| | | 1 | | // Copyright (c) ZeroC, Inc. |
| | | 2 | | |
| | | 3 | | using IceRpc.Extensions.DependencyInjection; |
| | | 4 | | using IceRpc.Features; |
| | | 5 | | using System.Buffers; |
| | | 6 | | using System.Diagnostics; |
| | | 7 | | using System.IO.Compression; |
| | | 8 | | using System.IO.Pipelines; |
| | | 9 | | using ZeroC.Slice; |
| | | 10 | | |
| | | 11 | | namespace IceRpc.Compressor; |
| | | 12 | | |
| | | 13 | | /// <summary>Represents a middleware that decompresses the payloads of incoming requests and compresses the payloads of |
| | | 14 | | /// outgoing responses.</summary> |
| | | 15 | | /// <remarks>This middleware decompresses the payload of an incoming request when the request carries a |
| | | 16 | | /// <see cref="RequestFieldKey.CompressionFormat" /> field with a supported compression format (currently |
| | | 17 | | /// <see cref="CompressionFormat.Brotli" /> or <see cref="CompressionFormat.Deflate" />).<br/> |
| | | 18 | | /// This middleware compresses the payload of a response and sets the <see cref="ResponseFieldKey.CompressionFormat" /> |
| | | 19 | | /// field when the request has the <see cref="ICompressFeature" /> feature set and the response's CompressionFormat |
| | | 20 | | /// field is unset.</remarks> |
| | | 21 | | /// <seealso cref="CompressorRouterExtensions"/> |
| | | 22 | | /// <seealso cref="CompressorDispatcherBuilderExtensions"/> |
| | | 23 | | public class CompressorMiddleware : IDispatcher |
| | | 24 | | { |
| | | 25 | | private readonly CompressionFormat _compressionFormat; |
| | | 26 | | private readonly CompressionLevel _compressionLevel; |
| | | 27 | | private readonly ReadOnlySequence<byte> _encodedCompressionFormatValue; |
| | | 28 | | private readonly IDispatcher _next; |
| | | 29 | | |
| | | 30 | | /// <summary>Constructs a Compressor middleware.</summary> |
| | | 31 | | /// <param name="next">The next dispatcher in the dispatch pipeline.</param> |
| | | 32 | | /// <param name="compressionFormat">The compression format for the compress operation.</param> |
| | | 33 | | /// <param name="compressionLevel">The compression level for the compress operation.</param> |
| | 9 | 34 | | public CompressorMiddleware( |
| | 9 | 35 | | IDispatcher next, |
| | 9 | 36 | | CompressionFormat compressionFormat, |
| | 9 | 37 | | CompressionLevel compressionLevel = CompressionLevel.Fastest) |
| | 9 | 38 | | { |
| | 9 | 39 | | _next = next; |
| | 9 | 40 | | if (compressionFormat != CompressionFormat.Brotli && compressionFormat != CompressionFormat.Deflate) |
| | 0 | 41 | | { |
| | 0 | 42 | | throw new NotSupportedException($"The compression format '{compressionFormat}' is not supported."); |
| | | 43 | | } |
| | 9 | 44 | | _compressionFormat = compressionFormat; |
| | 9 | 45 | | _compressionLevel = compressionLevel; |
| | 9 | 46 | | _encodedCompressionFormatValue = new(new byte[] { (byte)compressionFormat }); |
| | 9 | 47 | | } |
| | | 48 | | |
| | | 49 | | /// <inheritdoc/> |
| | | 50 | | public async ValueTask<OutgoingResponse> DispatchAsync( |
| | | 51 | | IncomingRequest request, |
| | | 52 | | CancellationToken cancellationToken = default) |
| | 9 | 53 | | { |
| | 9 | 54 | | if (request.Protocol.HasFields && request.Fields.ContainsKey(RequestFieldKey.CompressionFormat)) |
| | 5 | 55 | | { |
| | 5 | 56 | | CompressionFormat compressionFormat = request.Fields.DecodeValue( |
| | 5 | 57 | | RequestFieldKey.CompressionFormat, |
| | 10 | 58 | | (ref SliceDecoder decoder) => decoder.DecodeCompressionFormat()); |
| | | 59 | | |
| | 5 | 60 | | if (compressionFormat == CompressionFormat.Brotli) |
| | 2 | 61 | | { |
| | 2 | 62 | | request.Payload = PipeReader.Create( |
| | 2 | 63 | | new BrotliStream(request.Payload.AsStream(), CompressionMode.Decompress)); |
| | 2 | 64 | | } |
| | 3 | 65 | | else if (compressionFormat == CompressionFormat.Deflate) |
| | 2 | 66 | | { |
| | 2 | 67 | | request.Payload = PipeReader.Create( |
| | 2 | 68 | | new DeflateStream(request.Payload.AsStream(), CompressionMode.Decompress)); |
| | 2 | 69 | | } |
| | | 70 | | // else nothing to do |
| | 5 | 71 | | } |
| | | 72 | | |
| | 9 | 73 | | OutgoingResponse response = await _next.DispatchAsync(request, cancellationToken).ConfigureAwait(false); |
| | | 74 | | |
| | | 75 | | // The ICompressFeature is typically set through the Slice compress attribute. |
| | | 76 | | |
| | 9 | 77 | | if (request.Protocol.HasFields && |
| | 9 | 78 | | response.StatusCode == StatusCode.Ok && |
| | 9 | 79 | | request.Features.Get<ICompressFeature>() is ICompressFeature compress && |
| | 9 | 80 | | compress.Value && |
| | 9 | 81 | | !response.Fields.ContainsKey(ResponseFieldKey.CompressionFormat)) |
| | 4 | 82 | | { |
| | 4 | 83 | | if (_compressionFormat == CompressionFormat.Brotli) |
| | 2 | 84 | | { |
| | 4 | 85 | | response.Use(next => PipeWriter.Create(new BrotliStream(next.AsStream(), _compressionLevel))); |
| | 2 | 86 | | } |
| | | 87 | | else |
| | 2 | 88 | | { |
| | 2 | 89 | | Debug.Assert(_compressionFormat == CompressionFormat.Deflate); |
| | 4 | 90 | | response.Use(next => PipeWriter.Create(new DeflateStream(next.AsStream(), _compressionLevel))); |
| | 2 | 91 | | } |
| | | 92 | | |
| | 4 | 93 | | response.Fields = response.Fields.With(ResponseFieldKey.CompressionFormat, _encodedCompressionFormatValue); |
| | 4 | 94 | | } |
| | | 95 | | |
| | 9 | 96 | | return response; |
| | 9 | 97 | | } |
| | | 98 | | } |