# Source code for sqlobject.postgres.pgconnection

    from getpass import getuser
    import re
    from sqlobject import col
    from sqlobject import dberrors
    from sqlobject import sqlbuilder
    from sqlobject.compat import PY2
    from sqlobject.converters import registerConverter, sqlrepr
    from sqlobject.dbconnection import DBAPI

    class ErrorMessage(str):
        def __new__(cls, e, append_msg=''):
            obj = str.__new__(cls, e.args[0] + append_msg)
            if hasattr(e, 'pgcode'):  # psycopg2 or psycopg2.errors
                obj.code = getattr(e, 'pgcode', None)
                obj.error = getattr(e, 'pgerror', None)
            else:
                obj.code = getattr(e, 'code', None)
                obj.error = getattr(e, 'error', None)
            obj.module = e.__module__
            obj.exception = e.__class__.__name__
            return obj

    class PostgresConnection(DBAPI):

        supportTransactions = True
        dbName = 'postgres'
        schemes = [dbName, 'postgresql']

        odbc_keywords = ('Server', 'Port', 'UID', 'Password', 'Database')

        def __init__(self, dsn=None, host=None, port=None, db=None,
                     user=None, password=None, **kw):
            drivers = kw.pop('driver', None) or 'psycopg'
            for driver in drivers.split(','):
                driver = driver.strip()
                if not driver:
                    continue
                try:
                    if driver in ('psycopg', 'psycopg2'):
                        import psycopg2 as psycopg
                        self.module = psycopg
                    elif driver == 'pygresql':
                        import pgdb
                        self.module = pgdb
                    elif driver in ('py-postgresql', 'pypostgresql'):
                        from postgresql.driver import dbapi20
                        self.module = dbapi20
                    elif driver == 'pg8000':
                        import pg8000
                        self.module = pg8000
                    elif driver == 'pyodbc':
                        import pyodbc
                        self.module = pyodbc
                    elif driver == 'pypyodbc':
                        import pypyodbc
                        self.module = pypyodbc
                    elif driver == 'odbc':
                        try:
                            import pyodbc
                        except ImportError:
                            import pypyodbc as pyodbc
                        self.module = pyodbc
                    else:
                        raise ValueError(
                            'Unknown PostgreSQL driver "%s", '
                            'expected psycopg, psycopg2, '
                            'pygresql, pypostgresql, pg8000, '
                            'odbc, pyodbc or pypyodbc' % driver)
                except ImportError:
                    pass
                else:
                    break
            else:
                raise ImportError(
                    'Cannot find a PostgreSQL driver, tried %s' % drivers)

            if driver.startswith('psycopg'):
                # Register a converter for psycopg Binary type.
                registerConverter(type(self.module.Binary('')),
                                  PsycoBinaryConverter)
            elif driver in ('pygresql', 'py-postgresql', 'pypostgresql', 'pg8000'):
                registerConverter(type(self.module.Binary(b'')),
                                  PostgresBinaryConverter)
            elif driver in ('odbc', 'pyodbc', 'pypyodbc'):
                registerConverter(bytearray, OdbcBinaryConverter)

            self.db = db
            self.user = user
            self.password = password
            self.host = host
            self.port = port
            if driver in ('odbc', 'pyodbc', 'pypyodbc'):
                self.make_odbc_conn_str(kw.pop('odbcdrv', 'PostgreSQL ANSI'),
                                        db, host, port, user, password
                                        )
                sslmode = kw.pop("sslmode", None)
                if sslmode:
                    self.odbc_conn_str += ';sslmode=require'
            else:
                self.dsn_dict = dsn_dict = {}
                if host:
                    dsn_dict["host"] = host
                if port:
                    if driver == 'pygresql':
                        dsn_dict["host"] = "%s:%d" % (host, port)
                    elif driver.startswith('psycopg') and \
                            psycopg.__version__.split('.')[0] == '1':
                        dsn_dict["port"] = str(port)
                    else:
                        dsn_dict["port"] = port
                if db:
                    dsn_dict["database"] = db
                if user:
                    dsn_dict["user"] = user
                if password:
                    dsn_dict["password"] = password
                sslmode = kw.pop("sslmode", None)
                if sslmode:
                    dsn_dict["sslmode"] = sslmode
                self.use_dsn = dsn is not None
                if dsn is None:
                    if driver == 'pygresql':
                        dsn = ''
                        if host:
                            dsn += host
                        dsn += ':'
                        if db:
                            dsn += db
                        dsn += ':'
                        if user:
                            dsn += user
                        dsn += ':'
                        if password:
                            dsn += password
                    else:
                        dsn = []
                        if db:
                            dsn.append('dbname=%s' % db)
                        if user:
                            dsn.append('user=%s' % user)
                        if password:
                            dsn.append('password=%s' % password)
                        if host:
                            dsn.append('host=%s' % host)
                        if port:
                            dsn.append('port=%d' % port)
                        if sslmode:
                            dsn.append('sslmode=%s' % sslmode)
                        dsn = ' '.join(dsn)
                if driver in ('py-postgresql', 'pypostgresql'):
                    if host and host.startswith('/'):
                        dsn_dict["host"] = dsn_dict["port"] = None
                        dsn_dict["unix"] = host
                    else:
                        if "unix" in dsn_dict:
                            del dsn_dict["unix"]
                if driver == 'pg8000':
                    if host and host.startswith('/'):
                        dsn_dict["host"] = None
                        dsn_dict["unix_sock"] = host
                    if user is None:
                        dsn_dict["user"] = getuser()
                self.dsn = dsn
            self.driver = driver
            self.unicodeCols = kw.pop('unicodeCols', False)
            self.schema = kw.pop('schema', None)
            self.dbEncoding = kw.pop("charset", None)
            DBAPI.__init__(self, **kw)

        @classmethod
        def _connectionFromParams(cls, user, password, host, port, path, args):
            path = path.strip('/')
            if (host is None) and path.count('/'):  # Non-default unix socket
                path_parts = path.split('/')
                host = '/' + '/'.join(path_parts[:-1])
                path = path_parts[-1]
            return cls(host=host, port=port, db=path,
                       user=user, password=password, **args)

        def _setAutoCommit(self, conn, auto):
            # psycopg2 does not have an autocommit method.
            if hasattr(conn, 'autocommit'):
                try:
                    conn.autocommit(auto)
                except TypeError:
                    conn.autocommit = auto

        def makeConnection(self):
            try:
                if self.driver in ('odbc', 'pyodbc', 'pypyodbc'):
                    self.debugWriter.write(
                        "ODBC connect string: " + self.odbc_conn_str)
                    conn = self.module.connect(self.odbc_conn_str)
                elif self.use_dsn:
                    conn = self.module.connect(self.dsn)
                else:
                    conn = self.module.connect(**self.dsn_dict)
            except self.module.OperationalError as e:
                raise dberrors.OperationalError(
                    ErrorMessage(e, "used connection string %r" % self.dsn))

            # For printDebug in _executeRetry
            self._connectionNumbers[id(conn)] = self._connectionCount

            if self.autoCommit:
                self._setAutoCommit(conn, 1)
            c = conn.cursor()
            if self.schema:
                self._executeRetry(conn, c, "SET search_path TO " + self.schema)
            dbEncoding = self.dbEncoding
            if dbEncoding:
                if self.driver in ('odbc', 'pyodbc'):
                    conn.setdecoding(self.module.SQL_CHAR, encoding=dbEncoding)
                    conn.setdecoding(self.module.SQL_WCHAR, encoding=dbEncoding)
                    if PY2:
                        conn.setencoding(str, encoding=dbEncoding)
                        conn.setencoding(unicode, encoding=dbEncoding)  # noqa
                    else:
                        conn.setencoding(encoding=dbEncoding)
                self._executeRetry(conn, c,
                                   "SET client_encoding TO '%s'" % dbEncoding)
            c.close()
            return conn

        def _executeRetry(self, conn, cursor, query):
            if self.debug:
                self.printDebug(conn, query, 'QueryR')
            dbEncoding = self.dbEncoding
            if dbEncoding and isinstance(query, bytes) and (
                    self.driver == 'pg8000'):
                query = query.decode(dbEncoding)
            try:
                return cursor.execute(query)
            except self.module.OperationalError as e:
                raise dberrors.OperationalError(ErrorMessage(e))
            except self.module.IntegrityError as e:
                msg = ErrorMessage(e)
                if getattr(e, 'code', -1) == '23505' or \
                        getattr(e, 'pgcode', -1) == '23505' or \
                        getattr(e, 'sqlstate', -1) == '23505' or \
                        e.args[0] == '23505':
                    raise dberrors.DuplicateEntryError(msg)
                else:
                    raise dberrors.IntegrityError(msg)
            except self.module.InternalError as e:
                raise dberrors.InternalError(ErrorMessage(e))
            except self.module.ProgrammingError as e:
                msg = ErrorMessage(e)
                if (
                    (len(e.args) > 2) and (e.args[1] == 'ERROR')
                    and (e.args[2] == '23505')) \
                        or ((len(e.args) >= 2) and (e.args[1] == '23505')):
                    raise dberrors.DuplicateEntryError(msg)
                else:
                    raise dberrors.ProgrammingError(msg)
            except self.module.DataError as e:
                raise dberrors.DataError(ErrorMessage(e))
            except self.module.NotSupportedError as e:
                raise dberrors.NotSupportedError(ErrorMessage(e))
            except self.module.DatabaseError as e:
                msg = ErrorMessage(e)
                if 'duplicate key value violates unique constraint' in msg:
                    raise dberrors.DuplicateEntryError(msg)
                else:
                    raise dberrors.DatabaseError(msg)
            except self.module.InterfaceError as e:
                raise dberrors.InterfaceError(ErrorMessage(e))
            except self.module.Warning as e:
                raise Warning(ErrorMessage(e))
            except self.module.Error as e:
                raise dberrors.Error(ErrorMessage(e))

        def _queryInsertID(self, conn, soInstance, id, names, values):
            table = soInstance.sqlmeta.table
            idName = soInstance.sqlmeta.idName
            c = conn.cursor()
            if id is None and self.driver in ('py-postgresql', 'pypostgresql'):
                sequenceName = soInstance.sqlmeta.idSequence or \
                    '%s_%s_seq' % (table, idName)
                self._executeRetry(conn, c, "SELECT NEXTVAL('%s')" % sequenceName)
                id = c.fetchone()[0]
            if id is not None:
                names = [idName] + names
                values = [id] + values
            if names and values:
                q = self._insertSQL(table, names, values)
            else:
                q = "INSERT INTO %s DEFAULT VALUES" % table
            if id is None:
                q += " RETURNING " + idName
            if self.debug:
                self.printDebug(conn, q, 'QueryIns')
            self._executeRetry(conn, c, q)
            if id is None:
                id = c.fetchone()[0]
            c.close()
            if self.debugOutput:
                self.printDebug(conn, id, 'QueryIns', 'result')
            return id

        @classmethod
        def _queryAddLimitOffset(cls, query, start, end):
            if not start:
                return "%s LIMIT %i" % (query, end)
            if not end:
                return "%s OFFSET %i" % (query, start)
            return "%s LIMIT %i OFFSET %i" % (query, end - start, start)

        def createColumn(self, soClass, col):
            return col.postgresCreateSQL()

        def createReferenceConstraint(self, soClass, col):
            return col.postgresCreateReferenceConstraint()

        def createIndexSQL(self, soClass, index):
            return index.postgresCreateIndexSQL(soClass)

        def createIDColumn(self, soClass):
            key_type = {int: "SERIAL", str: "TEXT"}[soClass.sqlmeta.idType]
            return '%s %s PRIMARY KEY' % (soClass.sqlmeta.idName, key_type)

        def dropTable(self, tableName, cascade=False):
            self.query("DROP TABLE %s %s" % (tableName,
                                             cascade and 'CASCADE' or ''))

        def joinSQLType(self, join):
            return 'INT NOT NULL'

        def tableExists(self, tableName):
            result = self.queryOne(
                "SELECT COUNT(relname) FROM pg_class WHERE relname = %s" %
                self.sqlrepr(tableName))
            return result[0]

        def addColumn(self, tableName, column):
            self.query('ALTER TABLE %s ADD COLUMN %s' %
                       (tableName,
                        column.postgresCreateSQL()))

        def delColumn(self, sqlmeta, column):
            self.query('ALTER TABLE %s DROP COLUMN %s' % (sqlmeta.table,
                                                          column.dbName))

        def columnsFromSchema(self, tableName, soClass):

            keyQuery = """
            SELECT pg_catalog.pg_get_constraintdef(oid) as condef
            FROM pg_catalog.pg_constraint r
            WHERE r.conrelid = %s::regclass AND r.contype = 'f'"""

            colQuery = """
            SELECT a.attname,
            pg_catalog.format_type(a.atttypid, a.atttypmod), a.attnotnull,
            (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                FROM pg_catalog.pg_attrdef d
            WHERE d.adrelid=a.attrelid AND d.adnum = a.attnum)
            FROM pg_catalog.pg_attribute a
            WHERE a.attrelid =%s::regclass
            AND a.attnum > 0 AND NOT a.attisdropped
            ORDER BY a.attnum"""

            primaryKeyQuery = """
            SELECT pg_index.indisprimary,
                pg_catalog.pg_get_indexdef(pg_index.indexrelid)
            FROM pg_catalog.pg_class c, pg_catalog.pg_class c2,
                pg_catalog.pg_index AS pg_index
            WHERE c.relname = %s
                AND c.oid = pg_index.indrelid
                AND pg_index.indexrelid = c2.oid
                AND pg_index.indisprimary
            """

            otherKeyQuery = """
            SELECT pg_index.indisprimary,
                pg_catalog.pg_get_indexdef(pg_index.indexrelid)
            FROM pg_catalog.pg_class c, pg_catalog.pg_class c2,
                pg_catalog.pg_index AS pg_index
            WHERE c.relname = %s
                AND c.oid = pg_index.indrelid
                AND pg_index.indexrelid = c2.oid
                AND NOT pg_index.indisprimary
            """

            keyData = self.queryAll(keyQuery % self.sqlrepr(tableName))
            keyRE = re.compile(r"\((.+)\) REFERENCES (.+)\(")
            keymap = {}

            for (condef,) in keyData:
                match = keyRE.search(condef)
                if match:
                    field, reftable = match.groups()
                    keymap[field] = reftable.capitalize()

            primaryData = self.queryAll(primaryKeyQuery % self.sqlrepr(tableName))
            primaryRE = re.compile(r'CREATE .*? USING .* \((.+?)\)')
            primaryKey = None
            for isPrimary, indexDef in primaryData:
                match = primaryRE.search(indexDef)
                assert match, "Unparseable contraint definition: %r" % indexDef
                assert primaryKey is None, \
                    "Already found primary key (%r), " \
                    "then found: %r" % (primaryKey, indexDef)
                primaryKey = match.group(1)
            if primaryKey is None:
                # VIEWs don't have PRIMARY KEYs - accept help from user
                primaryKey = soClass.sqlmeta.idName
            assert primaryKey, "No primary key found in table %r" % tableName
            if primaryKey.startswith('"'):
                assert primaryKey.endswith('"')
                primaryKey = primaryKey[1:-1]

            otherData = self.queryAll(otherKeyQuery % self.sqlrepr(tableName))
            otherRE = primaryRE
            otherKeys = []
            for isPrimary, indexDef in otherData:
                match = otherRE.search(indexDef)
                assert match, "Unparseable constraint definition: %r" % indexDef
                otherKey = match.group(1)
                if otherKey.startswith('"'):
                    assert otherKey.endswith('"')
                    otherKey = otherKey[1:-1]
                otherKeys.append(otherKey)

            colData = self.queryAll(colQuery % self.sqlrepr(tableName))
            results = []
            if self.unicodeCols:
                client_encoding = self.queryOne("SHOW client_encoding")[0]
            for field, t, notnull, defaultstr in colData:
                if field == primaryKey:
                    continue
                if field in keymap:
                    colClass = col.ForeignKey
                    kw = {'foreignKey': soClass.sqlmeta.style.
                          dbTableToPythonClass(keymap[field])}
                    name = soClass.sqlmeta.style.dbColumnToPythonAttr(field)
                    if name.endswith('ID'):
                        name = name[:-2]
                    kw['name'] = name
                else:
                    colClass, kw = self.guessClass(t)
                    if self.unicodeCols and colClass is col.StringCol:
                        colClass = col.UnicodeCol
                        kw['dbEncoding'] = client_encoding
                    kw['name'] = soClass.sqlmeta.style.dbColumnToPythonAttr(field)
                kw['dbName'] = field
                kw['notNone'] = notnull
                if defaultstr is not None:
                    kw['default'] = self.defaultFromSchema(colClass, defaultstr)
                elif not notnull:
                    kw['default'] = None
                if field in otherKeys:
                    kw['alternateID'] = True
                results.append(colClass(**kw))
            return results

        def guessClass(self, t):
            if t.count('point'):  # poINT before INT
                return col.StringCol, {}
            elif t.count('int'):
                return col.IntCol, {}
            elif t.count('varying') or t.count('varchar'):
                if '(' in t:
                    return col.StringCol, {'length': int(t[t.index('(') + 1:-1])}
                else:  # varchar without length in Postgres means any length
                    return col.StringCol, {}
            elif t.startswith('character('):
                return col.StringCol, {'length': int(t[t.index('(') + 1:-1]),
                                       'varchar': False}
            elif t.count('float') or t.count('real') or t.count('double'):
                return col.FloatCol, {}
            elif t == 'text':
                return col.StringCol, {}
            elif t.startswith('timestamp'):
                return col.DateTimeCol, {}
            elif t.startswith('datetime'):
                return col.DateTimeCol, {}
            elif t.startswith('date'):
                return col.DateCol, {}
            elif t.startswith('bool'):
                return col.BoolCol, {}
            elif t.startswith('bytea'):
                return col.BLOBCol, {}
            else:
                return col.Col, {}

        def defaultFromSchema(self, colClass, defaultstr):
            """
            If the default can be converted to a python constant, convert it.
            Otherwise return is as a sqlbuilder constant.
            """
            if colClass == col.BoolCol:
                if defaultstr == 'false':
                    return False
                elif defaultstr == 'true':
                    return True
            return getattr(sqlbuilder.const, defaultstr)

        def _createOrDropDatabase(self, op="CREATE"):
            # We have to connect to *some* database, so we'll connect to
            # template1, which is a common open database.
            # @@: This doesn't use self.use_dsn or self.dsn_dict
            if self.driver == 'pygresql':
                dsn = '%s:template1:%s:%s' % (
                    self.host or '', self.user or '', self.password or '')
            else:
                dsn = 'dbname=template1'
                if self.user:
                    dsn += ' user=%s' % self.user
                if self.password:
                    dsn += ' password=%s' % self.password
                if self.host:
                    dsn += ' host=%s' % self.host
            conn = self.module.connect(dsn)
            cur = conn.cursor()
            # We must close the transaction with a commit so that
            # the CREATE DATABASE can work (which can't be in a transaction):
            try:
                self._executeRetry(conn, cur, 'COMMIT')
                self._executeRetry(conn, cur, '%s DATABASE %s' % (op, self.db))
            finally:
                cur.close()
                conn.close()

        def listTables(self):
            return [v[0] for v in self.queryAll(
                """SELECT c.relname FROM pg_catalog.pg_class c
                LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
                WHERE c.relkind IN ('r','') AND
                n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
                pg_catalog.pg_table_is_visible(c.oid)""")]

        def listDatabases(self):
            return [v[0] for v in self.queryAll("SELECT datname FROM pg_database")]

        def createEmptyDatabase(self):
            self._createOrDropDatabase()

        def dropDatabase(self):
            self._createOrDropDatabase(op="DROP")

    # Converter for Binary types
    def PsycoBinaryConverter(value, db):
        assert db == 'postgres'
        return str(value)

    if PY2:
        def escape_bytea(value):
            return ''.join(
                ['\\' + (x[1:].rjust(3, '0'))
                    for x in (oct(ord(c)) for c in value)]
            )
    else:
        def escape_bytea(value):
            return ''.join(
                ['\\' + (x[2:].rjust(3, '0'))
                    for x in (oct(ord(c)) for c in value.decode('latin1'))]
            )

    def PostgresBinaryConverter(value, db):
        assert db == 'postgres'
        return sqlrepr(escape_bytea(value), db)

    def OdbcBinaryConverter(value, db):
        assert db == 'postgres'
        value = bytes(value)
        if not PY2:
            value = value.decode('latin1')
        return value