python-bitcoinlib

-----------------

This Python2/3 library provides an easy interface to the bitcoin data

structures and protocol. The approach is low-level and "ground up", with a

focus on providing tools to manipulate the internals of how Bitcoin works.

"The Swiss Army Knife of the Bitcoin protocol." - Wladimir J. van der Laan

Requirements

------------

sudo apt-get install libssl-dev

The RPC interface, bitcoin.rpc, is designed to work with Bitcoin Core v0.11.0

Older versions mostly work but there do exist some incompatibilities.

Structure

---------

Everything consensus critical is found in the modules under bitcoin.core. This

rule is followed pretty strictly, for instance chain parameters are split into

consensus critical and non-consensus-critical.

bitcoin.core - Basic core definitions, datastructures, and

(context-independent) validation

bitcoin.core.key - ECC pubkeys

bitcoin.core.script - Scripts and opcodes

bitcoin.core.scripteval - Script evaluation/verification

bitcoin.core.serialize - Serialization

In the future the bitcoin.core may use the Satoshi sourcecode directly as a

library. Non-consensus critical modules include the following:

bitcoin - Chain selection

bitcoin.base58 - Base58 encoding

bitcoin.bloom - Bloom filters (incomplete)

bitcoin.net - Network communication (in flux)

bitcoin.messages - Network messages (in flux)

bitcoin.rpc - Bitcoin Core RPC interface support

bitcoin.wallet - Wallet-related code, currently Bitcoin address and private

key support

Effort has been made to follow the Satoshi source relatively closely, for

instance Python code and classes that duplicate the functionality of

corresponding Satoshi C++ code uses the same naming conventions: CTransaction,

CBlockHeader, nValue etc. Otherwise Python naming conventions are followed.

Mutable vs. Immutable objects

-----------------------------

Like the Bitcoin Core codebase CTransaction is immutable and

CMutableTransaction is mutable; unlike the Bitcoin Core codebase this

distinction also applies to COutPoint, CTxIn, CTxOut, and CBlock.

Endianness Gotchas

------------------

Rather confusingly Bitcoin Core shows transaction and block hashes as

little-endian hex rather than the big-endian the rest of the world uses for

SHA256. python-bitcoinlib provides the convenience functions x() and lx() in

bitcoin.core to convert from big-endian and little-endian hex to raw bytes to

accomodate this. In addition see b2x() and b2lx() for conversion from bytes to

big/little-endian hex.

Module import style

-------------------

While not always good style, it's often convenient for quick scripts if import

* can be used. To support that all the modules have __all__ defined

appropriately.

Example Code

------------

See examples/ directory. For instance this example creates a transaction

spending a pay-to-script-hash transaction output:

$ PYTHONPATH=. examples/spend-pay-to-script-hash-txout.py

<hex-encoded transaction>

Also see dust-b-gone for a simple example of Bitcoin Core wallet interaction

through the RPC interface: https://github.com/petertodd/dust-b-gone

Selecting the chain to use

--------------------------

Do the following:

import bitcoin

bitcoin.SelectParams(NAME)

Where NAME is one of 'testnet', 'mainnet', or 'regtest'. The chain currently

selected is a global variable that changes behavior everywhere, just like in

the Satoshi codebase.

Unit tests

----------

Under bitcoin/tests using test data from Bitcoin Core. To run them:

python -m unittest discover && python3 -m unittest discover

Please run the tests on both Python2 and Python3 for your pull-reqs!

Alternately, if Tox (see https://tox.readthedocs.org/) is available on your

system, you can run unit tests for multiple Python versions:

./runtests.sh

Currently, the following implementations are tried (any not installed are

skipped):

* CPython 2.7

* CPython 3.3

* CPython 3.4

* CPython 3.5

* PyPy

* PyPy3

HTML coverage reports can then be found in the htmlcov/ subdirectory.

Documentation

-------------

Sphinx documentation is in the "doc" subdirectory. Run "make help" from there

to see how to build. You will need the Python "sphinx" package installed.

Currently this is just API documentation generated from the code and

docstrings. Higher level written docs would be useful, perhaps starting with

much of this README. Pages are written in reStructuredText and linked from

index.rst.