mcs/class/System.Net.Http/System.Net.Http/HttpContent.cs

   1 //
   2 // HttpContent.cs
   3 //
   4 // Authors:
   5 //      Marek Safar  <marek.safar@gmail.com>
   6 //
   7 // Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.Net.Http.Headers;
  30 using System.IO;
  31 using System.Threading.Tasks;
  32 using System.Text;
  33
  34 namespace System.Net.Http
  35 {
  36         public abstract class HttpContent : IDisposable
  37         {
  38                 sealed class FixedMemoryStream : MemoryStream
  39                 {
  40                         readonly long maxSize;
  41
  42                         public FixedMemoryStream (long maxSize)
  43                                 : base ()
  44                         {
  45                                 this.maxSize = maxSize;
  46                         }
  47
  48                         void CheckOverflow (int count)
  49                         {
  50                                 if (Length + count > maxSize)
  51                                         throw new HttpRequestException (string.Format ("Cannot write more bytes to the buffer than the configured maximum buffer size: {0}", maxSize));
  52                         }
  53
  54                         public override void WriteByte (byte value)
  55                         {
  56                                 CheckOverflow (1);
  57                                 base.WriteByte (value);
  58                         }
  59
  60                         public override void Write (byte[] buffer, int offset, int count)
  61                         {
  62                                 CheckOverflow (count);
  63                                 base.Write (buffer, offset, count);
  64                         }
  65                 }
  66
  67                 FixedMemoryStream buffer;
  68                 Stream stream;
  69                 bool disposed;
  70                 HttpContentHeaders headers;
  71
  72                 public HttpContentHeaders Headers {
  73                         get {
  74                                 return headers ?? (headers = new HttpContentHeaders (this));
  75                         }
  76                 }
  77
  78                 internal long? LoadedBufferLength {
  79                         get {
  80                                 return buffer == null ? (long?)null : buffer.Length;
  81                         }
  82                 }
  83
  84                 public Task CopyToAsync (Stream stream)
  85                 {
  86                         return CopyToAsync (stream, null);
  87                 }
  88
  89                 public Task CopyToAsync (Stream stream, TransportContext context)
  90                 {
  91                         if (stream == null)
  92                                 throw new ArgumentNullException ("stream");
  93
  94                         if (buffer != null)
  95                                 return buffer.CopyToAsync (stream);
  96
  97                         return SerializeToStreamAsync (stream, context);
  98                 }
  99
 100                 protected async virtual Task<Stream> CreateContentReadStreamAsync ()
 101                 {
 102                         await LoadIntoBufferAsync ().ConfigureAwait (false);
 103                         return buffer;
 104                 }
 105
 106                 static FixedMemoryStream CreateFixedMemoryStream (long maxBufferSize)
 107                 {
 108                         return new FixedMemoryStream (maxBufferSize);
 109                 }
 110
 111                 public void Dispose ()
 112                 {
 113                         Dispose (true);
 114                 }
 115
 116                 protected virtual void Dispose (bool disposing)
 117                 {
 118                         if (disposing && !disposed) {
 119                                 disposed = true;
 120
 121                                 if (buffer != null)
 122                                         buffer.Dispose ();
 123                         }
 124                 }
 125
 126                 public Task LoadIntoBufferAsync ()
 127                 {
 128                         return LoadIntoBufferAsync (int.MaxValue);
 129                 }
 130
 131                 public async Task LoadIntoBufferAsync (long maxBufferSize)
 132                 {
 133                         if (disposed)
 134                                 throw new ObjectDisposedException (GetType ().ToString ());
 135
 136                         if (buffer != null)
 137                                 return;
 138
 139                         buffer = CreateFixedMemoryStream (maxBufferSize);
 140                         await SerializeToStreamAsync (buffer, null).ConfigureAwait (false);
 141                         buffer.Seek (0, SeekOrigin.Begin);
 142                 }
 143
 144                 public async Task<Stream> ReadAsStreamAsync ()
 145                 {
 146                         if (disposed)
 147                                 throw new ObjectDisposedException (GetType ().ToString ());
 148
 149                         if (buffer != null)
 150                                 return new MemoryStream (buffer.GetBuffer (), 0, (int)buffer.Length, false);
 151
 152                         if (stream == null)
 153                                 stream = await CreateContentReadStreamAsync ().ConfigureAwait (false);
 154
 155                         return stream;
 156                 }
 157
 158                 public async Task<byte[]> ReadAsByteArrayAsync ()
 159                 {
 160                         await LoadIntoBufferAsync ().ConfigureAwait (false);
 161                         return buffer.ToArray ();
 162                 }
 163
 164                 public async Task<string> ReadAsStringAsync ()
 165                 {
 166                         await LoadIntoBufferAsync ().ConfigureAwait (false);
 167                         if (buffer.Length == 0)
 168                                 return string.Empty;
 169
 170                         var buf = buffer.GetBuffer ();
 171                         var buf_length = (int) buffer.Length;
 172                         int preambleLength = 0;
 173                         Encoding encoding;
 174
 175                         if (headers != null && headers.ContentType != null && headers.ContentType.CharSet != null) {
 176                                 encoding = Encoding.GetEncoding (headers.ContentType.CharSet);
 177                                 preambleLength = StartsWith (buf, buf_length, encoding.GetPreamble ());
 178                         } else {
 179                                 encoding = GetEncodingFromBuffer (buf, buf_length, ref preambleLength) ?? Encoding.UTF8;
 180                         }
 181
 182                         return encoding.GetString (buf, preambleLength, buf_length - preambleLength);
 183                 }
 184
 185                 static Encoding GetEncodingFromBuffer (byte[] buffer, int length, ref int preambleLength)
 186                 {
 187                         var encodings_with_preamble = new [] { Encoding.UTF8, Encoding.UTF32, Encoding.Unicode };
 188                         foreach (var enc in encodings_with_preamble) {
 189                                 if ((preambleLength = StartsWith (buffer, length, enc.GetPreamble ())) != 0)
 190                                         return enc;
 191                         }
 192
 193                         return null;
 194                 }
 195
 196                 static int StartsWith (byte[] array, int length, byte[] value)
 197                 {
 198                         if (length < value.Length)
 199                                 return 0;
 200
 201                         for (int i = 0; i < value.Length; ++i) {
 202                                 if (array [i] != value [i])
 203                                         return 0;
 204                         }
 205
 206                         return value.Length;
 207                 }
 208
 209                 protected internal abstract Task SerializeToStreamAsync (Stream stream, TransportContext context);
 210                 protected internal abstract bool TryComputeLength (out long length);
 211         }
 212 }