DynamicResponseBuilder.cs

// Licensed to Elasticsearch B.V under one or more agreements.
// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information

using System;
#if NET8_0_OR_GREATER
using System.Buffers;
#endif
using System.IO;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Elastic.Transport;

internal class DynamicResponseBuilder<T> : TypedResponseBuilder<T> where T : DynamicResponseBase, new()
{
	protected override T Build(ApiCallDetails apiCallDetails, BoundConfiguration boundConfiguration, Stream responseStream, string contentType, long contentLength) =>
		BuildCoreAsync(false, apiCallDetails, boundConfiguration, responseStream, contentType, contentLength).EnsureCompleted();

	protected override Task<T> BuildAsync(ApiCallDetails apiCallDetails, BoundConfiguration boundConfiguration, Stream responseStream, string contentType, long contentLength, CancellationToken cancellationToken = default) =>
		BuildCoreAsync(true, apiCallDetails, boundConfiguration, responseStream, contentType, contentLength, cancellationToken).AsTask();

	private static async ValueTask<T> BuildCoreAsync(bool isAsync, ApiCallDetails apiCallDetails, BoundConfiguration boundConfiguration, Stream responseStream,
		string contentType, long contentLength, CancellationToken cancellationToken = default)
	{
		//if not json store the result under "body"
		if (!boundConfiguration.ConnectionSettings.ProductRegistration.IsJsonContentType(contentType))
		{
			DynamicDictionary dictionary;
			string stringValue;

			if (apiCallDetails.ResponseBodyInBytes is not null)
			{
				stringValue = Encoding.UTF8.GetString(apiCallDetails.ResponseBodyInBytes);

				dictionary = new DynamicDictionary
				{
					["body"] = new DynamicValue(stringValue)
				};

				return new T { Body = dictionary };
			}

#if NET8_0_OR_GREATER
			if (contentLength is > (-1) and <= 1_048_576)
			{
				var buffer = ArrayPool<byte>.Shared.Rent((int)contentLength);
				responseStream.ReadExactly(buffer, 0, (int)contentLength);
				stringValue = Encoding.UTF8.GetString(buffer.AsSpan(0, (int)contentLength));
				ArrayPool<byte>.Shared.Return(buffer);

				dictionary = new DynamicDictionary
				{
					["body"] = new DynamicValue(stringValue)
				};

				return new T { Body = dictionary };
			}
#endif

			var sr = new StreamReader(responseStream);

			if (isAsync)
			{
				stringValue = await sr.ReadToEndAsync
			(
#if NET8_0_OR_GREATER
				cancellationToken
#endif
			).ConfigureAwait(false);
			}
			else
			{
				stringValue = sr.ReadToEnd();
			}

			dictionary = new DynamicDictionary
			{
				["body"] = new DynamicValue(stringValue)
			};

			return new T { Body = dictionary };
		}

		var body = LowLevelRequestResponseSerializer.Instance.Deserialize<DynamicDictionary>(responseStream);
		return new T { Body = body };
	}
}

internal class DynamicResponseBuilder : DynamicResponseBuilder<DynamicResponse>;