Response header Content-Disposition not doing anything - .net-core

I am trying to retrieve a file from my server (which is using ASP.NET Core MVC) and display it in the browser. After looking through many threads on here and other sites, the same solution seems to be suggested every time; which is to use Content-Disposition inline in the response header. I have my code as follows:
IFileInfo file = _fileProvider.GetFileInfo(filename);
Response.Headers.Add("Content-Disposition", $"inline; {file.Name}");
return File(file.CreateReadStream(), "application/pdf", file.Name);
While this seems to be the correct code based on other threads I've seen, the Content-Disposition header does absolutely nothing in my code. Whether I have the header, remove it, or make it something else (i.e. attachment), it downloads and saves the file but does not display it unless I manually open the file.
Does anyone know what I'm missing here?

Returning the File overload that accepts the filename param is overwriting your Content-Disposition header to be attachment; {filename}. Just do:
return File(file.CreateReadStream(), "application/pdf");
And you'll be fine.

Related

Prompting user for download, IE sets the filename as the .aspx name ("Would you like to download SomePage.aspx?fileID=12345")

I am at a loss here. I am trying to transmit a file on the local intranet site. When I get a download prompt in IE11, it says:
Do you want to open or save "SomePage.aspx?fileID=12345"? [open] [save] [cancel]
Instead of..
Do you want to open or save "Document.pdf"? [open] [save] [cancel]
It works perfectly fine on Chrome. The file gets downloaded with the correct filename. But for some reason, IE isn't setting the name and instead uses the ASPX name.
The code is rather straightforward:
testFile = New System.IO.FileInfo("\\someshare\somefolder$\Document.pdf")
Response.Clear()
Response.AddHeader("Content-Disposition", "attachment; filename=" & testFile.Name)
Response.AddHeader("Content-Length", testFile.Length.ToString())
Response.ContentType = "application/octet-stream"
Response.TransmitFile(testFile.FullName)
I've tried a number of different header options and the MIME type makes no difference.
Does anyone have a clue why this would be happening?
Notes: Not HTTPS. It is not limited to PDF, same happens with .TIF, .DOC, and every other format I've tested.
EDIT: Have also tried Response.WriteFile as well as Response.BinaryWrite .. same thing each time.
EDIT2: Simplified everything down to a single button on a completely blank page.
You should have quote marks around the file name. See 19.5.1 on http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html
i.e.
Content-Disposition: attachment; filename="fname.ext"
so...
Response.AddHeader("Content-Disposition", String.Format("attachment; filename=""{0}""", testFile.Name))
Unfortunately I have not been able to test if this solves your issue as I don't have access to IE11 at the moment.
So I know this question is older, but the solution I finally came up with to this problem is to add the following two lines to my code.
Response.SuppressContent = True
and
HttpContext.Current.ApplicationInstance.CompleteRequest()
You have said in previous comments that you have tried the CompleteRequest command to no avail.
As a note, I am not 100% certain to the logistics of the Response.SuppressContent() command.
The documentation says that it indicates "whether to send HTTP content to the client". This seems counter intuitive to the process of sending the request body back to the client, however, it appears to only suppress the parts of the response that include any HTML.
It seems that the partial or incomplete HTML is what causes the filename to appear as the page name regardless of the headers set and sent. Stripping this out should cause the file to download properly.
Interestingly, this solution is actually born out of a secondary issue where once I was able to export the file using ClosedXML, i was receiving messages when opening the document that there were errors than excel would try to fix.
Response.SuppressContent actually fixed that as well. Hope this helps or at least points you in the right direction.

Getting Filename from virtual URL?

I have a URL like "http://www.ti.com/lit/gpn/TPS767D318-Q1"
which is a path eventually being routed to "http://www.ti.com/lit/ds/symlink/tps767d318-q1.pdf" on the browser(rendering a pdf file). I am processing this URL in a Console application in order to fetch the "pdf" filename that you see in the second URL i provided.
I checked the UriResponse.Absoluteuri property in the httpresponse object and it says "http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=TPS767D318-Q1&fileType=pdf"
looks like this is a nested virtual path. Can anybody help on where i can get to the end URL to extract the pdf file name? i did not find it anywhere in the response object. I also checked in the Response headers and nothing there either.
Any help will be appreciated...Thanks
Not sure about ASP, but at the protocol level the initial request may cause a Redirect to be issued by the application/server on the other end, so you can look at the initial HTTP response and check if it's a redirect code, 301, 302 etc. If so, you can follow the 302s until you hit a 200, and that's the final URL you can use to check the filename.
Look at the Content-Disposition header, it might look something like: Content-Disposition: attachment; filename=tps767d318-q1.pdf. This is a common technique for webservices that fetch and "download" files from database, network shares, etc.
It turns out that the URL in my question is actually returning HTML content and doing a "meta tag" redirect. So I had to do the following:
var redirect = Regex.Match(new string(buffer, 0, count), #"\<meta(?=[^>]*http-equiv\W*refresh)[^>]*?content\s*\=[^=>]*url\s*\=\s*(?<Url>[^'"">]+)", RegexOptions.IgnoreCase | RegexOptions.Singleline);
if (redirect.Success)
{
Uri uri = new Uri(new Uri(externalUrl, UriKind.Absolute), new Uri(redirect.Groups["Url"].Value, UriKind.RelativeOrAbsolute));
return SaveUrlToTemporaryFile(uri.AbsoluteUri, needsFullDownload);
}
I'm getting the final URL out of the meta tags from the returned HTML content, and calling my download routine again.

How can I return a pdf from a web request in ASP.NET?

Simply put, I'd like someone to be able to click a link, and get a one-time-use pdf. We have the library to create PDF files, so that's not an issue.
We could generate a link to an aspx page, have that page generate the pdf, save the pdf to the filesystem, and then Response.Redirect to the saved pdf. Then we'd somehow have to keep track of and clean up the PDF file.
Since we don't ever need to keep this data, what I'd like to do instead, if possible, is to have the aspx page generate the pdf, and serve it directly back as a response to the original request. Is this possible?
(In our case, we're using C#, and we want to serve a pdf back, but it seems like any solution would probably work for various .NET languages and returned filetypes.)
Assuming you can get a byte[] representing your PDF:
Response.Clear();
Response.ContentType = "application/pdf";
Response.AddHeader("Content-Disposition",
"attachment;filename=\"FileName.pdf\"");
Response.BinaryWrite(yourPdfAsByteArray);
Response.Flush();
Response.End();
Look at how HTTP works. The client (=browser) doesn't rely on extensions, it only wants the server to return some metadata along with the document.
Metadata can be added with Response.AddHeader, and one 'metadata line' consists of Name and Value.
Content-Type is the property you are interested in, and the value is MIME type of the data (study: RFC1945 for HTTP headers, google for MIME type).
For ordinal aspx pages (html, ....) the property is 'text/html' (not so trivial, but for this example it is enough.). If you return JPG image, it can have name 'image.gif', but as long as you send 'image/jpeg' in Content-Type, it is processed as JPG image.
Content-type for pdf is 'application/pdf'.
The browser will act according to default behaviour, for example, with Adobe plugin, it will display the PDF in it's window, if you don't have any plugin for PDF, it should download the file, etc..
Content-Disposition header says, what you should do with the data. If you want explicitly the client to 'download' some HTML/PDF/whatever, and not display it by default, value 'attachment' is what you want. It should have another parameter, (as suggested by Justin Niessner), which is used in case of something like:
http://server/download.aspx?file=11 -> Content-Disposition: attachment;filename=file.jpg says, how the file should be by default named.

ajax request that returns json array, IE6/7 is caching it and data is not fresh

for some reason, IE6/7 is caching the ajax call that returns a json result set back.
My page makes the call, and returns a json result which I then inject into the page.
How can I force IE6/7 to make this call and not use a cached return value?
You might want to add
Cache-Control: no-cache
to your HTML response headers when you're serving the JSON to tell the browser to not to cache the response.
In ASP.NET (or ASP.NET MVC) you can do it like this:
Response.Headers.Add("Cache-Control", "no-cache");
you can change your settings in ie, but the problem most likely lies on your server. You can't go out and change all your users' browser settings. But if you want to at least check it on your browser, go to Internet Options->General (Tab)->Browsing History(section)->Settings (button)->"Every time I visit the webpage"
Make sure you set it back, though, at some point.
To fix it on the server, have a look at http://www.mnot.net/cache_docs/
Using curl (w/ cygwin) for debugging is your great way to figure out what's actually being sent across the wire.
If cache-control doesn't work for you (see DrJokepu's answer), according to the spec the content from any URL with a query string should be non-cacheable, so you might append a pointless query parameter to your request URL. The value doesn't matter, but if you really want to be thorough you can append the epoch value, e.g.:
var url = "myrealurl?x=" + (new Date()).getTime();
But this is a hack; really this should be solved with proper caching headers at the server end.
In the controller action that returns a JsonResult, you need to specify in your headers to avoid caching:
ControllerContext.HttpContext.Response.AddHeader("Cache-Control", "no-cache");

"name" web pdf for better default save filename in Acrobat?

My app generates PDFs for user consumption. The "Content-Disposition" http header is set as mentioned here. This is set to "inline; filename=foo.pdf", which should be enough for Acrobat to give "foo.pdf" as the filename when saving the pdf.
However, upon clicking the "Save" button in the browser-embedded Acrobat, the default name to save is not that filename but instead the URL with slashes changed to underscores. Huge and ugly. Is there a way to affect this default filename in Adobe?
There IS a query string in the URLs, and this is non-negotiable. This may be significant, but adding a "&foo=/title.pdf" to the end of the URL doesn't affect the default filename.
Update 2: I've tried both
content-disposition inline; filename=foo.pdf
Content-Type application/pdf; filename=foo.pdf
and
content-disposition inline; filename=foo.pdf
Content-Type application/pdf; name=foo.pdf
(as verified through Firebug) Sadly, neither worked.
A sample url is
/bar/sessions/958d8a22-0/views/1493881172/export?format=application/pdf&no-attachment=true
which translates to a default Acrobat save as filename of
http___localhost_bar_sessions_958d8a22-0_views_1493881172_export_format=application_pdf&no-attachment=true.pdf
Update 3: Julian Reschke brings actual insight and rigor to this case. Please upvote his answer.
This seems to be broken in FF (https://bugzilla.mozilla.org/show_bug.cgi?id=433613) and IE but work in Opera, Safari, and Chrome. http://greenbytes.de/tech/tc2231/#inlwithasciifilenamepdf
Part of the problem is that the relevant RFC 2183 doesn't really state what to do with a disposition type of "inline" and a filename.
Also, as far as I can tell, the only UA that actually uses the filename for type=inline is Firefox (see test case).
Finally, it's not obvious that the plugin API actually makes that information available (maybe someboy familiar with the API can elaborate).
That being said, I have sent a pointer to this question to an Adobe person; maybe the right people will have a look.
Related: see attempt to clarify Content-Disposition in HTTP in draft-reschke-rfc2183-in-http -- this is early work in progress, feedback appreciated.
Update: I have added a test case, which seems to indicate that the Acrobat reader plugin doesn't use the response headers (in Firefox), although the plugin API provides access to them.
Set the file name in ContentType as well. This should solve the problem.
context.Response.ContentType = "application/pdf; name=" + fileName;
// the usual stuff
context.Response.AddHeader("content-disposition", "inline; filename=" + fileName);
After you set content-disposition header, also add content-length header, then use binarywrite to stream the PDF.
context.Response.AddHeader("Content-Length", fileBytes.Length.ToString());
context.Response.BinaryWrite(fileBytes);
Like you, I tried and tried to get this to work. Finally I gave up on this idea, and just opted for a workaround.
I'm using ASP.NET MVC Framework, so I modified my routes for that controller/action to make sure that the served up PDF file is the last part of the location portion of the URI (before the query string), and pass everything else in the query string.
Eg:
Old URI:
http://server/app/report/showpdf?param1=foo&param2=bar&filename=myreport.pdf
New URI:
http://server/app/report/showpdf/myreport.pdf?param1=foo&param2=bar
The resulting header looks exactly like what you've described (content-type is application/pdf, disposition is inline, filename is uselessly part of the header). Acrobat shows it in the browser window (no save as dialog) and the filename that is auto-populated if a user clicks the Acrobat Save button is the report filename.
A few considerations:
In order for the filenames to look decent, they shouldn't have any escaped characters (ie, no spaces, etc)... which is a bit limiting. My filenames are auto-generated in this case, and before had spaces in them, which were showing up as '%20's in the resulting save dialog filename. I just replaced the spaces with underscores, and that worked out.
This is by no names the best solution, but it does work. It also means that you have to have the filename available to make it part of the original URI, which might mess with your program's workflow. If it's currently being generated or retrieved from a database during the server-side call that generates the PDF, you might need to move the code that generates the filename to javascript as part of a form submission or if it comes from a database make it a quick ajax call to get the filename when building the URL that results in the inlined PDF.
If you're taking the filename from a user input on a form, then that should be validated not to contain escaped characters, which will annoy users.
Hope that helps.
Try placing the file name at the end of the URL, before any other parameters. This worked for me.
http://www.setasign.de/support/tips-and-tricks/filename-in-browser-plugin/
In ASP.NET 2.0 change the URL from
http://www. server.com/DocServe.aspx?DocId=XXXXXXX
to
http://www. server.com/DocServe.aspx/MySaveAsFileName?DocId=XXXXXXX
This works for Acrobat 8 and the default SaveAs filename is now MySaveAsFileName.pdf.
However, you have to restrict the allowed characters in MySaveAsFileName (no periods, etc.).
Apache's mod_rewrite can solve this.
I have a web service with an endpoint at /foo/getDoc.service. Of course Acrobat will save files as getDoc.pdf. I added the following lines in apache.conf:
LoadModule RewriteModule modules/mod_rewrite.so
RewriteEngine on
RewriteRule ^/foo/getDoc/(.*)$ /foo/getDoc.service [P,NE]
Now when I request /foo/getDoc/filename.pdf?bar&qux, it gets internally rewritten to /foo/getDoc.service?bar&qux, so I'm hitting the correct endpoint of the web service, but Acrobat thinks it will save my file as filename.pdf.
If you use asp.net, you can control pdf filename through page (url) file name.
As other users wrote, Acrobat is a bit s... when it choose the pdf file name when you press "save" button: it takes the page name, removes the extension and add ".pdf".
So /foo/bar/GetMyPdf.aspx gives GetMyPdf.pdf.
The only solution I found is to manage "dynamic" page names through an asp.net handler:
create a class that implements IHttpHandler
map an handler in web.config bounded to the class
Mapping1: all pages have a common radix (MyDocument_):
<httpHandlers>
<add verb="*" path="MyDocument_*.ashx" type="ITextMiscWeb.MyDocumentHandler"/>
Mapping2: completely free file name (need a folder in path):
<add verb="*" path="/CustomName/*.ashx" type="ITextMiscWeb.MyDocumentHandler"/>
Some tips here (the pdf is dynamically created using iTextSharp):
http://fhtino.blogspot.com/2006/11/how-to-show-or-download-pdf-file-from.html
Instead of attachment you can try inline:
Response.AddHeader("content-disposition", "inline;filename=MyFile.pdf");
I used inline in a previous web application that generated Crystal Reports output into PDF and sent that in browser to the user.
File download dialog (PDF) with save and open option
Points To Remember:
Return Stream with correct array size from service
Read the byte arrary from stream with correct byte length on the basis of stream length.
set correct contenttype
Here is the code for read stream and open the File download dialog for PDF file
private void DownloadSharePointDocument()
{
Uri uriAddress = new Uri("http://hyddlf5187:900/SharePointDownloadService/FulfillmentDownload.svc/GetDocumentByID/1/drmfree/");
HttpWebRequest req = WebRequest.Create(uriAddress) as HttpWebRequest;
// Get response
using (HttpWebResponse httpWebResponse = req.GetResponse() as HttpWebResponse)
{
Stream stream = httpWebResponse.GetResponseStream();
int byteCount = Convert.ToInt32(httpWebResponse.ContentLength);
byte[] Buffer1 = new byte[byteCount];
using (BinaryReader reader = new BinaryReader(stream))
{
Buffer1 = reader.ReadBytes(byteCount);
}
Response.Clear();
Response.ClearHeaders();
// set the content type to PDF
Response.ContentType = "application/pdf";
Response.AddHeader("Content-Disposition", "attachment;filename=Filename.pdf");
Response.Buffer = true;
Response.BinaryWrite(Buffer1);
Response.Flush();
// Response.End();
}
}
I believe this has already been mentioned in one flavor or another but I'll try and state it in my own words.
Rather than this:
/bar/sessions/958d8a22-0/views/1493881172/export?format=application/pdf&no-attachment=true
I use this:
/bar/sessions/958d8a22-0/views/1493881172/NameThatIWantPDFToBe.pdf?GeneratePDF=1
Rather than having "export" process the request, when a request comes in, I look in the URL for GeneratePDF=1. If found, I run whatever code was running in "export" rather than allowing my system to attempt to search and serve a PDF in the location /bar/sessions/958d8a22-0/views/1493881172/NameThatIWantPDFToBe.pdf. If GeneratePDF is not found in the URL, I simply transmit the file requested. (note that I can't simply redirect to the file requested - or else I'd end up in an endless loop)
You could always have two links. One that opens the document inside the browser, and another to download it (using an incorrect content type). This is what Gmail does.
For anyone still looking at this, I used the solution found here and it worked wonderfully. Thanks Fabrizio!
The way I solved this (with PHP) is as follows:
Suppose your URL is SomeScript.php?id=ID&data=DATA and the file you want to use is TEST.pdf.
Change the URL to SomeScript.php/id/ID/data/DATA/EXT/TEST.pdf.
It's important that the last parameter is the file name you want Adobe to use (the 'EXT' can be about anything). Make sure there are no special chars in the above string, BTW.
Now, at the top of SomeScript.php, add:
$_REQUEST = MakeFriendlyURI( $_SERVER['PHP\_SELF'], $_SERVER['SCRIPT_FILENAME']);
Then add this function to SomeScript.php (or your function library):
function MakeFriendlyURI($URI, $ScriptName) {
/* Need to remove everything up to the script name */
$MyName = '/^.*'.preg_quote(basename($ScriptName)."/", '/').'/';
$Str = preg_replace($MyName,'',$URI);
$RequestArray = array();
/* Breaks down like this
0 1 2 3 4 5
PARAM1/VAL1/PARAM2/VAL2/PARAM3/VAL3
*/
$tmp = explode('/',$Str);
/* Ok so build an associative array with Key->value
This way it can be returned back to $_REQUEST or $_GET
*/
for ($i=0;$i < count($tmp); $i = $i+2){
$RequestArray[$tmp[$i]] = $tmp[$i+1];
}
return $RequestArray;
}//EO MakeFriendlyURI
Now $_REQUEST (or $_GET if you prefer) is accessed like normal $_REQUEST['id'], $_REQUEST['data'], etc.
And Adobe will use your desired file name as the default save as or email info when you send it inline.
I was redirected here because i have the same problem. I also tried Troy Howard's workaround but it is doesn't seem to work.
The approach I did on this one is to NO LONGER use response object to write the file on the fly. Since the PDF is already existing on the server, what i did was to redirect my page pointing to that PDF file. Works great.
http://forums.asp.net/t/143631.aspx
I hope my vague explanation gave you an idea.
Credits to Vivek.
Nginx
location /file.pdf
{
# more_set_headers "Content-Type: application/pdf; name=save_as_file.pdf";
add_header Content-Disposition "inline; filename=save_as_file.pdf";
alias /var/www/file.pdf;
}
Check with
curl -I https://example.com/file.pdf
Firefox 62.0b5 (64-bit): OK.
Chrome 67.0.3396.99 (64-Bit): OK.
IE 11: No comment.
Try this, if your executable is "get.cgi"
http://server,org/get.cgi/filename.pdf?file=filename.pdf
Yes, it's completely insane. There is no file called "filename.pdf" on the server, there is directory at all under the executable get.cgi.
But it seems to work. The server ignores the filename.pdf and the pdf reader ignores the "get.cgi"
Dan

Resources