Update for PyGreSQL 3.0, from D'Arcy J.M. Cain

src/interfaces/python/pgdb.py

@@ -0,0 +1,401 @@
+""" pgdb - DB-SIG compliant module for PygreSQL.
+
+	(c) 1999, Pascal Andre <andre@via.ecp.fr>.
+	See package documentation for further information on copyright.
+
+	Even though this file is distributed with a release version of
+	PyGreSQL, this is beta software. Inline documentation is sparse.
+	See DB-SIG 2.0 specification for usage information.
+
+		basic usage:
+
+		pgdb.connect(connect_string) -> connection
+			connect_string = 'host:database:user:password:opt:tty'
+			All parts are optional. You may also pass host through
+			password as keyword arguments. To pass a port, pass it in
+			the host keyword parameter:
+				pgdb.connect(host='localhost:5432')
+
+		connection.cursor() -> cursor
+
+		connection.commit()
+
+		connection.close()
+
+		connection.rollback()
+
+		cursor.execute(query[, params])
+			execute a query, binding params (a dictionary) if it is
+			passed. The binding syntax is the same as the % operator
+			for dictionaries, and no quoting is done.
+
+		cursor.executemany(query, list of params)
+			execute a query many times, binding each param dictionary
+			from the list.
+
+		cursor.fetchone() -> [value, value, ...]
+
+		cursor.fetchall() -> [[value, value, ...], ...]
+
+		cursor.fetchmany([size]) -> [[value, value, ...], ...]
+			returns size or cursor.arraysize number of rows from result
+			set. Default cursor.arraysize is 1.
+
+		cursor.description -> [(column_name, type_name, display_size,
+			internal_size, precision, scale, null_ok), ...]
+
+			Note that precision, scale and null_ok are not implemented.
+
+		cursor.rowcount
+			number of rows available in the result set. Available after
+			a call to execute.
+
+		cursor.close()
+
+"""
+
+import _pg
+import string
+import exceptions
+import types
+import DateTime
+import time
+
+### module constants
+
+# compliant with DB SIG 2.0
+apilevel = '2.0'
+
+# module may be shared, but not connections
+threadsafety = 1
+
+# this module use extended python format codes
+paramstyle = 'pyformat'
+
+### exception hierarchy
+
+class Warning(StandardError):
+	pass
+
+class Error(StandardError):
+	pass
+
+class InterfaceError(Error):
+	pass
+
+class DatabaseError(Error):
+	pass
+
+class DataError(DatabaseError):
+	pass
+
+class OperationalError(DatabaseError):
+	pass
+
+class IntegrityError(DatabaseError):
+	pass
+
+class InternalError(DatabaseError):
+	pass
+
+class ProgrammingError(DatabaseError):
+	pass
+
+class NotSupportedError(DatabaseError):
+	pass
+
+### internal type handling class
+class pgdbTypeCache:
+
+	def __init__(self, cnx):
+		self.__source = cnx.source()
+		self.__type_cache = {}
+
+	def typecast(self, typ, value):
+		# for NULL values, no typecast is necessary
+		if value == None:
+			return value
+
+		if typ == STRING:
+			pass
+		elif typ == BINARY:
+			pass
+		elif typ == INTEGER:
+			value = int(value)
+		elif typ == LONG:
+			value = long(value)
+		elif typ == FLOAT:
+			value = float(value)
+		elif typ == MONEY:
+			value = string.replace(value, "$", "")
+			value = string.replace(value, ",", "")
+			value = float(value)
+		elif typ == DATETIME:
+			# format may differ ... we'll give string
+			pass
+		elif typ == ROWID:
+			value = long(value)
+		return value
+
+	def getdescr(self, oid):
+		try:
+			return self.__type_cache[oid]
+		except:
+			self.__source.execute(
+				"SELECT typname, typprtlen, typlen "
+				"FROM pg_type WHERE oid = %s" % oid
+			)
+			res = self.__source.fetch(1)[0]
+			# column name is omitted from the return value. It will
+			# have to be prepended by the caller.
+			res = (
+				res[0],
+				string.atoi(res[1]), string.atoi(res[2]),
+				None, None, None
+			)
+			self.__type_cache[oid] = res
+			return res
+
+### cursor object
+
+class pgdbCursor:
+
+	def __init__(self, src, cache):
+		self.__cache = cache
+		self.__source = src
+		self.description = None
+		self.rowcount = -1
+		self.arraysize = 5
+
+	def close(self):
+		self.__source.close()
+		self.description = None
+		self.rowcount = -1
+
+	def execute(self, operation, params = None):
+		if type(params) == types.TupleType or type(params) == types.ListType:
+			self.executemany(operation, params)
+		else:
+			self.executemany(operation, (params,))
+
+	def executemany(self, operation, param_seq):
+		self.description = None
+		self.rowcount = -1
+
+		# first try to execute all queries
+		totrows = 0
+		sql = "INIT"
+		try:
+			for params in param_seq:
+				if params != None:
+					sql = operation % params
+				else:
+					sql = operation
+				rows = self.__source.execute(sql)
+				if rows != None: # true is __source is NOT a DQL
+					totrows = totrows + rows
+		except _pg.error, msg:
+			raise DatabaseError, "error '%s' in '%s'" % ( msg, sql )
+		except:
+			raise OperationalError, "internal error in '%s'" % sql
+
+		# then initialize result raw count and description
+		if self.__source.resulttype == _pg.RESULT_DQL:
+			self.rowcount = self.__source.ntuples
+			d = []
+			for typ in self.__source.listinfo():
+				# listinfo is a sequence of
+				# (index, column_name, type_oid)
+				# getdescr returns all items needed for a
+				# description tuple except the column_name.
+				desc = typ[1:2]+self.__cache.getdescr(typ[2])
+				d.append(desc)
+			self.description = d
+		else:
+			self.rowcount = totrows
+			self.description = None
+
+	def fetchone(self):
+		res = self.fetchmany(1, 0)
+		try:
+			return res[0]
+		except:
+			return None
+
+	def fetchall(self):
+		return self.fetchmany(-1, 0)
+
+	def fetchmany(self, size = None, keep = 1):
+		if size == None:
+			size = self.arraysize
+		if keep == 1:
+			self.arraysize = size
+		res = self.__source.fetch(size)
+		result = []
+		for r in res:
+			row = []
+			for i in range(len(r)):
+				row.append(self.__cache.typecast(
+						self.description[i][1],
+						r[i]
+					)
+				)
+			result.append(row)
+		return result
+
+	def setinputsizes(self, sizes):
+		pass
+
+	def setoutputsize(self, size, col = 0):
+		pass
+
+### connection object
+
+class pgdbCnx:
+
+	def __init__(self, cnx):
+		self.__cnx = cnx
+		self.__cache = pgdbTypeCache(cnx)
+		try:
+			src = self.__cnx.source()
+			src.execute("BEGIN")
+		except:
+			raise OperationalError, "invalid connection."
+
+	def close(self):
+		self.__cnx.close()
+
+	def commit(self):
+		try:
+			src = self.__cnx.source()
+			src.execute("COMMIT")
+			src.execute("BEGIN")
+		except:
+			raise OperationalError, "can't commit."
+
+	def rollback(self):
+		try:
+			src = self.__cnx.source()
+			src.execute("ROLLBACK")
+			src.execute("BEGIN")
+		except:
+			raise OperationalError, "can't rollback."
+
+	def cursor(self):
+		try:
+			src = self.__cnx.source()
+			return pgdbCursor(src, self.__cache)
+		except:
+			raise pgOperationalError, "invalid connection."
+
+### module interface
+
+# connects to a database
+def connect(dsn = None, user = None, password = None, host = None, database = None):
+	# first get params from DSN
+	dbport = -1
+	dbhost = ""
+	dbbase = ""
+	dbuser = ""
+	dbpasswd = ""
+	dbopt = ""
+	dbtty = ""
+	try:
+		params = string.split(dsn, ":")
+		dbhost = params[0]
+		dbbase = params[1]
+		dbuser = params[2]
+		dbpasswd = params[3]
+		dbopt = params[4]
+		dbtty = params[5]
+	except:
+		pass
+
+	# override if necessary
+	if user != None:
+		dbuser = user
+	if password != None:
+		dbpasswd = password
+	if database != None:
+		dbbase = database
+	if host != None:
+		try:
+			params = string.split(host, ":")
+			dbhost = params[0]
+			dbport = params[1]
+		except:
+			pass
+
+	# empty host is localhost
+	if dbhost == "":
+		dbhost = None
+	if dbuser == "":
+		dbuser = None
+
+	# open the connection
+	cnx = _pg.connect(host = dbhost, dbname = dbbase, port = dbport,
+						opt = dbopt, tty = dbtty,
+						user = dbuser, passwd = dbpasswd)
+	return pgdbCnx(cnx)
+
+### types handling
+
+# PostgreSQL is object-oriented: types are dynamic. We must thus use type names
+# as internal type codes.
+
+class pgdbType:
+
+	def __init__(self, *values):
+		self.values=  values
+
+	def __cmp__(self, other):
+		if other in self.values:
+			return 0
+		if other < self.values:
+			return 1
+		else:
+			return -1
+
+STRING = pgdbType(
+	'char', 'name', 'text', 'varchar'
+)
+
+# BLOB support is pg specific
+BINARY = pgdbType()
+INTEGER = pgdbType('int2', 'int4', 'serial')
+LONG = pgdbType('int8')
+FLOAT = pgdbType('float4', 'float8', 'numeric')
+BOOL = pgdbType('bool') 
+MONEY = pgdbType('money')
+
+# this may be problematic as type are quite different ... I hope it won't hurt
+DATETIME = pgdbType(
+	'abstime', 'reltime', 'tinterval', 'date', 'time', 'timespan', 'timestamp'
+)
+
+# OIDs are used for everything (types, tables, BLOBs, rows, ...). This may cause
+# confusion, but we are unable to find out what exactly is behind the OID (at
+# least not easily enough). Should this be undefined as BLOBs ?
+ROWID = pgdbType(
+	'oid', 'oid8'
+)
+
+# mandatory type helpers
+def Date(year, month, day):
+	return DateTime.DateTime(year, month, day)
+
+def Time(hour, minute, second):
+	return DateTime.TimeDelta(hour, minute, second)
+
+def Timestamp(year, month, day, hour, minute, second):
+	return DateTime.DateTime(year, month, day, hour, minute, second)
+
+def DateFromTicks(ticks):
+	return apply(Date, time.localtime(ticks)[:3])
+
+def TimeFromTicks(ticks):
+	return apply(Time, time.localtime(ticks)[3:6])
+
+def TimestampFromTicks(ticks):
+	return apply(Timestamp, time.localtime(ticks)[:6])
+