[TD-12250]<docs>: fix confused titles and syntax error of example code in python connector (#9252)

src/connector/python/README.md

@@ -41,6 +41,7 @@ cursor.execute("show databases")
 results = cursor.fetchall()
 for row in results:
     print(row)
+
 cursor.close()
 conn.close()
 ```
@@ -57,8 +58,10 @@ result = conn.query("show databases")
 num_of_fields = result.field_count
 for field in result.fields:
     print(field)
+
 for row in result:
     print(row)
+
 result.close()
 conn.execute("drop database pytest")
 conn.close()
@@ -75,12 +78,13 @@ def fetch_callback(p_param, p_result, num_of_rows):
     print("fetched ", num_of_rows, "rows")
     p = cast(p_param, POINTER(Counter))
     result = TaosResult(p_result)
-
+    
     if num_of_rows == 0:
         print("fetching completed")
         p.contents.done = True
         result.close()
         return
+    
     if num_of_rows < 0:
         p.contents.done = True
         result.check_error(num_of_rows)
@@ -90,6 +94,7 @@ def fetch_callback(p_param, p_result, num_of_rows):
     for row in result.rows_iter(num_of_rows):
         # print(row)
         None
+    
     p.contents.count += result.row_count
     result.fetch_rows_a(fetch_callback, p_param)
     
@@ -97,17 +102,19 @@ def fetch_callback(p_param, p_result, num_of_rows):
 
 def query_callback(p_param, p_result, code):
     # type: (c_void_p, c_void_p, c_int) -> None
-    if p_result == None:
+    if p_result is None:
         return
+    
     result = TaosResult(p_result)
     if code == 0:
         result.fetch_rows_a(fetch_callback, p_param)
+    
     result.check_error(code)
 
 
 class Counter(Structure):
     _fields_ = [("count", c_int), ("done", c_bool)]
-
+    
     def __str__(self):
         return "{ count: %d, done: %s }" % (self.count, self.done)
 
@@ -116,10 +123,11 @@ def test_query(conn):
     # type: (TaosConnection) -> None
     counter = Counter(count=0)
     conn.query_a("select * from log.log", query_callback, byref(counter))
-
+    
     while not counter.done:
         print("wait query callback")
         time.sleep(1)
+    
     print(counter)
     conn.close()
 
@@ -182,6 +190,7 @@ result = conn.query("select * from log")
 
 for row in result:
     print(row)
+
 result.close()
 stmt.close()
 conn.close()
@@ -237,18 +246,20 @@ result.close()
 result = conn.query("select * from log")
 for row in result:
     print(row)
+
 result.close()
 stmt.close()
 conn.close()
 ```
 
-### Statement API - Subscribe
+### Subscription
 
 ```python
 import taos
+import random
 
 conn = taos.connect()
-dbname = "pytest_taos_subscribe_callback"
+dbname = "pytest_taos_subscribe"
 conn.execute("drop database if exists %s" % dbname)
 conn.execute("create database if not exists %s" % dbname)
 conn.select_db(dbname)
@@ -256,7 +267,7 @@ conn.execute("create table if not exists log(ts timestamp, n int)")
 for i in range(10):
     conn.execute("insert into log values(now, %d)" % i)
 
-sub = conn.subscribe(True, "test", "select * from log", 1000)
+sub = conn.subscribe(False, "test", "select * from log", 1000)
 print("# consume from begin")
 for ts, n in sub.consume():
     print(ts, n)
@@ -268,9 +279,18 @@ for i in range(5):
     for ts, n in result:
         print(ts, n)
 
+sub.close(True)
+print("# keep progress consume")
+sub = conn.subscribe(False, "test", "select * from log", 1000)
+result = sub.consume()
+rows = result.fetch_all()
+# consume from latest subscription needs root privilege(for /var/lib/taos).
+assert result.row_count == 0
+print("## consumed ", len(rows), "rows")
+
 print("# consume with a stop condition")
 for i in range(10):
-    conn.execute("insert into log values(now, %d)" % int(random() * 10))
+    conn.execute("insert into log values(now, %d)" % random.randint(0, 10))
     result = sub.consume()
     try:
         ts, n = next(result)
@@ -283,12 +303,13 @@ for i in range(10):
         continue
 
 sub.close()
+# sub.close()
 
 conn.execute("drop database if exists %s" % dbname)
-conn.close()
+# conn.close()
 ```
 
-### Statement API - Subscribe asynchronously with callback
+### Subscription asynchronously with callback
 
 ```python
 from taos import *
@@ -300,7 +321,7 @@ import time
 def subscribe_callback(p_sub, p_result, p_param, errno):
     # type: (c_void_p, c_void_p, c_void_p, c_int) -> None
     print("# fetch in callback")
-    result = TaosResult(p_result)
+    result = TaosResult(c_void_p(p_result))
     result.check_error(errno)
     for row in result.rows_iter():
         ts, n = row()
@@ -311,42 +332,45 @@ def test_subscribe_callback(conn):
     # type: (TaosConnection) -> None
     dbname = "pytest_taos_subscribe_callback"
     try:
+        print("drop if exists")
         conn.execute("drop database if exists %s" % dbname)
+        print("create database")
         conn.execute("create database if not exists %s" % dbname)
-        conn.select_db(dbname)
-        conn.execute("create table if not exists log(ts timestamp, n int)")
-
+        print("create table")
+        # conn.execute("use %s" % dbname)
+        conn.execute("create table if not exists %s.log(ts timestamp, n int)" % dbname)
+        
         print("# subscribe with callback")
-        sub = conn.subscribe(False, "test", "select * from log", 1000, subscribe_callback)
-
+        sub = conn.subscribe(False, "test", "select * from %s.log" % dbname, 1000, subscribe_callback)
+        
         for i in range(10):
-            conn.execute("insert into log values(now, %d)" % i)
+            conn.execute("insert into %s.log values(now, %d)" % (dbname, i))
             time.sleep(0.7)
+        
         sub.close()
-
+        
         conn.execute("drop database if exists %s" % dbname)
-        conn.close()
+        # conn.close()
     except Exception as err:
         conn.execute("drop database if exists %s" % dbname)
-        conn.close()
+        # conn.close()
         raise err
 
 
 if __name__ == "__main__":
     test_subscribe_callback(connect())
-
 ```
 
-### Statement API - Stream
+### Stream
 
 ```python
 from taos import *
 from ctypes import *
+import time
 
 def stream_callback(p_param, p_result, p_row):
     # type: (c_void_p, c_void_p, c_void_p) -> None
-
-    if p_result == None or p_row == None:
+    if p_result is None or p_row is None:
         return
     result = TaosResult(p_result)
     row = TaosRow(result, p_row)
@@ -355,13 +379,12 @@ def stream_callback(p_param, p_result, p_row):
         p = cast(p_param, POINTER(Counter))
         p.contents.count += count
         print("[%s] inserted %d in 5s, total count: %d" % (ts.strftime("%Y-%m-%d %H:%M:%S"), count, p.contents.count))
-
     except Exception as err:
         print(err)
         raise err
 
 
-class Counter(ctypes.Structure):
+class Counter(Structure):
     _fields_ = [
         ("count", c_int),
     ]
@@ -378,16 +401,17 @@ def test_stream(conn):
         conn.execute("create database if not exists %s" % dbname)
         conn.select_db(dbname)
         conn.execute("create table if not exists log(ts timestamp, n int)")
-
+        
         result = conn.query("select count(*) from log interval(5s)")
         assert result.field_count == 2
         counter = Counter()
         counter.count = 0
         stream = conn.stream("select count(*) from log interval(5s)", stream_callback, param=byref(counter))
-
+        
         for _ in range(0, 20):
             conn.execute("insert into log values(now,0)(now+1s, 1)(now + 2s, 2)")
             time.sleep(2)
+        
         stream.close()
         conn.execute("drop database if exists %s" % dbname)
         conn.close()
@@ -399,12 +423,14 @@ def test_stream(conn):
 
 if __name__ == "__main__":
     test_stream(connect())
+
 ```
 
 ### Insert with line protocol
 
 ```python
 import taos
+from taos import SmlProtocol, SmlPrecision
 
 conn = taos.connect()
 dbname = "pytest_line"
@@ -413,29 +439,22 @@ conn.execute("create database if not exists %s precision 'us'" % dbname)
 conn.select_db(dbname)
 
 lines = [
-    'st,t1=3i64,t2=4f64,t3="t3" c1=3i64,c3=L"pass",c2=false,c4=4f64 1626006833639000000ns',
-    'st,t1=4i64,t3="t4",t2=5f64,t4=5f64 c1=3i64,c3=L"pass it again",c2=true,c4=5f64,c5=5f64,c6=7u64 1626006933640000000',
-    'stf,t1=4i64,t3="t4",t2=5f64,t4=5f64 c1=3i64,c3=L"pass it again_stf",c2=false,c5=5f64,c6=7u64 1626006933641000000',
+    'st,t1=3i64,t2=4f64,t3="t3" c1=3i64,c3=L"pass",c2=false,c4=4f64 1626006833639000000',
 ]
-conn.schemaless_insert(lines, 0, "ns")
+conn.schemaless_insert(lines, taos.SmlProtocol.LINE_PROTOCOL, taos.SmlPrecision.NOT_CONFIGURED)
 print("inserted")
 
-lines = [
-    'stf,t1=5i64,t3="t4",t2=5f64,t4=5f64 c1=3i64,c3=L"pass it again_stf",c2=false,c5=5f64,c6=7u64 1626006933641000000',
-]
-conn.schemaless_insert(lines, 0, "ns")
+conn.schemaless_insert(lines, taos.SmlProtocol.LINE_PROTOCOL, taos.SmlPrecision.NOT_CONFIGURED)
 
 result = conn.query("show tables")
 for row in result:
     print(row)
-result.close()
 
 
 conn.execute("drop database if exists %s" % dbname)
-conn.close()
 
 ```
 
-## License - AGPL-3.0
+## License
 
-Keep same with [TDengine](https://github.com/taosdata/TDengine).
+We use MIT license for Python connector.

src/connector/python/examples/query-async.py

@@ -29,7 +29,7 @@ def fetch_callback(p_param, p_result, num_of_rows):
 
 def query_callback(p_param, p_result, code):
     # type: (c_void_p, c_void_p, c_int) -> None
-    if p_result == None:
+    if p_result is None:
         return
     result = TaosResult(p_result)
     if code == 0:

src/connector/python/examples/stream.py

+from taos import *
+from ctypes import *
+import time
+
+def stream_callback(p_param, p_result, p_row):
+    # type: (c_void_p, c_void_p, c_void_p) -> None
+    if p_result is None or p_row is None:
+        return
+    result = TaosResult(p_result)
+    row = TaosRow(result, p_row)
+    try:
+        ts, count = row()
+        p = cast(p_param, POINTER(Counter))
+        p.contents.count += count
+        print("[%s] inserted %d in 5s, total count: %d" % (ts.strftime("%Y-%m-%d %H:%M:%S"), count, p.contents.count))
+    except Exception as err:
+        print(err)
+        raise err
+
+
+class Counter(Structure):
+    _fields_ = [
+        ("count", c_int),
+    ]
+
+    def __str__(self):
+        return "%d" % self.count
+
+
+def test_stream(conn):
+    # type: (TaosConnection) -> None
+    dbname = "pytest_taos_stream"
+    try:
+        conn.execute("drop database if exists %s" % dbname)
+        conn.execute("create database if not exists %s" % dbname)
+        conn.select_db(dbname)
+        conn.execute("create table if not exists log(ts timestamp, n int)")
+        
+        result = conn.query("select count(*) from log interval(5s)")
+        assert result.field_count == 2
+        counter = Counter()
+        counter.count = 0
+        stream = conn.stream("select count(*) from log interval(5s)", stream_callback, param=byref(counter))
+        
+        for _ in range(0, 20):
+            conn.execute("insert into log values(now,0)(now+1s, 1)(now + 2s, 2)")
+            time.sleep(2)
+        
+        stream.close()
+        conn.execute("drop database if exists %s" % dbname)
+        conn.close()
+    except Exception as err:
+        conn.execute("drop database if exists %s" % dbname)
+        conn.close()
+        raise err
+
+
+if __name__ == "__main__":
+    test_stream(connect())

src/connector/python/taos/__init__.py

@@ -86,7 +86,7 @@ def fetch_callback(p_param, p_result, num_of_rows):
 
 def query_callback(p_param, p_result, code):
     # type: (c_void_p, c_void_p, c_int) -> None
-    if p_result == None:
+    if p_result is None:
         return
     result = TaosResult(p_result)
     if code == 0:
@@ -335,7 +335,7 @@ from ctypes import *
 def stream_callback(p_param, p_result, p_row):
     # type: (c_void_p, c_void_p, c_void_p) -> None
 
-    if p_result == None or p_row == None:
+    if p_result is None or p_row is None:
         return
     result = TaosResult(p_result)
     row = TaosRow(result, p_row)

src/connector/python/taos/bind.py

@@ -317,7 +317,7 @@ class TaosMultiBind(ctypes.Structure):
 
     def _str_to_buffer(self, values):
         self.num = len(values)
-        is_null = [1 if v == None else 0 for v in values]
+        is_null = [1 if v is None else 0 for v in values]
         self.is_null = cast((c_byte * self.num)(*is_null), c_char_p)
         
         if sum(is_null) == self.num:

src/connector/python/taos/cinterface.py

@@ -373,9 +373,9 @@ def taos_fetch_block(result, fields=None, field_count=None):
     if num_of_rows == 0:
         return None, 0
     precision = taos_result_precision(result)
-    if fields == None:
+    if fields is None:
         fields = taos_fetch_fields(result)
-    if field_count == None:
+    if field_count is None:
         field_count = taos_field_count(result)
     blocks = [None] * field_count
     fieldLen = taos_fetch_lengths(result, field_count)
@@ -466,7 +466,7 @@ def taos_fetch_lengths(result, field_count=None):
     # type: (c_void_p, int) -> Array[int]
     """Make sure to call taos_fetch_row or taos_fetch_block before fetch_lengths"""
     lens = _libtaos.taos_fetch_lengths(result)
-    if field_count == None:
+    if field_count is None:
         field_count = taos_field_count(result)
     if not lens:
         raise OperationalError("field length empty, use taos_fetch_row/block before it")
@@ -823,7 +823,7 @@ def taos_stmt_use_result(stmt):
     @stmt: TAOS_STMT*
     """
     result = c_void_p(_libtaos.taos_stmt_use_result(stmt))
-    if result == None:
+    if result is None:
         raise StatementError(taos_stmt_errstr(stmt))
     return result
 

src/connector/python/taos/result.py

@@ -41,7 +41,7 @@ class TaosResult(object):
         if self._result is None or self.fields is None:
             raise OperationalError("Invalid use of fetch iterator")
 
-        if self._block == None or self._block_iter >= self._block_length:
+        if self._block is None or self._block_iter >= self._block_length:
             self._block, self._block_length = self.fetch_block()
             self._block_iter = 0
             # self._row_count += self._block_length
@@ -55,7 +55,7 @@ class TaosResult(object):
         """fields definitions of the current result"""
         if self._result is None:
             raise ResultError("no result object setted")
-        if self._fields == None:
+        if self._fields is None:
             self._fields = taos_fetch_fields(self._result)
 
         return self._fields
@@ -72,7 +72,7 @@ class TaosResult(object):
 
     @property
     def precision(self):
-        if self._precision == None:
+        if self._precision is None:
             self._precision = taos_result_precision(self._result)
         return self._precision
 
@@ -114,7 +114,7 @@ class TaosResult(object):
         if self._result is None:
             raise OperationalError("Invalid use of fetchall")
 
-        if self._fields == None:
+        if self._fields is None:
             self._fields = taos_fetch_fields(self._result)
         buffer = [[] for i in range(len(self._fields))]
         self._row_count = 0
@@ -150,7 +150,7 @@ class TaosResult(object):
         return taos_errstr(self._result)
 
     def check_error(self, errno=None, close=True):
-        if errno == None:
+        if errno is None:
             errno = self.errno()
         if errno != 0:
             msg = self.errstr()