I have an ASP.NET (webforms) page that renders MS-Excel back to the response stream on click of a button. Everything works perfectly in testing but on live deployment, I get this dialogue box after the browser appears to be trying to download the file:
where ReportsShow.aspx is the name of the aspx page that generates and renders the excel.
The button that triggers the download fires a postback so I am confounded as to why the page would not be found when it renders correctly on load?
I am clueless and any help would be greatly appreciated
EDIT: As requested by Mayank, here's the code structure:
// Get instance of reporting service
IReportingService reportingServiceClient = Reports.GetWebService();
// Get a fresh copy of the report
BusinessReport theReport = reportingServiceClient.GetReport(AcctList.ToArray());
ExcelExport excelExport = new ExcelExport();
const string templateFileName = "Business-Report.xls";
string newFileName = String.Empty;
try
{
newFileName = excelExport.CopyTemplateFile(Server.MapPath("~/ExportTemplates/" + templateFileName));
excelExport.WriteData(forexOptionReport, newFileName);
Response.Clear();
Response.AddHeader("content-disposition", string.Format("Attachment; filename=\"{0}\"", "Business-Report" + ".xls"));
Response.ContentType = "application/vnd.ms-excel";
Response.TransmitFile(newFileName);
Response.Flush();
}
catch (Exception ex)
{
Errors.LogException("Error in Reports.BtnDownloadToExcel_Click", ex);
throw;
}
finally
{
if (!String.IsNullOrEmpty(newFileName))
{
excelExport.DeleteFile(newFileName);
}
}
MORE INFO
I've analyzed this with fiddler and this is what I see for the particular request/response which is expected to present the excel for download:
This Stackoverflow Q/A states that the meaning of the forbidden icon is that the client is terminating/aborting the response
I have found the solution to this issue. The details are as described in this link
This SO question has some details and resources that would clarify what was happening.
The basic issue is that IE versions 8 and below fail to download files over SSL when they see the following headers in the response:
Cache-control: no-cache
Pragma: no-cache
These headers should be removed and replaced with:
Response.Headers.Set("Cache-Control", "private, max-age=0");
Related
I have a code set that runs on the server, which correctly generates a zip file and stores it on the server. I have that file location as a physical path.
Nothing I have attempted has allowed me to use the response to the client to download that file.
Attempt 1:
System.IO.FileInfo fi = new System.IO.FileInfo(zipFilePath);
//setup HTML Download of provided Zip.
//application/zip
Response.ClearContent();
Response.Clear();
Response.ClearHeaders();
Response.Buffer = true;
Response.ContentType = "application / zip";
Response.AddHeader("Content-Disposition",
"attachment; filename=\"" + System.IO.Path.GetFileName(zipFilePath) + "\";");
Response.AddHeader("Content-Length", fi.Length.ToString());
Response.TransmitFile(zipFilePath);
Response.Flush();
Response.End();
No result. Code executes without error but there is no download to the client.
Attempt 2:
//Almost the same as attempt 1, but with WriteFile instead
Response.WriteFile(zipFilePath);
No Result, same as Attempt 1.
Attempt 3:
//Note: Same Header Section as Attempts 1 and 2
System.IO.BinaryReader reader = new System.IO.BinaryReader(new System.IO.FileStream(zipFilePath, System.IO.FileMode.Open));
int CHUNK = 1024;
List<byte> FileArray = new List<byte>();
while (reader.BaseStream.Position < reader.BaseStream.Length)
FileArray.AddRange(reader.ReadBytes(CHUNK));
byte[] bArray = FileArray.ToArray();
reader.Close();
Response.OutputStream.Write(bArray, 0, bArray.Length);
Response.Flush();
Response.End();
No Result, Same as previous attempts
Attempt 4:
//Identical to Attempt 3, but using BinaryWrite
Response.BinaryWrite(bArray);
No Result, Same as previous Attempts.
The Question
Every one of these code blocks runs with no error, But The Save File dialog NEVER appears. I get nothing at all. I cannot figure out for the life of me what I might be missing.
The File Path has been verified as correct
The Code is running on the server, not on the client, I cannot use the 'WebClient.Download' method for this reason
If anyone has any suggestions, I'm all ears. I have no idea how to get this file to download to the client.
I tested your code (attempt 1) and got it working fine with a test file. If the file path would be wrong, you'd get an System.IO.FileNotFoundException so that's probably not the issue.
A couple of ways to address this:
Try inspecting the webpage in, for example, Chrome by right-clicking
and choose inspect. Then click on Network tab, and refresh the
page (where you're supposed to get the file). Check the response
headers for that request - what is it?
Try setting content-type to application/octet-stream
Use debugger in Visual Studio and step through.
This turned out to be an Ajax related error causing issues between UpdatePanels and POST Responses.
The issue was fixed on the page load of the page by adding the call
ScriptManager.GetCurrent(Page).RegisterPostBackControl(btnGenerate);
I am writing large CSV files to the Response with Response.BufferOutput set to false. This is because the file has the potential to take a long time to download so the user can see some progress. I generate a line for the CSV from a object and write to the response using Response.Write().
This works well however if there is an unexpected error after the Response has started writing then the client will receive a file with only part of the data and could be missing lots of lines but they might not realise it.
Is there a way to somehow cancel the file download without buffering all the content? Could there be some way to indicate that the response is invalid so the browser disregards the file?
Code below shows the main idea of my code
public void StreamCsvFile(string fileName,List<myObject> myObjectList)
{
Response.Clear();
Response.ContentType = "text/csv";
Response.AddHeader("content-disposition", "filename=" + fileName);
Response.BufferOutput = false;
string headerLine = GetHeaderLine();
Response.Write(headerLine)
try
{
foreach(var myObject in myObjectList)
{
string line = myObject.ToCsvString();
Response.Write("\n" + line);
}
}
finally
{
Response.End();
}
}
Write to a temporary file first.
Set the content-length on the response.
Use Response.TransmitFile to send this temp file.
Browsers will reject download if content length doesn't match.
I tried to get a pdf file opened in chrome but it seems to be stuck in the middle of somewhere during displaying process. The code seems to work because it can get PDF opened in IE, not sure why it got stuck in chrome. The screen will just grey out, show the "LOADING" sign, and stop at 7/8. The file is around 6MB or more.
public static void ReturnPDF(byte[] contents)
{
var response = HttpContext.Current.Response;
response.Clear();
response.AppendHeader("Content-Disposition", "inline;filename=" + "abc.pdf");
response.BufferOutput = true;
response.ContentType = System.Net.Mime.MediaTypeNames.Application.Pdf;
response.BinaryWrite(contents);
response.Flush();
response.Close();
response.End();
}
Any thoughts? Thanks
[UPDATE]
I tried firefox with version 30.0 and it WORKS. My IE is 8.0.7601.17514, which can also open pdf. My Chrome is 39.0.2171.95. Not sure wheather the version of the browser matters or not, here only chrome fails to open the inline PDF...
[SOLVED]
After adding content-length, chrome can open the inline PDF.
public static void ReturnPDF(byte[] contents)
{
var response = HttpContext.Current.Response;
response.Clear();
response.AppendHeader("Content-Disposition", "inline;filename=" + "abc.pdf");
//After adding Content-Length, chrome is able to open PDF inline
response.AppendHeader("Content-Length", contents.Length.ToString());
response.BufferOutput = true;
response.ContentType = System.Net.Mime.MediaTypeNames.Application.Pdf;
response.BinaryWrite(contents);
response.Flush();
response.Close();
response.End();
}
The OP's original code created the response like this:
response.Clear();
response.AppendHeader("Content-Disposition", "inline;filename=" + "abc.pdf");
response.BufferOutput = true;
response.ContentType = System.Net.Mime.MediaTypeNames.Application.Pdf;
response.BinaryWrite(contents);
response.End();
This code especially does not set the Content-Length header. Some web browser versions (not only Chrome but also certain versions of other browsers) without that header tend to prematurely consider the download finished.
Detecting when a download is finished on a connection initially created as persistent, may not be trivial if neither a non-identity Transfer-Encoding nor a Content-Length has been supplied.
Thus, the solution here is to add
response.AppendHeader("Content-Length", contents.Length.ToString());
before writing the contents.
Try with "Content-disposition: attachment" header.
Thanks mkl's suggestions.
I added the content length in the header and the pdf can be successfully opened in Chrome!
I have an aspx (say 1.aspx) page from where first I am downloading a pdf file and then I want to redirect to some Thanks.aspx page. The code is this:
protected void btnSubmit_Click(object sender, EventArgs e)
{
string pathId = string.Empty;
if (Page.IsValid)
{
try
{
pathId = hidId.Value;
DownloadPDF(pathId);
Response.Redirect("Thanks.aspx");
}
catch (Exception ex)
{
throw ex;
}
}
}
protected void DownloadPDF(string pathId)
{
if (!(string.IsNullOrEmpty(pathId)))
{
try
{
Response.ContentType = "application/pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + pathId + ".pdf");
string path = ConfigurationManager.AppSettings["Pdf_Path"].ToString() + "\\" + pathId.Trim() + ".pdf";
Response.TransmitFile(path);
}
catch (Exception ex)
{
throw ex;
}
finally
{
HttpContext.Current.ApplicationInstance.CompleteRequest();
}
}
}
The problem is that, the file save dialog is coming properly and I am able to download the file also, but it is not getting redirected to the Thanks.aspx page.
How to resolve this?
If the file is just downloaded, no preprocessing is done, you could try the following:
Response.AddHeader("Refresh", "12;URL=nextpage.aspx");
Where the number is the seconds before refresh is done :)
I've found it easier to put the PDF download page in an iframe. That way you can activate the PDF download on the client side by just pointing the iframe source to the PDF download page. After that you can either move to a new page, or just show the thank you text right that on the page that has the iframe in it.
In HTTP, a request can only have a single response. Since the first response is the PDF file, the seconds response (i.e. the redirect) cannot be implemented.
You can try to redesign the two pages by redirecting to thanks.aspx and have thanks.aspx start the download automatically.
A Response.Redirect actually sends a response to the browser that basically says this resource has moved to some other URL. However, you're trying to send a file down in a response too, so those two things are probably clashing with each other. Try sending back a little JavaScript that sends them to the page you want to send them too instead of using a Response.Redirect.
ScriptManager.RegisterStartupScript(Me, Me.GetType(), "redirectScript", "window.location.href='whateverurlhere.aspx';", True)
See the article mentioned in this accepted answer: https://stackoverflow.com/a/11018277/1037864
(direct link: http://gruffcode.com/2010/10/28/detecting-the-file-download-dialog-in-the-browser/)
The idea is to set a cookie and send it together with the file. Meanwhile you let the waiting page block the UI while it is waiting for the cookie to arrive.
I tried many things (like the ideas here) but nothing worked for my particular situation. In the end for me I used an approach where my C# sets a cookie that the JavaScript looks for and the form buttons/etc are disabled accordingly until the cookie is detected.
My code is here in case anyone thinks this solution might work for you:
https://gist.github.com/cemerson/9811a384d7f41bc683b2bd9ed4bf5b17
When the user clicks a button, I want to build a string, then have the user download that string as a file (it's a CSV file).
var response = HttpContext.Current.Response;
response.ClearContent();
response.Clear();
byte[] bytes = Encoding.ASCII.GetBytes(csvtext);
using (var stream = new MemoryStream(bytes))
{
response.AddHeader("Content-Disposition", "attachment; filename=somefile.csv");
response.AddHeader("Content-Length", stream.Length.ToString());
response.ContentType = "text/plain";
stream.WriteTo(response.OutputStream);
}
This is what I have so far, and I have a feeling I'm pretty close, but I get the following error message:
Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near '[The first bit of the CSV file]'.
I'm at a loss, and a deadline is fast approaching. Any help is greatly appreciated.
My guess is that you are in an AJAX Update Panel. If you are doing this type of action it must be done via a postback.
You can't do this with a partial/async postback with Ajax. You'll need to make whatever button you have triggering this download a PostBackTrigger for your UpdatePanel. Details here: http://www.asp.net/Ajax/Documentation/Live/mref/T_System_Web_UI_PostBackTrigger.aspx