HttpHandler and "Save As" prompt

These days I work a lot with Reporting Services and an ASP.NET application which serve reports on an aspx page.

The first implementation was to put a button on the page and call the Reporting Services web service to render the report.

But now the customer asked to change the file name of the generated pdf reports, more than this he wants the file name to change dynamically depending on parameters.
By default the exported report file name is the name of the report (the rdl file), and I don't see anything on the Reporting Web Service to change this.

But RS web service also expose one method to render the report as an array of bytes. So I created a HttpHandler to fetch the report's bytes and flush it in the response content. The HttpHandler allows me to control the generated file name.
The problem is pdf is a known file type so the browser open Adobe Acrobat instead of asking the user to save the file. I knew this is possible so I was happy to google and find this entry from Andrew L. Van Slaars :
Forcing an "open, save" prompt for known file types

Hope this will bring more exposure to the tip.

I end up with this piece of code for my HttpHandler :

public class ReportHandler : IHttpHandler
{
  public void ProcessRequest(HttpContext context)
  {
    string reportName = context.Request["reportName"];
    string fileName = string.Empty;
    byte[] buffer = null;

    // Method from the business layer
    // Get the report as an array of bytes
    // Build the file name
    buffer = GetQuoteReportAsPdfUrl(reportName, out fileName);

    context.Response.Clear();
    context.Response.ContentType = "application/pdf";

    // This line opens the Save prompt instead of Adobe Acrobat
    context.Response.AddHeader("Content-Disposition",
        "attachment;filename=" + fileName);
    context.Response.AddHeader("Content-Length",
        buffer.Length.ToString());
   context.Response.OutputStream.Write(buffer,0,buffer.Length);
   context.Response.End();
  }

  public bool IsReusable
  {
    get { return true; }
  }
}
Published Friday, March 23, 2007 11:17 PM by pluginbaby

Comments

Monday, May 7, 2007 3:43 PM by Mike

# re: HttpHandler and "Save As" prompt

To rajbk:

Response.BinaryWrite is nothing more than a wrapper around OutputStream.Write.  Calling it would add no value. If you Reflect on it, you will see this:

Public Sub BinaryWrite(ByVal buffer As Byte())

   Me.OutputStream.Write(buffer, 0, buffer.Length)

End Sub