Merge pull request #5169 from taosdata/feature/sangshuduo/TD-2843-python-connector-for-mac

[TD-2843] feature: porting python connector for mac.

src/connector/python/osx/python3/LICENSE

+  Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+
+This program is free software: you can use, redistribute, and/or modify
+it under the terms of the GNU Affero General Public License, version 3
+or later ("AGPL"), as published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.

src/connector/python/osx/python3/README.md

+# TDengine python client interface
\ No newline at end of file

src/connector/python/osx/python3/setup.py

+import setuptools
+
+with open("README.md", "r") as fh:
+    long_description = fh.read()
+
+setuptools.setup(
+    name="taos",
+    version="2.0.4",
+    author="Taosdata Inc.",
+    author_email="support@taosdata.com",
+    description="TDengine python client package",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+    url="https://github.com/pypa/sampleproject",
+    packages=setuptools.find_packages(),
+    classifiers=[
+        "Programming Language :: Python :: 3",
+        "Operating System :: MacOS X",
+    ],
+)

src/connector/python/osx/python3/taos/__init__.py

+
+from .connection import TDengineConnection
+from .cursor import TDengineCursor
+
+# Globals
+apilevel = '2.0.4'
+threadsafety = 0
+paramstyle = 'pyformat'
+
+__all__ = ['connection', 'cursor']
+
+def connect(*args, **kwargs):
+    """ Function to return a TDengine connector object
+
+    Current supporting keyword parameters:
+    @dsn: Data source name as string
+    @user: Username as string(optional)
+    @password: Password as string(optional)
+    @host: Hostname(optional)
+    @database: Database name(optional)
+
+    @rtype: TDengineConnector
+    """
+    return TDengineConnection(*args, **kwargs)

src/connector/python/osx/python3/taos/cinterface.py

+import ctypes
+from .constants import FieldType
+from .error import *
+import math
+import datetime
+
+def _convert_millisecond_to_datetime(milli):
+    return datetime.datetime.fromtimestamp(milli/1000.0)
+
+def _convert_microsecond_to_datetime(micro):
+    return datetime.datetime.fromtimestamp(micro/1000000.0)
+
+def _crow_timestamp_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C bool row to python row
+    """
+    _timestamp_converter = _convert_millisecond_to_datetime
+    if micro:
+        _timestamp_converter = _convert_microsecond_to_datetime
+
+    if num_of_rows > 0:
+        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)]))
+    else:
+        return list(map(_timestamp_converter, ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)]))
+
+def _crow_bool_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C bool row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
+    else:
+        return [ None if ele == FieldType.C_BOOL_NULL else bool(ele) for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_bool))[:abs(num_of_rows)] ]
+
+def _crow_tinyint_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C tinyint row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
+    else:
+        return [ None if ele == FieldType.C_TINYINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[:abs(num_of_rows)] ]
+    
+def _crow_smallint_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C smallint row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)]]
+    else:
+        return [ None if ele == FieldType.C_SMALLINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[:abs(num_of_rows)] ]
+
+def _crow_int_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C int row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)] ]
+    else:
+        return [ None if ele == FieldType.C_INT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[:abs(num_of_rows)] ]
+
+def _crow_bigint_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C bigint row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)] ]
+    else:
+        return [ None if ele == FieldType.C_BIGINT_NULL else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[:abs(num_of_rows)] ]
+
+def _crow_float_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C float row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)] ]
+    else:
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[:abs(num_of_rows)] ]
+
+def _crow_double_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C double row to python row
+    """
+    if num_of_rows > 0:
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)] ]
+    else:
+        return [ None if math.isnan(ele) else ele for ele in ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[:abs(num_of_rows)] ]
+
+def _crow_binary_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C binary row to python row
+    """
+    assert(nbytes is not None)
+    if num_of_rows > 0:
+        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)]]
+    else:
+        return [ None if ele.value[0:1] == FieldType.C_BINARY_NULL else ele.value.decode('utf-8') for ele in (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char * nbytes)))[:abs(num_of_rows)]]
+
+def _crow_nchar_to_python(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C nchar row to python row
+    """
+    assert(nbytes is not None)
+    res=[]
+    for i in range(abs(num_of_rows)):
+        try:
+            if num_of_rows >= 0:
+                tmpstr = ctypes.c_char_p(data)
+                res.append( tmpstr.value.decode() )
+            else:
+                res.append( (ctypes.cast(data+nbytes*i,  ctypes.POINTER(ctypes.c_wchar * (nbytes//4))))[0].value )
+        except ValueError:
+            res.append(None)
+
+    return res 
+
+def _crow_binary_to_python_block(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C binary row to python row
+    """
+    assert(nbytes is not None)
+    res=[]
+    if num_of_rows > 0:
+        for i in range(abs(num_of_rows)):
+            try:
+                rbyte=ctypes.cast(data+nbytes*i,ctypes.POINTER(ctypes.c_short))[:1].pop()
+                tmpstr = ctypes.c_char_p(data+nbytes*i+2)
+                res.append( tmpstr.value.decode()[0:rbyte] )
+            except ValueError:
+                res.append(None)
+    else:
+        for i in range(abs(num_of_rows)):
+            try:
+                rbyte=ctypes.cast(data+nbytes*i,ctypes.POINTER(ctypes.c_short))[:1].pop()
+                tmpstr = ctypes.c_char_p(data+nbytes*i+2)
+                res.append( tmpstr.value.decode()[0:rbyte] )
+            except ValueError:
+                res.append(None)
+    return res
+
+def _crow_nchar_to_python_block(data, num_of_rows, nbytes=None, micro=False):
+    """Function to convert C nchar row to python row
+    """
+    assert(nbytes is not None)
+    res=[]
+    if num_of_rows >= 0:
+        for i in range(abs(num_of_rows)):
+            try:
+                tmpstr = ctypes.c_char_p(data+nbytes*i+2)
+                res.append( tmpstr.value.decode() )
+            except ValueError:
+                res.append(None)
+    else:
+        for i in range(abs(num_of_rows)):
+            try:
+                res.append( (ctypes.cast(data+nbytes*i+2,  ctypes.POINTER(ctypes.c_wchar * (nbytes//4))))[0].value )
+            except ValueError:
+                res.append(None)
+    return res
+
+_CONVERT_FUNC = {
+    FieldType.C_BOOL: _crow_bool_to_python,
+    FieldType.C_TINYINT : _crow_tinyint_to_python,
+    FieldType.C_SMALLINT : _crow_smallint_to_python,
+    FieldType.C_INT : _crow_int_to_python,
+    FieldType.C_BIGINT : _crow_bigint_to_python,
+    FieldType.C_FLOAT : _crow_float_to_python,
+    FieldType.C_DOUBLE : _crow_double_to_python,
+    FieldType.C_BINARY: _crow_binary_to_python,
+    FieldType.C_TIMESTAMP : _crow_timestamp_to_python, 
+    FieldType.C_NCHAR : _crow_nchar_to_python
+}
+
+_CONVERT_FUNC_BLOCK = {
+    FieldType.C_BOOL: _crow_bool_to_python,
+    FieldType.C_TINYINT : _crow_tinyint_to_python,
+    FieldType.C_SMALLINT : _crow_smallint_to_python,
+    FieldType.C_INT : _crow_int_to_python,
+    FieldType.C_BIGINT : _crow_bigint_to_python,
+    FieldType.C_FLOAT : _crow_float_to_python,
+    FieldType.C_DOUBLE : _crow_double_to_python,
+    FieldType.C_BINARY: _crow_binary_to_python_block,
+    FieldType.C_TIMESTAMP : _crow_timestamp_to_python, 
+    FieldType.C_NCHAR : _crow_nchar_to_python_block
+}
+
+# Corresponding TAOS_FIELD structure in C
+class TaosField(ctypes.Structure):
+    _fields_ = [('name', ctypes.c_char * 65),
+                ('type', ctypes.c_char),
+                ('bytes', ctypes.c_short)]
+
+# C interface class
+class CTaosInterface(object):
+
+    libtaos = ctypes.CDLL('libtaos.dylib')
+
+    libtaos.taos_fetch_fields.restype = ctypes.POINTER(TaosField)
+    libtaos.taos_init.restype = None
+    libtaos.taos_connect.restype = ctypes.c_void_p
+    #libtaos.taos_use_result.restype = ctypes.c_void_p
+    libtaos.taos_fetch_row.restype = ctypes.POINTER(ctypes.c_void_p)
+    libtaos.taos_errstr.restype = ctypes.c_char_p
+    libtaos.taos_subscribe.restype = ctypes.c_void_p
+    libtaos.taos_consume.restype = ctypes.c_void_p
+    libtaos.taos_fetch_lengths.restype = ctypes.c_void_p
+    libtaos.taos_free_result.restype = None
+    libtaos.taos_errno.restype = ctypes.c_int
+    libtaos.taos_query.restype = ctypes.POINTER(ctypes.c_void_p)
+
+    def __init__(self, config=None):
+        '''
+        Function to initialize the class
+        @host     : str, hostname to connect
+        @user     : str, username to connect to server
+        @password : str, password to connect to server
+        @db       : str, default db to use when log in
+        @config   : str, config directory
+
+        @rtype    : None
+        '''
+        if config is None:
+            self._config = ctypes.c_char_p(None)
+        else:
+            try:
+                self._config = ctypes.c_char_p(config.encode('utf-8'))
+            except AttributeError:
+                raise AttributeError("config is expected as a str")
+
+        if config != None:
+            CTaosInterface.libtaos.taos_options(3, self._config)
+
+        CTaosInterface.libtaos.taos_init()
+
+    @property
+    def config(self):
+        """ Get current config
+        """
+        return self._config
+
+    def connect(self, host=None, user="root", password="taosdata", db=None, port=0):
+        '''
+        Function to connect to server
+
+        @rtype: c_void_p, TDengine handle
+        '''
+        # host
+        try:
+            _host = ctypes.c_char_p(host.encode(
+                "utf-8")) if host != None else ctypes.c_char_p(None)
+        except AttributeError:
+            raise AttributeError("host is expected as a str")
+
+        # user
+        try:
+            _user = ctypes.c_char_p(user.encode("utf-8"))
+        except AttributeError:
+            raise AttributeError("user is expected as a str")
+
+        # password
+        try:
+            _password = ctypes.c_char_p(password.encode("utf-8"))
+        except AttributeError:
+            raise AttributeError("password is expected as a str")
+
+        # db
+        try:
+            _db = ctypes.c_char_p(
+                db.encode("utf-8")) if db != None else ctypes.c_char_p(None)
+        except AttributeError:
+            raise AttributeError("db is expected as a str")
+
+        # port
+        try:
+            _port = ctypes.c_int(port)
+        except TypeError:
+            raise TypeError("port is expected as an int")
+
+        connection = ctypes.c_void_p(CTaosInterface.libtaos.taos_connect(
+            _host, _user, _password, _db, _port))
+
+        if connection.value == None:
+            print('connect to TDengine failed')
+            raise ConnectionError("connect to TDengine failed")
+            # sys.exit(1)
+        #else:
+        #    print('connect to TDengine success')
+
+        return connection
+
+    @staticmethod
+    def close(connection):
+        '''Close the TDengine handle
+        '''
+        CTaosInterface.libtaos.taos_close(connection)
+        #print('connection is closed')
+
+    @staticmethod
+    def query(connection, sql):
+        '''Run SQL
+
+        @sql: str, sql string to run
+
+        @rtype: 0 on success and -1 on failure
+        '''
+        try:
+            return CTaosInterface.libtaos.taos_query(connection, ctypes.c_char_p(sql.encode('utf-8')))
+        except AttributeError:
+            raise AttributeError("sql is expected as a string")
+        # finally:
+        #     CTaosInterface.libtaos.close(connection)
+
+    @staticmethod
+    def affectedRows(result):
+        """The affected rows after runing query
+        """
+        return CTaosInterface.libtaos.taos_affected_rows(result)
+
+    @staticmethod
+    def subscribe(connection, restart, topic, sql, interval):
+        """Create a subscription
+         @restart boolean, 
+         @sql string, sql statement for data query, must be a 'select' statement.
+         @topic string, name of this subscription
+        """
+        return ctypes.c_void_p(CTaosInterface.libtaos.taos_subscribe(
+            connection,
+            1 if restart else 0,
+            ctypes.c_char_p(topic.encode('utf-8')),
+            ctypes.c_char_p(sql.encode('utf-8')),
+            None,
+            None,
+            interval))
+
+    @staticmethod
+    def consume(sub):
+        """Consume data of a subscription
+        """
+        result = ctypes.c_void_p(CTaosInterface.libtaos.taos_consume(sub))
+        fields = []
+        pfields = CTaosInterface.fetchFields(result)
+        for i in range(CTaosInterface.libtaos.taos_num_fields(result)):
+            fields.append({'name': pfields[i].name.decode('utf-8'),
+                           'bytes': pfields[i].bytes,
+                           'type': ord(pfields[i].type)})
+        return result, fields
+
+    @staticmethod
+    def unsubscribe(sub, keepProgress):
+        """Cancel a subscription
+        """
+        CTaosInterface.libtaos.taos_unsubscribe(sub, 1 if keepProgress else 0)
+
+    @staticmethod
+    def useResult(result):
+        '''Use result after calling self.query
+        '''
+        fields = []
+        pfields = CTaosInterface.fetchFields(result)
+        for i in range(CTaosInterface.fieldsCount(result)):
+            fields.append({'name': pfields[i].name.decode('utf-8'),
+                           'bytes': pfields[i].bytes,
+                           'type': ord(pfields[i].type)})
+
+        return fields
+
+    @staticmethod
+    def fetchBlock(result, fields):
+        pblock = ctypes.c_void_p(0)
+        num_of_rows = CTaosInterface.libtaos.taos_fetch_block(
+            result, ctypes.byref(pblock))
+        if num_of_rows == 0:
+            return None, 0
+        isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
+        blocks = [None] * len(fields)
+        fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
+        fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
+        for i in range(len(fields)):
+            data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
+            if fields[i]['type'] not in _CONVERT_FUNC_BLOCK:
+                raise DatabaseError("Invalid data type returned from database")
+            blocks[i] = _CONVERT_FUNC_BLOCK[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)
+
+        return blocks, abs(num_of_rows)
+    @staticmethod
+    def fetchRow(result, fields):
+        pblock = ctypes.c_void_p(0)
+        pblock = CTaosInterface.libtaos.taos_fetch_row(result)  
+        if pblock : 
+            num_of_rows = 1
+            isMicro = (CTaosInterface.libtaos.taos_result_precision(result) == FieldType.C_TIMESTAMP_MICRO)
+            blocks = [None] * len(fields)
+            fieldL = CTaosInterface.libtaos.taos_fetch_lengths(result)
+            fieldLen = [ele for ele in ctypes.cast(fieldL,  ctypes.POINTER(ctypes.c_int))[:len(fields)]]
+            for i in range(len(fields)):
+                data = ctypes.cast(pblock, ctypes.POINTER(ctypes.c_void_p))[i]
+                if fields[i]['type'] not in _CONVERT_FUNC:
+                    raise DatabaseError("Invalid data type returned from database")
+                if data is None:
+                    blocks[i] = [None]
+                else:
+                    blocks[i] = _CONVERT_FUNC[fields[i]['type']](data, num_of_rows, fieldLen[i], isMicro)         
+        else:
+            return None, 0
+        return blocks, abs(num_of_rows)
+
+    @staticmethod
+    def freeResult(result):
+        CTaosInterface.libtaos.taos_free_result(result)
+        result.value = None
+
+    @staticmethod
+    def fieldsCount(result):
+        return CTaosInterface.libtaos.taos_field_count(result)
+
+    @staticmethod
+    def fetchFields(result):
+        return CTaosInterface.libtaos.taos_fetch_fields(result)
+
+    # @staticmethod
+    # def fetchRow(result, fields):
+    #     l = []
+    #     row = CTaosInterface.libtaos.taos_fetch_row(result)
+    #     if not row:
+    #         return None
+
+    #     for i in range(len(fields)):
+    #         l.append(CTaosInterface.getDataValue(
+    #             row[i], fields[i]['type'], fields[i]['bytes']))
+
+    #     return tuple(l)
+
+    # @staticmethod
+    # def getDataValue(data, dtype, byte):
+    #     '''
+    #     '''
+    #     if not data:
+    #         return None
+
+    #     if (dtype == CTaosInterface.TSDB_DATA_TYPE_BOOL):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_bool))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_TINYINT):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_byte))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_SMALLINT):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_short))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_INT):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_int))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_BIGINT):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_FLOAT):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_float))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_DOUBLE):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_double))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_BINARY):
+    #         return (ctypes.cast(data,  ctypes.POINTER(ctypes.c_char))[0:byte]).rstrip('\x00')
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_TIMESTAMP):
+    #         return ctypes.cast(data,  ctypes.POINTER(ctypes.c_long))[0]
+    #     elif (dtype == CTaosInterface.TSDB_DATA_TYPE_NCHAR):
+    #         return (ctypes.cast(data,  ctypes.c_char_p).value).rstrip('\x00')
+
+    @staticmethod
+    def errno(result):
+        """Return the error number.
+        """
+        return CTaosInterface.libtaos.taos_errno(result)
+
+    @staticmethod
+    def errStr(result):
+        """Return the error styring
+        """
+        return CTaosInterface.libtaos.taos_errstr(result).decode('utf-8')
+
+
+if __name__ == '__main__':
+    cinter = CTaosInterface()
+    conn = cinter.connect()
+    result = cinter.query(conn, 'show databases')
+
+    print('Query Affected rows: {}'.format(cinter.affectedRows(result)))
+
+    fields = CTaosInterface.useResult(result)
+
+    data, num_of_rows = CTaosInterface.fetchBlock(result, fields)
+
+    print(data)
+
+    cinter.freeResult(result)
+    cinter.close(conn)

src/connector/python/osx/python3/taos/connection.py

+from .cursor import TDengineCursor
+from .subscription import TDengineSubscription
+from .cinterface import CTaosInterface
+
+class TDengineConnection(object):
+    """ TDengine connection object
+    """
+    def __init__(self, *args, **kwargs):
+        self._conn = None
+        self._host = None
+        self._user = "root"
+        self._password = "taosdata"
+        self._database = None
+        self._port = 0
+        self._config = None
+        self._chandle = None
+
+        self.config(**kwargs)
+
+    def config(self, **kwargs):
+        # host
+        if 'host' in kwargs:
+            self._host = kwargs['host']
+
+        # user
+        if 'user' in kwargs:
+            self._user = kwargs['user']
+
+        # password
+        if 'password' in kwargs:
+            self._password = kwargs['password']
+        
+        # database
+        if 'database' in kwargs:
+            self._database = kwargs['database']
+
+        # port
+        if 'port' in kwargs:
+            self._port = kwargs['port']
+
+        # config
+        if 'config' in kwargs:
+            self._config = kwargs['config']
+
+        self._chandle = CTaosInterface(self._config)
+        self._conn = self._chandle.connect(self._host, self._user, self._password, self._database, self._port)
+
+    def close(self):
+        """Close current connection.
+        """
+        return CTaosInterface.close(self._conn)
+
+    def subscribe(self, restart, topic, sql, interval):
+        """Create a subscription.
+        """
+        if self._conn is None:
+            return None
+        sub = CTaosInterface.subscribe(self._conn, restart, topic, sql, interval)
+        return TDengineSubscription(sub)
+
+    def cursor(self):
+        """Return a new Cursor object using the connection.
+        """
+        return TDengineCursor(self)
+
+    def commit(self):
+        """Commit any pending transaction to the database.
+
+        Since TDengine do not support transactions, the implement is void functionality.
+        """
+        pass
+
+    def rollback(self):
+        """Void functionality
+        """
+        pass
+
+    def clear_result_set(self):
+        """Clear unused result set on this connection.
+        """
+        pass
+
+if __name__ == "__main__":
+    conn = TDengineConnection(host='192.168.1.107')
+    conn.close()
+    print("Hello world")
\ No newline at end of file

src/connector/python/osx/python3/taos/constants.py

+"""Constants in TDengine python
+"""
+
+from .dbapi import *
+
+class FieldType(object):
+    """TDengine Field Types
+    """
+    # type_code
+    C_NULL = 0
+    C_BOOL = 1
+    C_TINYINT = 2
+    C_SMALLINT = 3
+    C_INT = 4
+    C_BIGINT = 5
+    C_FLOAT = 6
+    C_DOUBLE = 7
+    C_BINARY = 8
+    C_TIMESTAMP = 9
+    C_NCHAR = 10
+    # NULL value definition
+    # NOTE: These values should change according to C definition in tsdb.h
+    C_BOOL_NULL = 0x02
+    C_TINYINT_NULL = -128
+    C_SMALLINT_NULL = -32768
+    C_INT_NULL = -2147483648
+    C_BIGINT_NULL = -9223372036854775808
+    C_FLOAT_NULL = float('nan')
+    C_DOUBLE_NULL = float('nan')
+    C_BINARY_NULL = bytearray([int('0xff', 16)])
+    # Timestamp precision definition
+    C_TIMESTAMP_MILLI = 0
+    C_TIMESTAMP_MICRO = 1

src/connector/python/osx/python3/taos/cursor.py

+from .cinterface import CTaosInterface
+from .error import *
+from .constants import FieldType
+import threading
+
+# querySeqNum = 0
+
+class TDengineCursor(object):
+    """Database cursor which is used to manage the context of a fetch operation.
+
+    Attributes:
+        .description: Read-only attribute consists of 7-item sequences:
+
+            > name (mondatory)
+            > type_code (mondatory)
+            > display_size
+            > internal_size
+            > precision
+            > scale
+            > null_ok
+
+            This attribute will be None for operations that do not return rows or
+            if the cursor has not had an operation invoked via the .execute*() method yet.
+
+        .rowcount:This read-only attribute specifies the number of rows that the last
+            .execute*() produced (for DQL statements like SELECT) or affected
+    """
+
+    def __init__(self, connection=None):
+        self._description = []
+        self._rowcount = -1
+        self._connection = None
+        self._result = None
+        self._fields = None
+        self._block = None
+        self._block_rows = -1
+        self._block_iter = 0
+        self._affected_rows = 0
+        self._logfile = ""
+        self._threadId = threading.get_ident()
+
+        if connection is not None:
+            self._connection = connection
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._result is None or self._fields is None:
+            raise OperationalError("Invalid use of fetch iterator")
+
+        if self._block_rows <= self._block_iter:
+            block, self._block_rows = CTaosInterface.fetchRow(
+                self._result, self._fields)
+            if self._block_rows == 0:
+                raise StopIteration
+            self._block = list(map(tuple, zip(*block)))
+            self._block_iter = 0
+
+        data = self._block[self._block_iter]
+        self._block_iter += 1
+
+        return data
+
+    @property
+    def description(self):
+        """Return the description of the object.
+        """
+        return self._description
+
+    @property
+    def rowcount(self):
+        """Return the rowcount of the object
+        """
+        return self._rowcount
+
+    @property
+    def affected_rows(self):
+        """Return the rowcount of insertion
+        """
+        return self._affected_rows
+
+    def callproc(self, procname, *args):
+        """Call a stored database procedure with the given name.
+
+        Void functionality since no stored procedures.
+        """
+        pass
+
+    def log(self, logfile):
+        self._logfile = logfile
+
+    def close(self):
+        """Close the cursor.
+        """
+        if self._connection is None:
+            return False
+
+        self._reset_result()
+        self._connection = None
+
+        return True
+
+    def execute(self, operation, params=None):
+        """Prepare and execute a database operation (query or command).
+        """
+        # if threading.get_ident() != self._threadId:
+        #     info ="Cursor execute:Thread ID not match,creater:"+str(self._threadId)+" caller:"+str(threading.get_ident())
+        #     raise OperationalError(info)
+            # print(info)
+            # return None
+
+        if not operation:
+            return None
+
+        if not self._connection:
+            # TODO : change the exception raised here
+            raise ProgrammingError("Cursor is not connected")
+
+        self._reset_result()
+
+        stmt = operation
+        if params is not None:
+            pass
+
+        # global querySeqNum
+        # querySeqNum += 1
+        # localSeqNum = querySeqNum # avoid raice condition
+        # print("   >> Exec Query ({}): {}".format(localSeqNum, str(stmt)))
+        self._result = CTaosInterface.query(self._connection._conn, stmt)
+        # print("   << Query ({}) Exec Done".format(localSeqNum))
+        if (self._logfile):
+            with open(self._logfile, "a") as logfile:
+                logfile.write("%s;\n" % operation)
+
+        errno = CTaosInterface.libtaos.taos_errno(self._result)
+        if errno == 0:
+            if CTaosInterface.fieldsCount(self._result) == 0:
+                self._affected_rows += CTaosInterface.affectedRows(
+                    self._result )
+                return CTaosInterface.affectedRows(self._result )
+            else:
+                self._fields = CTaosInterface.useResult(
+                    self._result)
+                return self._handle_result()
+        else:
+            raise ProgrammingError(
+                CTaosInterface.errStr(
+                    self._result), errno)
+
+    def executemany(self, operation, seq_of_parameters):
+        """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
+        """
+        pass
+
+    def fetchone(self):
+        """Fetch the next row of a query result set, returning a single sequence, or None when no more data is available.
+        """
+        pass
+
+    def fetchmany(self):
+        pass
+
+    def istype(self, col, dataType):
+        if (dataType.upper() == "BOOL"):
+            if (self._description[col][1] == FieldType.C_BOOL):
+                return True
+        if (dataType.upper() == "TINYINT"):
+            if (self._description[col][1] == FieldType.C_TINYINT):
+                return True
+        if (dataType.upper() == "INT"):
+            if (self._description[col][1] == FieldType.C_INT):
+                return True
+        if (dataType.upper() == "BIGINT"):
+            if (self._description[col][1] == FieldType.C_INT):
+                return True
+        if (dataType.upper() == "FLOAT"):
+            if (self._description[col][1] == FieldType.C_FLOAT):
+                return True
+        if (dataType.upper() == "DOUBLE"):
+            if (self._description[col][1] == FieldType.C_DOUBLE):
+                return True
+        if (dataType.upper() == "BINARY"):
+            if (self._description[col][1] == FieldType.C_BINARY):
+                return True
+        if (dataType.upper() == "TIMESTAMP"):
+            if (self._description[col][1] == FieldType.C_TIMESTAMP):
+                return True
+        if (dataType.upper() == "NCHAR"):
+            if (self._description[col][1] == FieldType.C_NCHAR):
+                return True
+
+        return False
+
+    def fetchall_row(self):
+        """Fetch all (remaining) rows of a query result, returning them as a sequence of sequences (e.g. a list of tuples). Note that the cursor's arraysize attribute can affect the performance of this operation.
+        """
+        if self._result is None or self._fields is None:
+            raise OperationalError("Invalid use of fetchall")
+
+        buffer = [[] for i in range(len(self._fields))]
+        self._rowcount = 0
+        while True:
+            block, num_of_fields = CTaosInterface.fetchRow(self._result, self._fields)
+            errno = CTaosInterface.libtaos.taos_errno(self._result)
+            if errno != 0:
+                raise ProgrammingError(CTaosInterface.errStr(self._result), errno)
+            if num_of_fields == 0:
+                break
+            self._rowcount += num_of_fields
+            for i in range(len(self._fields)):
+                buffer[i].extend(block[i])
+        return list(map(tuple, zip(*buffer)))
+
+    def fetchall(self):
+        if self._result is None or self._fields is None:
+            raise OperationalError("Invalid use of fetchall")
+
+        buffer = [[] for i in range(len(self._fields))]
+        self._rowcount = 0
+        while True:
+            block, num_of_fields = CTaosInterface.fetchBlock(self._result, self._fields)
+            errno = CTaosInterface.libtaos.taos_errno(self._result)
+            if errno != 0:
+                raise ProgrammingError(CTaosInterface.errStr(self._result), errno)
+            if num_of_fields == 0: break
+            self._rowcount += num_of_fields
+            for i in range(len(self._fields)):
+                buffer[i].extend(block[i])
+        return list(map(tuple, zip(*buffer)))
+    def nextset(self):
+        """
+        """
+        pass
+
+    def setinputsize(self, sizes):
+        pass
+
+    def setutputsize(self, size, column=None):
+        pass
+
+    def _reset_result(self):
+        """Reset the result to unused version.
+        """
+        self._description = []
+        self._rowcount = -1
+        if self._result is not None:
+            CTaosInterface.freeResult(self._result)
+        self._result = None
+        self._fields = None
+        self._block = None
+        self._block_rows = -1
+        self._block_iter = 0
+        self._affected_rows = 0
+
+    def _handle_result(self):
+        """Handle the return result from query.
+        """
+        # if threading.get_ident() != self._threadId:
+        #     info = "Cursor handleresult:Thread ID not match,creater:"+str(self._threadId)+" caller:"+str(threading.get_ident())
+        #     raise OperationalError(info)
+            # print(info)
+            # return None
+
+        self._description = []
+        for ele in self._fields:
+            self._description.append(
+                (ele['name'], ele['type'], None, None, None, None, False))
+
+        return self._result
+

src/connector/python/osx/python3/taos/dbapi.py

+"""Type Objects and Constructors.
+"""
+
+import time
+import datetime
+
+class DBAPITypeObject(object):
+    def __init__(self, *values):
+        self.values = values
+
+    def __com__(self, other):
+        if other in self.values:
+            return 0
+        if other < self.values:
+            return 1
+        else:
+            return -1
+
+Date = datetime.date
+Time = datetime.time
+Timestamp = datetime.datetime
+
+def DataFromTicks(ticks):
+    return Date(*time.localtime(ticks)[:3])
+
+def TimeFromTicks(ticks):
+    return Time(*time.localtime(ticks)[3:6])
+
+def TimestampFromTicks(ticks):
+    return Timestamp(*time.localtime(ticks)[:6])
+
+Binary = bytes
+
+# STRING = DBAPITypeObject(*constants.FieldType.get_string_types())
+# BINARY = DBAPITypeObject(*constants.FieldType.get_binary_types())
+# NUMBER = BAPITypeObject(*constants.FieldType.get_number_types())
+# DATETIME = DBAPITypeObject(*constants.FieldType.get_timestamp_types())
+# ROWID = DBAPITypeObject()
\ No newline at end of file

src/connector/python/osx/python3/taos/error.py

+"""Python exceptions
+"""
+
+class Error(Exception):
+    def __init__(self, msg=None, errno=None):
+        self.msg = msg
+        self._full_msg = self.msg
+        self.errno = errno
+    
+    def __str__(self):
+        return self._full_msg
+
+class Warning(Exception):
+    """Exception raised for important warnings like data truncations while inserting.
+    """
+    pass
+
+class InterfaceError(Error):
+    """Exception raised for errors that are related to the database interface rather than the database itself. 
+    """
+    pass
+
+class DatabaseError(Error):
+    """Exception raised for errors that are related to the database. 
+    """
+    pass
+
+class DataError(DatabaseError):
+    """Exception raised for errors that are due to problems with the processed data like division by zero, numeric value out of range.
+    """
+    pass
+
+class OperationalError(DatabaseError):
+    """Exception raised for errors that are related to the database's operation and not necessarily under the control of the programmer
+    """
+    pass
+
+
+class IntegrityError(DatabaseError):
+    """Exception raised when the relational integrity of the database is affected.
+    """
+    pass
+
+class InternalError(DatabaseError):
+    """Exception raised when the database encounters an internal error.
+    """
+    pass
+
+class ProgrammingError(DatabaseError):
+    """Exception raised for programming errors.
+    """
+    pass
+
+class NotSupportedError(DatabaseError):
+    """Exception raised in case a method or database API was used which is not supported by the database,.
+    """
+    pass
\ No newline at end of file

src/connector/python/osx/python3/taos/subscription.py

+from .cinterface import CTaosInterface
+from .error import *
+
+class TDengineSubscription(object):
+    """TDengine subscription object
+    """
+    def __init__(self, sub):
+        self._sub = sub
+
+
+    def consume(self):
+        """Consume rows of a subscription
+        """
+        if self._sub is None:
+            raise OperationalError("Invalid use of consume")
+        
+        result, fields = CTaosInterface.consume(self._sub)
+        buffer = [[] for i in range(len(fields))]
+        while True:
+            block, num_of_fields = CTaosInterface.fetchBlock(result, fields)
+            if num_of_fields == 0: break
+            for i in range(len(fields)):
+                buffer[i].extend(block[i])
+
+        self.fields = fields
+        return list(map(tuple, zip(*buffer)))
+
+
+    def close(self, keepProgress = True):
+        """Close the Subscription.
+        """
+        if self._sub is None:
+            return False
+
+        CTaosInterface.unsubscribe(self._sub, keepProgress)
+        return True
+
+
+if __name__ == '__main__':
+    from .connection import TDengineConnection
+    conn = TDengineConnection(host="127.0.0.1", user="root", password="taosdata", database="test")
+
+    # Generate a cursor object to run SQL commands
+    sub = conn.subscribe(True, "test", "select * from meters;", 1000)
+
+    for i in range(0,10):
+        data = sub.consume()
+        for d in data:
+            print(d)
+
+    sub.close()
+    conn.close()
\ No newline at end of file