I need to send a CSV file in HTTP response. How can I set the output response as CSV format?
This is not working:
Response.ContentType = "application/CSV";
Using text/csv
is the most appropriate type.
You should also consider adding a Content-Disposition
header to the response. Often a text/csv will be loaded by a Internet Explorer directly into a hosted instance of Excel. This may or may not be a desirable result.
Response.AddHeader("Content-Disposition", "attachment;filename=myfilename.csv");
The above will cause a file "Save as" dialog to appear which may be what you intend.
Over the years I've been honing a perfect set of headers for this that work brilliantly in all browsers that I know of
// these headers avoid IE problems when using https:
// see http://support.microsoft.com/kb/812935
header("Cache-Control: must-revalidate");
header("Pragma: must-revalidate");
header("Content-type: application/vnd.ms-excel");
header("Content-disposition: attachment; filename=$filename.csv");
Try one of these other mime-types (from here: http://filext.com/file-extension/CSV )
Also, the mime-type might be case sensitive...
I have found that the problem with IE is that it sniffs the return data and makes up its own mind about what content-type it thinks it has been sent. There are a number of side effect that this causes, such as always openning a saveAs dialog for text files because you are using compression of data trasnferes. The solution is (in php code)......
header('X-Content-Type-Options: nosniff');
Setting the content type and the content disposition as described above produces wildly varying results with different browsers:
IE8: SaveAs dialog as desired, and Excel as the default app. 100% good.
Firefox: SaveAs dialog does show up, but Firefox has no idea it is a spreadsheet. Suggests opening it with Visual Studio! 50% good
Chrome: the hints are fully ignored. The CSV data is shown in the browser. 0% good.
Of course in all of these cases I'm referring to the browsers as they come out of they box, with no customization of the mime/application mappings.
For C# MVC 4.5 you need to do like this:
Response.Clear();
Response.ContentType = "application/CSV";
Response.AddHeader("content-disposition", "attachment; filename=\"" + fileName + ".csv\"");
Response.Write(dataNeedToPrint);
Response.End();
return new EmptyResult(); //this line is important else it will not work.