Initial Configuration Push

deps/sqlalchemy/dialects/postgresql/pg8000.py

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+# postgresql/pg8000.py
+# Copyright (C) 2005-2016 the SQLAlchemy authors and contributors <see AUTHORS
+# file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: http://www.opensource.org/licenses/mit-license.php
+
+"""
+.. dialect:: postgresql+pg8000
+    :name: pg8000
+    :dbapi: pg8000
+    :connectstring: \
+postgresql+pg8000://user:password@host:port/dbname[?key=value&key=value...]
+    :url: https://pythonhosted.org/pg8000/
+
+
+.. _pg8000_unicode:
+
+Unicode
+-------
+
+pg8000 will encode / decode string values between it and the server using the
+PostgreSQL ``client_encoding`` parameter; by default this is the value in
+the ``postgresql.conf`` file, which often defaults to ``SQL_ASCII``.
+Typically, this can be changed to ``utf-8``, as a more useful default::
+
+    #client_encoding = sql_ascii # actually, defaults to database
+                                 # encoding
+    client_encoding = utf8
+
+The ``client_encoding`` can be overriden for a session by executing the SQL:
+
+SET CLIENT_ENCODING TO 'utf8';
+
+SQLAlchemy will execute this SQL on all new connections based on the value
+passed to :func:`.create_engine` using the ``client_encoding`` parameter::
+
+    engine = create_engine(
+        "postgresql+pg8000://user:pass@host/dbname", client_encoding='utf8')
+
+
+.. _pg8000_isolation_level:
+
+pg8000 Transaction Isolation Level
+-------------------------------------
+
+The pg8000 dialect offers the same isolation level settings as that
+of the :ref:`psycopg2 <psycopg2_isolation_level>` dialect:
+
+* ``READ COMMITTED``
+* ``READ UNCOMMITTED``
+* ``REPEATABLE READ``
+* ``SERIALIZABLE``
+* ``AUTOCOMMIT``
+
+.. versionadded:: 0.9.5 support for AUTOCOMMIT isolation level when using
+   pg8000.
+
+.. seealso::
+
+    :ref:`postgresql_isolation_level`
+
+    :ref:`psycopg2_isolation_level`
+
+
+"""
+from ... import util, exc
+import decimal
+from ... import processors
+from ... import types as sqltypes
+from .base import (
+    PGDialect, PGCompiler, PGIdentifierPreparer, PGExecutionContext,
+    _DECIMAL_TYPES, _FLOAT_TYPES, _INT_TYPES)
+import re
+from sqlalchemy.dialects.postgresql.json import JSON
+
+
+class _PGNumeric(sqltypes.Numeric):
+    def result_processor(self, dialect, coltype):
+        if self.asdecimal:
+            if coltype in _FLOAT_TYPES:
+                return processors.to_decimal_processor_factory(
+                    decimal.Decimal, self._effective_decimal_return_scale)
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                # pg8000 returns Decimal natively for 1700
+                return None
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype)
+        else:
+            if coltype in _FLOAT_TYPES:
+                # pg8000 returns float natively for 701
+                return None
+            elif coltype in _DECIMAL_TYPES or coltype in _INT_TYPES:
+                return processors.to_float
+            else:
+                raise exc.InvalidRequestError(
+                    "Unknown PG numeric type: %d" % coltype)
+
+
+class _PGNumericNoBind(_PGNumeric):
+    def bind_processor(self, dialect):
+        return None
+
+
+class _PGJSON(JSON):
+
+    def result_processor(self, dialect, coltype):
+        if dialect._dbapi_version > (1, 10, 1):
+            return None  # Has native JSON
+        else:
+            return super(_PGJSON, self).result_processor(dialect, coltype)
+
+
+class PGExecutionContext_pg8000(PGExecutionContext):
+    pass
+
+
+class PGCompiler_pg8000(PGCompiler):
+    def visit_mod_binary(self, binary, operator, **kw):
+        return self.process(binary.left, **kw) + " %% " + \
+            self.process(binary.right, **kw)
+
+    def post_process_text(self, text):
+        if '%%' in text:
+            util.warn("The SQLAlchemy postgresql dialect "
+                      "now automatically escapes '%' in text() "
+                      "expressions to '%%'.")
+        return text.replace('%', '%%')
+
+
+class PGIdentifierPreparer_pg8000(PGIdentifierPreparer):
+    def _escape_identifier(self, value):
+        value = value.replace(self.escape_quote, self.escape_to_quote)
+        return value.replace('%', '%%')
+
+
+class PGDialect_pg8000(PGDialect):
+    driver = 'pg8000'
+
+    supports_unicode_statements = True
+
+    supports_unicode_binds = True
+
+    default_paramstyle = 'format'
+    supports_sane_multi_rowcount = True
+    execution_ctx_cls = PGExecutionContext_pg8000
+    statement_compiler = PGCompiler_pg8000
+    preparer = PGIdentifierPreparer_pg8000
+    description_encoding = 'use_encoding'
+
+    colspecs = util.update_copy(
+        PGDialect.colspecs,
+        {
+            sqltypes.Numeric: _PGNumericNoBind,
+            sqltypes.Float: _PGNumeric,
+            JSON: _PGJSON,
+        }
+    )
+
+    def __init__(self, client_encoding=None, **kwargs):
+        PGDialect.__init__(self, **kwargs)
+        self.client_encoding = client_encoding
+
+    def initialize(self, connection):
+        self.supports_sane_multi_rowcount = self._dbapi_version >= (1, 9, 14)
+        super(PGDialect_pg8000, self).initialize(connection)
+
+    @util.memoized_property
+    def _dbapi_version(self):
+        if self.dbapi and hasattr(self.dbapi, '__version__'):
+            return tuple(
+                [
+                    int(x) for x in re.findall(
+                        r'(\d+)(?:[-\.]?|$)', self.dbapi.__version__)])
+        else:
+            return (99, 99, 99)
+
+    @classmethod
+    def dbapi(cls):
+        return __import__('pg8000')
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username='user')
+        if 'port' in opts:
+            opts['port'] = int(opts['port'])
+        opts.update(url.query)
+        return ([], opts)
+
+    def is_disconnect(self, e, connection, cursor):
+        return "connection is closed" in str(e)
+
+    def set_isolation_level(self, connection, level):
+        level = level.replace('_', ' ')
+
+        # adjust for ConnectionFairy possibly being present
+        if hasattr(connection, 'connection'):
+            connection = connection.connection
+
+        if level == 'AUTOCOMMIT':
+            connection.autocommit = True
+        elif level in self._isolation_lookup:
+            connection.autocommit = False
+            cursor = connection.cursor()
+            cursor.execute(
+                "SET SESSION CHARACTERISTICS AS TRANSACTION "
+                "ISOLATION LEVEL %s" % level)
+            cursor.execute("COMMIT")
+            cursor.close()
+        else:
+            raise exc.ArgumentError(
+                "Invalid value '%s' for isolation_level. "
+                "Valid isolation levels for %s are %s or AUTOCOMMIT" %
+                (level, self.name, ", ".join(self._isolation_lookup))
+            )
+
+    def set_client_encoding(self, connection, client_encoding):
+        # adjust for ConnectionFairy possibly being present
+        if hasattr(connection, 'connection'):
+            connection = connection.connection
+
+        cursor = connection.cursor()
+        cursor.execute("SET CLIENT_ENCODING TO '" + client_encoding + "'")
+        cursor.execute("COMMIT")
+        cursor.close()
+
+    def do_begin_twophase(self, connection, xid):
+        connection.connection.tpc_begin((0, xid, ''))
+
+    def do_prepare_twophase(self, connection, xid):
+        connection.connection.tpc_prepare()
+
+    def do_rollback_twophase(
+            self, connection, xid, is_prepared=True, recover=False):
+        connection.connection.tpc_rollback((0, xid, ''))
+
+    def do_commit_twophase(
+            self, connection, xid, is_prepared=True, recover=False):
+        connection.connection.tpc_commit((0, xid, ''))
+
+    def do_recover_twophase(self, connection):
+        return [row[1] for row in connection.connection.tpc_recover()]
+
+    def on_connect(self):
+        fns = []
+        if self.client_encoding is not None:
+            def on_connect(conn):
+                self.set_client_encoding(conn, self.client_encoding)
+            fns.append(on_connect)
+
+        if self.isolation_level is not None:
+            def on_connect(conn):
+                self.set_isolation_level(conn, self.isolation_level)
+            fns.append(on_connect)
+
+        if len(fns) > 0:
+            def on_connect(conn):
+                for fn in fns:
+                    fn(conn)
+            return on_connect
+        else:
+            return None
+
+dialect = PGDialect_pg8000