/// <summary>
/// Checks if a new compressor object is needed for the stream identified by <c>streamId</c>. This method will
/// modify the <c>content-encoding</c> header contained in <paramref name="headers"/>.
/// </summary>
/// <param name="ctx">the context.</param>
/// <param name="headers">Object representing headers which are to be written</param>
/// <param name="endOfStream">Indicates if the stream has ended</param>
/// <exception cref="Http2Exception">if any problems occur during initialization.</exception>
/// <returns>The channel used to compress data.</returns>
private EmbeddedChannel NewCompressor(IChannelHandlerContext ctx, IHttp2Headers headers, bool endOfStream)
{
if (endOfStream)
{
return(null);
}
if (!headers.TryGet(HttpHeaderNames.ContentEncoding, out var encoding))
{
encoding = HttpHeaderValues.Identity;
}
var compressor = NewContentCompressor(ctx, encoding);
if (compressor is object)
{
var targetContentEncoding = GetTargetContentEncoding(encoding);
if (HttpHeaderValues.Identity.ContentEqualsIgnoreCase(targetContentEncoding))
{
_ = headers.Remove(HttpHeaderNames.ContentEncoding);
}
else
{
_ = headers.Set(HttpHeaderNames.ContentEncoding, targetContentEncoding);
}
// The content length will be for the decompressed data. Since we will compress the data
// this content-length will not be correct. Instead of queuing messages or delaying sending
// header frames...just remove the content-length header
_ = headers.Remove(HttpHeaderNames.ContentLength);
}
return(compressor);
}
/// <summary>
/// Checks if a new decompressor object is needed for the stream identified by <paramref name="streamId"/>.
/// This method will modify the <c>content-encoding</c> header contained in <paramref name="headers"/>.
/// </summary>
/// <param name="ctx">The context</param>
/// <param name="streamId">The identifier for the headers inside <paramref name="headers"/></param>
/// <param name="headers">Object representing headers which have been read</param>
/// <param name="endOfStream">Indicates if the stream has ended</param>
/// <exception cref="Http2Exception">If the <c>content-encoding</c> is not supported</exception>
private void InitDecompressor(IChannelHandlerContext ctx, int streamId, IHttp2Headers headers, bool endOfStream)
{
var stream = _connection.Stream(streamId);
if (stream is null)
{
return;
}
Http2Decompressor decompressor = Decompressor(stream);
if (decompressor is null && !endOfStream)
{
// Determine the content encoding.
if (!headers.TryGet(HttpHeaderNames.ContentEncoding, out var contentEncoding))
{
contentEncoding = HttpHeaderValues.Identity;
}
EmbeddedChannel channel = NewContentDecompressor(ctx, contentEncoding);
if (channel is object)
{
decompressor = new Http2Decompressor(channel);
_ = stream.SetProperty(_propertyKey, decompressor);
// Decode the content and remove or replace the existing headers
// so that the message looks like a decoded message.
var targetContentEncoding = GetTargetContentEncoding(contentEncoding);
if (HttpHeaderValues.Identity.ContentEqualsIgnoreCase(targetContentEncoding))
{
_ = headers.Remove(HttpHeaderNames.ContentEncoding);
}
else
{
_ = headers.Set(HttpHeaderNames.ContentEncoding, targetContentEncoding);
}
}
}
if (decompressor is object)
{
// The content length will be for the compressed data. Since we will decompress the data
// this content-length will not be correct. Instead of queuing messages or delaying sending
// header frames...just remove the content-length header
_ = headers.Remove(HttpHeaderNames.ContentLength);
// The first time that we initialize a decompressor, decorate the local flow controller to
// properly convert consumed bytes.
if (!_flowControllerInitialized)
{
_flowControllerInitialized = true;
var localEndpoint = _connection.Local;
localEndpoint.FlowController = new ConsumedBytesConverter(this, localEndpoint.FlowController);
}
}
}