private async Task <Dictionary <string, StringValues> > ReadHeadersAsync(CancellationToken cancellationToken)
{
int totalSize = 0;
var accumulator = new KeyValueAccumulator();
var line = await _stream.ReadLineAsync(HeadersLengthLimit - totalSize, cancellationToken).ConfigureAwait(false);
while (!string.IsNullOrEmpty(line))
{
if (HeadersLengthLimit - totalSize < line.Length)
{
throw new InvalidDataException($"Multipart headers length limit {HeadersLengthLimit} exceeded.");
}
totalSize += line.Length;
int splitIndex = line.IndexOf(':');
if (splitIndex <= 0)
{
throw new InvalidDataException($"Invalid header line: {line}");
}
var name = line.Substring(0, splitIndex);
var value = line.Substring(splitIndex + 1, line.Length - splitIndex - 1).Trim();
accumulator.Append(name, value);
if (accumulator.KeyCount > HeadersCountLimit)
{
throw new InvalidDataException($"Multipart headers count limit {HeadersCountLimit} exceeded.");
}
line = await _stream.ReadLineAsync(HeadersLengthLimit - totalSize, cancellationToken).ConfigureAwait(false);
}
return(accumulator.GetResults());
}
public override async Task <int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
if (_finished)
{
return(0);
}
PositionInnerStream();
if (!await _innerStream.EnsureBufferedAsync(_boundary.FinalBoundaryLength, cancellationToken).ConfigureAwait(false))
{
throw new IOException("Unexpected end of Stream, the content may have already been read by another component. ");
}
var bufferedData = _innerStream.BufferedData;
// scan for a boundary match, full or partial.
int matchOffset;
int matchCount;
int read;
if (SubMatch(bufferedData, _boundary.BoundaryBytes, out matchOffset, out matchCount))
{
// We found a possible match, return any data before it.
if (matchOffset > bufferedData.Offset)
{
// Sync, it's already buffered
read = _innerStream.Read(buffer, offset, Math.Min(count, matchOffset - bufferedData.Offset));
return(UpdatePosition(read));
}
var length = _boundary.BoundaryBytes.Length;
Debug.Assert(matchCount == length);
// "The boundary may be followed by zero or more characters of
// linear whitespace. It is then terminated by either another CRLF"
// or -- for the final boundary.
var boundary = _bytePool.Rent(length);
read = _innerStream.Read(boundary, 0, length);
_bytePool.Return(boundary);
Debug.Assert(read == length); // It should have all been buffered
var remainder = await _innerStream.ReadLineAsync(lengthLimit : 100, cancellationToken : cancellationToken).ConfigureAwait(false); // Whitespace may exceed the buffer.
remainder = remainder.Trim();
if (string.Equals("--", remainder, StringComparison.Ordinal))
{
FinalBoundaryFound = true;
}
Debug.Assert(FinalBoundaryFound || string.Equals(string.Empty, remainder, StringComparison.Ordinal), "Un-expected data found on the boundary line: " + remainder);
_finished = true;
return(0);
}
// No possible boundary match within the buffered data, return the data from the buffer.
read = _innerStream.Read(buffer, offset, Math.Min(count, bufferedData.Count));
return(UpdatePosition(read));
}