CODEWITHSUNDEEP
c#-4.0
Hossain Muctadir
Hossain Muctadir

Reputation: 3626

Write large file to HTTP response

I am currently developing an asp application with c# .net. I have to query a large(10GB) SQLite database and write the data as CSV format to HTTP response. I am doing this

        /*query database, use string builder to create a csv*/
        Response.ContentType = "text/plain";
        Response.AddHeader("Content-Length", result.Length.ToString());
        Response.AddHeader("Content-Disposition", "attachment; filename=\"Data.csv\"");
        Response.Write(result);
        Response.Flush();

Which works file with small amount of data. But when the file size increases I get a OutOfMemoryException. I think using StringBuilder to create a string is causing the issue. I can not figure out any way to solve the issue. Can anyone please help me resolve this?

Upvotes: 2

Views: 4319

Answers (2)

Hossain Muctadir
Hossain Muctadir

Reputation: 3626

I actually solved the problem. I did this

Response.Clear();
Response.ContentType = "text/plain";
Response.AddHeader("Content-Disposition", "attachment; filename=\"Data.csv\"");
foreach(var item in dbItem)
{
     /*create a string with database data*/
     Response.write(string);
     Response.Flush();
}
Response.End();

Upvotes: 2

Kirill Bestemyanov
Kirill Bestemyanov

Reputation: 11964

You need to read data by DataReader and write it into Response.OutputStream. Something like this:

SqlDataReader dr;
//initialize datareader to your table
...
Response.Clear();
Response.ContentType = "text/plain";
Response.AddHeader("Content-Disposition", "attachment; filename=\"Data.csv\"");
var writer = new StreamWriter(Response.OutputStream);
while (dr.Read())
{
    writer.WriteLine(dr[1].ToString()+";"+dr[2].ToString()+";"+dr[3].ToString()+";");
    Response.Flush();
}

Upvotes: 3

Related Questions