File size: 6,439 Bytes
7b715bc | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 | // Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;
namespace System.Net.Http
{
internal sealed class DecompressionHandler : HttpMessageHandler
{
private readonly HttpMessageHandler _innerHandler;
private readonly DecompressionMethods _decompressionMethods;
private const string s_gzip = "gzip";
private const string s_deflate = "deflate";
private static StringWithQualityHeaderValue s_gzipHeaderValue = new StringWithQualityHeaderValue(s_gzip);
private static StringWithQualityHeaderValue s_deflateHeaderValue = new StringWithQualityHeaderValue(s_deflate);
public DecompressionHandler(DecompressionMethods decompressionMethods, HttpMessageHandler innerHandler)
{
_innerHandler = innerHandler ?? throw new ArgumentNullException(nameof(innerHandler));
if (decompressionMethods == DecompressionMethods.None)
{
throw new ArgumentOutOfRangeException(nameof(decompressionMethods));
}
_decompressionMethods = decompressionMethods;
}
internal bool GZipEnabled => (_decompressionMethods & DecompressionMethods.GZip) != 0;
internal bool DeflateEnabled => (_decompressionMethods & DecompressionMethods.Deflate) != 0;
protected internal override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
if (GZipEnabled)
{
request.Headers.AcceptEncoding.Add(s_gzipHeaderValue);
}
if (DeflateEnabled)
{
request.Headers.AcceptEncoding.Add(s_deflateHeaderValue);
}
HttpResponseMessage response = await _innerHandler.SendAsync(request, cancellationToken).ConfigureAwait(false);
ICollection<string> contentEncodings = response.Content.Headers.ContentEncoding;
if (contentEncodings.Count > 0)
{
string last = null;
foreach (string encoding in contentEncodings)
{
last = encoding;
}
if (GZipEnabled && last == s_gzip)
{
response.Content = new GZipDecompressedContent(response.Content);
}
else if (DeflateEnabled && last == s_deflate)
{
response.Content = new DeflateDecompressedContent(response.Content);
}
}
return response;
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
_innerHandler.Dispose();
}
base.Dispose(disposing);
}
private abstract class DecompressedContent : HttpContent
{
HttpContent _originalContent;
bool _contentConsumed;
public DecompressedContent(HttpContent originalContent)
{
_originalContent = originalContent;
_contentConsumed = false;
// Copy original response headers, but with the following changes:
// Content-Length is removed, since it no longer applies to the decompressed content
// The last Content-Encoding is removed, since we are processing that here.
Headers.AddHeaders(originalContent.Headers);
Headers.ContentLength = null;
Headers.ContentEncoding.Clear();
string prevEncoding = null;
foreach (string encoding in originalContent.Headers.ContentEncoding)
{
if (prevEncoding != null)
{
Headers.ContentEncoding.Add(prevEncoding);
}
prevEncoding = encoding;
}
}
protected abstract Stream GetDecompressedStream(Stream originalStream);
protected override async Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
using (Stream decompressedStream = await CreateContentReadStreamAsync().ConfigureAwait(false))
{
await decompressedStream.CopyToAsync(stream).ConfigureAwait(false);
}
}
protected override async Task<Stream> CreateContentReadStreamAsync()
{
if (_contentConsumed)
{
throw new InvalidOperationException(SR.net_http_content_stream_already_read);
}
_contentConsumed = true;
Stream originalStream = _originalContent.TryReadAsStream() ?? await _originalContent.ReadAsStreamAsync().ConfigureAwait(false);
return GetDecompressedStream(originalStream);
}
protected internal override bool TryComputeLength(out long length)
{
length = 0;
return false;
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
_originalContent.Dispose();
}
base.Dispose(disposing);
}
}
private sealed class GZipDecompressedContent : DecompressedContent
{
public GZipDecompressedContent(HttpContent originalContent)
: base(originalContent)
{ }
protected override Stream GetDecompressedStream(Stream originalStream) =>
new GZipStream(originalStream, CompressionMode.Decompress);
}
private sealed class DeflateDecompressedContent : DecompressedContent
{
public DeflateDecompressedContent(HttpContent originalContent)
: base(originalContent)
{ }
protected override Stream GetDecompressedStream(Stream originalStream) =>
new DeflateStream(originalStream, CompressionMode.Decompress);
}
}
}
|