StopShopping/StopShopping.Api/Middlewares/DevelopmentCookieMiddleware.cs

using System.Text;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Primitives;
using Microsoft.Net.Http.Headers;
using StopShopping.Services.Extensions;

namespace StopShopping.Api.Middlewares;

public class DevelopmentCookieMiddleware
{
    public DevelopmentCookieMiddleware(
        RequestDelegate requestDelegate,
        IOptions<AppOptions> options)
    {
        _next = requestDelegate;
        _appOptions = options.Value;
    }

    private readonly RequestDelegate _next;
    private readonly AppOptions _appOptions;

    public async Task InvokeAsync(HttpContext httpContext)
    {
        int? port = null;
        var origin = httpContext.Request.Headers[HeaderNames.Origin];
        if (origin.Count > 0 && null != origin[0])
        {
            Uri uri = new(origin[0]!);
            port = uri.Port;
        }
        else
        {
            var referer = httpContext.Request.Headers[HeaderNames.Referer];
            if (referer.Count > 0 && null != referer[0])
            {
                Uri uri = new(referer[0]!);
                port = uri.Port;
            }
        }

        if (port.HasValue)
        {
            var modified = ModifyCookie(httpContext.Request.Headers[HeaderNames.Cookie], port.Value);
            httpContext.Request.Headers[HeaderNames.Cookie] = modified;
        }

        httpContext.Response.OnStarting(() =>
        {
            if (port.HasValue)
            {
                var cookieHeader = httpContext.Response.Headers[HeaderNames.SetCookie];
                ModifyResponseCookie(cookieHeader, httpContext, port.Value);
            }
            return Task.CompletedTask;
        });

        await _next(httpContext);
    }

    private void ModifyResponseCookie(StringValues cookieHeader, HttpContext httpContext, int port)
    {
        foreach (var cookieItem in cookieHeader)
        {
            if (cookieItem != null)
            {
                var cookies = cookieItem.Split(';');
                foreach (var item in cookies)
                {
                    if (null != item)
                    {
                        var pairs = item.Split('=');
                        if (2 == pairs.Length)
                        {
                            if (pairs[0].Trim() == _appOptions.CSRFCookieName)
                            {
                                var val = pairs[1];
                                httpContext.Response.Cookies.Delete(pairs[0]);
                                httpContext.Response.Cookies.Append($"{_appOptions.CSRFCookieName}_{port}", val);
                            }
                            else if (pairs[0].Trim() == HttpExtensions.REFRESH_TOKEN_COOKIE_KEY)
                            {
                                var val = pairs[1];
                                httpContext.Response.Cookies.Delete(pairs[0]);
                                httpContext.Response.Cookies.Append($"{HttpExtensions.REFRESH_TOKEN_COOKIE_KEY}_{port}", val);
                            }
                        }
                    }
                }
            }
        }
    }

    private StringValues ModifyCookie(StringValues cookie, int port)
    {
        List<string> result = [];
        var csrfCookieName = $"{_appOptions.CSRFCookieName}_{port}";
        var refreshTokenCookieName = $"{HttpExtensions.REFRESH_TOKEN_COOKIE_KEY}_{port}";
        foreach (var cookieItem in cookie)
        {
            if (null != cookieItem)
            {
                StringBuilder itemBuilder = new();
                var cookies = cookieItem.Split(';');
                foreach (var item in cookies)
                {
                    if (null != item)
                    {
                        var pairs = item.Split('=');
                        if (pairs.Length == 2)
                        {
                            if (0 != itemBuilder.Length)
                                itemBuilder.Append(';');
                            if (pairs[0].Trim() == csrfCookieName)
                            {
                                itemBuilder.Append(_appOptions.CSRFCookieName);
                                itemBuilder.Append('=');
                                itemBuilder.Append(pairs[1].Trim());
                            }
                            else if (pairs[0].Trim() == refreshTokenCookieName)
                            {
                                itemBuilder.Append(HttpExtensions.REFRESH_TOKEN_COOKIE_KEY);
                                itemBuilder.Append('=');
                                itemBuilder.Append(pairs[1].Trim());
                            }
                            else
                            {
                                itemBuilder.Append(item);
                            }
                        }
                        else
                        {
                            itemBuilder.Append(item);
                        }
                    }
                }

                result.Add(itemBuilder.ToString());
            }
        }
        return new StringValues(result.ToArray());
    }
}