
... })
... })
... }
... )
# `return_zero`, in this case, is an example attribute of the `ModuleClass1` object
>>> w3.module1.return_zero
0
>>> w3.module2.submodule1.return_one
1
>>> w3.module2.submodule2.submodule2a.return_two
2.. py:method:: w3.attach_modules(modules)
The ``attach_modules()`` method can be used to attach external modules after the ``Web3`` instance has been
instantiated.
Modules are attached via a `dict` with module names as the keys. The values can either be the module classes
themselves, if there are no submodules, or two-item tuples with the module class as the 0th index and a similarly
built `dict` containing the submodule information as the 1st index. This pattern may be repeated as necessary.
.. note:: Module classes must inherit from the ``web3.module.Module`` class.
.. code-block:: python
>>> from web3 import Web3, EthereumTesterProvider
>>> w3 = Web3(EthereumTesterProvider())
>>> w3.attach_modules({
... 'module1': ModuleClass1, # the module class itself may be used for a single module with no submodules
... 'module2': (ModuleClass2, { # a tuple with module class and corresponding submodule dict may be used for modules with submodules
... 'submodule1': ModuleClass3,
... 'submodule2': (ModuleClass4, { # this pattern may be repeated as necessary
... 'submodule2a': ModuleClass5,
... })
... })
... })
>>> w3.module1.return_zero
0
>>> w3.module2.submodule1.return_one
1
>>> w3.module2.submodule2.submodule2a.return_two
2