connection.py

import socket
from xml.etree import ElementTree as ET
import logging

from django.conf import settings

from .exceptions import TransactionError
if settings.PREMIERE_LOG_TO_DB:
    from ..models import RequestLog


log = logging.getLogger(__name__)

class Premiere(object):
    ALLOWED_METHODS = (
        'DiscountMigration', 'GetAssociations', 'GetCardBalance',
        'GetCardTransactions', 'GetDiscountMigrations', 'GetHallGeometries',
        'GetHallPlan', 'GetHalls', 'GetMovies', 'GetReservationTypes',
        'GetReservations', 'GetSales', 'GetSessionPrices', 'GetSessions',
        'Reservation', 'ReservationClear', 'ReturnOpenDateTickets',
        'SaleApproved', 'SaleCancel', 'SaleOpenDateTickets', 'SalePayReturn',
        'SaleReservation', 'GetAllMovieProperties', 'GetFirstMovieSession',
        'SheduleSessions', 'Query_CardSystem', 'Login',
    )

    def __init__(self, url=None, sid=None):
        if url is None:
            url = settings.PREMIERE_URL
        if sid is None:
            sid = settings.PREMIERE_SID
        self.url = url
        self.sid = sid
        log.debug('Created instance to access %s with sid %s' % (url, sid))


    def _get(self, **kwargs):
        log.debug('Calling method %s' % kwargs['QueryCode'])
        default_kwargs = {
            'ServiceID': self.sid,
            'Encoding': 'Windows-1251',
            'Version': 3,
        }
        default_kwargs.update(kwargs)
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        host, port = self.url.split(':')
        port = int(port)
        sock.connect((host, port))
        msg_string = ''
        for key, value in default_kwargs.iteritems():
            msg_string += '&{key}={val}'.format(key=key, val=value)
        length = '{:0>10}'.format(len(msg_string)-1)
        msg_string = length + msg_string
        sock.send(msg_string)
        resp_len = sock.recv(10)
        response = ''
        while len(response) < int(resp_len):
            to_read = min(int(resp_len), 1024)
            response += sock.recv(to_read)
        sock.shutdown(socket.SHUT_RDWR)
        sock.close()
        if settings.PREMIERE_LOG_TO_DB:
            self.log_event(default_kwargs.get('QueryCode'), query_string=msg_string)
        log.debug('Param string: "%s"' % msg_string)
        self._resp = response
        log.debug('Got response: "%s"' % response.decode('windows-1251').encode('utf-8'))
        return self.parse_response(response)

    def __getattr__(self, attname):
        if attname not in self.ALLOWED_METHODS: # TODO: fix the list of allowed methods
            raise AttributeError('Method is not allowed')
        return self._get_by_method(attname)

    def _get_by_method(self, attname):
        def func(**kwargs):
            kwargs['QueryCode'] = attname
            return self._get(**kwargs)
        return func

    def parse_response(self, value):
        value = value[1:] #bug in Premiere response - it's not a valid XML
        if hasattr(self, 'proxy'):
            start, end = value.find('<Data><![CDATA[') + 15, value.rfind(']]></Data>')
            value = value[start:end]
            # self._resp = value
        root = ET.fromstring(value)
        if hasattr(self, 'proxy'):
            return root
        status = root.find('Result').text
        error_code = root.find('Error').text
        error_message = root.find('Remark').text
        data = root.find('Data')
        if status != 'Ok':
            log.debug('Premiere response returned error!')
            raise TransactionError('Error ocured: (%s) %s' % (error_code, error_message.encode('utf-8')))
        return data

    def log_event(self, method_name, query_string):
        RequestLog.objects.create(method=method_name, query_string=query_string)