postgres_backend.py :  » Project-Management » Trac » Trac-0.11.7 » trac » db » Python Open Source

Home
Python Open Source
1.3.1.2 Python
2.Ajax
3.Aspect Oriented
4.Blog
5.Build
6.Business Application
7.Chart Report
8.Content Management Systems
9.Cryptographic
10.Database
11.Development
12.Editor
13.Email
14.ERP
15.Game 2D 3D
16.GIS
17.GUI
18.IDE
19.Installer
20.IRC
21.Issue Tracker
22.Language Interface
23.Log
24.Math
25.Media Sound Audio
26.Mobile
27.Network
28.Parser
29.PDF
30.Project Management
31.RSS
32.Search
33.Security
34.Template Engines
35.Test
36.UML
37.USB Serial
38.Web Frameworks
39.Web Server
40.Web Services
41.Web Unit
42.Wiki
43.Windows
44.XML
Python Open Source » Project Management » Trac 
Trac » Trac 0.11.7 » trac » db » postgres_backend.py
# -*- coding: utf-8 -*-
#
# Copyright (C)2005-2009 Edgewall Software
# Copyright (C) 2005 Christopher Lenz <cmlenz@gmx.de>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.org/wiki/TracLicense.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://trac.edgewall.org/log/.
#
# Author: Christopher Lenz <cmlenz@gmx.de>

import re, sys, os, time

from trac.core import *
from trac.config import Option
from trac.db.api import IDatabaseConnector,_parse_db_str
from trac.db.util import ConnectionWrapper
from trac.util import get_pkginfo
from trac.util.compat import close_fds
from trac.util.text import to_unicode
from trac.util.translation import _

has_psycopg = False
has_pgsql = False
PGSchemaError = None
try:
    import psycopg2 as psycopg
    import psycopg2.extensions
    from psycopg2 import ProgrammingError
    psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
    has_psycopg = True
except ImportError:
    try:
        from pyPgSQL import PgSQL
        from pyPgSQL.libpq import OperationalError
        has_pgsql = True
    except ImportError:
        pass


_like_escape_re = re.compile(r'([/_%])')


class PostgreSQLConnector(Component):
    """PostgreSQL database support."""

    implements(IDatabaseConnector)

    pg_dump_path = Option('trac', 'pg_dump_path', 'pg_dump',
        """Location of pg_dump for Postgres database backups""")

    def __init__(self):
        self._version = None
        self.error = None

    def get_supported_schemes(self):
        if not (has_psycopg or has_pgsql):
            self.error = _("Cannot load Python bindings for PostgreSQL")
        yield ('postgres', self.error and -1 or 1)

    def get_connection(self, path, log=None, user=None, password=None,
                       host=None, port=None, params={}):
        cnx = PostgreSQLConnection(path, log, user, password, host, port,
                                   params)
        if not self._version:
            if has_psycopg:
                self._version = get_pkginfo(psycopg).get('version',
                                                         psycopg.__version__)
                name = 'psycopg2'
            elif has_pgsql:
                import pyPgSQL
                self._version = get_pkginfo(pyPgSQL).get('version',
                                                         pyPgSQL.__version__)
                name = 'pyPgSQL'
            else:
                name = 'unknown postgreSQL driver'
                self._version = '?'
            self.env.systeminfo.append((name, self._version))
        return cnx

    def init_db(self, path, log=None, user=None, password=None, host=None,
                port=None, params={}):
        cnx = self.get_connection(path, log, user, password, host, port,
                                  params)
        cursor = cnx.cursor()
        if cnx.schema:
            cursor.execute('CREATE SCHEMA "%s"' % cnx.schema)
            cursor.execute('SET search_path TO %s', (cnx.schema,))
        from trac.db_default import schema
        for table in schema:
            for stmt in self.to_sql(table):
                cursor.execute(stmt)
        cnx.commit()

    def to_sql(self, table):
        sql = ['CREATE TABLE "%s" (' % table.name]
        coldefs = []
        for column in table.columns:
            ctype = column.type
            if column.auto_increment:
                ctype = 'SERIAL'
            if len(table.key) == 1 and column.name in table.key:
                ctype += ' PRIMARY KEY'
            coldefs.append('    "%s" %s' % (column.name, ctype))
        if len(table.key) > 1:
            coldefs.append('    CONSTRAINT "%s_pk" PRIMARY KEY ("%s")'
                           % (table.name, '","'.join(table.key)))
        sql.append(',\n'.join(coldefs) + '\n)')
        yield '\n'.join(sql)
        for index in table.indices:
            unique = index.unique and 'UNIQUE' or ''
            yield 'CREATE %s INDEX "%s_%s_idx" ON "%s" ("%s")' % \
                    (unique, table.name, 
                     '_'.join(index.columns), table.name,
                     '","'.join(index.columns))

    def backup(self, dest_file):
        try:
            from subprocess import Popen,PIPE
        except ImportError:
            raise TracError('Python >= 2.4 or the subprocess module '
                            'is required for pre-upgrade backup support')
        db_url = self.env.config.get('trac', 'database')
        scheme, db_prop = _parse_db_str(db_url)
        db_prop.setdefault('params', {})
        db_name = os.path.basename(db_prop['path'])

        args = [self.pg_dump_path, '-C', '--inserts', '-x', '-Z', '8']
        if 'user' in db_prop:
            args.extend(['-U', db_prop['user']])
        if 'host' in db_prop['params']:
            host = db_prop['params']['host']
        else:
            host = db_prop.get('host', 'localhost')
        args.extend(['-h', host])
        if '/' not in host:
            args.extend(['-p', str(db_prop.get('port', '5432'))])

        if 'schema' in db_prop['params']:
            args.extend(['-n', '"%s"' % db_prop['params']['schema']])

        dest_file += ".gz"
        args.extend(['-f', dest_file, db_name])

        environ = os.environ.copy()
        if 'password' in db_prop:
            environ['PGPASSWORD'] = str(db_prop['password'])
        p = Popen(args, env=environ, stderr=PIPE, close_fds=close_fds)
        errmsg = p.communicate()[1]
        if p.returncode != 0:
            raise TracError("Backup attempt failed (%s)" % to_unicode(errmsg))
        if not os.path.exists(dest_file):
            raise TracError("Backup attempt failed")
        return dest_file


class PostgreSQLConnection(ConnectionWrapper):
    """Connection wrapper for PostgreSQL."""

    poolable = True

    def __init__(self, path, log=None, user=None, password=None, host=None,
                 port=None, params={}):
        if path.startswith('/'):
            path = path[1:]
        if 'host' in params:
            host = params['host']
        if has_psycopg:
            dsn = []
            if path:
                dsn.append('dbname=' + path)
            if user:
                dsn.append('user=' + user)
            if password:
                dsn.append('password=' + password)
            if host:
                dsn.append('host=' + host)
            if port:
                dsn.append('port=' + str(port))
            cnx = psycopg.connect(' '.join(dsn))
            cnx.set_client_encoding('UNICODE')
        elif has_pgsql:
            # Don't use chatty, inefficient server-side cursors.
            # http://pypgsql.sourceforge.net/pypgsql-faq.html#id2787367
            PgSQL.fetchReturnsList = 1
            PgSQL.noPostgresCursor = 1
            cnx = PgSQL.connect('', user, password, host, path, port, 
                                client_encoding='utf-8', unicode_results=True)
        try:
            self.schema = None
            if 'schema' in params:
                self.schema = params['schema']
                cnx.cursor().execute('SET search_path TO %s', (self.schema,))
                cnx.commit()
        except PGSchemaError:
            cnx.rollback()
        ConnectionWrapper.__init__(self, cnx, log)

    def cast(self, column, type):
        # Temporary hack needed for the union of selects in the search module
        return 'CAST(%s AS %s)' % (column, type)

    def concat(self, *args):
        return '||'.join(args)

    def like(self):
        # Temporary hack needed for the case-insensitive string matching in the
        # search module
        return "ILIKE %s ESCAPE '/'"

    def like_escape(self, text):
        return _like_escape_re.sub(r'/\1', text)

    def get_last_id(self, cursor, table, column='id'):
        cursor.execute("SELECT CURRVAL('%s_%s_seq')" % (table, column))
        return cursor.fetchone()[0]
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.