homework-jianmu/docs-examples/csharp/AsyncQueryExample.cs

238 lines
9.3 KiB
C#

using TDengineDriver;
using System.Runtime.InteropServices;
namespace TDengineExample
{
public class AsyncQueryExample
{
static void Main()
{
IntPtr conn = GetConnection();
QueryAsyncCallback queryAsyncCallback = new QueryAsyncCallback(QueryCallback);
TDengine.QueryAsync(conn, "select * from meters", queryAsyncCallback, IntPtr.Zero);
Thread.Sleep(2000);
TDengine.Close(conn);
TDengine.Cleanup();
}
static void QueryCallback(IntPtr param, IntPtr taosRes, int code)
{
if (code == 0 && taosRes != IntPtr.Zero)
{
FetchRowAsyncCallback fetchRowAsyncCallback = new FetchRowAsyncCallback(FetchRowCallback);
TDengine.FetchRowAsync(taosRes, fetchRowAsyncCallback, param);
}
else
{
Console.WriteLine($"async query data failed, failed code {code}");
}
}
static void FetchRowCallback(IntPtr param, IntPtr taosRes, int numOfRows)
{
if (numOfRows > 0)
{
Console.WriteLine($"{numOfRows} rows async retrieved");
DisplayRes(taosRes);
TDengine.FetchRowAsync(taosRes, FetchRowCallback, param);
}
else
{
if (numOfRows == 0)
{
Console.WriteLine("async retrieve complete.");
}
else
{
Console.WriteLine($"FetchRowAsync callback error, error code {numOfRows}");
}
TDengine.FreeResult(taosRes);
}
}
public static void DisplayRes(IntPtr res)
{
if (!IsValidResult(res))
{
TDengine.Cleanup();
System.Environment.Exit(1);
}
List<TDengineMeta> metaList = TDengine.FetchFields(res);
int fieldCount = metaList.Count;
// metaList.ForEach((item) => { Console.Write("{0} ({1}) \t|\t", item.name, item.size); });
List<object> dataList = QueryRes(res, metaList);
for (int index = 0; index < dataList.Count; index++)
{
if (index % fieldCount == 0 && index != 0)
{
Console.WriteLine("");
}
Console.Write("{0} \t|\t", dataList[index].ToString());
}
Console.WriteLine("");
}
public static bool IsValidResult(IntPtr res)
{
if ((res == IntPtr.Zero) || (TDengine.ErrorNo(res) != 0))
{
if (res != IntPtr.Zero)
{
Console.Write("reason: " + TDengine.Error(res));
return false;
}
Console.WriteLine("");
return false;
}
return true;
}
private static List<object> QueryRes(IntPtr res, List<TDengineMeta> meta)
{
IntPtr taosRow;
List<object> dataRaw = new();
while ((taosRow = TDengine.FetchRows(res)) != IntPtr.Zero)
{
dataRaw.AddRange(FetchRow(taosRow, res));
}
if (TDengine.ErrorNo(res) != 0)
{
Console.Write("Query is not complete, Error {0} {1}", TDengine.ErrorNo(res), TDengine.Error(res));
}
TDengine.FreeResult(res);
Console.WriteLine("");
return dataRaw;
}
public static List<object> FetchRow(IntPtr taosRow, IntPtr taosRes)//, List<TDengineMeta> metaList, int numOfFiled
{
List<TDengineMeta> metaList = TDengine.FetchFields(taosRes);
int numOfFiled = TDengine.FieldCount(taosRes);
List<object> dataRaw = new();
IntPtr colLengthPrt = TDengine.FetchLengths(taosRes);
int[] colLengthArr = new int[numOfFiled];
Marshal.Copy(colLengthPrt, colLengthArr, 0, numOfFiled);
for (int i = 0; i < numOfFiled; i++)
{
TDengineMeta meta = metaList[i];
IntPtr data = Marshal.ReadIntPtr(taosRow, IntPtr.Size * i);
if (data == IntPtr.Zero)
{
dataRaw.Add("NULL");
continue;
}
switch ((TDengineDataType)meta.type)
{
case TDengineDataType.TSDB_DATA_TYPE_BOOL:
bool v1 = Marshal.ReadByte(data) != 0;
dataRaw.Add(v1);
break;
case TDengineDataType.TSDB_DATA_TYPE_TINYINT:
sbyte v2 = (sbyte)Marshal.ReadByte(data);
dataRaw.Add(v2);
break;
case TDengineDataType.TSDB_DATA_TYPE_SMALLINT:
short v3 = Marshal.ReadInt16(data);
dataRaw.Add(v3);
break;
case TDengineDataType.TSDB_DATA_TYPE_INT:
int v4 = Marshal.ReadInt32(data);
dataRaw.Add(v4);
break;
case TDengineDataType.TSDB_DATA_TYPE_BIGINT:
long v5 = Marshal.ReadInt64(data);
dataRaw.Add(v5);
break;
case TDengineDataType.TSDB_DATA_TYPE_FLOAT:
float v6 = (float)Marshal.PtrToStructure(data, typeof(float));
dataRaw.Add(v6);
break;
case TDengineDataType.TSDB_DATA_TYPE_DOUBLE:
double v7 = (double)Marshal.PtrToStructure(data, typeof(double));
dataRaw.Add(v7);
break;
case TDengineDataType.TSDB_DATA_TYPE_BINARY:
string v8 = Marshal.PtrToStringUTF8(data, colLengthArr[i]);
dataRaw.Add(v8);
break;
case TDengineDataType.TSDB_DATA_TYPE_TIMESTAMP:
long v9 = Marshal.ReadInt64(data);
dataRaw.Add(v9);
break;
case TDengineDataType.TSDB_DATA_TYPE_NCHAR:
string v10 = Marshal.PtrToStringUTF8(data, colLengthArr[i]);
dataRaw.Add(v10);
break;
case TDengineDataType.TSDB_DATA_TYPE_UTINYINT:
byte v12 = Marshal.ReadByte(data);
dataRaw.Add(v12.ToString());
break;
case TDengineDataType.TSDB_DATA_TYPE_USMALLINT:
ushort v13 = (ushort)Marshal.ReadInt16(data);
dataRaw.Add(v13);
break;
case TDengineDataType.TSDB_DATA_TYPE_UINT:
uint v14 = (uint)Marshal.ReadInt32(data);
dataRaw.Add(v14);
break;
case TDengineDataType.TSDB_DATA_TYPE_UBIGINT:
ulong v15 = (ulong)Marshal.ReadInt64(data);
dataRaw.Add(v15);
break;
case TDengineDataType.TSDB_DATA_TYPE_JSONTAG:
string v16 = Marshal.PtrToStringUTF8(data, colLengthArr[i]);
dataRaw.Add(v16);
break;
default:
dataRaw.Add("nonsupport data type");
break;
}
}
return dataRaw;
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "power";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
Console.WriteLine("Connect to TDengine failed");
Environment.Exit(0);
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
}
}
//output:
// Connect to TDengine success
// 8 rows async retrieved
// 1538548685500 | 11.8 | 221 | 0.28 | california.losangeles | 2 |
// 1538548696600 | 13.4 | 223 | 0.29 | california.losangeles | 2 |
// 1538548685000 | 10.8 | 223 | 0.29 | california.losangeles | 3 |
// 1538548686500 | 11.5 | 221 | 0.35 | california.losangeles | 3 |
// 1538548685000 | 10.3 | 219 | 0.31 | california.sanfrancisco | 2 |
// 1538548695000 | 12.6 | 218 | 0.33 | california.sanfrancisco | 2 |
// 1538548696800 | 12.3 | 221 | 0.31 | california.sanfrancisco | 2 |
// 1538548696650 | 10.3 | 218 | 0.25 | california.sanfrancisco | 3 |
// async retrieve complete.