Implement DB-API as a subclass of PG-API.

James William Pye · James William Pye · commit 5d3835fbef9f · 2009-05-25T15:22:37.000-07:00
DB-API's connect() will now inherit defaults similar to postgresql.open and
libpq-based drivers.

Should have been this way earlier, but the desire of a strict implementation
intervened with any such production.

This gives DB-API users direct access to PG-API interfaces.
diff --git a/postgresql/cluster.py b/postgresql/cluster.py
@@ -56,6 +56,7 @@ class Cluster(pg_api.Cluster):
 	to be a base class for managing a cluster, and is intended to be extended to
 	accommodate for a particular purpose.
 	"""
+	driver = pg_driver.default
 	installation = None
 	data_directory = None
 	DEFAULT_CLUSTER_ENCODING = DEFAULT_CLUSTER_ENCODING
@@ -413,7 +414,7 @@ def connector(self, **kw):
 		listen_addresses and port configuration in settings.
 		"""
 		host, port = self.address()
-		return pg_driver.default.fit(
+		return self.driver.fit(
 			host = host or 'localhost',
 			port = port or 5432,
 			**kw
@@ -472,7 +473,7 @@ def ready_for_connections(self):
 		e = None
 		host, port = self.address()
 		try:
-			pg_driver.connect(
+			self.driver.connect(
 				user = ' -*- ping -*- ',
 				host = host or 'localhost',
 				port = port or 5432,
diff --git a/postgresql/documentation/changes.py b/postgresql/documentation/changes.py
@@ -9,17 +9,32 @@
 0.9.0
 -----
 
+ * Performance improvements.
  * Extend `postgresql.open` to take keyword arguments.
  * Implement query libraries and connection categories[#1010581 & #1010618].
  * Implement ``clone()`` on Connections, Statements, and Cursors.
- * Refactor ``ps.load()`` into ``ps.load_chunks()`` and ``ps.load_rows()``.
  * Display the line and mark the location of the POSITION for syntax errors.
- * Performance improvements.
+ * Refactor ``ps.load()`` into ``ps.load_chunks()`` and ``ps.load_rows()``.
  * Refactor `postgresql.api.InterfaceElement`.
  * Refactor driver.pq3.Connection to use protocol.client3.Connection.
  * Refactor driver.pq3.Cursor into types selected by PreparedStatements.
  * Fix memory leak due to circular references and __del__. [Reported by Valentine Gogichashvili]
    Additionally, try to avoid circular references at that level.
+ * Correct StoredProcedure's statement production. It was falsely using a
+   a mechanism that would use SQL predefined type names instead of
+   qualified names. [Reported by Dallas Morisett]
+ * Make DB-API connect() inherit defaults like postgresql.open()
+ * Make DB-API extend PG-API so that DB-API connections will now have direct
+   access to PG-API features.
+
+
+0.8.2
+-----
+
+ * Correct StoredProcedure's statement production. It was falsely using a
+   a mechanism that would use SQL predefined type names instead of
+   qualified names. [Reported by Dallas Morisett]
+
 
 0.8.1 released on 2009-04-30
 ----------------------------
diff --git a/postgresql/driver/dbapi20.py b/postgresql/driver/dbapi20.py
@@ -15,9 +15,11 @@
 import time
 import re
 
+from .. import clientparameters as pg_param
 from .. import driver as pg_driver
 from .. import types as pg_type
 from .. import string as pg_str
+from .pq3 import Connection
 
 ##
 # Basically, is it a mapping, or is it a sequence?
@@ -82,6 +84,9 @@ def dbapi_type(typid):
 		return ROWID
 
 class Portal(object):
+	"""
+	Manages read() interfaces to a chunks iterator.
+	"""
 	def __init__(self, chunks):
 		self.chunks = chunks
 		self.buf = []
@@ -93,6 +98,10 @@ def __next__(self):
 			self.pos += 1
 			return r
 		except IndexError:
+			# Any alledged infinite recursion will stop on the StopIteration
+			# thrown by this next(). Recursion is unlikely to occur more than
+			# once; specifically, empty chunks would need to be returned
+			# by this invocation of next().
 			self.buf = next(self.chunks)
 			self.pos = 0
 			return self.__next__()
@@ -125,8 +134,7 @@ class Cursor(object):
 	description = None
 
 	def __init__(self, C):
-		self.connection = C
-		self.database = C.database
+		self.database = self.connection = C
 		self.description = ()
 		self.__portals = []
 
@@ -173,6 +181,7 @@ def fetchone(self):
 	def __next__(self):
 		return next(self._portal)
 	next = __next__
+
 	def __iter__(self):
 		return self
 
@@ -275,7 +284,7 @@ def close(self):
 			self.__portals = None
 			for p in ps: p.close()
 
-class Connection(object):
+class Connection(Connection):
 	"""
 	DB-API 2.0 connection implementation for PG-API connection objects.
 	"""
@@ -299,7 +308,7 @@ def autocommit_set(self, val):
 		else:
 			if self._xact is not None:
 				return
-			self._xact = self.database.xact()
+			self._xact = self.xact()
 			self._xact.start()
 
 	def autocommit_get(self):
@@ -315,19 +324,19 @@ def autocommit_del(self):
 	)
 	del autocommit_set, autocommit_get, autocommit_del
 
-	def __init__(self, connection):
-		self.database = connection
-		self._xact = self.database.xact()
+	def connect(self, *args, **kw):
+		super().connect(*args, **kw)
+		self._xact = self.xact()
 		self._xact.start()
 
 	def close(self):
-		if self.database.closed:
+		if self.closed:
 			raise Error(
 				"connection already closed",
 				source = 'CLIENT',
-				creator = self.database
+				creator = self
 			)
-		self.database.close()
+		super().close()
 
 	def cursor(self):
 		return Cursor(self)
@@ -340,10 +349,10 @@ def commit(self):
 				details = {
 					'hint': 'The "autocommit" property on the connection was set to True.'
 				},
-				creator = self.database
+				creator = self
 			)
 		self._xact.commit()
-		self._xact = self.database.xact()
+		self._xact = self.xact()
 		self._xact.start()
 
 	def rollback(self):
@@ -354,16 +363,22 @@ def rollback(self):
 				details = {
 					'hint': 'The "autocommit" property on the connection was set to True.'
 				},
-				creator = self.database
+				creator = self
 			)
 		self._xact.rollback()
-		self._xact = self.database.xact()
+		self._xact = self.xact()
 		self._xact.start()
 
+driver = pg_driver.Driver(connection = Connection)
 def connect(**kw):
 	"""
 	Create a DB-API connection using the given parameters.
 	"""
-	db = pg_driver.connect(**kw)
-	dbapi = Connection(db)
-	return dbapi
+	std_params = pg_param.collect(prompt_title = None)
+	params = pg_param.normalize(
+		list(pg_param.denormalize_parameters(std_params)) + \
+		list(pg_param.denormalize_parameters(kw))
+	)
+	# Resolve the password, but never prompt.
+	pg_param.resolve_password(params, prompt_title = None)
+	return driver.connect(**params)
diff --git a/postgresql/test/test_dbapi20.py b/postgresql/test/test_dbapi20.py
@@ -4,6 +4,7 @@
 import unittest
 from ..unittest import TestCaseWithCluster
 import time
+from contextlib import nested
 
 ##
 # Various Adjustments for pg.driver.dbapi20
@@ -108,10 +109,16 @@ def tearDown(self):
 		finally:
 			con.close()
 
+	def connection(self):
+		return nested()
+
 	def _connect(self):
-		c = self.db.connector()
-		c.connect()
-		return self.driver.Connection(c)
+		host, port = self.cluster.address()
+		return self.driver.connect(
+			user = 'test',
+			host = host,
+			port = port,
+		)
 
 	def test_connect(self):
 		con = self._connect()
diff --git a/postgresql/unittest.py b/postgresql/unittest.py
@@ -69,6 +69,9 @@ def initialize_database(self):
 			).first() is None:
 				c.execute('create database test')
 
+	def connection(self, *args, **kw):
+		return self.cluster.connection(*args, user = 'test', **kw)
+
 	def run(self, *args, **kw):
 		if not self.cluster.initialized():
 			self.cluster.encoding = 'utf-8'
@@ -91,7 +94,7 @@ def run(self, *args, **kw):
 			self.cluster.start()
 			self.cluster.wait_until_started()
 
-		db = self.cluster.connection(user = 'test',)
+		db = self.connection()
 		with db:
 			self.db = db
 			return super().run(*args, **kw)
