asp.net core middleware interception request and return the data, and the data encryption and decryption.

Original: ASP.NET Core middleware interception request and return the data, and the data encryption and decryption.

GitHub demo https://github.com/zhanglilong23/Asp.NetCore.Demo

This project uses middleware to intercept data request, and the request for data decryption. After a successful interception return data access interface, and then returns the data encrypted returned.

Wherein log4net omitted portion (demo described there)

Post process the data carried in the AES decryption Body

AES encryption data is returned

1: Custom middleware, and the default implementation of the Invoke method incidental use error logging and access time, write more rough.

public class HttpContextMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger _logger;

        /// <summary>
        /// 计时器
        /// </summary>
        private Stopwatch _stopwatch;
        //加密解密key
        private readonly string securitykey = "0123456789abcdef";

        /// <summary>
        /// 构造 Http 请求中间件
        /// </summary>
        /// <param name="next"></param>
        /// <param name="loggerFactory"></param>
        /// <param name="cacheService"></param>
        public HttpContextMiddleware(RequestDelegate next, ILoggerFactory loggerFactory)
        {
            _next = next;
            _logger = loggerFactory.CreateLogger<HttpContextMiddleware>();
        }

        /// <summary>
        /// 1：将Post方法中Body中的数据进行AES解密
        /// 2：将返回数据进行AES加密
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public async Task Invoke(HttpContext context)
        {
            context.Request.EnableBuffering();
            _stopwatch = new Stopwatch();
            _stopwatch.Start();
            _logger.LogInformation($"Handling request: " + context.Request.Path);
            var api = new ApiRequestInputViewModel
            {
                HttpType = context.Request.Method,
                Query = context.Request.QueryString.Value,
                RequestUrl = context.Request.Path,
                RequestName = "",
                RequestIP = context.Request.Host.Value
            };

            var request = context.Request.Body;
            var response = context.Response.Body;

            try
            {
                using (var newRequest = new MemoryStream())
                {
                    //替换request流
                    context.Request.Body = newRequest;

                    using (var newResponse = new MemoryStream())
                    {
                        //替换response流
                        context.Response.Body = newResponse;

                        using (var reader = new StreamReader(request))
                        {
                            //读取原始请求流的内容
                            api.Body = await reader.ReadToEndAsync();
                            if (string.IsNullOrEmpty(api.Body))
                                await _next.Invoke(context);
                            //示例加密字符串，使用 AES-ECB-PKCS7 方式加密，密钥为：0123456789abcdef
                            // 加密参数：{"value":"哈哈哈"}
                            // 加密后数据： oedwSKGyfLX8ADtx2Z8k1Q7+pIoAkdqllaOngP4TvQ4=
                            api.Body = SecurityHelper.AESDecrypt(api.Body, securitykey);
                        }
                        using (var writer = new StreamWriter(newRequest))
                        {
                            await writer.WriteAsync(api.Body);
                            await writer.FlushAsync();
                            newRequest.Position = 0;
                            context.Request.Body = newRequest;
                            await _next(context);
                        }

                        using (var reader = new StreamReader(newResponse))
                        {
                            newResponse.Position = 0;
                            api.ResponseBody = await reader.ReadToEndAsync();
                            if (!string.IsNullOrWhiteSpace(api.ResponseBody))
                            {
                                api.ResponseBody = SecurityHelper.AESEncrypt(api.ResponseBody, securitykey);
                            }
                        }
                        using (var writer = new StreamWriter(response))
                        {
                            await writer.WriteAsync(api.ResponseBody);
                            await writer.FlushAsync();
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.LogError($" http中间件发生错误: " + ex.ToString());
            }
            finally
            {
                context.Request.Body = request;
                context.Response.Body = response;
            }

            // 响应完成时存入缓存
            context.Response.OnCompleted(() =>
            {
                _stopwatch.Stop();
                api.ElapsedTime = _stopwatch.ElapsedMilliseconds;

                _logger.LogDebug($"RequestLog:{DateTime.Now.ToString("yyyyMMddHHmmssfff") + (new Random()).Next(0, 10000)}-{api.ElapsedTime}ms", $"{JsonConvert.SerializeObject(api)}");
                return Task.CompletedTask;
            });

            _logger.LogInformation($"Finished handling request.{_stopwatch.ElapsedMilliseconds}ms");
        }
    }

2: Implementing middleware extensions

  public static class MiddlewareExtensions
    {
        public static IApplicationBuilder UseHttpContextMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<HttpContextMiddleware>();
        }
    }

3: Using middleware Startup

public void Configure(IApplicationBuilder app, IHostingEnvironment env,ILoggerFactory loggerFactory)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }
            app.UseHttpContextMiddleware(); //引入自定义的HtppContextMiddleware中间件
            loggerFactory.AddLog4Net(); //引入log4net
            app.UseHttpsRedirection();
            app.UseMvc();
        }