I am writing a windows service to get some data from my database, then send it to my provider and get the response. I have some issues which make me simulate a console application to test my code.
Here is my code:
static async Task Main(string[] args)
{
send();
}
public static DataSet dataAccess()
{
DataSet ds = new DataSet();
ds.Tables.Add();
ds.Tables.Add();
ds.Tables[0].Columns.Add("id");
ds.Tables[0].Columns.Add("token");
ds.Tables[1].Columns.Add("token_id");
ds.Tables[1].Columns.Add("type");
ds.Tables[1].Columns.Add("value");
ds.Tables[0].Rows.Add("1", "token1");
ds.Tables[0].Rows.Add("2", "token2");
ds.Tables[1].Rows.Add("1", "t1", "v1");
ds.Tables[1].Rows.Add("1", "t1", "v2");
ds.Tables[1].Rows.Add("1", "t2", "v3");
ds.Tables[1].Rows.Add("2", "t2", "v4");
ds.Tables[1].Rows.Add("2", "t3", "v5");
ds.Tables[1].Rows.Add("2", "t3", "v6");
ds.Tables[1].Rows.Add("2", "t4", "v7");
ds.Relations.Add("rel_token", ds.Tables[0].Columns["id"], ds.Tables[1].Columns["token_id"]);
return ds;
}
private static async Task send()
{
DataSet ds;
DataTable dt;
while (true)
{
try
{
ds = dataAccess();
if (ds == null)
{
break;
}
List<Task> lst = new List<Task>();
foreach (DataRow dr in ds.Tables[0].Rows)
{
dt = dr.GetChildRows("rel_token").CopyToDataTable();
dt.Columns.Remove("token_id");
lst.Add(send_call((dr["token"]).ToString(), dt));
}
await Task.WhenAll(lst);
await Task.Delay(30000);
}
catch (HttpRequestException e)
{
string erMsg = e.Message;
}
}
}
private static HttpClient req { get; set; }
private static async Task send_call(string strToken, DataTable dt)
{
try
{
// DataTable to Json
string strJson = "";
foreach (DataRow dr in dt.Rows)
{
if (dt.Rows.IndexOf(dr) > 0)
{
strJson += ",";
}
strJson += "{";
foreach (DataColumn dc in dt.Columns)
{
if (dr.IsNull(dc))
{
continue;
}
if (dt.Columns.IndexOf(dc) > 0)
{
strJson += ",";
}
strJson += string.Format("\"{0}\":{1}{2}{1}",
dc.ColumnName,
dc.DataType == typeof(string) || dc.DataType == typeof(Guid) ? "\"" : null,
dc.DataType == typeof(bool) ? dr[dc].ToString().ToLower() : dr[dc]);
}
strJson += "}";
}
//
req.DefaultRequestHeaders.Add("token", strToken);
StringContent sc = new StringContent(strJson, Encoding.UTF8, "application/json");
HttpResponseMessage res = await req.PostAsync("my webhook url", sc);
string response = await res.Content.ReadAsStringAsync();
using (StreamWriter sw = new StreamWriter(@"C:\responseJson.txt", true, Encoding.UTF8))
{
sw.WriteLine(response);
}
}
catch (HttpRequestException e)
{
string strError = e.Message;
}
}
Code explanation:
dataAccess()
value is different, I just use a static data
for simulation.Issues:
When I run the program I see no request in destination, so I start debugging and noticed the pointer will reach this line:
HttpResponseMessage res = await req.PostAsync("my webhook url", sc);
But the call wouldn't initiated and after that the pointer comes back at:
await Task.WhenAll(lst);
then comes to:
send();
And finished!
So the PostAsync
method didn't work and due to that response
didn't fill so the responseJson.txt
didn't created.
Things I have tried:
send();
I used await send();
but I faced this error:System.NullReferenceException: 'Object reference not set to an instance of an object.
strJson
. The list converted to JSON properly.my webhook url
.Note: I had asked this question yesterday but because I explained it complicatedly I deleted that today and design a smaller one.
Create the HttpClient
before trying to use it, by using the new
keyword.
private static HttpClient req { get; set; } = new HttpClient();
public async Task Main()
{
await send();
}