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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc {
using System;
using System.Net.Mime;
using System.Text;
using System.Web;
using System.Web.Mvc.Resources;
public abstract class FileResult : ActionResult {
protected FileResult(string contentType) {
if (String.IsNullOrEmpty(contentType)) {
throw new ArgumentException(MvcResources.Common_NullOrEmpty, "contentType");
}
ContentType = contentType;
}
private string _fileDownloadName;
public string ContentType {
get;
private set;
}
public string FileDownloadName {
get {
return _fileDownloadName ?? String.Empty;
}
set {
_fileDownloadName = value;
}
}
public override void ExecuteResult(ControllerContext context) {
if (context == null) {
throw new ArgumentNullException("context");
}
HttpResponseBase response = context.HttpContext.Response;
response.ContentType = ContentType;
if (!String.IsNullOrEmpty(FileDownloadName)) {
// From RFC 2183, Sec. 2.3:
// The sender may want to suggest a filename to be used if the entity is
// detached and stored in a separate file. If the receiving MUA writes
// the entity to a file, the suggested filename should be used as a
// basis for the actual filename, where possible.
string headerValue = ContentDispositionUtil.GetHeaderValue(FileDownloadName);
context.HttpContext.Response.AddHeader("Content-Disposition", headerValue);
}
WriteFile(response);
}
protected abstract void WriteFile(HttpResponseBase response);
private static class ContentDispositionUtil {
private const string _hexDigits = "0123456789ABCDEF";
private static void AddByteToStringBuilder(byte b, StringBuilder builder) {
builder.Append('%');
int i = b;
AddHexDigitToStringBuilder(i >> 4, builder);
AddHexDigitToStringBuilder(i % 16, builder);
}
private static void AddHexDigitToStringBuilder(int digit, StringBuilder builder) {
builder.Append(_hexDigits[digit]);
}
private static string CreateRfc2231HeaderValue(string filename) {
StringBuilder builder = new StringBuilder("attachment; filename*=UTF-8''");
byte[] filenameBytes = Encoding.UTF8.GetBytes(filename);
foreach (byte b in filenameBytes) {
if (IsByteValidHeaderValueCharacter(b)) {
builder.Append((char)b);
}
else {
AddByteToStringBuilder(b, builder);
}
}
return builder.ToString();
}
public static string GetHeaderValue(string fileName) {
try {
// first, try using the .NET built-in generator
ContentDisposition disposition = new ContentDisposition() { FileName = fileName };
return disposition.ToString();
}
catch (FormatException) {
// otherwise, fall back to RFC 2231 extensions generator
return CreateRfc2231HeaderValue(fileName);
}
}
// Application of RFC 2231 Encoding to Hypertext Transfer Protocol (HTTP) Header Fields, sec. 3.2
// http://greenbytes.de/tech/webdav/draft-reschke-rfc2231-in-http-latest.html
private static bool IsByteValidHeaderValueCharacter(byte b) {
if ((byte)'0' <= b && b <= (byte)'9') {
return true; // is digit
}
if ((byte)'a' <= b && b <= (byte)'z') {
return true; // lowercase letter
}
if ((byte)'A' <= b && b <= (byte)'Z') {
return true; // uppercase letter
}
switch (b) {
case (byte)'-':
case (byte)'.':
case (byte)'_':
case (byte)'~':
case (byte)':':
case (byte)'!':
case (byte)'$':
case (byte)'&':
case (byte)'+':
return true;
}
return false;
}
}
}
}
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