132 lines
4.6 KiB
C#
132 lines
4.6 KiB
C#
namespace System.Web.Mvc {
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using System;
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using System.Net.Mime;
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using System.Text;
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using System.Web;
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using System.Web.Mvc.Resources;
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public abstract class FileResult : ActionResult {
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protected FileResult(string contentType) {
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if (String.IsNullOrEmpty(contentType)) {
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throw new ArgumentException(MvcResources.Common_NullOrEmpty, "contentType");
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}
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ContentType = contentType;
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}
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private string _fileDownloadName;
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public string ContentType {
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get;
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private set;
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}
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public string FileDownloadName {
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get {
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return _fileDownloadName ?? String.Empty;
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}
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set {
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_fileDownloadName = value;
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}
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}
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public override void ExecuteResult(ControllerContext context) {
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if (context == null) {
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throw new ArgumentNullException("context");
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}
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HttpResponseBase response = context.HttpContext.Response;
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response.ContentType = ContentType;
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if (!String.IsNullOrEmpty(FileDownloadName)) {
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// From RFC 2183, Sec. 2.3:
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// The sender may want to suggest a filename to be used if the entity is
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// detached and stored in a separate file. If the receiving MUA writes
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// the entity to a file, the suggested filename should be used as a
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// basis for the actual filename, where possible.
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string headerValue = ContentDispositionUtil.GetHeaderValue(FileDownloadName);
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context.HttpContext.Response.AddHeader("Content-Disposition", headerValue);
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}
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WriteFile(response);
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}
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protected abstract void WriteFile(HttpResponseBase response);
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private static class ContentDispositionUtil {
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private const string _hexDigits = "0123456789ABCDEF";
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private static void AddByteToStringBuilder(byte b, StringBuilder builder) {
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builder.Append('%');
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int i = b;
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AddHexDigitToStringBuilder(i >> 4, builder);
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AddHexDigitToStringBuilder(i % 16, builder);
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}
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private static void AddHexDigitToStringBuilder(int digit, StringBuilder builder) {
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builder.Append(_hexDigits[digit]);
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}
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private static string CreateRfc2231HeaderValue(string filename) {
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StringBuilder builder = new StringBuilder("attachment; filename*=UTF-8''");
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byte[] filenameBytes = Encoding.UTF8.GetBytes(filename);
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foreach (byte b in filenameBytes) {
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if (IsByteValidHeaderValueCharacter(b)) {
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builder.Append((char)b);
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}
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else {
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AddByteToStringBuilder(b, builder);
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}
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}
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return builder.ToString();
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}
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public static string GetHeaderValue(string fileName) {
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try {
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// first, try using the .NET built-in generator
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ContentDisposition disposition = new ContentDisposition() { FileName = fileName };
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return disposition.ToString();
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}
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catch (FormatException) {
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// otherwise, fall back to RFC 2231 extensions generator
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return CreateRfc2231HeaderValue(fileName);
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}
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}
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// Application of RFC 2231 Encoding to Hypertext Transfer Protocol (HTTP) Header Fields, sec. 3.2
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// http://greenbytes.de/tech/webdav/draft-reschke-rfc2231-in-http-latest.html
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private static bool IsByteValidHeaderValueCharacter(byte b) {
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if ((byte)'0' <= b && b <= (byte)'9') {
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return true; // is digit
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}
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if ((byte)'a' <= b && b <= (byte)'z') {
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return true; // lowercase letter
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}
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if ((byte)'A' <= b && b <= (byte)'Z') {
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return true; // uppercase letter
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}
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switch (b) {
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case (byte)'-':
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case (byte)'.':
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case (byte)'_':
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case (byte)'~':
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case (byte)':':
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case (byte)'!':
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case (byte)'$':
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case (byte)'&':
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case (byte)'+':
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return true;
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}
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return false;
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}
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}
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}
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}
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