• https://github.com/PyMySQL/PyMySQL/blob/master/pymysql/connections.py


    # Python implementation of the MySQL client-server protocol
    # http://dev.mysql.com/doc/internals/en/client-server-protocol.html
    # Error codes:
    # http://dev.mysql.com/doc/refman/5.5/en/error-messages-client.html
    from __future__ import print_function
    from ._compat import PY2, range_type, text_type, str_type, JYTHON, IRONPYTHON
    
    import errno
    from functools import partial
    import hashlib
    import io
    import os
    import socket
    import struct
    import sys
    import traceback
    import warnings
    
    from .charset import MBLENGTH, charset_by_name, charset_by_id
    from .constants import CLIENT, COMMAND, CR, FIELD_TYPE, SERVER_STATUS
    from .converters import escape_item, escape_string, through, conversions as _conv
    from .cursors import Cursor
    from .optionfile import Parser
    from .util import byte2int, int2byte
    from . import err
    
    try:
        import ssl
        SSL_ENABLED = True
    except ImportError:
        ssl = None
        SSL_ENABLED = False
    
    try:
        import getpass
        DEFAULT_USER = getpass.getuser()
        del getpass
    except (ImportError, KeyError):
        # KeyError occurs when there's no entry in OS database for a current user.
        DEFAULT_USER = None
    
    
    DEBUG = False
    
    _py_version = sys.version_info[:2]
    
    
    # socket.makefile() in Python 2 is not usable because very inefficient and
    # bad behavior about timeout.
    # XXX: ._socketio doesn't work under IronPython.
    if _py_version == (2, 7) and not IRONPYTHON:
        # read method of file-like returned by sock.makefile() is very slow.
        # So we copy io-based one from Python 3.
        from ._socketio import SocketIO
    
        def _makefile(sock, mode):
            return io.BufferedReader(SocketIO(sock, mode))
    elif _py_version == (2, 6):
        # Python 2.6 doesn't have fast io module.
        # So we make original one.
        class SockFile(object):
            def __init__(self, sock):
                self._sock = sock
    
            def read(self, n):
                read = self._sock.recv(n)
                if len(read) == n:
                    return read
                while True:
                    data = self._sock.recv(n-len(read))
                    if not data:
                        return read
                    read += data
                    if len(read) == n:
                        return read
    
        def _makefile(sock, mode):
            assert mode == 'rb'
            return SockFile(sock)
    else:
        # socket.makefile in Python 3 is nice.
        def _makefile(sock, mode):
            return sock.makefile(mode)
    
    
    TEXT_TYPES = set([
        FIELD_TYPE.BIT,
        FIELD_TYPE.BLOB,
        FIELD_TYPE.LONG_BLOB,
        FIELD_TYPE.MEDIUM_BLOB,
        FIELD_TYPE.STRING,
        FIELD_TYPE.TINY_BLOB,
        FIELD_TYPE.VAR_STRING,
        FIELD_TYPE.VARCHAR,
        FIELD_TYPE.GEOMETRY])
    
    sha_new = partial(hashlib.new, 'sha1')
    
    NULL_COLUMN = 251
    UNSIGNED_CHAR_COLUMN = 251
    UNSIGNED_SHORT_COLUMN = 252
    UNSIGNED_INT24_COLUMN = 253
    UNSIGNED_INT64_COLUMN = 254
    
    DEFAULT_CHARSET = 'latin1'
    
    MAX_PACKET_LEN = 2**24-1
    
    
    def dump_packet(data): # pragma: no cover
        def is_ascii(data):
            if 65 <= byte2int(data) <= 122:
                if isinstance(data, int):
                    return chr(data)
                return data
            return '.'
    
        try:
            print("packet length:", len(data))
            for i in range(1, 6):
                f = sys._getframe(i)
                print("call[%d]: %s (line %d)" % (i, f.f_code.co_name, f.f_lineno))
            print("-" * 66)
        except ValueError:
            pass
        dump_data = [data[i:i+16] for i in range_type(0, min(len(data), 256), 16)]
        for d in dump_data:
            print(' '.join(map(lambda x: "{:02X}".format(byte2int(x)), d)) +
                  '   ' * (16 - len(d)) + ' ' * 2 +
                  ''.join(map(lambda x: "{}".format(is_ascii(x)), d)))
        print("-" * 66)
        print()
    
    
    SCRAMBLE_LENGTH = 20
    
    def _scramble(password, message):
        if not password:
            return b''
        if DEBUG: print('password=' + str(password))
        stage1 = sha_new(password).digest()
        stage2 = sha_new(stage1).digest()
        s = sha_new()
        s.update(message[:SCRAMBLE_LENGTH]) 
        s.update(stage2)
        result = s.digest()
        return _my_crypt(result, stage1)
    
    
    def _my_crypt(message1, message2):
        length = len(message1)
        result = b''
        for i in range_type(length):
            x = (struct.unpack('B', message1[i:i+1])[0] ^
                 struct.unpack('B', message2[i:i+1])[0])
            result += struct.pack('B', x)
        return result
    
    # old_passwords support ported from libmysql/password.c
    SCRAMBLE_LENGTH_323 = 8
    
    
    class RandStruct_323(object):
        def __init__(self, seed1, seed2):
            self.max_value = 0x3FFFFFFF
            self.seed1 = seed1 % self.max_value
            self.seed2 = seed2 % self.max_value
    
        def my_rnd(self):
            self.seed1 = (self.seed1 * 3 + self.seed2) % self.max_value
            self.seed2 = (self.seed1 + self.seed2 + 33) % self.max_value
            return float(self.seed1) / float(self.max_value)
    
    
    def _scramble_323(password, message):
        hash_pass = _hash_password_323(password)
        hash_message = _hash_password_323(message[:SCRAMBLE_LENGTH_323])
        hash_pass_n = struct.unpack(">LL", hash_pass)
        hash_message_n = struct.unpack(">LL", hash_message)
    
        rand_st = RandStruct_323(hash_pass_n[0] ^ hash_message_n[0],
                                 hash_pass_n[1] ^ hash_message_n[1])
        outbuf = io.BytesIO()
        for _ in range_type(min(SCRAMBLE_LENGTH_323, len(message))):
            outbuf.write(int2byte(int(rand_st.my_rnd() * 31) + 64))
        extra = int2byte(int(rand_st.my_rnd() * 31))
        out = outbuf.getvalue()
        outbuf = io.BytesIO()
        for c in out:
            outbuf.write(int2byte(byte2int(c) ^ byte2int(extra)))
        return outbuf.getvalue()
    
    
    def _hash_password_323(password):
        nr = 1345345333
        add = 7
        nr2 = 0x12345671
    
        # x in py3 is numbers, p27 is chars
        for c in [byte2int(x) for x in password if x not in (' ', '	', 32, 9)]:
            nr ^= (((nr & 63) + add) * c) + (nr << 8) & 0xFFFFFFFF
            nr2 = (nr2 + ((nr2 << 8) ^ nr)) & 0xFFFFFFFF
            add = (add + c) & 0xFFFFFFFF
    
        r1 = nr & ((1 << 31) - 1)  # kill sign bits
        r2 = nr2 & ((1 << 31) - 1)
        return struct.pack(">LL", r1, r2)
    
    
    def pack_int24(n):
        return struct.pack('<I', n)[:3]
    
    # https://dev.mysql.com/doc/internals/en/integer.html#packet-Protocol::LengthEncodedInteger
    def lenenc_int(i):
        if (i < 0):
            raise ValueError("Encoding %d is less than 0 - no representation in LengthEncodedInteger" % i)
        elif (i < 0xfb):
            return int2byte(i)
        elif (i < (1 << 16)):
            return b'xfc' + struct.pack('<H', i)
        elif (i < (1 << 24)):
            return b'xfd' + struct.pack('<I', i)[:3]
        elif (i < (1 << 64)):
            return b'xfe' + struct.pack('<Q', i)
        else:
            raise ValueError("Encoding %x is larger than %x - no representation in LengthEncodedInteger" % (i, (1 << 64)))
    
    class MysqlPacket(object):
        """Representation of a MySQL response packet.
    
        Provides an interface for reading/parsing the packet results.
        """
        __slots__ = ('_position', '_data')
    
        def __init__(self, data, encoding):
            self._position = 0
            self._data = data
    
        def get_all_data(self):
            return self._data
    
        def read(self, size):
            """Read the first 'size' bytes in packet and advance cursor past them."""
            result = self._data[self._position:(self._position+size)]
            if len(result) != size:
                error = ('Result length not requested length:
    '
                         'Expected=%s.  Actual=%s.  Position: %s.  Data Length: %s'
                         % (size, len(result), self._position, len(self._data)))
                if DEBUG:
                    print(error)
                    self.dump()
                raise AssertionError(error)
            self._position += size
            return result
    
        def read_all(self):
            """Read all remaining data in the packet.
    
            (Subsequent read() will return errors.)
            """
            result = self._data[self._position:]
            self._position = None  # ensure no subsequent read()
            return result
    
        def advance(self, length):
            """Advance the cursor in data buffer 'length' bytes."""
            new_position = self._position + length
            if new_position < 0 or new_position > len(self._data):
                raise Exception('Invalid advance amount (%s) for cursor.  '
                                'Position=%s' % (length, new_position))
            self._position = new_position
    
        def rewind(self, position=0):
            """Set the position of the data buffer cursor to 'position'."""
            if position < 0 or position > len(self._data):
                raise Exception("Invalid position to rewind cursor to: %s." % position)
            self._position = position
    
        def get_bytes(self, position, length=1):
            """Get 'length' bytes starting at 'position'.
    
            Position is start of payload (first four packet header bytes are not
            included) starting at index '0'.
    
            No error checking is done.  If requesting outside end of buffer
            an empty string (or string shorter than 'length') may be returned!
            """
            return self._data[position:(position+length)]
    
        if PY2:
            def read_uint8(self):
                result = ord(self._data[self._position])
                self._position += 1
                return result
        else:
            def read_uint8(self):
                result = self._data[self._position]
                self._position += 1
                return result
    
        def read_uint16(self):
            result = struct.unpack_from('<H', self._data, self._position)[0]
            self._position += 2
            return result
    
        def read_uint24(self):
            low, high = struct.unpack_from('<HB', self._data, self._position)
            self._position += 3
            return low + (high << 16)
    
        def read_uint32(self):
            result = struct.unpack_from('<I', self._data, self._position)[0]
            self._position += 4
            return result
    
        def read_uint64(self):
            result = struct.unpack_from('<Q', self._data, self._position)[0]
            self._position += 8
            return result
    
        def read_string(self):
            end_pos = self._data.find(b'', self._position)
            if end_pos < 0:
                return None
            result = self._data[self._position:end_pos]
            self._position = end_pos + 1
            return result
    
        def read_length_encoded_integer(self):
            """Read a 'Length Coded Binary' number from the data buffer.
    
            Length coded numbers can be anywhere from 1 to 9 bytes depending
            on the value of the first byte.
            """
            c = self.read_uint8()
            if c == NULL_COLUMN:
                return None
            if c < UNSIGNED_CHAR_COLUMN:
                return c
            elif c == UNSIGNED_SHORT_COLUMN:
                return self.read_uint16()
            elif c == UNSIGNED_INT24_COLUMN:
                return self.read_uint24()
            elif c == UNSIGNED_INT64_COLUMN:
                return self.read_uint64()
    
        def read_length_coded_string(self):
            """Read a 'Length Coded String' from the data buffer.
    
            A 'Length Coded String' consists first of a length coded
            (unsigned, positive) integer represented in 1-9 bytes followed by
            that many bytes of binary data.  (For example "cat" would be "3cat".)
            """
            length = self.read_length_encoded_integer()
            if length is None:
                return None
            return self.read(length)
    
        def read_struct(self, fmt):
            s = struct.Struct(fmt)
            result = s.unpack_from(self._data, self._position)
            self._position += s.size
            return result
    
        def is_ok_packet(self):
            # https://dev.mysql.com/doc/internals/en/packet-OK_Packet.html
            return self._data[0:1] == b'' and len(self._data) >= 7
    
        def is_eof_packet(self):
            # http://dev.mysql.com/doc/internals/en/generic-response-packets.html#packet-EOF_Packet
            # Caution: xFE may be LengthEncodedInteger.
            # If xFE is LengthEncodedInteger header, 8bytes followed.
            return self._data[0:1] == b'xfe' and len(self._data) < 9
    
        def is_auth_switch_request(self):
            # http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest
            return self._data[0:1] == b'xfe'
    
        def is_resultset_packet(self):
            field_count = ord(self._data[0:1])
            return 1 <= field_count <= 250
    
        def is_load_local_packet(self):
            return self._data[0:1] == b'xfb'
    
        def is_error_packet(self):
            return self._data[0:1] == b'xff'
    
        def check_error(self):
            if self.is_error_packet():
                self.rewind()
                self.advance(1)  # field_count == error (we already know that)
                errno = self.read_uint16()
                if DEBUG: print("errno =", errno)
                err.raise_mysql_exception(self._data)
    
        def dump(self):
            dump_packet(self._data)
    
    
    class FieldDescriptorPacket(MysqlPacket):
        """A MysqlPacket that represents a specific column's metadata in the result.
    
        Parsing is automatically done and the results are exported via public
        attributes on the class such as: db, table_name, name, length, type_code.
        """
    
        def __init__(self, data, encoding):
            MysqlPacket.__init__(self, data, encoding)
            self._parse_field_descriptor(encoding)
    
        def _parse_field_descriptor(self, encoding):
            """Parse the 'Field Descriptor' (Metadata) packet.
    
            This is compatible with MySQL 4.1+ (not compatible with MySQL 4.0).
            """
            self.catalog = self.read_length_coded_string()
            self.db = self.read_length_coded_string()
            self.table_name = self.read_length_coded_string().decode(encoding)
            self.org_table = self.read_length_coded_string().decode(encoding)
            self.name = self.read_length_coded_string().decode(encoding)
            self.org_name = self.read_length_coded_string().decode(encoding)
            self.charsetnr, self.length, self.type_code, self.flags, self.scale = (
                self.read_struct('<xHIBHBxx'))
            # 'default' is a length coded binary and is still in the buffer?
            # not used for normal result sets...
    
        def description(self):
            """Provides a 7-item tuple compatible with the Python PEP249 DB Spec."""
            return (
                self.name,
                self.type_code,
                None,  # TODO: display_length; should this be self.length?
                self.get_column_length(),  # 'internal_size'
                self.get_column_length(),  # 'precision'  # TODO: why!?!?
                self.scale,
                self.flags % 2 == 0)
    
        def get_column_length(self):
            if self.type_code == FIELD_TYPE.VAR_STRING:
                mblen = MBLENGTH.get(self.charsetnr, 1)
                return self.length // mblen
            return self.length
    
        def __str__(self):
            return ('%s %r.%r.%r, type=%s, flags=%x'
                    % (self.__class__, self.db, self.table_name, self.name,
                       self.type_code, self.flags))
    
    
    class OKPacketWrapper(object):
        """
        OK Packet Wrapper. It uses an existing packet object, and wraps
        around it, exposing useful variables while still providing access
        to the original packet objects variables and methods.
        """
    
        def __init__(self, from_packet):
            if not from_packet.is_ok_packet():
                raise ValueError('Cannot create ' + str(self.__class__.__name__) +
                                 ' object from invalid packet type')
    
            self.packet = from_packet
            self.packet.advance(1)
    
            self.affected_rows = self.packet.read_length_encoded_integer()
            self.insert_id = self.packet.read_length_encoded_integer()
            self.server_status, self.warning_count = self.read_struct('<HH')
            self.message = self.packet.read_all()
            self.has_next = self.server_status & SERVER_STATUS.SERVER_MORE_RESULTS_EXISTS
    
        def __getattr__(self, key):
            return getattr(self.packet, key)
    
    
    class EOFPacketWrapper(object):
        """
        EOF Packet Wrapper. It uses an existing packet object, and wraps
        around it, exposing useful variables while still providing access
        to the original packet objects variables and methods.
        """
    
        def __init__(self, from_packet):
            if not from_packet.is_eof_packet():
                raise ValueError(
                    "Cannot create '{0}' object from invalid packet type".format(
                        self.__class__))
    
            self.packet = from_packet
            self.warning_count, self.server_status = self.packet.read_struct('<xhh')
            if DEBUG: print("server_status=", self.server_status)
            self.has_next = self.server_status & SERVER_STATUS.SERVER_MORE_RESULTS_EXISTS
    
        def __getattr__(self, key):
            return getattr(self.packet, key)
    
    
    class LoadLocalPacketWrapper(object):
        """
        Load Local Packet Wrapper. It uses an existing packet object, and wraps
        around it, exposing useful variables while still providing access
        to the original packet objects variables and methods.
        """
    
        def __init__(self, from_packet):
            if not from_packet.is_load_local_packet():
                raise ValueError(
                    "Cannot create '{0}' object from invalid packet type".format(
                        self.__class__))
    
            self.packet = from_packet
            self.filename = self.packet.get_all_data()[1:]
            if DEBUG: print("filename=", self.filename)
    
        def __getattr__(self, key):
            return getattr(self.packet, key)
    
    
    class Connection(object):
        """
        Representation of a socket with a mysql server.
    
        The proper way to get an instance of this class is to call
        connect().
    
        Establish a connection to the MySQL database. Accepts several
        arguments:
    
        :param host: Host where the database server is located
        :param user: Username to log in as
        :param password: Password to use.
        :param database: Database to use, None to not use a particular one.
        :param port: MySQL port to use, default is usually OK. (default: 3306)
        :param bind_address: When the client has multiple network interfaces, specify
            the interface from which to connect to the host. Argument can be
            a hostname or an IP address.
        :param unix_socket: Optionally, you can use a unix socket rather than TCP/IP.
        :param charset: Charset you want to use.
        :param sql_mode: Default SQL_MODE to use.
        :param read_default_file:
            Specifies  my.cnf file to read these parameters from under the [client] section.
        :param conv:
            Conversion dictionary to use instead of the default one.
            This is used to provide custom marshalling and unmarshaling of types.
            See converters.
        :param use_unicode:
            Whether or not to default to unicode strings.
            This option defaults to true for Py3k.
        :param client_flag: Custom flags to send to MySQL. Find potential values in constants.CLIENT.
        :param cursorclass: Custom cursor class to use.
        :param init_command: Initial SQL statement to run when connection is established.
        :param connect_timeout: Timeout before throwing an exception when connecting.
            (default: 10, min: 1, max: 31536000)
        :param ssl:
            A dict of arguments similar to mysql_ssl_set()'s parameters.
            For now the capath and cipher arguments are not supported.
        :param read_default_group: Group to read from in the configuration file.
        :param compress: Not supported
        :param named_pipe: Not supported
        :param autocommit: Autocommit mode. None means use server default. (default: False)
        :param local_infile: Boolean to enable the use of LOAD DATA LOCAL command. (default: False)
        :param max_allowed_packet: Max size of packet sent to server in bytes. (default: 16MB)
            Only used to limit size of "LOAD LOCAL INFILE" data packet smaller than default (16KB).
        :param defer_connect: Don't explicitly connect on contruction - wait for connect call.
            (default: False)
        :param auth_plugin_map: A dict of plugin names to a class that processes that plugin.
            The class will take the Connection object as the argument to the constructor.
            The class needs an authenticate method taking an authentication packet as
            an argument.  For the dialog plugin, a prompt(echo, prompt) method can be used
            (if no authenticate method) for returning a string from the user. (experimental)
        :param db: Alias for database. (for compatibility to MySQLdb)
        :param passwd: Alias for password. (for compatibility to MySQLdb)
        """
    
        _sock = None
        _auth_plugin_name = ''
        _closed = False
    
        def __init__(self, host=None, user=None, password="",
                     database=None, port=0, unix_socket=None,
                     charset='', sql_mode=None,
                     read_default_file=None, conv=None, use_unicode=None,
                     client_flag=0, cursorclass=Cursor, init_command=None,
                     connect_timeout=10, ssl=None, read_default_group=None,
                     compress=None, named_pipe=None, no_delay=None,
                     autocommit=False, db=None, passwd=None, local_infile=False,
                     max_allowed_packet=16*1024*1024, defer_connect=False,
                     auth_plugin_map={}, read_timeout=None, write_timeout=None,
                     bind_address=None):
            if no_delay is not None:
                warnings.warn("no_delay option is deprecated", DeprecationWarning)
    
            if use_unicode is None and sys.version_info[0] > 2:
                use_unicode = True
    
            if db is not None and database is None:
                database = db
            if passwd is not None and not password:
                password = passwd
    
            if compress or named_pipe:
                raise NotImplementedError("compress and named_pipe arguments are not supported")
    
            self._local_infile = bool(local_infile)
            if self._local_infile:
                client_flag |= CLIENT.LOCAL_FILES
    
            if read_default_group and not read_default_file:
                if sys.platform.startswith("win"):
                    read_default_file = "c:\my.ini"
                else:
                    read_default_file = "/etc/my.cnf"
    
            if read_default_file:
                if not read_default_group:
                    read_default_group = "client"
    
                cfg = Parser()
                cfg.read(os.path.expanduser(read_default_file))
    
                def _config(key, arg):
                    if arg:
                        return arg
                    try:
                        return cfg.get(read_default_group, key)
                    except Exception:
                        return arg
    
                user = _config("user", user)
                password = _config("password", password)
                host = _config("host", host)
                database = _config("database", database)
                unix_socket = _config("socket", unix_socket)
                port = int(_config("port", port))
                bind_address = _config("bind-address", bind_address)
                charset = _config("default-character-set", charset)
                if not ssl:
                    ssl = {}
                if isinstance(ssl, dict):
                    for key in ["ca", "capath", "cert", "key", "cipher"]:
                        value = _config("ssl-" + key, ssl.get(key))
                        if value:
                            ssl[key] = value
    
            self.ssl = False
            if ssl:
                if not SSL_ENABLED:
                    raise NotImplementedError("ssl module not found")
                self.ssl = True
                client_flag |= CLIENT.SSL
                self.ctx = self._create_ssl_ctx(ssl)
    
            self.host = host or "localhost"
            self.port = port or 3306
            self.user = user or DEFAULT_USER
            self.password = password or ""
            self.db = database
            self.unix_socket = unix_socket
            self.bind_address = bind_address
            if not (0 < connect_timeout <= 31536000):
                raise ValueError("connect_timeout should be >0 and <=31536000")
            self.connect_timeout = connect_timeout or None
            if read_timeout is not None and read_timeout <= 0:
                raise ValueError("read_timeout should be >= 0")
            self._read_timeout = read_timeout
            if write_timeout is not None and write_timeout <= 0:
                raise ValueError("write_timeout should be >= 0")
            self._write_timeout = write_timeout
            if charset:
                self.charset = charset
                self.use_unicode = True
            else:
                self.charset = DEFAULT_CHARSET
                self.use_unicode = False
    
            if use_unicode is not None:
                self.use_unicode = use_unicode
    
            self.encoding = charset_by_name(self.charset).encoding
    
            client_flag |= CLIENT.CAPABILITIES
            if self.db:
                client_flag |= CLIENT.CONNECT_WITH_DB
            self.client_flag = client_flag
    
            self.cursorclass = cursorclass
    
            self._result = None
            self._affected_rows = 0
            self.host_info = "Not connected"
    
            #: specified autocommit mode. None means use server default.
            self.autocommit_mode = autocommit
    
            if conv is None:
                conv = _conv
            # Need for MySQLdb compatibility.
            self.encoders = dict([(k, v) for (k, v) in conv.items() if type(k) is not int])
            self.decoders = dict([(k, v) for (k, v) in conv.items() if type(k) is int])
            self.sql_mode = sql_mode
            self.init_command = init_command
            self.max_allowed_packet = max_allowed_packet
            self._auth_plugin_map = auth_plugin_map
            if defer_connect:
                self._sock = None
            else:
                self.connect()
    
        def _create_ssl_ctx(self, sslp):
            if isinstance(sslp, ssl.SSLContext):
                return sslp
            ca = sslp.get('ca')
            capath = sslp.get('capath')
            hasnoca = ca is None and capath is None
            ctx = ssl.create_default_context(cafile=ca, capath=capath)
            ctx.check_hostname = not hasnoca and sslp.get('check_hostname', True)
            ctx.verify_mode = ssl.CERT_NONE if hasnoca else ssl.CERT_REQUIRED
            if 'cert' in sslp:
                ctx.load_cert_chain(sslp['cert'], keyfile=sslp.get('key'))
            if 'cipher' in sslp:
                ctx.set_ciphers(sslp['cipher'])
            ctx.options |= ssl.OP_NO_SSLv2
            ctx.options |= ssl.OP_NO_SSLv3
            return ctx
    
        def close(self):
            """Send the quit message and close the socket"""
            if self._closed:
                raise err.Error("Already closed")
            self._closed = True
            if self._sock is None:
                return
            send_data = struct.pack('<iB', 1, COMMAND.COM_QUIT)
            try:
                self._write_bytes(send_data)
            except Exception:
                pass
            finally:
                self._force_close()
    
        @property
        def open(self):
            return self._sock is not None
    
        def _force_close(self):
            """Close connection without QUIT message"""
            if self._sock:
                try:
                    self._sock.close()
                except:
                    pass
            self._sock = None
            self._rfile = None
    
        __del__ = _force_close
    
        def autocommit(self, value):
            self.autocommit_mode = bool(value)
            current = self.get_autocommit()
            if value != current:
                self._send_autocommit_mode()
    
        def get_autocommit(self):
            return bool(self.server_status &
                        SERVER_STATUS.SERVER_STATUS_AUTOCOMMIT)
    
        def _read_ok_packet(self):
            pkt = self._read_packet()
            if not pkt.is_ok_packet():
                raise err.OperationalError(2014, "Command Out of Sync")
            ok = OKPacketWrapper(pkt)
            self.server_status = ok.server_status
            return ok
    
        def _send_autocommit_mode(self):
            """Set whether or not to commit after every execute()"""
            self._execute_command(COMMAND.COM_QUERY, "SET AUTOCOMMIT = %s" %
                                  self.escape(self.autocommit_mode))
            self._read_ok_packet()
    
        def begin(self):
            """Begin transaction."""
            self._execute_command(COMMAND.COM_QUERY, "BEGIN")
            self._read_ok_packet()
    
        def commit(self):
            """Commit changes to stable storage"""
            self._execute_command(COMMAND.COM_QUERY, "COMMIT")
            self._read_ok_packet()
    
        def rollback(self):
            """Roll back the current transaction"""
            self._execute_command(COMMAND.COM_QUERY, "ROLLBACK")
            self._read_ok_packet()
    
        def show_warnings(self):
            """SHOW WARNINGS"""
            self._execute_command(COMMAND.COM_QUERY, "SHOW WARNINGS")
            result = MySQLResult(self)
            result.read()
            return result.rows
    
        def select_db(self, db):
            """Set current db"""
            self._execute_command(COMMAND.COM_INIT_DB, db)
            self._read_ok_packet()
    
        def escape(self, obj, mapping=None):
            """Escape whatever value you pass to it.
            
            Non-standard, for internal use; do not use this in your applications.
            """
            if isinstance(obj, str_type):
                return "'" + self.escape_string(obj) + "'"
            return escape_item(obj, self.charset, mapping=mapping)
    
        def literal(self, obj):
            """Alias for escape()
            
            Non-standard, for internal use; do not use this in your applications.
            """
            return self.escape(obj, self.encoders)
    
        def escape_string(self, s):
            if (self.server_status &
                    SERVER_STATUS.SERVER_STATUS_NO_BACKSLASH_ESCAPES):
                return s.replace("'", "''")
            return escape_string(s)
    
        def cursor(self, cursor=None):
            """Create a new cursor to execute queries with"""
            if cursor:
                return cursor(self)
            return self.cursorclass(self)
    
        def __enter__(self):
            """Context manager that returns a Cursor"""
            return self.cursor()
    
        def __exit__(self, exc, value, traceback):
            """On successful exit, commit. On exception, rollback"""
            if exc:
                self.rollback()
            else:
                self.commit()
    
        # The following methods are INTERNAL USE ONLY (called from Cursor)
        def query(self, sql, unbuffered=False):
            # if DEBUG:
            #     print("DEBUG: sending query:", sql)
            if isinstance(sql, text_type) and not (JYTHON or IRONPYTHON):
                if PY2:
                    sql = sql.encode(self.encoding)
                else:
                    sql = sql.encode(self.encoding, 'surrogateescape')
            self._execute_command(COMMAND.COM_QUERY, sql)
            self._affected_rows = self._read_query_result(unbuffered=unbuffered)
            return self._affected_rows
    
        def next_result(self, unbuffered=False):
            self._affected_rows = self._read_query_result(unbuffered=unbuffered)
            return self._affected_rows
    
        def affected_rows(self):
            return self._affected_rows
    
        def kill(self, thread_id):
            arg = struct.pack('<I', thread_id)
            self._execute_command(COMMAND.COM_PROCESS_KILL, arg)
            return self._read_ok_packet()
    
        def ping(self, reconnect=True):
            """Check if the server is alive"""
            if self._sock is None:
                if reconnect:
                    self.connect()
                    reconnect = False
                else:
                    raise err.Error("Already closed")
            try:
                self._execute_command(COMMAND.COM_PING, "")
                return self._read_ok_packet()
            except Exception:
                if reconnect:
                    self.connect()
                    return self.ping(False)
                else:
                    raise
    
        def set_charset(self, charset):
            # Make sure charset is supported.
            encoding = charset_by_name(charset).encoding
    
            self._execute_command(COMMAND.COM_QUERY, "SET NAMES %s" % self.escape(charset))
            self._read_packet()
            self.charset = charset
            self.encoding = encoding
    
        def connect(self, sock=None):
            self._closed = False
            try:
                if sock is None:
                    if self.unix_socket and self.host in ('localhost', '127.0.0.1'):
                        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
                        sock.settimeout(self.connect_timeout)
                        sock.connect(self.unix_socket)
                        self.host_info = "Localhost via UNIX socket"
                        if DEBUG: print('connected using unix_socket')
                    else:
                        kwargs = {}
                        if self.bind_address is not None:
                            kwargs['source_address'] = (self.bind_address, 0)
                        while True:
                            try:
                                sock = socket.create_connection(
                                    (self.host, self.port), self.connect_timeout,
                                    **kwargs)
                                break
                            except (OSError, IOError) as e:
                                if e.errno == errno.EINTR:
                                    continue
                                raise
                        self.host_info = "socket %s:%d" % (self.host, self.port)
                        if DEBUG: print('connected using socket')
                        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
                    sock.settimeout(None)
                    sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
                self._sock = sock
                self._rfile = _makefile(sock, 'rb')
                self._next_seq_id = 0
    
                self._get_server_information()
                self._request_authentication()
    
                if self.sql_mode is not None:
                    c = self.cursor()
                    c.execute("SET sql_mode=%s", (self.sql_mode,))
    
                if self.init_command is not None:
                    c = self.cursor()
                    c.execute(self.init_command)
                    c.close()
                    self.commit()
    
                if self.autocommit_mode is not None:
                    self.autocommit(self.autocommit_mode)
            except BaseException as e:
                self._rfile = None
                if sock is not None:
                    try:
                        sock.close()
                    except:
                        pass
    
                if isinstance(e, (OSError, IOError, socket.error)):
                    exc = err.OperationalError(
                            2003,
                            "Can't connect to MySQL server on %r (%s)" % (
                                self.host, e))
                    # Keep original exception and traceback to investigate error.
                    exc.original_exception = e
                    exc.traceback = traceback.format_exc()
                    if DEBUG: print(exc.traceback)
                    raise exc
    
                # If e is neither DatabaseError or IOError, It's a bug.
                # But raising AssertionError hides original error.
                # So just reraise it.
                raise
    
        def write_packet(self, payload):
            """Writes an entire "mysql packet" in its entirety to the network
            addings its length and sequence number.
            """
            # Internal note: when you build packet manualy and calls _write_bytes()
            # directly, you should set self._next_seq_id properly.
            data = pack_int24(len(payload)) + int2byte(self._next_seq_id) + payload
            if DEBUG: dump_packet(data)
            self._write_bytes(data)
            self._next_seq_id = (self._next_seq_id + 1) % 256
    
        def _read_packet(self, packet_type=MysqlPacket):
            """Read an entire "mysql packet" in its entirety from the network
            and return a MysqlPacket type that represents the results.
            """
            buff = b''
            while True:
                packet_header = self._read_bytes(4)
                if DEBUG: dump_packet(packet_header)
    
                btrl, btrh, packet_number = struct.unpack('<HBB', packet_header)
                bytes_to_read = btrl + (btrh << 16)
                if packet_number != self._next_seq_id:
                    self._force_close()
                    if packet_number == 0:
                        # MariaDB sends error packet with seqno==0 when shutdown
                        raise err.OperationalError(
                            CR.CR_SERVER_LOST,
                            "Lost connection to MySQL server during query")
                    raise err.InternalError(
                        "Packet sequence number wrong - got %d expected %d"
                        % (packet_number, self._next_seq_id))
                self._next_seq_id = (self._next_seq_id + 1) % 256
    
                recv_data = self._read_bytes(bytes_to_read)
                if DEBUG: dump_packet(recv_data)
                buff += recv_data
                # https://dev.mysql.com/doc/internals/en/sending-more-than-16mbyte.html
                if bytes_to_read == 0xffffff:
                    continue
                if bytes_to_read < MAX_PACKET_LEN:
                    break
    
            packet = packet_type(buff, self.encoding)
            packet.check_error()
            return packet
    
        def _read_bytes(self, num_bytes):
            self._sock.settimeout(self._read_timeout)
            while True:
                try:
                    data = self._rfile.read(num_bytes)
                    break
                except (IOError, OSError) as e:
                    if e.errno == errno.EINTR:
                        continue
                    self._force_close()
                    raise err.OperationalError(
                        CR.CR_SERVER_LOST,
                        "Lost connection to MySQL server during query (%s)" % (e,))
            if len(data) < num_bytes:
                self._force_close()
                raise err.OperationalError(
                    CR.CR_SERVER_LOST, "Lost connection to MySQL server during query")
            return data
    
        def _write_bytes(self, data):
            self._sock.settimeout(self._write_timeout)
            try:
                self._sock.sendall(data)
            except IOError as e:
                self._force_close()
                raise err.OperationalError(
                    CR.CR_SERVER_GONE_ERROR,
                    "MySQL server has gone away (%r)" % (e,))
    
        def _read_query_result(self, unbuffered=False):
            if unbuffered:
                try:
                    result = MySQLResult(self)
                    result.init_unbuffered_query()
                except:
                    result.unbuffered_active = False
                    result.connection = None
                    raise
            else:
                result = MySQLResult(self)
                result.read()
            self._result = result
            if result.server_status is not None:
                self.server_status = result.server_status
            return result.affected_rows
    
        def insert_id(self):
            if self._result:
                return self._result.insert_id
            else:
                return 0
    
        def _execute_command(self, command, sql):
            if not self._sock:
                raise err.InterfaceError("(0, '')")
    
            # If the last query was unbuffered, make sure it finishes before
            # sending new commands
            if self._result is not None:
                if self._result.unbuffered_active:
                    warnings.warn("Previous unbuffered result was left incomplete")
                    self._result._finish_unbuffered_query()
                while self._result.has_next:
                    self.next_result()
                self._result = None
    
            if isinstance(sql, text_type):
                sql = sql.encode(self.encoding)
    
            packet_size = min(MAX_PACKET_LEN, len(sql) + 1)  # +1 is for command
    
            # tiny optimization: build first packet manually instead of
            # calling self..write_packet()
            prelude = struct.pack('<iB', packet_size, command)
            packet = prelude + sql[:packet_size-1]
            self._write_bytes(packet)
            if DEBUG: dump_packet(packet)
            self._next_seq_id = 1
    
            if packet_size < MAX_PACKET_LEN:
                return
    
            sql = sql[packet_size-1:]
            while True:
                packet_size = min(MAX_PACKET_LEN, len(sql))
                self.write_packet(sql[:packet_size])
                sql = sql[packet_size:]
                if not sql and packet_size < MAX_PACKET_LEN:
                    break
    
        def _request_authentication(self):
            # https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse
            if int(self.server_version.split('.', 1)[0]) >= 5:
                self.client_flag |= CLIENT.MULTI_RESULTS
    
            if self.user is None:
                raise ValueError("Did not specify a username")
    
            charset_id = charset_by_name(self.charset).id
            if isinstance(self.user, text_type):
                self.user = self.user.encode(self.encoding)
    
            data_init = struct.pack('<iIB23s', self.client_flag, 1, charset_id, b'')
    
            if self.ssl and self.server_capabilities & CLIENT.SSL:
                self.write_packet(data_init)
    
                self._sock = self.ctx.wrap_socket(self._sock, server_hostname=self.host)
                self._rfile = _makefile(self._sock, 'rb')
    
            data = data_init + self.user + b''
    
            authresp = b''
            if self._auth_plugin_name in ('', 'mysql_native_password'):
                authresp = _scramble(self.password.encode('latin1'), self.salt)
    
            if self.server_capabilities & CLIENT.PLUGIN_AUTH_LENENC_CLIENT_DATA:
                data += lenenc_int(len(authresp)) + authresp
            elif self.server_capabilities & CLIENT.SECURE_CONNECTION:
                data += struct.pack('B', len(authresp)) + authresp
            else:  # pragma: no cover - not testing against servers without secure auth (>=5.0)
                data += authresp + b''
    
            if self.db and self.server_capabilities & CLIENT.CONNECT_WITH_DB:
                if isinstance(self.db, text_type):
                    self.db = self.db.encode(self.encoding)
                data += self.db + b''
    
            if self.server_capabilities & CLIENT.PLUGIN_AUTH:
                name = self._auth_plugin_name
                if isinstance(name, text_type):
                    name = name.encode('ascii')
                data += name + b''
    
            self.write_packet(data)
            auth_packet = self._read_packet()
    
            # if authentication method isn't accepted the first byte
            # will have the octet 254
            if auth_packet.is_auth_switch_request():
                # https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest
                auth_packet.read_uint8() # 0xfe packet identifier
                plugin_name = auth_packet.read_string()
                if self.server_capabilities & CLIENT.PLUGIN_AUTH and plugin_name is not None:
                    auth_packet = self._process_auth(plugin_name, auth_packet)
                else:
                    # send legacy handshake
                    data = _scramble_323(self.password.encode('latin1'), self.salt) + b''
                    self.write_packet(data)
                    auth_packet = self._read_packet()
    
        def _process_auth(self, plugin_name, auth_packet):
            plugin_class = self._auth_plugin_map.get(plugin_name)
            if not plugin_class:
                plugin_class = self._auth_plugin_map.get(plugin_name.decode('ascii'))
            if plugin_class:
                try:
                    handler = plugin_class(self)
                    return handler.authenticate(auth_packet)
                except AttributeError:
                    if plugin_name != b'dialog':
                        raise err.OperationalError(2059, "Authentication plugin '%s'" 
                                  " not loaded: - %r missing authenticate method" % (plugin_name, plugin_class))
                except TypeError:
                    raise err.OperationalError(2059, "Authentication plugin '%s'" 
                        " not loaded: - %r cannot be constructed with connection object" % (plugin_name, plugin_class))
            else:
                handler = None
            if plugin_name == b"mysql_native_password":
                # https://dev.mysql.com/doc/internals/en/secure-password-authentication.html#packet-Authentication::Native41
                data = _scramble(self.password.encode('latin1'), auth_packet.read_all())
            elif plugin_name == b"mysql_old_password":
                # https://dev.mysql.com/doc/internals/en/old-password-authentication.html
                data = _scramble_323(self.password.encode('latin1'), auth_packet.read_all()) + b''
            elif plugin_name == b"mysql_clear_password":
                # https://dev.mysql.com/doc/internals/en/clear-text-authentication.html
                data = self.password.encode('latin1') + b''
            elif plugin_name == b"dialog":
                pkt = auth_packet
                while True:
                    flag = pkt.read_uint8()
                    echo = (flag & 0x06) == 0x02
                    last = (flag & 0x01) == 0x01
                    prompt = pkt.read_all()
    
                    if prompt == b"Password: ":
                        self.write_packet(self.password.encode('latin1') + b'')
                    elif handler:
                        resp = 'no response - TypeError within plugin.prompt method'
                        try:
                            resp = handler.prompt(echo, prompt)
                            self.write_packet(resp + b'')
                        except AttributeError:
                            raise err.OperationalError(2059, "Authentication plugin '%s'" 
                                      " not loaded: - %r missing prompt method" % (plugin_name, handler))
                        except TypeError:
                            raise err.OperationalError(2061, "Authentication plugin '%s'" 
                                      " %r didn't respond with string. Returned '%r' to prompt %r" % (plugin_name, handler, resp, prompt))
                    else:
                        raise err.OperationalError(2059, "Authentication plugin '%s' (%r) not configured" % (plugin_name, handler))
                    pkt = self._read_packet()
                    pkt.check_error()
                    if pkt.is_ok_packet() or last:
                        break
                return pkt
            else:
                raise err.OperationalError(2059, "Authentication plugin '%s' not configured" % plugin_name)
    
            self.write_packet(data)
            pkt = self._read_packet()
            pkt.check_error()
            return pkt
    
        # _mysql support
        def thread_id(self):
            return self.server_thread_id[0]
    
        def character_set_name(self):
            return self.charset
    
        def get_host_info(self):
            return self.host_info
    
        def get_proto_info(self):
            return self.protocol_version
    
        def _get_server_information(self):
            i = 0
            packet = self._read_packet()
            data = packet.get_all_data()
    
            if DEBUG: dump_packet(data)
            self.protocol_version = byte2int(data[i:i+1])
            i += 1
    
            server_end = data.find(b'', i)
            self.server_version = data[i:server_end].decode('latin1')
            i = server_end + 1
    
            self.server_thread_id = struct.unpack('<I', data[i:i+4])
            i += 4
    
            self.salt = data[i:i+8]
            i += 9  # 8 + 1(filler)
    
            self.server_capabilities = struct.unpack('<H', data[i:i+2])[0]
            i += 2
    
            if len(data) >= i + 6:
                lang, stat, cap_h, salt_len = struct.unpack('<BHHB', data[i:i+6])
                i += 6
                # TODO: deprecate server_language and server_charset.
                # mysqlclient-python doesn't provide it.
                self.server_language = lang
                try:
                    self.server_charset = charset_by_id(lang).name
                except KeyError:
                    # unknown collation
                    self.server_charset = None
    
                self.server_status = stat
                if DEBUG: print("server_status: %x" % stat)
    
                self.server_capabilities |= cap_h << 16
                if DEBUG: print("salt_len:", salt_len)
                salt_len = max(12, salt_len - 9)
    
            # reserved
            i += 10
    
            if len(data) >= i + salt_len:
                # salt_len includes auth_plugin_data_part_1 and filler
                self.salt += data[i:i+salt_len]
                i += salt_len
    
            i+=1
            # AUTH PLUGIN NAME may appear here.
            if self.server_capabilities & CLIENT.PLUGIN_AUTH and len(data) >= i:
                # Due to Bug#59453 the auth-plugin-name is missing the terminating
                # NUL-char in versions prior to 5.5.10 and 5.6.2.
                # ref: https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::Handshake
                # didn't use version checks as mariadb is corrected and reports
                # earlier than those two.
                server_end = data.find(b'', i)
                if server_end < 0: # pragma: no cover - very specific upstream bug
                    # not found  and last field so take it all
                    self._auth_plugin_name = data[i:].decode('latin1')
                else:
                    self._auth_plugin_name = data[i:server_end].decode('latin1')
    
        def get_server_info(self):
            return self.server_version
    
        Warning = err.Warning
        Error = err.Error
        InterfaceError = err.InterfaceError
        DatabaseError = err.DatabaseError
        DataError = err.DataError
        OperationalError = err.OperationalError
        IntegrityError = err.IntegrityError
        InternalError = err.InternalError
        ProgrammingError = err.ProgrammingError
        NotSupportedError = err.NotSupportedError
    
    
    class MySQLResult(object):
    
        def __init__(self, connection):
            """
            :type connection: Connection
            """
            self.connection = connection
            self.affected_rows = None
            self.insert_id = None
            self.server_status = None
            self.warning_count = 0
            self.message = None
            self.field_count = 0
            self.description = None
            self.rows = None
            self.has_next = None
            self.unbuffered_active = False
    
        def __del__(self):
            if self.unbuffered_active:
                self._finish_unbuffered_query()
    
        def read(self):
            try:
                first_packet = self.connection._read_packet()
    
                if first_packet.is_ok_packet():
                    self._read_ok_packet(first_packet)
                elif first_packet.is_load_local_packet():
                    self._read_load_local_packet(first_packet)
                else:
                    self._read_result_packet(first_packet)
            finally:
                self.connection = None
    
        def init_unbuffered_query(self):
            self.unbuffered_active = True
            first_packet = self.connection._read_packet()
    
            if first_packet.is_ok_packet():
                self._read_ok_packet(first_packet)
                self.unbuffered_active = False
                self.connection = None
            elif first_packet.is_load_local_packet():
                self._read_load_local_packet(first_packet)
                self.unbuffered_active = False
                self.connection = None
            else:
                self.field_count = first_packet.read_length_encoded_integer()
                self._get_descriptions()
    
                # Apparently, MySQLdb picks this number because it's the maximum
                # value of a 64bit unsigned integer. Since we're emulating MySQLdb,
                # we set it to this instead of None, which would be preferred.
                self.affected_rows = 18446744073709551615
    
        def _read_ok_packet(self, first_packet):
            ok_packet = OKPacketWrapper(first_packet)
            self.affected_rows = ok_packet.affected_rows
            self.insert_id = ok_packet.insert_id
            self.server_status = ok_packet.server_status
            self.warning_count = ok_packet.warning_count
            self.message = ok_packet.message
            self.has_next = ok_packet.has_next
    
        def _read_load_local_packet(self, first_packet):
            if not self.connection._local_infile:
                raise RuntimeError(
                    "**WARN**: Received LOAD_LOCAL packet but local_infile option is false.")
            load_packet = LoadLocalPacketWrapper(first_packet)
            sender = LoadLocalFile(load_packet.filename, self.connection)
            try:
                sender.send_data()
            except:
                self.connection._read_packet()  # skip ok packet
                raise
    
            ok_packet = self.connection._read_packet()
            if not ok_packet.is_ok_packet(): # pragma: no cover - upstream induced protocol error
                raise err.OperationalError(2014, "Commands Out of Sync")
            self._read_ok_packet(ok_packet)
    
        def _check_packet_is_eof(self, packet):
            if not packet.is_eof_packet():
                return False
            #TODO: Support CLIENT.DEPRECATE_EOF
            # 1) Add DEPRECATE_EOF to CAPABILITIES
            # 2) Mask CAPABILITIES with server_capabilities
            # 3) if server_capabilities & CLIENT.DEPRECATE_EOF: use OKPacketWrapper instead of EOFPacketWrapper
            wp = EOFPacketWrapper(packet)
            self.warning_count = wp.warning_count
            self.has_next = wp.has_next
            return True
    
        def _read_result_packet(self, first_packet):
            self.field_count = first_packet.read_length_encoded_integer()
            self._get_descriptions()
            self._read_rowdata_packet()
    
        def _read_rowdata_packet_unbuffered(self):
            # Check if in an active query
            if not self.unbuffered_active:
                return
    
            # EOF
            packet = self.connection._read_packet()
            if self._check_packet_is_eof(packet):
                self.unbuffered_active = False
                self.connection = None
                self.rows = None
                return
    
            row = self._read_row_from_packet(packet)
            self.affected_rows = 1
            self.rows = (row,)  # rows should tuple of row for MySQL-python compatibility.
            return row
    
        def _finish_unbuffered_query(self):
            # After much reading on the MySQL protocol, it appears that there is,
            # in fact, no way to stop MySQL from sending all the data after
            # executing a query, so we just spin, and wait for an EOF packet.
            while self.unbuffered_active:
                packet = self.connection._read_packet()
                if self._check_packet_is_eof(packet):
                    self.unbuffered_active = False
                    self.connection = None  # release reference to kill cyclic reference.
    
        def _read_rowdata_packet(self):
            """Read a rowdata packet for each data row in the result set."""
            rows = []
            while True:
                packet = self.connection._read_packet()
                if self._check_packet_is_eof(packet):
                    self.connection = None  # release reference to kill cyclic reference.
                    break
                rows.append(self._read_row_from_packet(packet))
    
            self.affected_rows = len(rows)
            self.rows = tuple(rows)
    
        def _read_row_from_packet(self, packet):
            row = []
            for encoding, converter in self.converters:
                try:
                    data = packet.read_length_coded_string()
                except IndexError:
                    # No more columns in this row
                    # See https://github.com/PyMySQL/PyMySQL/pull/434
                    break
                if data is not None:
                    if encoding is not None:
                        data = data.decode(encoding)
                    if DEBUG: print("DEBUG: DATA = ", data)
                    if converter is not None:
                        data = converter(data)
                row.append(data)
            return tuple(row)
    
        def _get_descriptions(self):
            """Read a column descriptor packet for each column in the result."""
            self.fields = []
            self.converters = []
            use_unicode = self.connection.use_unicode
            conn_encoding = self.connection.encoding
            description = []
    
            for i in range_type(self.field_count):
                field = self.connection._read_packet(FieldDescriptorPacket)
                self.fields.append(field)
                description.append(field.description())
                field_type = field.type_code
                if use_unicode:
                    if field_type == FIELD_TYPE.JSON:
                        # When SELECT from JSON column: charset = binary
                        # When SELECT CAST(... AS JSON): charset = connection encoding
                        # This behavior is different from TEXT / BLOB.
                        # We should decode result by connection encoding regardless charsetnr.
                        # See https://github.com/PyMySQL/PyMySQL/issues/488
                        encoding = conn_encoding  # SELECT CAST(... AS JSON) 
                    elif field_type in TEXT_TYPES:
                        if field.charsetnr == 63:  # binary
                            # TEXTs with charset=binary means BINARY types.
                            encoding = None
                        else:
                            encoding = conn_encoding
                    else:
                        # Integers, Dates and Times, and other basic data is encoded in ascii
                        encoding = 'ascii'
                else:
                    encoding = None
                converter = self.connection.decoders.get(field_type)
                if converter is through:
                    converter = None
                if DEBUG: print("DEBUG: field={}, converter={}".format(field, converter))
                self.converters.append((encoding, converter))
    
            eof_packet = self.connection._read_packet()
            assert eof_packet.is_eof_packet(), 'Protocol error, expecting EOF'
            self.description = tuple(description)
    
    
    class LoadLocalFile(object):
        def __init__(self, filename, connection):
            self.filename = filename
            self.connection = connection
    
        def send_data(self):
            """Send data packets from the local file to the server"""
            if not self.connection._sock:
                raise err.InterfaceError("(0, '')")
            conn = self.connection
    
            try:
                with open(self.filename, 'rb') as open_file:
                    packet_size = min(conn.max_allowed_packet, 16*1024)  # 16KB is efficient enough
                    while True:
                        chunk = open_file.read(packet_size)
                        if not chunk:
                            break
                        conn.write_packet(chunk)
            except IOError:
                raise err.OperationalError(1017, "Can't find file '{0}'".format(self.filename))
            finally:
                # send the empty packet to signify we are done sending data
                conn.write_packet(b'')




  • 相关阅读:
    5G 时代,云计算迎来新风口
    阿里云VS腾讯云 谁才是中国未来的云计算之王?
    IaaS,PaaS,SaaS 的区别
    财经天下周刊:中国云计算——马化腾的救命稻草 任正非的“下个荣耀”
    HDOJ-1671 Phone List
    【转】Java进阶之路
    Delphi XE2 之 FireMonkey 入门(30)
    Delphi XE2 之 FireMonkey 入门(29)
    Delphi XE2 之 FireMonkey 入门(28)
    Delphi XE2 之 FireMonkey 入门(27)
  • 原文地址:https://www.cnblogs.com/rsapaper/p/7955061.html
Copyright © 2020-2023  润新知