C#: Enable unobtrusive HttpClient request-response logging

HttpLoggingHandler.cs

//Original share here https://github.com/reactiveui/refit/issues/258#issuecomment-243394076 on Aug 30, 2016
//var httpClient = new HttpClient(new HttpLoggingHandler()){ BaseAddress = /**/};

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;

namespace Service.Shared.Clients;

public class HttpLoggingHandler : DelegatingHandler
{
    public HttpLoggingHandler(HttpMessageHandler innerHandler)
        : base(innerHandler)
    { }

    async protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        await Task.Delay(1, cancellationToken).ConfigureAwait(false);

        var req = request;
        var id = Guid.NewGuid().ToString();
        var msg = $"[{id} -   Request]";
        var uri = req.RequestUri ?? throw new ArgumentNullException(nameof(request), "RequestUri can´t be null");
        var scheme = req.RequestUri.Scheme.ToUpperInvariant();

        WriteLine($"{msg}========Start==========");
        WriteLine($"{msg} {req.Method} {uri.PathAndQuery} {scheme}/{req.Version}");
        WriteLine($"{msg} Host: {uri.Scheme}://{uri.Host}");

        foreach (var header in req.Headers)
            WriteLine($"{msg} {header.Key}: {string.Join(", ", header.Value)}");

        if (req.Content != null)
        {
            foreach (var header in req.Content.Headers)
                WriteLine($"{msg} {header.Key}: {string.Join(", ", header.Value)}");

            if (req.Content is StringContent || IsTextBasedContentType(req.Headers) || IsTextBasedContentType(req.Content.Headers))
            {
                var result = await req.Content.ReadAsStringAsync(cancellationToken);

                WriteLine($"{msg} Content:");
                WriteLine($"{msg} {string.Join("", result.Cast<char>().Take(255))}...");
            }
        }

        var start = DateTime.Now;

        var response = await base.SendAsync(request, cancellationToken).ConfigureAwait(false);

        var end = DateTime.Now;

        WriteLine($"{msg} Duration: {end - start}");
        WriteLine($"{msg}==========End==========");

        msg = $"[{id} - Response]";
        WriteLine($"{msg}=========Start=========");

        var resp = response;

        WriteLine($"{msg} {scheme}/{resp.Version} {(int)resp.StatusCode} {resp.ReasonPhrase}");

        foreach (var header in resp.Headers)
            WriteLine($"{msg} {header.Key}: {string.Join(", ", header.Value)}");

        if (resp.Content != null)
        {
            foreach (var header in resp.Content.Headers)
                WriteLine($"{msg} {header.Key}: {string.Join(", ", header.Value)}");

            if (resp.Content is StringContent || IsTextBasedContentType(resp.Headers) || IsTextBasedContentType(resp.Content.Headers))
            {
                start = DateTime.Now;
                var result = await resp.Content.ReadAsStringAsync(cancellationToken);
                end = DateTime.Now;

                WriteLine($"{msg} Content:");
                WriteLine($"{msg} {string.Join("", result.Cast<char>().Take(255))}...");
                WriteLine($"{msg} Duration: {end - start}");
            }
        }

        WriteLine($"{msg}==========End==========");
        return response;
    }

    private static readonly string[] types = new[] { "html", "text", "xml", "json", "txt" };
    
    private static void WriteLine(FormattableString message) =>
        Debug.WriteLine(message);
        
    private static bool IsTextBasedContentType(HttpHeaders headers)
    {
        if (!headers.TryGetValues("Content-Type", out var values))
            return false;
        var header = string.Join(" ", values).ToLowerInvariant();

        return types.Any(t => header.Contains(t));
    }
}

output.txt

[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request]=========Start=========
[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request]========Start==========
[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request] GET / HTTPS/1.1
[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request] Host: https://www.google.com
[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request] Duration: 00:00:00.2298277
[83544d2e-6f8b-4e6c-9827-a5e58557f99c -  Request]==========End==========
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response]=========Start=========
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] HTTPS/1.1 200 OK
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] X-XSS-Protection: 1; mode=block
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] X-Frame-Options: SAMEORIGIN
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Alternate-Protocol: 443:quic
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Alt-Svc: quic=":443"; ma=2592000; v="35,34,33,32,31,30"
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Vary: Accept-Encoding
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Transfer-Encoding: chunked
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Accept-Ranges: none
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Cache-Control: max-age=0, private
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Date: Tue, 30 Aug 2016 10:02:32 GMT
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] P3P: CP="This is not a P3P policy! See https://www.google.com/support/accounts/answer/151657?hl=en for more info."
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Set-Cookie: NID=85=SAxtO23sG2Xuap7whetoj9Hn353S-wRFCEifyNFeFBIRWkd5fL4h2ws3rgyvk_dfIPbX_5SYqELFHWj4nXO62FxWpC3eeurykZEZQtI-EO9KsQDWpju9SaQ3XY9xwUa7; expires=Wed, 01-Mar-2017 10:02:32 GMT; path=/; domain=.google.com.br; HttpOnly
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Server: gws
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Content-Type: text/html; charset=ISO-8859-1
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Expires: -1
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Content:
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] <!doctype html><html itemscope="" itemtype="http://schema.org/WebPage" lang="pt"><head><meta content="text/html; charset=UTF-8" http-equiv="Content-Type"><meta content="/images/branding/googleg/1x/googleg_standard_color_128dp.png" itemprop="image"><title>...
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response] Duration: 00:00:00.0503445
[83544d2e-6f8b-4e6c-9827-a5e58557f99c - Response]==========End==========