Question

我正在开发一个WebAPI并且一直在接收我的POST数据：

[HttpPost]
        public Int16 Foo()
        {
            var input = new StreamReader(HttpContext.Current.Request.InputStream).ReadToEnd();
            Model_Deserialized model = JsonConvert.DeserializeObject<Model_Deserialized>(input);
            ...
        }

最近我觉得需要记录发送的所有请求。我正在尝试使用http://weblogs.asp.net/fredriknormen/log-message-request-and-response-in-asp-net-webapi中建议的方法，但在执行这些步骤之后，我的输入变量开始是一个空字符串。

这就是我的消息处理程序的样子

public abstract class MessageHandler : DelegatingHandler
    {
        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            var corrId = string.Format("{0}{1}", DateTime.Now.Ticks, Thread.CurrentThread.ManagedThreadId);
            var requestInfo = string.Format("{0} {1}", request.Method, request.RequestUri);

            var requestMessage = await request.Content.ReadAsByteArrayAsync();

            String ip;

            if (request.Properties.ContainsKey("MS_HttpContext"))
            {
                var ctx = request.Properties["MS_HttpContext"] as HttpContextWrapper;
                if (ctx != null)
                {
                    ip = ctx.Request.UserHostAddress;
                }
            }

            else
            {
                 ip = "error";
            }

            await IncommingMessageAsync(corrId, requestInfo, requestMessage, ip);

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

            return response;
        }


        protected abstract Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message, String ip);
    }

这是我的MessageLoggingHandler

public class MessageLoggingHandler : MessageHandler
    {
        protected override async Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message, String ip)
        {
            await Task.Run(() =>
                WriteToFile(ip + "{" + correlationId + "} - Request: {" + requestInfo + "}\r\n{" + Encoding.UTF8.GetString(message) + "}"));
        }


        private void WriteToFile(string text)
        {
            string path = "C:\\Logs\\ServiceLog" + DateTime.Now.Year + "-" + DateTime.Now.Month + "-" + DateTime.Now.Day + ".txt";
            using (StreamWriter writer = new StreamWriter(path, true))
            {
                writer.WriteLine(DateTime.Now.ToString("dd/MM/yyyy hh:mm:ss tt") + "--" + text);
                writer.Close();
            }
        }
    }

我还将此添加到我的Global.asax

GlobalConfiguration.Configuration.MessageHandlers.Add(new MessageLoggingHandler());

在我的web.config中，我已经尝试添加

<add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
<compilation debug="true" targetFramework="4.5">

是否仍然坚持使用此方法而不是创建日志记录例程并从每个函数调用它？

Answer 1

要清楚HttpContext不能为空 - 它是静态的。那么HttpContext.Current是否为空？或者我的猜测是HttpContext.Current.Request.InputStream为空。 Web api自动读取流并将其处理，并将帖子正文反序列化为您的操作输入。因此，您应该将Web Api操作编码为以下内容：

[HttpPost]
public Int16 Foo(Model_Deserialized model)
{

    ...
}

添加MessageHandler后，HttpContext为null

1 个答案: