pwman3/pwman/data/drivers/sqlite.py

#============================================================================
# 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; 
# 
# 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) 2006 Ivan Kelly <ivan@ivankelly.net>
#============================================================================

"""SQLite Database implementation."""
from pwman.data.database import Database, DatabaseException
from pwman.data.nodes import Node
from pwman.data.tags import Tag

from pysqlite2 import dbapi2 as sqlite
import pwman.util.config as config
import cPickle

class SQLiteDatabase(Database):
    """SQLite Database implementation"""
    
    def __init__(self):
        """Initialise SQLitePwmanDatabase instance."""
        Database.__init__(self)

        try:
            self._filename = config.get_value('Database', 'filename')
        except KeyError, e:
            raise DatabaseException(
                "SQLite: missing parameter [%s]" % (e))

    def _open(self):
        try:
            self._con = sqlite.connect(self._filename)
            self._cur = self._con.cursor()
            self._checktables()
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (s))

    def close(self):
        self._cur.close()
        self._con.close()

    def listtags(self, all=False):
        sql = ''
        params = []
        if len(self._filtertags) == 0 or all:
            sql = "SELECT DATA FROM TAGS ORDER BY DATA ASC"
        else:
            sql = ("SELECT TAGS.DATA FROM LOOKUP"
                   +" INNER JOIN TAGS ON LOOKUP.TAG = TAGS.ID"
                   +" WHERE NODE IN (")
            first = True
            for t in self._filtertags:
                if not first:
                    sql += " INTERSECT "
                else:
                    first = False
                    
                sql += ("SELECT NODE FROM LOOKUP OUTER JOIN TAGS ON TAG = TAGS.ID "
                        + " WHERE TAGS.DATA = ?")
                params.append(cPickle.dumps(t))
            sql += ") EXCEPT SELECT DATA FROM TAGS WHERE "
            first = True
            for t in self._filtertags:
                if not first:
                    sql += " OR "
                else:
                    first = False
                sql += "TAGS.DATA = ?"
                params.append(cPickle.dumps(t))
        try:
            self._cur.execute(sql, params)

            tags = []
            row = self._cur.fetchone()
            while (row != None):
                tag = cPickle.loads(str(row[0]))
                tags.append(tag)
                row = self._cur.fetchone()
            return tags
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (e))
        
    def getnodes(self, ids):
        nodes = []
        for i in ids:
            sql = "SELECT DATA FROM NODES WHERE ID = ?"
            try:
                self._cur.execute(sql, [i])

                row = self._cur.fetchone()
                if row != None:
                    node = cPickle.loads(str(row[0]))
                    node.set_id(i)
                    nodes.append(node)
            except sqlite.DatabaseError, e:
                raise DatabaseException("SQLite: %s" % (e))
        return nodes

    def editnode(self, id, node):
        if not isinstance(node, Node): raise DatabaseException(
                "Tried to insert foreign object into database [%s]" % node)
        try:
            sql = "UPDATE NODES SET DATA = ? WHERE ID = ?";
            self._cur.execute(sql, [cPickle.dumps(node), id])
            
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (e))
        self._setnodetags(node)
        self._checktags()
        self._commit()

    def addnodes(self, nodes):
        for n in nodes:
            sql = "INSERT INTO NODES(DATA) VALUES(?)"
            if not isinstance(n, Node): raise DatabaseException(
                "Tried to insert foreign object into database [%s]", n)
            value = cPickle.dumps(n)
            try:
                self._cur.execute(sql, [value])
            except sqlite.DatabaseError, e:
                raise DatabaseException("SQLite: %s" % (e))
            id = self._cur.lastrowid
            n.set_id(id)

            self._setnodetags(n)
            self._commit()
            
    def removenodes(self, nodes):
        for n in nodes:
            if not isinstance(n, Node): raise DatabaseException(
                "Tried to delete foreign object from database [%s]", n)
            try:
                sql = "DELETE FROM NODES WHERE ID = ?";
                self._cur.execute(sql, [n.get_id()])
                
            except sqlite.DatabaseError, e:
                raise DatabaseException("SQLite: %s" % (e))
            self._deletenodetags(n)

        self._checktags()
        self._commit()

    def listnodes(self):
        sql = ''
        params = []
        if len(self._filtertags) == 0:
            sql = "SELECT ID FROM NODES ORDER BY ID ASC"
        else:
            first = True
            for t in self._filtertags:
                if not first:
                    sql += " INTERSECT "
                else:
                    first = False
                sql += ("SELECT NODE FROM LOOKUP OUTER JOIN TAGS ON TAG = TAGS.ID"
                        + " WHERE TAGS.DATA = ? ")

                params.append(cPickle.dumps(t))
        try:
            self._cur.execute(sql, params)

            ids = []
            row = self._cur.fetchone()
            while (row != None):
                ids.append(row[0])
                row = self._cur.fetchone()
            return ids
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (e))

    def _commit(self):
        try:
            self._con.commit()
        except sqlite.DatabaseError, e:
            self._con.rollback()
            raise DatabaseException(
                "SQLite: Error commiting data to db [%s]" % (e))

    def _tagids(self, tags):
        ids = []
        for t in tags:
            sql = "SELECT ID FROM TAGS WHERE DATA = ?"
            if not isinstance(t, Tag): raise DatabaseException(
                "Tried to insert foreign object into database [%s]", t)
            data = cPickle.dumps(t)
            
            try:
                self._cur.execute(sql, [data])
                row = self._cur.fetchone()
                if (row != None):
                    ids.append(row[0])
                else:
                    sql = "INSERT INTO TAGS(DATA) VALUES(?)"
                    self._cur.execute(sql, [data])
                    ids.append(self._cur.lastrowid)
            except sqlite.DatabaseError, e:
                raise DatabaseException("SQLite: %s" % (e))
        return ids

    def _deletenodetags(self, node):
        try:
            sql = "DELETE FROM LOOKUP WHERE NODE = ?"
            self._cur.execute(sql, [node.get_id()])
            
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (e))
        self._commit()
        
    def _setnodetags(self, node):
        self._deletenodetags(node)
        ids = self._tagids(node.get_tags())
        
        for i in ids:
            sql = "INSERT OR REPLACE INTO LOOKUP VALUES(?, ?)"
            params = [node.get_id(), i]
            
            try:
                self._cur.execute(sql, params)
            except sqlite.DatabaseError, e:
                raise DatabaseException("SQLite: %s" % (e))
        self._commit()

    def _checktags(self):
        try:
            sql = "DELETE FROM TAGS WHERE ID NOT IN (SELECT TAG FROM LOOKUP GROUP BY TAG)"
            self._cur.execute(sql)
        except sqlite.DatabaseError, e:
            raise DatabaseException("SQLite: %s" % (e))
        self._commit()
        
    def _checktables(self):
        """ Check if the Pwman tables exist """
        self._cur.execute("PRAGMA TABLE_INFO(NODES)")
        if (self._cur.fetchone() == None):
            # table doesn't exist, create it
            # SQLite does have constraints implemented at the moment
            # so datatype will just be a string
            self._cur.execute("CREATE TABLE NODES"
                             + "(ID INTEGER PRIMARY KEY AUTOINCREMENT,"
                             + "DATA BLOB NOT NULL)")
            self._cur.execute("CREATE TABLE TAGS"
                              + "(ID INTEGER PRIMARY KEY AUTOINCREMENT,"
                              + "DATA BLOB NOT NULL UNIQUE)")
            self._cur.execute("CREATE TABLE LOOKUP"
                              + "(NODE INTEGER NOT NULL, TAG INTEGER NOT NULL,"
                              + " PRIMARY KEY(NODE, TAG))")

            self._cur.execute("CREATE TABLE KEY"
                              + "(THEKEY TEXT NOT NULL DEFAULT '')");
            self._cur.execute("INSERT INTO KEY VALUES('')");
            
            try:
                self._con.commit()
            except DatabaseError, e:
                self._con.rollback()
                raise e

    def savekey(self, key):
        sql = "UPDATE KEY SET THEKEY = ?"
        values = [key]
        self._cur.execute(sql, values)
        try:
            self._con.commit()
        except sqlite.DatabaseError, e:
            self._con.rollback()
            raise DatabaseException(
                "SQLite: Error saving key [%s]" % (e))
        
        
    def loadkey(self):
        self._cur.execute("SELECT THEKEY FROM KEY");
        keyrow = self._cur.fetchone()
        if (keyrow[0] == ''):
            return None
        else:
            return keyrow[0]