/// <summary>
/// Reads the next <see cref="MultipartSection"/>.
/// </summary>
/// <param name="cancellationToken">The token to monitor for cancellation requests.
/// The default value is <see cref="CancellationToken.None"/>.</param>
/// <returns></returns>
public async Task <MultipartSection?> ReadNextSectionAsync(CancellationToken cancellationToken = new CancellationToken())
{
// Drain the prior section.
await _currentStream.DrainAsync(cancellationToken);
// If we're at the end return null
if (_currentStream.FinalBoundaryFound)
{
// There may be trailer data after the last boundary.
await _stream.DrainAsync(HeadersLengthLimit, cancellationToken);
return(null);
}
var headers = await ReadHeadersAsync(cancellationToken);
_boundary.ExpectLeadingCrlf = true;
_currentStream = new MultipartReaderStream(_stream, _boundary)
{
LengthLimit = BodyLengthLimit
};
long?baseStreamOffset = _stream.CanSeek ? (long?)_stream.Position : null;
return(new MultipartSection()
{
Headers = headers, Body = _currentStream, BaseStreamOffset = baseStreamOffset
});
}
/// <summary>
/// Initializes a new instance of <see cref="MultipartReader"/>.
/// </summary>
/// <param name="boundary">The multipart boundary.</param>
/// <param name="stream">The <see cref="Stream"/> containing multipart data.</param>
/// <param name="bufferSize">The minimum buffer size to use.</param>
public MultipartReader(string boundary, Stream stream, int bufferSize)
{
if (boundary == null)
{
throw new ArgumentNullException(nameof(boundary));
}
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (bufferSize < boundary.Length + 8) // Size of the boundary + leading and trailing CRLF + leading and trailing '--' markers.
{
throw new ArgumentOutOfRangeException(nameof(bufferSize), bufferSize, "Insufficient buffer space, the buffer must be larger than the boundary: " + boundary);
}
_stream = new BufferedReadStream(stream, bufferSize);
_boundary = new MultipartBoundary(boundary, false);
// This stream will drain any preamble data and remove the first boundary marker.
// TODO: HeadersLengthLimit can't be modified until after the constructor.
_currentStream = new MultipartReaderStream(_stream, _boundary)
{
LengthLimit = HeadersLengthLimit
};
}
