How to rotate an image which is retrieved by ashx handler

Question

I have an image which is returned from MySql. Its datatype is image in Mysql. I handle the image with ashx. the code below show my ashx file.

string imageID = context.Request.QueryString["imageID"];
using(SqlConnection objConnection = new SqlConnection(portalConnectionString))
{
    objConnection.Open();
    SqlCommand fetchTaskImageCMD = new SqlCommand("fetch_task_image", objConnection);
    fetchTaskImageCMD.CommandType = CommandType.StoredProcedure;
    fetchTaskImageCMD.Parameters.Add("@IMAGE_ID", SqlDbType.VarChar).Value = imageID;

    try
    {
        SqlDataReader dr = fetchTaskImageCMD.ExecuteReader();
        dr.Read();

        byte[] bufferImg = (Byte[])dr[0];

        context.Response.OutputStream.Write(bufferImg, 0, bufferImg.Length);
    }

    catch
    {
        System.Diagnostics.Debug.WriteLine("Image Handler Failed : /DesktopModules/ImageHandler.ashx");
    }

    objConnection.Close();
}

And the code below is showing how I am calling my ashx file from my asp.net code behind class in c#.

protected void Page_Load(object sender, System.EventArgs e)
{
   FetchedImage.ImageUrl = "/DesktopModules/ImageHandler.ashx?imageType=" + imageType + "&imageID=" + imageID;
}

My question is how I am going to rotate this image and save back to database,then.

Any comment will be appreciated.

Answer 1

If you want to rotate it and save it back to the database, use GDI+ on the server instead of streaming it back to the client.

System.Drawing.Image can be instantiated from a byte array, and from that you can use GDI+ methods to rotate the image, extract a byte array from the rotated image and save that.

Let me know if you need an example, but googling System.Drawing.Image will help you.