Start working on postgresql driver

[ci skip]

pwman/data/drivers/postgresql.py

@@ -1,24 +1,23 @@
-#============================================================================
+# ============================================================================
 # This file is part of Pwman3.
-# 
+#
 # Pwman3 is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License, version 2
-# as published by the Free Software Foundation; 
-# 
+# as published by the Free Software Foundation;
+#
 # Pwman3 is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-# 
+#
 # You should have received a copy of the GNU General Public License
 # along with Pwman3; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-#============================================================================
+# ============================================================================
 # Copyright (C) 2012 Oz Nahum <nahumoz@gmail.com>
-#============================================================================
-#============================================================================
+# ============================================================================
 # Copyright (C) 2006 Ivan Kelly <ivan@ivankelly.net>
-#============================================================================
+# ============================================================================
 
 """Postgresql Database implementation."""
 from pwman.data.database import Database, DatabaseException
@@ -29,19 +28,20 @@ import pgdb
 import pwman.util.config as config
 import cPickle
 
+
 class PostgresqlDatabase(Database):
     """Postgresql Database implementation"""
-    
+
     def __init__(self):
         """Initialise PostgresqlDatabase instance."""
         Database.__init__(self)
 
         self._tagidcache = {}
-        
-        config.add_defaults({"Database" : {"server": "localhost",
-                                           "port"  : "5432",
-                                           "database" : "pwman",
-                                           "table_prefix" : "pwman_"}})
+
+        config.add_defaults({"Database": {"server": "localhost",
+                                          "port": "5432",
+                                          "database": "pwman",
+                                          "table_prefix": "pwman_"}})
         try:
             self._server = config.get_value('Database', 'server')
             self._port = config.get_value('Database', 'port')
@@ -68,15 +68,15 @@ class PostgresqlDatabase(Database):
 
     def _get_cur(self):
         try:
-            if (self._con != None):
+            if self._con is not None:
                 return self._con.cursor()
-        except pgdb.DatabaseError as e:
+        except pgdb.DatabaseError:
             pass
         server = "%s:%s" % (self._server, self._port)
-        self._con = pgdb.connect(host = server,
-                                 database = self._database,
-                                 user = self._user,
-                                 password = self._password)
+        self._con = pgdb.connect(host=server,
+                                 database=self._database,
+                                 user=self._user,
+                                 password=self._password)
         self._cur = self._con.cursor()
         return self._cur
 
@@ -92,9 +92,10 @@ class PostgresqlDatabase(Database):
             sql = "SELECT DATA FROM %sTAGS ORDER BY DATA ASC" % (self._prefix)
         else:
             sql = ("SELECT %sTAGS.DATA FROM %sLOOKUP"
-                   +" INNER JOIN %sTAGS ON %sLOOKUP.TAG = %sTAGS.ID"
-                   +" WHERE NODE IN (") % (self._prefix, self._prefix, self._prefix,
-                                           self._prefix, self._prefix)
+                   + " INNER JOIN %sTAGS ON %sLOOKUP.TAG = %sTAGS.ID"
+                   + " WHERE NODE IN (") % (self._prefix, self._prefix,
+                                            self._prefix,
+                                            self._prefix, self._prefix)
             first = True
 
             i += 1
@@ -104,13 +105,16 @@ class PostgresqlDatabase(Database):
                     sql += " INTERSECT "
                 else:
                     first = False
-                
-                sql += ("SELECT NODE FROM %sLOOKUP LEFT JOIN %sTAGS ON TAG = %sTAGS.ID "
-                        + " WHERE %sTAGS.DATA = %%(%s)s") % (self._prefix, self._prefix,
-                                                             self._prefix, self._prefix,
-                                                             paramname)
+
+                sql += ("SELECT NODE FROM %sLOOKUP LEFT JOIN %sTAGS ON TAG "
+                        "= %sTAGS.ID "
+                        " WHERE %sTAGS.DATA = %%(%s)s" % (self._prefix,
+                                                          self._prefix,
+                                                          self._prefix,
+                                                          self._prefix,
+                                                          paramname))
                 params[paramname] = cPickle.dumps(t)
-            sql += ") EXCEPT SELECT DATA FROM %sTAGS WHERE " %(self._prefix)
+            sql += ") EXCEPT SELECT DATA FROM %sTAGS WHERE " % self._prefix
             first = True
             for t in self._filtertags:
                 if not first:
@@ -124,14 +128,14 @@ class PostgresqlDatabase(Database):
 
             tags = []
             row = cursor.fetchone()
-            while (row != None):
+            while row:
                 tag = cPickle.loads(str(row[0]))
                 tags.append(tag)
                 row = cursor.fetchone()
             return tags
         except pgdb.DatabaseError as e:
             raise DatabaseException("Postgresql: %s" % (e))
-        
+
     def getnodes(self, ids):
         nodes = []
         idstr = ""
@@ -145,15 +149,15 @@ class PostgresqlDatabase(Database):
                 first = False
             else:
                 idstr += ", %d" % (i)
-            
-        sql = "SELECT ID,DATA FROM %sNODES WHERE ID IN (%s)" % (self._prefix,
-                                                                pgdb.escape_string(idstr))
+
+        sql = ("SELECT ID,DATA FROM %sNODES WHERE ID IN (%s)"
+               "" % (self._prefix, pgdb.escape_string(idstr)))
         try:
             cursor = self._get_cur()
             cursor.execute(sql)
-            
+
             row = cursor.fetchone()
-            while row != None:
+            while row:
                 node = cPickle.loads(str(row[1]))
                 node.set_id(row[0])
                 nodes.append(node)
@@ -163,14 +167,16 @@ class PostgresqlDatabase(Database):
         return nodes
 
     def editnode(self, id, node):
-        if not isinstance(node, Node): raise DatabaseException(
-                "Tried to insert foreign object into database [%s]" % node)
+        if not isinstance(node, Node):
+            raise DatabaseException("Tried to insert foreign object into "
+                                    "database [%s]" % node)
         try:
             cursor = self._get_cur()
-            sql = "UPDATE %sNODES SET DATA = %%(data)s WHERE ID = %%(id)d" % (self._prefix)
-            cursor.execute(sql, {"data":cPickle.dumps(node),
+            sql = ("UPDATE %sNODES SET DATA = %%(data)s WHERE ID = %%(id)d"
+                   "" % (self._prefix))
+            cursor.execute(sql, {"data": cPickle.dumps(node),
                                  "id": id})
-            
+
         except pgdb.DatabaseError as e:
             raise DatabaseException("Postgresql: %s" % (e))
         self._setnodetags(node)
@@ -181,8 +187,9 @@ class PostgresqlDatabase(Database):
         cursor = self._get_cur()
         for n in nodes:
             sql = "INSERT INTO %sNODES(DATA) VALUES(%%(data)s)" % (self._prefix)
-            if not isinstance(n, Node): raise DatabaseException(
-                "Tried to insert foreign object into database [%s]", n)
+            if not isinstance(n, Node):
+                raise DatabaseException("Tried to insert foreign object into "
+                                        "database [%s]", n)
             values = {"data": cPickle.dumps(n)}
             try:
                 cursor.execute(sql, values)
@@ -193,16 +200,17 @@ class PostgresqlDatabase(Database):
 
             self._setnodetags(n)
         self._commit()
-            
+
     def removenodes(self, nodes):
         cursor = self._get_cur()
         for n in nodes:
-            if not isinstance(n, Node): raise DatabaseException(
-                "Tried to delete foreign object from database [%s]", n)
+            if not isinstance(n, Node):
+                raise DatabaseException("Tried to delete foreign object"
+                                        "from database [%s]", n)
             try:
                 sql = "DELETE FROM %sNODES WHERE ID = %%(id)d" % (self._prefix)
                 cursor.execute(sql, {"id": n.get_id()})
-                
+
             except pgdb.DatabaseError as e:
                 raise DatabaseException("Postgresql: %s" % (e))
             self._deletenodetags(n)
@@ -227,17 +235,20 @@ class PostgresqlDatabase(Database):
                 i += 1
                 paramname = "tag%d" % (i)
 
-                sql += (("SELECT NODE FROM %sLOOKUP LEFT JOIN %sTAGS ON TAG = %sTAGS.ID"
-                         + " WHERE %sTAGS.DATA = %%(%s)s ") % (self._prefix, self._prefix,
-                                                               self._prefix, self._prefix,
-                                                               paramname))
+                sql += (("SELECT NODE FROM %sLOOKUP LEFT JOIN %sTAGS ON"
+                         " TAG = %sTAGS.ID"
+                         " WHERE %sTAGS.DATA = %%(%s)s ") % (self._prefix,
+                                                             self._prefix,
+                                                             self._prefix,
+                                                             self._prefix,
+                                                             paramname))
                 params[paramname] = cPickle.dumps(t)
         try:
             cursor.execute(sql, params)
 
             ids = []
             row = cursor.fetchone()
-            while (row != None):
+            while row:
                 ids.append(row[0])
                 row = cursor.fetchone()
             return ids
@@ -261,20 +272,22 @@ class PostgresqlDatabase(Database):
                 ids.append(self._tagidcache[pickled])
                 continue
             except KeyError as e:
-                pass # not in cache
+                pass  # not in cache
             sql = "SELECT ID FROM %sTAGS WHERE DATA = %%(tag)s" % (self._prefix)
-            if not isinstance(t, Tag): raise DatabaseException(
-                "Tried to insert foreign object into database [%s]", t)
-            data = {"tag" : pickled }
-            
+            if not isinstance(t, Tag):
+                raise DatabaseException("Tried to insert foreign object"
+                                        " into database [%s]", t)
+            data = {"tag": pickled}
+
             try:
                 cursor.execute(sql, data)
                 row = cursor.fetchone()
-                if (row != None):
+                if row:
                     ids.append(row[0])
                     self._tagidcache[pickled] = row[0]
                 else:
-                    sql = "INSERT INTO %sTAGS(DATA) VALUES(%%(tag)s)" % (self._prefix)
+                    sql = "INSERT INTO %sTAGS(DATA) VALUES(%%(tag)s)" % (
+                        self._prefix)
                     cursor.execute(sql, data)
                     id = self._lastrowid("TAGS")
                     ids.append(id)
@@ -287,19 +300,20 @@ class PostgresqlDatabase(Database):
         try:
             cursor = self._get_cur()
             sql = "DELETE FROM %sLOOKUP WHERE NODE = %%(node)d" % (self._prefix)
-            cursor.execute(sql, {"node":node.get_id()})
-            
+            cursor.execute(sql, {"node": node.get_id()})
+
         except pgdb.DatabaseError as e:
             raise DatabaseException("Postgresql: %s" % (e))
-        
+
     def _setnodetags(self, node):
         self._deletenodetags(node)
         ids = self._tagids(node.get_tags())
-        
+
         for i in ids:
-            sql = "INSERT INTO %sLOOKUP VALUES(%%(node)d, %%(tag)d)" % (self._prefix)
+            sql = "INSERT INTO %sLOOKUP VALUES(%%(node)d, %%(tag)d)" % (
+                self._prefix)
             params = {"node": node.get_id(), "tag": i}
-            
+
             try:
                 cursor = self._get_cur()
                 cursor.execute(sql, params)
@@ -320,39 +334,37 @@ class PostgresqlDatabase(Database):
 
     def _lastrowid(self, name):
         cursor = self._get_cur()
-        cursor.execute("SELECT LAST_VALUE FROM %s%s_ID_SEQ" % (self._prefix, name))
+        cursor.execute("SELECT LAST_VALUE FROM %s%s_ID_SEQ" % (self._prefix,
+                                                               name))
         row = cursor.fetchone()
-        if row == None:
-            return 0;
+        if not row:
+            return 0
         else:
             return row[0]
-        
+
     def _checktables(self):
         """ Check if the Pwman tables exist """
         cursor = self._get_cur()
-        cursor.execute(
-            "SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = '%snodes'"
-            % (self._prefix))
+        cursor.execute("SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE "
+                       "TABLE_NAME = '%snodes'" % (self._prefix))
 
-        if (cursor.fetchone() == None):
+        if not cursor.fetchone():
             # table doesn't exist, create it
-            cursor.execute(("CREATE TABLE %sNODES" 
-                               +"(ID SERIAL PRIMARY KEY, DATA TEXT NOT NULL)")
-                              % (self._prefix))
+            cursor.execute(("CREATE TABLE %sNODES "
+                            "(ID SERIAL PRIMARY KEY, DATA TEXT NOT NULL)"
+                            % (self._prefix)))
             cursor.execute(("CREATE TABLE %sTAGS"
-                               + "(ID SERIAL PRIMARY KEY,"
-                               + "DATA TEXT NOT NULL UNIQUE)")
-                              % (self._prefix))
+                            "(ID SERIAL PRIMARY KEY,"
+                            "DATA TEXT NOT NULL UNIQUE)") % (self._prefix))
             cursor.execute(("CREATE TABLE %sLOOKUP"
-                               + "(NODE INTEGER NOT NULL, TAG INTEGER NOT NULL,"
-                               + " PRIMARY KEY(NODE, TAG))")
-                              % (self._prefix))
+                            "(NODE INTEGER NOT NULL, TAG INTEGER NOT NULL,"
+                            " PRIMARY KEY(NODE, TAG))") % self._prefix)
 
             cursor.execute(("CREATE TABLE %sKEY"
-                               + "(THEKEY TEXT NOT NULL DEFAULT '')")
-                              % (self._prefix));
-            cursor.execute("INSERT INTO %sKEY VALUES('')" % (self._prefix));
-            
+                           + "(THEKEY TEXT NOT NULL DEFAULT '')")
+                           % (self._prefix))
+            cursor.execute("INSERT INTO %sKEY VALUES('')" % (self._prefix))
+
             try:
                 self._con.commit()
             except pgdb.DatabaseError as e:
@@ -370,11 +382,10 @@ class PostgresqlDatabase(Database):
             self._con.rollback()
             raise DatabaseException(
                 "Postgresql: Error saving key [%s]" % (e))
-        
-        
+
     def loadkey(self):
         cursor = self._get_cur()
-        cursor.execute("SELECT THEKEY FROM %sKEY" % (self._prefix));
+        cursor.execute("SELECT THEKEY FROM %sKEY" % (self._prefix))
         keyrow = cursor.fetchone()
         if (keyrow[0] == ''):
             return None