IronPython, MS SQL, and PEP 249
Over the past week and a half I've spent a little bit of time getting Django 0.96.1 running on IronPython. The 1st step in doing this was getting a database provider that would run on .NET that would work with Django. For DB backends Django basically follows PEP 249 with a few extensions. Here's the basic DB provider I came up with. It's not quite complete but it was good enough for me to get Django's tutorial running. To use this you just need to copy one of the existing DB backends and replace the code in base.py with the code below. For the rest of the code you can pull it from ado_mssql.
Basically this just uses the .NET System.Data namespace to do the communication with the database server.
import clr
clr.AddReference('System.Data')
from System import Data
from System.Data import SqlClient
import System
DatabaseError = Data.DataException
from threading import local
class SqlCursor(object):
arraysize = 1
def __init__(self, connection):
self.connection = connection
self.transaction = None
self.reader = None
self.record_enum = None
def execute(self, sql, params=()):
parameters = []
# translate to named parameters
if type(params) in (list, tuple):
# indexed params, replace any %s w/ @GeneratedName#
if sql.find('%s') != -1:
cmd = ''
sqlSplit = sql.split('%s')
for text, value, index in zip(sqlSplit, params, range(len(params))):
cmd += text + <'@GeneratedName'> + str(index)
parameters.Add(SqlClient.SqlParameter(<'@GeneratedName'> + str(index), str(value)))
sql = cmd + sqlSplit[-1]
else:
for name, value in params.iteritems():
sql = sql.replace('%(' + name +')s', <'@'> + name)
parameters.Add(SqlClient.SqlParameter(<'@'> + name, str(value)))
command = SqlClient.SqlCommand(sql, self.connection)
for param in parameters: command.Parameters.Add(param)
self.record_enum = None
self.reader = command.ExecuteReader()
def close(self):
self.reader.Close()
def executemany(self, sql, param_list):
res = []
for s in sql:
res.append(execute(s, param_list))
return res
def fetchall(self):
return [self._make_record(record) for record in self.reader]
def fetchone(self):
if self.record_enum is None:
self.record_enum = iter(self.reader)
if self.record_enum.MoveNext():
return self._make_record(self.record_enum.Current)
return None
def fetchmany(self, size=None):
if size is None: size = SqlCursor.arraysize
res = []
for i in range(size):
x = self.fetchone()
if x is None: break
res.append(x)
return res
def _make_record(self, record):
return tuple((self._fix_one_record(record[i]) for i in xrange(record.FieldCount)))
def _fix_one_record(self, record):
if type(record) is System.DateTime:
return datetime.datetime(record)
return record
@property
def rowcount(self):
if self.record is not None:
return self.reader.RecordsAffected
return -1
class DatabaseWrapper(local):
def __init__(self, **kwargs):
self.connection = None
self.queries = []
self.transaction = None
def cursor(self):
from django.conf import settings
if self.connection is None:
if not settings.DATABASE_HOST:
settings.DATABASE_HOST = "(local)"
if settings.DATABASE_NAME == '' or settings.DATABASE_USER == '':
conn_string = "Data Source=%s;Initial Catalog=%s;Integrated Security=SSPI;MultipleActiveResultSets=True" % (settings.DATABASE_HOST, settings.DATABASE_NAME)
else:
conn_string = "Data Source=%s;Initial Catalog=%s;User ID=%s;Password=%s;Integrated Security=SSPI;MultipleActiveResultSets=True" % (settings.DATABASE_HOST, settings.DATABASE_NAME, settings.DATABASE_USER, settings.DATABASE_PASSWORD)
self.connection = SqlClient.SqlConnection(conn_string)
self.connection.Open()
cursor = SqlCursor(self.connection)
if settings.DEBUG:
return util.CursorDebugWrapper(cursor, self)
return cursor
def _commit(self):
if self.transaction is not None:
return self.transaction.Commit()
def _rollback(self):
if self.transaction is not None:
return self.transaction.Rollback()
def close(self):
if self.connection is not None:
self.connection = None
self.transaction = None