WireMock.Net/src/WireMock.Net/Http/HttpResponseMessageHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using WireMock.Util;

namespace WireMock.Http;

internal static class HttpResponseMessageHelper
{
    public static async Task<ResponseMessage> CreateAsync(
        HttpResponseMessage httpResponseMessage,
        Uri requiredUri,
        Uri originalUri,
        bool deserializeJson,
        bool decompressGzipAndDeflate)
    {
        var responseMessage = new ResponseMessage { StatusCode = (int)httpResponseMessage.StatusCode };

        // Set both content and response headers, replacing URLs in values
        var headers = (httpResponseMessage.Content?.Headers.Union(httpResponseMessage.Headers) ?? Enumerable.Empty<KeyValuePair<string, IEnumerable<string>>>()).ToArray();
        if (httpResponseMessage.Content != null)
        {
            var stream = await httpResponseMessage.Content.ReadAsStreamAsync().ConfigureAwait(false);
            IEnumerable<string>? contentTypeHeader = null;
            if (headers.Any(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentType, StringComparison.OrdinalIgnoreCase)))
            {
                contentTypeHeader = headers.First(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentType, StringComparison.OrdinalIgnoreCase)).Value;
            }

            IEnumerable<string>? contentEncodingHeader = null;
            if (headers.Any(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentEncoding, StringComparison.OrdinalIgnoreCase)))
            {
                contentEncodingHeader = headers.First(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentEncoding, StringComparison.OrdinalIgnoreCase)).Value;
            }

            if (httpResponseMessage.StatusCode != HttpStatusCode.NoContent) // A body is not allowed for 204.
            {
                var bodyParserSettings = new BodyParserSettings
                {
                    Stream = stream,
                    ContentType = contentTypeHeader?.FirstOrDefault(),
                    DeserializeJson = deserializeJson,
                    ContentEncoding = contentEncodingHeader?.FirstOrDefault(),
                    DecompressGZipAndDeflate = decompressGzipAndDeflate
                };
                responseMessage.BodyData = await BodyParser.ParseAsync(bodyParserSettings).ConfigureAwait(false);
            }
        }

        foreach (var header in headers)
        {
            // If Location header contains absolute redirect URL, and base URL is one that we proxy to,
            // we need to replace it to original one.
            if (string.Equals(header.Key, HttpKnownHeaderNames.Location, StringComparison.OrdinalIgnoreCase)
                && Uri.TryCreate(header.Value.First(), UriKind.Absolute, out Uri absoluteLocationUri)
                && string.Equals(absoluteLocationUri.Host, requiredUri.Host, StringComparison.OrdinalIgnoreCase))
            {
                var replacedLocationUri = new Uri(originalUri, absoluteLocationUri.PathAndQuery);
                responseMessage.AddHeader(header.Key, replacedLocationUri.ToString());
            }
            else
            {
                responseMessage.AddHeader(header.Key, header.Value.ToArray());
            }
        }

        return responseMessage;
    }
}