Export to excel not working from HttpHandler J-Query AJAX - asp.net

Question

im have a weird problem whereby my functionality of exporting to excel doesnt seem to work.
im using J-Query and AJAX to pass html data to a http handler which has some simple context.Response code which all seems fine. Anyway, heres my code:
// my hyperlink for user to click
Click Here to Export
my J-Query/AJAX code
<script type="text/javascript">
$(document).ready(function () {
$("#hyperLink").click(function (e) {
var result = $('#output').html();
var newRes = result.replace('\n', '');
$.ajax({
url: "ExportToExcelhandler.ashx",
data: { 'htmlData': newRes },
dataType: "json",
type: "POST",
success: function (data) {
alert(data);
}
});
});
});
</script>
and my handler:
public void ProcessRequest(HttpContext context)
{
string htmlStuff = context.Request["htmlData"];
string trimStart = "";
string trimEnd = "";
if (htmlStuff != null)
{
trimStart = htmlStuff.Substring(75, htmlStuff.Length - 75);
trimEnd = trimStart.Remove(trimStart.Length - 8, 8) + "";
}
string final= trimEnd;
context.Response.Clear();
context.Response.Buffer = true;
context.Response.AddHeader("content-disposition", "attachment; filename=excelData.xls");
context.Response.ContentType = "application/vnd.ms-excel";
HttpResponse response = context.Response;
context.Response.Output.Write(finalHtmlData);
context.Response.Flush();
context.Response.End();
}
-- Granted, I'm doing some weird things with replace function in my J-Query, and Substring and Remove in my handler; this is because i had to trim my html data so that only the table with the data inside it was included (caused error otherwise). The html data is just report data. So the html data is passed fine to the handler, and it goes through the ProcessRequest method fine, yet doesn't export to excel. Any help would be greatly appreciated, thanks.

Answer 1

Split this into two HTTP handlers, one to generate the Excel data and the second to retrieve the data and have a resource point at it, like this:
GenerateExcelDocument HTTP handler code:
public void ProcessRequest(HttpContext context)
{
string htmlStuff = context.Request["htmlData"];
var docIdentifier = this.GenerateExcelDocument(htmlStuff);
context.Response.ContentType = "text/plain";
context.Response.Write(docIdentifier.ToString("N"));
}
private Guid GenerateExcelDocument()
{
var identifier = Guid.NewGuid();
string trimStart = "";
string trimEnd = "";
if (htmlStuff != null)
{
trimStart = htmlStuff.Substring(75, htmlStuff.Length - 75);
trimEnd = trimStart.Remove(trimStart.Length - 8, 8) + "";
}
// Logic that generates your document and saves it using the identifier
// Can save to database, file system, etc.
return identifier;
}
Now you can call this HTTP handler, like this:
$(document).ready(function () {
$("#hyperLink").click(function (e) {
var result = $('#output').html();
var newRes = result.replace('\n', '');
$.ajax({
url: "GenerateExcelDocument.ashx",
data: { 'htmlData': newRes },
dataType: "json",
type: "POST",
success: function (result) {
window.location.href = '/RetrieveExcelDocument.ashx/' + result;
}
});
});
});
Note: The success callback is where you can hook up the HTML resource to the file retrieval from the server (think href of the anchor tag that worked without passing data to the handler before).
Finally, we need to build the retrieval HTTP handler logic to actually get the Excel document, based upon the identifier returned from the GenerateExcelDocument HTTP handler call, like this:
RetrieveExcelDocument HTTP handler code:
public void ProcessRequest(HttpContext context)
{
var identifier = new Guid(context.Request.Url.Segments[1]);
// Get Excel document content from database, file system, etc. here
var fileContent = GetExcelDocument(identifier);
context.Response.AddHeader("content-disposition",
"attachment; filename=excelData.xls");
context.Response.ContentType = "application/vnd.ms-excel";
context.Response.OutputStream.Write(fileContent, 0, fileContent.Length);
}