Introduction

django-bitcoin is a Django web framework <http://djangoproject.com/>_ application for building Bitcoin web apps.

.. contents ::

Features

• Simple Bitcoin wallet management

• Bitcoin payment processing

• Bitcoin market information

Installation

django-bitcoin requires memcached (for locks) in order to run, and whatever you want to use for your celery queue.

Execute pip install -r django_bitcoin/requirements.txt

If you want to use the mock objects included, note that mock==0.8.0 is required. The mocksignature feature was later dropped in favor of autospeccing, but django-bitcoin doesn't support that yet.

Finally, just add the app to your settings.py INSTALLED_APPS like::

INSTALLED_APPS = [
    ...
    'django_bitcoin',
    ...
]

Also you have to run a local bitcoind instance, and specify connection string in settings::

BITCOIND_CONNECTION_STRING = "http://bitcoinuser:password@localhost:8332"

Usage

Wallet websites, escrow services using the "Wallet" model

You can use the Wallet class to do different bitcoin-moving applications. Typical example would be a marketplace-style site, where there are multiple sellers and buyer. Or job freelance site, where escrow is needed. Or even an exchange could be done with this abstraction (a little extra classes would be needed however).

Note that while you move bitcoins between Wallet-objects, only bitcoin transactions needed are incoming and outgoing transactions. Transactions between the system "Wallet"-objects don't generate "real" bitcoin transactions. Every transaction (except incoming transactions) is logged to WalletTransaction object to ease accounting.

This also means that outgoing bitcoin transactions are "mixed"::

from django_bitcoin import Wallet, currency

class Profile(models.Model):
    wallet = ForeignKey(Wallet)
    outgoing_bitcoin_address = CharField()

class Escrow(models.Model):
    wallet = ForeignKey(Wallet)
    buyer_happy = BooleanField(default=False)

buyer = Profile.objects.create()
seller = Profile.objects.create()

purchase = Escrow.objects.create()

AMOUNT_USD = "9.99"

m = currency.Money(AMOUNT_USD, "USD")
btc_amount = currency.exchange(m, "BTC")

print "Send " + str(btc_amount) + " BTC to address " + buyer.wallet.receiving_address()

sleep(5000)  # wait for transaction

if p1.wallet.total_balance() >= btc_amount:
    p1.send_to_wallet(purchase, btc_amount)

    sleep(1000)  # wait for product/service delivery

    if purchase.buyer_happy:
        purchase.wallet.send_to_wallet(seller.wallet)
        seller.wallet.send_to_address(seller.outgoing_bitcoin_address, seller.wallet.total_balance())
    else:
        print "WHY U NO HAPPY"
        # return bitcoins to buyer, 50/50 split or something

Templatetags

To display transaction history and simple wallet tagline in your views, use the following templatetags::

{% load currency_conversions %}
<!-- display balance tagline, estimate in USD and received/sent -->
{% wallet_tagline profile.bitcoin_wallet %}
<!-- display list of transactions as a table -->
{% wallet_history profile.bitcoin_wallet %}

Easy way to convert currencies from each other: btc2usd, usd2btc, eur2btc, btc2eur

Also currency2btc, btc2currency for any currencies on bitcoincharts.com::

{% load currency_conversions %}
Hi, for the pizza: send me {{bitcoin_amount}}BTC (about {{ bitcoin_amount|btc2usd }}USD).

Display QR code of the bitcoin payment using google charts API::

{% load currency_conversions %}
Pay the following payment with your android bitcoin wallet:
{% bitcoin_payment_qr wallet.receiving_address bitcoin_amount %}.

The same but display also description and an estimate in EUR:
{% bitcoin_payment_qr wallet.receiving_address bitcoin_amount "One beer" "EUR" %}.

Transaction notifications

To enable bitcoin transaction notifications, set the following flag in your settings.py::

BITCOIN_TRANSACTION_SIGNALING = True

After that, you need to setup a cron job to run each minute, something like the following::

* * * * * (cd $APP_PATH && python manage.py python manage.py CheckTransactions >> $APP_PATH/logs/email_sends.log 2>&1)

After that you can define your balance_changed and balance_changed_confirmed signals::

from django_bitcoin.models import balance_changed, balance_changed_confirmed
from django.dispatch import receiver


@receiver(balance_changed)
def balance_changed_handler(sender, **kwargs):
    pass
    # try:
    # print "balance changed", sender.id, kwargs["changed"], sender.total_balance()


@receiver(balance_changed_confirmed)
def balance_changed_confirmed_handler(sender, **kwargs):
    pass

Community

Currently django-bitcoin is used at production in

• Probably nowhere

More to come?

If you have a site using django-bitcoin, drop me an email and I will link to it here.

Support and source code

Issue tracker at Github.com

Links

On confirmation numbers

http://eprint.iacr.org/2012/248.pdf
http://blockchain.info/double-spends