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Ethereum ABI Utils

Project description

Ethereum Contract
=================

|Build Status| |Documentation Status| |PyPi version|

Python utilities for working with the Ethereum ABI

Installation
------------

.. code:: sh

pip install eth-abi

Documentation
-------------

Decoding
~~~~~~~~

These functions are intended for decoding return values from the EVM.

- ``eth_abi.decode_single(type, data)``

This function tries to decode ``data`` into the python type that
corresponds to the provided ``type``. This function accepts data of type
bytes.

.. code-block:: python

::

>>> decode_single('uint256', b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0009')
12345

The **value** parameter is expected to be one of the recognized EVM
types.

.. note:: This function cannot be used to decode dynamic or array types
such as ``bytes32[]``.

- ``eth_abi.decode_abi(types, data)``

This function decodes ``data`` into the python type corresponding to the
provided ``types``. This function accepts arrays of type byte.

.. code-block:: python

::

>>> decode_abi(['uint256'], b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0009')
[12345]
>>> decode_abi(['bytes32', 'bytes32'], b'a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
['a', 'b']

The **values** parameter is expected to be an iterable whose values are
all one of the recognized EVM types.

Encoding
~~~~~~~~

These functions are intended for encoding python values into
representations that are suitable for interacting with the EVM.

- ``eth_abi.encode_single(type, value)``

This function encodes ``value`` in the ABI encoding for the provided
``type``.

.. code-block:: python

::

>>> encode_single('uint256', 12345)
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0009'

The **value** parameter is expected to be one of the recognized EVM
types.

.. note:: This function cannot be used to encode array types such as
``bytes32[]``.

- ``eth_abi.encode_abi(types, values)``

This function encodes ``values`` in the ABI encoding for the
corresponding type provided by the ``types`` argument.

.. code-block:: python

::

>>> encode_abi(['uint256'], [12345])
b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0009'
>>> encode_abi(['bytes32', 'bytes32'], ['a', 'b'])
b'a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'

The **values** parameter is expected to be an iterable whose values are
all one of the recognized EVM types.

Development
-----------

Clone the repository and then run:

.. code:: sh

pip install -e . -r requirements-dev.txt

Running the tests
~~~~~~~~~~~~~~~~~

You can run the tests with:

.. code:: sh

py.test tests

Or you can install ``tox`` to run the full test suite.

Releasing
~~~~~~~~~

Pandoc is required for transforming the markdown README to the proper
format to render correctly on pypi.

For Debian-like systems:

::

apt install pandoc

Or on OSX:

.. code:: sh

brew install pandoc

To release a new version:

.. code:: sh

make release bump=$$VERSION_PART_TO_BUMP$$

How to bumpversion
^^^^^^^^^^^^^^^^^^

The version format for this repo is ``{major}.{minor}.{patch}`` for
stable, and ``{major}.{minor}.{patch}-{stage}.{devnum}`` for unstable
(``stage`` can be alpha or beta).

To issue the next version in line, specify which part to bump, like
``make release bump=minor`` or ``make release bump=devnum``.

If you are in a beta version, ``make release bump=stage`` will switch to
a stable.

To issue an unstable version when the current version is stable, specify
the new version explicitly, like
``make release bump="--new-version 4.0.0-alpha.1 devnum"``

.. |Build Status| image:: https://circleci.com/gh/ethereum/eth-abi.svg?style=shield
:target: https://circleci.com/gh/ethereum/eth-abi
.. |Documentation Status| image:: https://readthedocs.org/projects/eth-abi/badge/?version=latest
:target: https://readthedocs.org/projects/eth-abi/?badge=latest
.. |PyPi version| image:: https://img.shields.io/pypi/v/eth-abi.svg
:target: https://pypi.python.org/pypi/eth-abi


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