ens 0.6.1
Ethereum Name Service, made easy in Python
License: MIT
Requires Python: >=3.5
Keywords: ethereum eth web3 web3.py ENS

Ethereum Name Service via Python
================================

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Access the Ethereum Name Service using this python library. Note: **this
is a work in progress**

Using this library is not a way to skip learning how ENS works. If you
are registering a name, a small misunderstanding can cause you to lose
**all** your deposit. Go `read about
ENS <http://docs.ens.domains/en/latest/userguide.html>`__ first. Your
funds are your responsibility.

Beta-quality warning
--------------------

This is a preview for developers, and an invitation for contributions.
Please do not use this in production until this warning is removed,
especially when putting funds at risk. Examples of funds being at risk
include: sending ether/tokens to resolved addresses and participating in
name auctions.

If you supply the a domain with type ``bytes``, it will be assumed to be
UTF-8 encoded, like in `Ethereum
contracts <https://github.com/ethereum/wiki/wiki/Ethereum-Contract-ABI#argument-encoding>`__.

Setup
-----

::

    pip install ens

Any issues? See `Setup details <#setup-details>`__

Usage
-----

All examples in Python 3

Name info
~~~~~~~~~

Get address from name
^^^^^^^^^^^^^^^^^^^^^

Default to {name}.eth:

::

    from ens import ens


    # look up the hex representation of the address for a name

    eth_address = ens.address('jasoncarver.eth')

    assert eth_address == '0x5b2063246f2191f18f2675cedb8b28102e957458'


    # ens.py will assume you want a .eth name if you don't specify a full name

    assert ens.address('jasoncarver') == eth_address

Get name from address
^^^^^^^^^^^^^^^^^^^^^

::

    domain = ens.name('0x5b2063246f2191f18f2675cedb8b28102e957458')


    # name() also accepts the bytes version of the address

    assert ens.name(b'[ c$o!\x91\xf1\x8f&u\xce\xdb\x8b(\x10.\x95tX') == domain


    # confirm that the name resolves back to the address that you looked up:

    assert ens.address(domain) == '0x5b2063246f2191f18f2675cedb8b28102e957458'

Get owner of name
^^^^^^^^^^^^^^^^^

::

    eth_address = ens.owner('exchange.eth')

Set up your name
~~~~~~~~~~~~~~~~

Point your name to your address
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Do you want to set up your name so that ``ens.address()`` will show the
address it points to?

::

    ens.setup_address('jasoncarver.eth', '0x5b2063246f2191f18f2675cedb8b28102e957458')

You must already be the owner of the domain (or its parent).

In the common case where you want to point the name to the owning
address, you can skip the address

::

    ens.setup_address('jasoncarver.eth')

You can claim arbitrarily deep subdomains. *Gas costs scale up with the
number of subdomains!*

::

    ens.setup_address('supreme.executive.power.derives.from.a.mandate.from.the.masses.jasoncarver.eth')

Wait for the transaction to be mined, then:

::

    assert ens.address('supreme.executive.power.derives.from.a.mandate.from.the.masses.jasoncarver.eth') == \
        '0x5b2063246f2191f18f2675cedb8b28102e957458'

Point your address to your name
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Do you want to set up your address so that ``ens.name()`` will show the
name that points to it?

This is like Caller ID. It enables you and others to take an account and
determine what name points to it. Sometimes this is referred to as
"reverse" resolution.

::

    ens.setup_name('jasoncarver.eth', '0x5b2063246f2191f18f2675cedb8b28102e957458')

If you don't supply the address, ``setup_name`` will assume you want the
address returned by ``ens.address(name)``.

::

    ens.setup_name('jasoncarver.eth')

If the name doesn't already point to an address, ``ens.setup_name`` will
call ``ens.setup_address`` for you.

Wait for the transaction to be mined, then:

::

    assert ens.name('0x5b2063246f2191f18f2675cedb8b28102e957458') == 'jasoncarver.eth'

Auctions for names ending in .eth
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Get auction status
^^^^^^^^^^^^^^^^^^

Example with domain 'payment.eth':

::

    from ens.registrar import Status


    status = ens.registrar.status('payment')


    # if you forget to strip out .eth, ens.py will do it for you

    assert ens.registrar.status('payment.eth') == status


    # these are the possible statuses

    assert status in (
      Status.Open,
      Status.Auctioning,
      Status.Owned,
      Status.Forbidden,
      Status.Revealing,
      Status.NotYetAvailable
      )


    # if you get the integer status from another source, you can compare it directly

    assert Status.Owned == 2

Start auctions
^^^^^^^^^^^^^^

::

    # start one auction (which tips people off that you're interested)

    ens.registrar.start('you_saw_him_repressin_me_didnt_ya')


    # start many auctions (which provides a bit of cover)

    ens.registrar.start(['exchange', 'tickets', 'payment', 'trading', 'registry'])

Bid on auction
^^^^^^^^^^^^^^

Bid on a 'trading.eth' with 5211 ETH, and secret "I promise I will not
forget my secret":

::

    from web3utils import web3

    ens.registrar.bid(
          'trading',
          web3.toWei('5211', 'ether'),
          "I promise I will not forget my secret",
          transact={'from': web3.eth.accounts[0]}
          )

(if you want to "mask" your bid, set a higher value in the transact
dict)

Reveal your bid
^^^^^^^^^^^^^^^

You must **always** reveal your bid, whether you won or lost. Otherwise
you will lose the full deposit.

Example of revealing your bid on 'registry.eth' with 0.01 ETH, and
secret "For real, though: losing your secret means losing ether":

::

    ens.registrar.reveal(
          'registry',
          web3.toWei('0.01', 'ether'),
          "For real, though: losing your secret means losing ether",
          transact={'from': web3.eth.accounts[0]}
          )

Claim the name you won
^^^^^^^^^^^^^^^^^^^^^^

aka "Finalize" auction, which makes you the owner in ENS.

::

    ens.registrar.finalize('gambling')

Get detailed information on an auction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Find out the owner of the auction Deed -- see `docs on the
difference <http://docs.ens.domains/en/latest/userguide.html#managing-ownership>`__
between owning the name and the deed

::

    deed = ens.registrar.deed('ethfinex')

    assert deed.owner() == '0x9a02ed4ca9ad55b75ff9a05debb36d5eb382e184'

When was the auction completed? (a timezone-aware datetime object)

::

    close_datetime = ens.registrar.close_at('ethfinex')

    assert str(close_datetime) == '2017-06-05 08:10:03+00:00'

How much is held on deposit?

::

    from decimal import Decimal

    deposit = ens.registrar.deposit('ethfinex')

    assert web3.fromWei(deposit, 'ether') == Decimal('0.01')

What was the highest bid?

::

    top_bid = ens.registrar.top_bid('ethfinex')

    assert web3.fromWei(top_bid, 'ether') == Decimal('201709.02')

Setup details
-------------

If Python 2 is your default, or you're not sure
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In your shell

::

    if pip --version | grep "python 2"; then
      python3 -m venv ~/.py3venv
      source ~/.py3venv/bin/activate
    fi

Now, with Python 3
~~~~~~~~~~~~~~~~~~

In your shell: ``pip install ens``

*ens.py* requires an up-to-date Ethereum blockchain, preferably local.
If your setup isn't working, try running ``geth --fast`` until it's
fully-synced. I highly recommend using the default IPC communication
method, for speed and security.

"No matching distribution found for ens"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you are seeing something like:

::

    Collecting ens
      Could not find a version that satisfies the requirement ens (from versions: )
    No matching distribution found for ens

Then retry the first Setup section, to make sure you're in Python 3

Optionally, a custom web3 provider
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In Python:

::

    from ens import ENS
    from web3 import IPCProvider 

    ens = ENS(IPCProvider('/your/custom/ipc/path'))

Developer Setup
---------------

::

    git clone git@github.com:carver/ens.py.git
    cd ens.py/

    python3 -m venv venv
    . venv/bin/activate

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

Testing Setup
~~~~~~~~~~~~~

Re-run flake on file changes:

::

    $ when-changed -s -1 -r ens/ tests/ -c "clear; echo; echo \"running flake - $(date)\"; warn()
    {
    notify-send -t 5000 'Flake8 failure ⚠⚠⚠⚠⚠' 'flake8 on ens.py failed'
    }
    if ! git diff | flake8 --diff | grep "\.py"; then if ! flake8 ens/ tests/; then warn; fi else warn; fi; echo done"

Why does ens.py require python 3?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

*Short version*

It turns out that the distinction between ``str`` and ``bytes`` is
important. If you want to write code for the future (Ethereum), don't
use a language from the past.

*Long version*

Interacting with the EVM requires clarity on the bits you're using. For
example, a sha3 hash expects to receive a series of bytes to process.
Calculating the sha3 hash of a string is (or should be) a Type Error;
the hash algorithm doesn't know what to do with a series of characters,
aka Unicode code points. As the caller, you need to know which thing
you're calculating the hash of: 1. a series of bytes:
``b'[ c$o!\x91\xf1\x8f&u\xce\xdb\x8b(\x10.\x95tX'`` 2. the bytes
represented by a string in hex format:
``'0x5b2063246f2191f18f2675cedb8b28102e957458'`` 3. the bytes generated
by encoding a string using utf-8: **Oops, the bytes from #1 cannot be
read using utf-8!** 4. the bytes generated by encoding a string using
utf-16: ``'⁛④Ⅿ\uf191⚏칵诛ဨ键塴'``

Python 3 doesn't let you ignore a lot of these details. That's good,
because precision in dealing with the EVM is critical. Ether is at
stake.

If you are resistant -- I get it, I've been there. It is not intuitive
for most people. But it's seriously worth it to `learn about
encoding <https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/>`__
if you're going to develop on top of Ethereum. Your ETH depends on it!

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