Initial checkin of new API implementation

[plcapi.git] / PLC / PostgreSQL.py

diff --git a/PLC/PostgreSQL.py b/PLC/PostgreSQL.py
new file mode 100644 (file)
index 0000000..8376804
--- /dev/null
+++ b/PLC/PostgreSQL.py
@@ -0,0 +1,135 @@
+#
+# PostgreSQL database interface. Sort of like DBI(3) (Database
+# independent interface for Perl).
+#
+# Mark Huang <mlhuang@cs.princeton.edu>
+# Copyright (C) 2006 The Trustees of Princeton University
+#
+# $Id$
+#
+
+import pgdb
+from types import StringTypes, NoneType
+import traceback
+import commands
+from pprint import pformat
+
+from PLC.Debug import profile, log
+from PLC.Faults import *
+
+class PostgreSQL:
+    def __init__(self, api):
+        self.api = api
+
+        # Initialize database connection
+        self.db = pgdb.connect(user = api.config.PLC_DB_USER,
+                               password = api.config.PLC_DB_PASSWORD,
+                               host = "%s:%d" % (api.config.PLC_DB_HOST, api.config.PLC_DB_PORT),
+                               database = api.config.PLC_DB_NAME)
+        self.cursor = self.db.cursor()
+
+        (self.rowcount, self.description, self.lastrowid) = \
+                        (None, None, None)
+
+    def quote(self, params):
+        """
+        Returns quoted version(s) of the specified parameter(s).
+        """
+
+        # pgdb._quote functions are good enough for general SQL quoting
+        if hasattr(params, 'has_key'):
+            params = pgdb._quoteitem(params)
+        elif isinstance(params, list) or isinstance(params, tuple):
+            params = map(pgdb._quote, params)
+        else:
+            params = pgdb._quote(params)
+
+        return params
+
+    quote = classmethod(quote)
+
+    def param(self, name, value):
+        # None is converted to the unquoted string NULL
+        if isinstance(value, NoneType):
+            conversion = "s"
+        # True and False are also converted to unquoted strings
+        elif isinstance(value, bool):
+            conversion = "s"
+        elif isinstance(value, float):
+            conversion = "f"
+        elif not isinstance(value, StringTypes):
+            conversion = "d"
+        else:
+            conversion = "s"
+
+        return '%(' + name + ')' + conversion
+
+    param = classmethod(param)
+
+    def begin_work(self):
+        # Implicit in pgdb.connect()
+        pass
+
+    def commit(self):
+        self.db.commit()
+
+    def rollback(self):
+        self.db.rollback()
+
+    def do(self, query, params = None):
+        self.execute(query, params)
+        return self.rowcount
+
+    def last_insert_id(self):
+        return self.lastrowid
+
+    def execute(self, query, params = None):
+        self.execute_array(query, (params,))
+
+    def execute_array(self, query, param_seq):
+        cursor = self.cursor
+        try:
+            cursor.executemany(query, param_seq)
+            (self.rowcount, self.description, self.lastrowid) = \
+                            (cursor.rowcount, cursor.description, cursor.lastrowid)
+        except pgdb.DatabaseError, e:
+            self.rollback()
+            uuid = commands.getoutput("uuidgen")
+            print >> log, "Database error %s:" % uuid
+            print >> log, e
+            print >> log, "Query:"
+            print >> log, query
+            print >> log, "Params:"
+            print >> log, pformat(param_seq[0])
+            raise PLCDBError("Please contact " + \
+                             self.api.config.PLC_NAME + " Support " + \
+                             "<" + self.api.config.PLC_MAIL_SUPPORT_ADDRESS + ">" + \
+                             " and reference " + uuid)
+
+    def selectall(self, query, params = None, hashref = True, key_field = None):
+        """
+        Return each row as a dictionary keyed on field name (like DBI
+        selectrow_hashref()). If key_field is specified, return rows
+        as a dictionary keyed on the specified field (like DBI
+        selectall_hashref()).
+
+        If params is specified, the specified parameters will be bound
+        to the query (see PLC.DB.parameterize() and
+        pgdb.cursor.execute()).
+        """
+
+        self.execute(query, params)
+        rows = self.cursor.fetchall()
+
+        if hashref:
+            # Return each row as a dictionary keyed on field name
+            # (like DBI selectrow_hashref()).
+            labels = [column[0] for column in self.description]
+            rows = [dict(zip(labels, row)) for row in rows]
+
+        if key_field is not None and key_field in labels:
+            # Return rows as a dictionary keyed on the specified field
+            # (like DBI selectall_hashref()).
+            return dict([(row[key_field], row) for row in rows])
+        else:
+            return rows