ccurl.interface.py

A python interface to load Ccurl library <https://github.com/iotaledger/ccurl> and perform proof of work locally, without relying on a node. To be used together with PyOTA <https://github.com/iotaledger/iota.py>, the Python Client Library for IOTA. For more info, read the docs <https://pyota.readthedocs.io/en/latest/>__.

Motivation

Currently, PyOTA doesn't support performing proof of work locally. The attach_to_tangle API command sends the prepared transaction trytes to an IOTA node, that does the PoW by filling out attachment_timestamp* fields and calculating nonce with Curl P-81. In case of bundles, transactions are chained together through their transaction hash.

Installation

To use the module, follow the steps: - Clone the repo from GitHub:

$ git clone https://github.com/iotaledger/ccurl.interface.py.git

Make sure you have cmake <https://cmake.org/>__ available on your system. This is a build dependecy for the ccurl library.
Build ccurl according to build instructions <https://github.com/iotaledger/ccurl/blob/master/README.md>__ and put the .so library into the src folder, or run the init script in the main folder to build and initialize:

$ ./init.sh

Create a vitual environment / activate the one you use for PyOTA.
Install th python package from source by running:

$ pip install -e .

How to use?

Once installed, you can use the module to replace attach_to_tangle core api call in PyOTA. Just import the ccurl_interface module from the pow package and you are good to go.

An example code below illustrates how to do PoW for a bundle consisting of two transactions.

Code Example

import iota
from pprint import pprint
from pow import ccurl_interface

# Generate seed
myseed = iota.crypto.types.Seed.random()

# Generate two addresses
addres_generator = iota.crypto.addresses.AddressGenerator(myseed)
addys = addres_generator.get_addresses(1, count=2)

# Preparing transactions
pt = iota.ProposedTransaction(address = iota.Address(addys[0]),
                              tag     = iota.Tag(b'LOCALATTACHINTERFACE99999'),
                              value   = 0)

pt2 = iota.ProposedTransaction(address = iota.Address(addys[1]),
                               tag     = iota.Tag(b'LOCALATTACHINTERFACE99999'),
                               value   = 0)

# Preparing bundle that consists of both transactions prepared in the previous example
pb = iota.ProposedBundle(transactions=[pt2,pt])

# Generate bundle hash
pb.finalize()

# Declare an api instance
api = iota.Iota("https://nodes.thetangle.org:443")

# Get tips to be approved by your bundle
gta = api.get_transactions_to_approve(depth=3)

minimum_weight_magnitude = 14 # target is mainnet

# perform PoW locally
bundle_trytes =\
    ccurl_interface.attach_to_tangle(
        pb.as_tryte_strings(),
        gta['trunkTransaction'],
        gta['branchTransaction'],
        mwm
    )

# Broadcast transactions on the Tangle
broadcasted = api.broadcast_and_store(bundle_trytes)

bundle_broadcasted =iota.Bundle.from_tryte_strings(broadcasted['trytes'])

pprint('Local pow broadcasted transactions are:')
pprint(bundle_broadcasted.as_json_compatible())

Tests

Run nosetests to test in current environment. Run tox -v -p all to test in Python 2.7, 3.5, 3.6 and 3.8.

Contribute

Raise issues: https://github.com/iotaledger/ccurl.interface.py/issues

iotaledger / ccurl.interface.py

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