Login module for Keybase

keybase-login.py

#! /usr/bin/env python2.7

'''
Login module doe Keybase.
'''

import json
import hmac
import base64
import hashlib
import getpass
import binascii

import pyscrypt
import requests

# Keybase API URLs.
KEYBASE_LOGIN = 'https://keybase.io/_/api/1.0/login.json'
KEYBASE_GET_SALT = 'https://keybase.io/_/api/1.0/getsalt.json'


def http_debug(response):
    '''
    Print the HTTP request/response debug log.
    '''
    print 'http-request\n{0}\n'.format('-' * len('http-request'))
    print 'url ({0}): {1}'.format(response.request.method,
                                  response.request.url)
    print 'request-headers:'
    print json.dumps(dict(response.request.headers), indent=4)
    if response.request.method != 'GET':
        if response.request.body is not None:
            print 'request-payload:'
            print json.dumps(json.loads(response.request.body), indent=4)
    print '\nhttp-response\n{0}\n'.format('-' * len('http-response'))
    print 'status-code: {0} {1}'.format(response.status_code, response.reason)
    print 'url: {0}'.format(response.url)
    print 'time-elapsed: {0}s'.format(response.elapsed.total_seconds())
    print 'response-headers:'
    print json.dumps(dict(response.headers), indent=4)
    print 'response-content:'
    print None if response.content is '' else json.dumps(response.json(),
                                                         indent=4)


def getsalt(username, debug=False):
    '''
    keybase-auth: First step of authentication; gets salt, login_session.
    https://keybase.io/docs/api/1.0/call/getsalt
    '''
    params = {
        'email_or_username': username.strip()
    }

    try:
        response = requests.get(KEYBASE_GET_SALT, params=params)
        if debug:
            http_debug(response)
        return response.json()
    except requests.exceptions.RequestException as http_error:
        print http_error[0][0]
    except (ValueError, KeyError):
        print 'Unable to parse response from Keybase.'

    return None


def login(username, password, debug=True):
    '''
    keybase-auth: Second step of authentication; gets session, me.
    https://keybase.io/docs/api/1.0/call/login
    '''
    required = set(['salt', 'login_session'])
    salt_data, salt, login_session = getsalt(username, debug), None, None

    if salt_data is not None and required.issubset(set(salt_data.keys())):
        salt, login_session = salt_data['salt'], salt_data['login_session']

    hashed = pyscrypt.hash(password=password, N=2**15, r=8, p=1, dkLen=224,
                           salt=binascii.unhexlify(salt))[192:224]
    hmac_hashed = hmac.new(hashed, base64.decodestring(login_session),
                           hashlib.sha512).hexdigest()

    params = {
        'hmac_pwh': hmac_hashed,
        'login_session': login_session,
        'email_or_username': username.strip()
    }

    try:
        response = requests.post(KEYBASE_LOGIN, params=params)
        if debug:
            http_debug(response)
        print response.json()
    except requests.exceptions.RequestException as http_error:
        print http_error[0][0]
    except (ValueError, KeyError):
        print 'Unable to parse response from Keybase.'