How to download images automatically from database table when it is updated? - mysql

Question

I have this sample code to download images from database table manually by clicking a button.
In Html page:
<asp:Button ID="Button1" runat="server" Text="Convert Byte to All Image " OnClick="Button1_Click" />
Code behind:
protected void Button1_Click(object sender, EventArgs e)
{
string sConn = ConfigurationManager.ConnectionStrings["conString"].ToString();
SqlConnection objConn = new SqlConnection(sConn);
objConn.Open();
string sTSQL = "Select TOP 1500 FileData, FileValue from Demo_Tbl where Active=1 and FileGroup='C_Photo'";
SqlCommand objCmd = new SqlCommand(sTSQL, objConn);
objCmd.CommandType = CommandType.Text;
SqlDataAdapter adapter = new SqlDataAdapter();
DataTable dt = new DataTable();
adapter.SelectCommand = objCmd;
adapter.SelectCommand.CommandTimeout = 10000;
adapter.Fill(dt);
objConn.Close();
for (int i = 0; i < dt.Rows.Count; i++)
{
string FileValue = dt.Rows[i]["FileValue"].ToString();
object FileData = dt.Rows[i]["FileData"];
System.IO.File.WriteAllBytes(Server.MapPath("/Images/" + FileValue), (byte[])FileData);
}
Response.Write("Images has been fetched");
}
I want this download to happen automatically when Demo_Tbl table is updated by some one each time. Also I want the download target folder in cloud database(https.clode.azure.com) blobs.
I need some one to help me on this since I'm clue less.

Answer 1

Yeah, its a good idea to download on the update event.
If you write the download code on the update event, it will need to wait the download method before the update event finished. I would recommend you to insert a queue message to Azure storage queue, then use Azure webjob QueueTrigger to download the file to Azure Blob. Here is a similar scenario that use Azure Webjob QueueTrigger to resize the image. I think it will help with your scenario.