Masuit.MyBlogs/src/Masuit.MyBlogs.Core/Extensions/TranslateMiddleware.cs

using Masuit.MyBlogs.Core.Common;
using Masuit.Tools;
using Masuit.Tools.AspNetCore.Mime;
using Microsoft.AspNetCore.Http;
using Microsoft.International.Converters.TraditionalChineseToSimplifiedConverter;
using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace Masuit.MyBlogs.Core.Extensions
{
    /// <summary>
    /// 简繁转换拦截器
    /// </summary>
    public class TranslateMiddleware
    {
        private readonly RequestDelegate _next;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="next"></param>
        public TranslateMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public Task Invoke(HttpContext context)
        {
            var path = context.Request.Path.Value ?? "";
            if (path.StartsWith("/_blazor") || path.StartsWith("/api") || path.StartsWith("/file") || path.StartsWith("/download") || context.Request.IsRobot())
            {
                return _next(context);
            }

            string lang = context.Request.Query["lang"];
            lang ??= context.Request.Cookies["lang"];
            if (string.IsNullOrEmpty(lang))
            {
                if (context.Request.Location().Location.Contains(new[] { "台湾", "香港", "澳门", "Taiwan", "TW", "HongKong", "HK" }))
                {
                    return Traditional(context);
                }

                return _next(context);
            }
            if (lang == "zh-cn")
            {
                return _next(context);
            }

            return Traditional(context);
        }

        private async Task Traditional(HttpContext context)
        {
            var accept = context.Request.Headers["Accept"][0];
            if (accept.StartsWith("text") || accept.Contains(ContentType.Json))
            {
                //设置stream存放ResponseBody
                var responseOriginalBody = context.Response.Body;
                var memStream = new MemoryStream();
                context.Response.Body = memStream;

                // 执行其他中间件
                await _next(context);

                //处理执行其他中间件后的ResponseBody
                memStream.Position = 0;
                var responseReader = new StreamReader(memStream, Encoding.UTF8);
                var responseBody = await responseReader.ReadToEndAsync();
                memStream = new MemoryStream(Encoding.UTF8.GetBytes(ChineseConverter.Convert(responseBody, ChineseConversionDirection.SimplifiedToTraditional)));
                await memStream.CopyToAsync(responseOriginalBody);
                context.Response.Body = responseOriginalBody;
            }
            else
            {
                await _next(context);
            }
        }
    }
}