ASP.NET MVC: How can I get the browser to open and display a PDF instead of displaying a download prompt?



download pdf in mvc 4 (3)

I had same issue,but none of the solutions not worked in Firefox until I changed the Options of my browser. In Options

window,then Application Tab change the Portable Document Format to Preview in Firefox.

https://ffff65535.com

Ok, so I have an action method that generates a PDF and returns it to the browser. The problem is that instead of automatically opening the PDF, IE displays a download prompt even though it knows what kind of file it is. Chrome does the same thing. In both browsers if I click a link to a PDF file that is stored on a server it will open up just fine and never display a download prompt.

Here is the code that is called to return the PDF:

public FileResult Report(int id)
{
    var customer = customersRepository.GetCustomer(id);
    if (customer != null)
    {
        return File(RenderPDF(this.ControllerContext, "~/Views/Forms/Report.aspx", customer), "application/pdf", "Report - Customer # " + id.ToString() + ".pdf");
    }
    return null;
}

Here's the response header from the server:

HTTP/1.1 200 OK
Server: ASP.NET Development Server/10.0.0.0
Date: Thu, 16 Sep 2010 06:14:13 GMT
X-AspNet-Version: 4.0.30319
X-AspNetMvc-Version: 2.0
Content-Disposition: attachment; filename="Report - Customer # 60.pdf"
Cache-Control: private, s-maxage=0
Content-Type: application/pdf
Content-Length: 79244
Connection: Close

Do I have to add something special to the response to get the browser to open the PDF automatically?

Any help is greatly appreciated! Thanks!


I use following classes for having more options with content-disposition header.

It works quite like Marnix answer, but instead of fully generating the header with the ContentDisposition class, which unfortunately does not comply to RFC when file name has to be utf-8 encoded, it tweaks instead the header generated by MVC, which complies to RFC.

(Originally, I have written that in part using this response to another question and this another one.)

using System;
using System.IO;
using System.Web;
using System.Web.Mvc;

namespace Whatever
{
    /// <summary>
    /// Add to FilePathResult some properties for specifying file name without forcing a download and specifying size.
    /// And add a workaround for allowing error cases to still display error page.
    /// </summary>
    public class FilePathResultEx : FilePathResult
    {
        /// <summary>
        /// In case a file name has been supplied, control whether it should be opened inline or downloaded.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public bool Inline { get; set; }

        /// <summary>
        /// Whether file size should be indicated or not.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public bool IncludeSize { get; set; }

        public FilePathResultEx(string fileName, string contentType) : base(fileName, contentType) { }

        public override void ExecuteResult(ControllerContext context)
        {
            FileResultUtils.ExecuteResultWithHeadersRestoredOnFailure(context, base.ExecuteResult);
        }

        protected override void WriteFile(HttpResponseBase response)
        {
            if (Inline)
                FileResultUtils.TweakDispositionAsInline(response);
            // File.Exists is more robust than testing through FileInfo, especially in case of invalid path: it does yield false rather than an exception.
            // We wish not to crash here, in order to let FilePathResult crash in its usual way.
            if (IncludeSize && File.Exists(FileName))
            {
                var fileInfo = new FileInfo(FileName);
                FileResultUtils.TweakDispositionSize(response, fileInfo.Length);
            }
            base.WriteFile(response);
        }
    }

    /// <summary>
    /// Add to FileStreamResult some properties for specifying file name without forcing a download and specifying size.
    /// And add a workaround for allowing error cases to still display error page.
    /// </summary>
    public class FileStreamResultEx : FileStreamResult
    {
        /// <summary>
        /// In case a file name has been supplied, control whether it should be opened inline or downloaded.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public bool Inline { get; set; }

        /// <summary>
        /// If greater than <c>0</c>, the content size to include in content-disposition header.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public long Size { get; set; }

        public FileStreamResultEx(Stream fileStream, string contentType) : base(fileStream, contentType) { }

        public override void ExecuteResult(ControllerContext context)
        {
            FileResultUtils.ExecuteResultWithHeadersRestoredOnFailure(context, base.ExecuteResult);
        }

        protected override void WriteFile(HttpResponseBase response)
        {
            if (Inline)
                FileResultUtils.TweakDispositionAsInline(response);
            FileResultUtils.TweakDispositionSize(response, Size);
            base.WriteFile(response);
        }
    }

    /// <summary>
    /// Add to FileContentResult some properties for specifying file name without forcing a download and specifying size.
    /// And add a workaround for allowing error cases to still display error page.
    /// </summary>
    public class FileContentResultEx : FileContentResult
    {
        /// <summary>
        /// In case a file name has been supplied, control whether it should be opened inline or downloaded.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public bool Inline { get; set; }

        /// <summary>
        /// Whether file size should be indicated or not.
        /// </summary>
        /// <remarks>If <c>FileDownloadName</c> is <c>null</c> or empty, this property has no effect (due to current implementation).</remarks>
        public bool IncludeSize { get; set; }

        public FileContentResultEx(byte[] fileContents, string contentType) : base(fileContents, contentType) { }

        public override void ExecuteResult(ControllerContext context)
        {
            FileResultUtils.ExecuteResultWithHeadersRestoredOnFailure(context, base.ExecuteResult);
        }

        protected override void WriteFile(HttpResponseBase response)
        {
            if (Inline)
                FileResultUtils.TweakDispositionAsInline(response);
            if (IncludeSize)
                FileResultUtils.TweakDispositionSize(response, FileContents.LongLength);
            base.WriteFile(response);
        }
    }

    public static class FileResultUtils
    {
        public static void ExecuteResultWithHeadersRestoredOnFailure(ControllerContext context, Action<ControllerContext> executeResult)
        {
            if (context == null)
                throw new ArgumentNullException("context");
            if (executeResult == null)
                throw new ArgumentNullException("executeResult");
            var response = context.HttpContext.Response;
            var previousContentType = response.ContentType;
            try
            {
                executeResult(context);
            }
            catch
            {
                if (response.HeadersWritten)
                    throw;
                // Error logic will usually output a content corresponding to original content type. Restore it if response can still be rewritten.
                // (Error logic should ensure headers positionning itself indeed... But this is not the case at least with HandleErrorAttribute.)
                response.ContentType = previousContentType;
                // If a content-disposition header have been set (through DownloadFilename), it must be removed too.
                response.Headers.Remove(ContentDispositionHeader);
                throw;
            }
        }

        private const string ContentDispositionHeader = "Content-Disposition";

        // Unfortunately, the content disposition generation logic is hidden in an Mvc.Net internal class, while not trivial (UTF-8 support).
        // Hacking it after its generation. 
        // Beware, do not try using System.Net.Mime.ContentDisposition instead, it does not conform to the RFC. It does some base64 UTF-8
        // encoding while it should append '*' to parameter name and use RFC 5987 encoding. http://tools.ietf.org/html/rfc6266#section-4.3
        // And https://.com/a/22221217/1178314 comment.
        // To ask for a fix: https://github.com/aspnet/Mvc
        // Other class : System.Net.Http.Headers.ContentDispositionHeaderValue looks better. But requires to detect if the filename needs encoding
        // and if yes, use the 'Star' suffixed property along with setting the sanitized name in non Star property.
        // MVC 6 relies on ASP.NET 5 https://github.com/aspnet/HttpAbstractions which provide a forked version of previous class, with a method
        // for handling that: https://github.com/aspnet/HttpAbstractions/blob/dev/src/Microsoft.Net.Http.Headers/ContentDispositionHeaderValue.cs
        // MVC 6 stil does not give control on FileResult content-disposition header.
        public static void TweakDispositionAsInline(HttpResponseBase response)
        {
            var disposition = response.Headers[ContentDispositionHeader];
            const string downloadModeToken = "attachment;";
            if (string.IsNullOrEmpty(disposition) || !disposition.StartsWith(downloadModeToken, StringComparison.OrdinalIgnoreCase))
                return;

            response.Headers.Remove(ContentDispositionHeader);
            response.Headers.Add(ContentDispositionHeader, "inline;" + disposition.Substring(downloadModeToken.Length));
        }

        public static void TweakDispositionSize(HttpResponseBase response, long size)
        {
            if (size <= 0)
                return;
            var disposition = response.Headers[ContentDispositionHeader];
            const string sizeToken = "size=";
            // Due to current ancestor semantics (no file => inline, file name => download), handling lack of ancestor content-disposition
            // is non trivial. In this case, the content is by default inline, while the Inline property is <c>false</c> by default.
            // This could lead to an unexpected behavior change. So currently not handled.
            if (string.IsNullOrEmpty(disposition) || disposition.Contains(sizeToken))
                return;

            response.Headers.Remove(ContentDispositionHeader);
            response.Headers.Add(ContentDispositionHeader, disposition + "; " + sizeToken + size.ToString());
        }
    }
}

Sample usage:

public FileResult Download(int id)
{
    // some code to get filepath and filename for browser
    ...

    return
        new FilePathResultEx(filepath, System.Web.MimeMapping.GetMimeMapping(filename))
        {
            FileDownloadName = filename,
            Inline = true
        };
}

Note that specifying a file name with Inline will not work with Internet Explorer (11 included, Windows 10 Edge included, tested with some pdf files), while it works with Firefox and Chrome. Internet Explorer will ignore the file name. For Internet Explorer, you need to hack your url path, which is quite bad imo. See this answer.


Response.AppendHeader("Content-Disposition", "inline; filename=foo.pdf");
return File(...




pdf