Question

只需要处理一个漂亮而简单的HttpListener，突然出现这个异常突然出现。

An operation was attempted on a nonexistent network connection.

找一个解决方案的时间，找不到一个。一旦我将数据从网页提交到HttpListener，代码就会崩溃。有人可以向我解释我如何解决这个问题吗？

守则如下：

C＃

public static void StartListening()
    {

        Stream ouputStream;


        HttpListener listener = new HttpListener();
        SetPrefixes(listener);

        if (listener.Prefixes.Count > 0)
        {
            listener.Start();

            Console.WriteLine("HttpClient Started");  

            while(true)
            {
                HttpListenerContext context = listener.GetContext();
                HttpListenerRequest request= context.Request;
                HttpListenerResponse response = context.Response;

                string html = Properties.Resources.index;
                byte[] webPageBuffer = Encoding.UTF8.GetBytes(html);

                response.ContentLength64 = webPageBuffer.Length;
                ouputStream = response.OutputStream;
                ouputStream.Write(webPageBuffer, 0, webPageBuffer.Length);

                ouputStream.Flush();

                Common.Wait(2000);  

                String url = request.RawUrl;
                String[] queryStringArray = url.Split('/');
                String postedtext = GetPostedText(request);                   

                byte[] buffer = null;

                // Lots of if statements because a switch would not work here.
                if(queryStringArray[0] == "myForm")
                {
                    buffer = System.Text.Encoding.UTF8.GetBytes("I recieved myForm");
                }
                if(queryStringArray[1] == "doSomething")
                {
                    buffer = System.Text.Encoding.UTF8.GetBytes("I recieved doSomething");
                }
                if(buffer != null)
                {
                    response.AddHeader("Cache-Control", "no-cache");
                    response.AddHeader("Acces-Control-Allow-Origin","*");

                    response.ContentLength64 = buffer.Length;
                    ouputStream = response.OutputStream;
                    ouputStream.Write(buffer, 0, buffer.Length);
                    ouputStream.Close();
                }
            }
        }
    }

    private static void SetContext(HttpListenerContext context, Stream ouputStream)
    {
        // De GetContext methode blokkeert terwijl die wacht op een aanvraag(request)


    }

    private static void SetPrefixes(HttpListener listener)
    {
        String[] prefixes = new String[] { "http://localhost:8100/", "http://192.168.33.28:8000/" };

        int i = 0;

        foreach (string s in prefixes)
        {
            listener.Prefixes.Add(s);
            i++;
        }
    }


    private static string GetPostedText(HttpListenerRequest request)
    {
        string recievedText;

        using(StreamReader reader = new StreamReader(request.InputStream, request.ContentEncoding))
        {
            recievedText= reader.ReadToEnd();
        }

        if (recievedText != "")
        {
            Console.WriteLine("{0} RECIEVED: " + recievedText, DateTime.Now);
        }

        return recievedText;
    }

HTML

<html>
    <head> 
        <title>http</title>
        <meta charset="utf-8">
        <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
        <style>

            body{
        font-size: 12px;
        font-family: Arial;
        }

        legend{
            font-weight: bold;
            font-size: 14px !important;
        }


        fieldset{
            width:200px;
            margin: 0;
            position: absolute;
            top: 50%;
            left: 50%;
            margin-right: -50%;
            transform: translate(-50%, -50%) }

        .wrapper{
            width: 100%;
        }

        </style>


        <script language="javascript">

        //<!-- Create variable timer -->
            var timer;


        //<!-- Create Fucntion CheckOne -->
        /* 
            Wannneer de functie aangroepen word, word eerst de timeout van de variable timer geleegd.
            Daarna word er een timeout ingesteld van 2000 (2sec). Die timeout wordt ingeschakeld nadat het textveld niet meer actief beschouwd word(niet meer gebruikt word, de focus blijft wel op het veld.).
            Na die 2 seconden krijgt de volgende textbox de focus met de zelfde manier maar onder een andere functie.
            Zodra hier ook de 2 seconden om zijn verspringt de focus weer maar nu naar een sumbit (verzenden) knop. Dit is gedaan omdat je dan makkelijk op een OK knop kan drukken op het apparaat.
        */

            function CheckOne() {
                 clearTimeout(timer)
                 timer = setTimeout(function(){
                     document.getElementById("two").focus();
                     //clearTimeout(timer);
                 }, 750)
            }

            function CheckTwo(){
                clearTimeout(timer);
                timer = setTimeout(function(){
                     document.getElementById("sub").focus();
                 }, 750)
            }


        </script> 




    </head> 

    <body> 

    <div class="wrapper"> 
        <fieldset> 
            <legend>HttpListener </legend><br/> 
            <form id="searchForm" action="http://localhost:8100/myForm/doSomething" >
                Locatienummer: <br />
                <input type="text" id="one" onkeyup="CheckOne()" name="locatienummer"><br />
                Bonnummer: <br />
                <input type="text" id="two" onkeyup="CheckTwo()" name="bonnummer"><br /><br />
                <input id="sub" type="submit" value="Verzenden" />
            </form> 
        </fieldset> 
    </div> 
    <!-- Include the needed files--> 

        <script>
    $("#searchForm").submit(function (event)
    {
        // Stop form from submitting normally
        event.preventDefault();

        // Get some values from elements on the page:
        var $form = $(this),

        locatieValue = $form.find("input[name='locatienummer']").val(),
        bonValue = $form.find("input[name='bonnummer']").val(),

        url = $form.attr("action");

        // Send the data using post
        $.post(url, { a: locatieValue, b: bonValue });

    });
        </script>

    </body> 
</html>

Answer 1

基本上，在完成请求流的处理之前，您正在写入响应流，因此会触发您的问题。如果您重新排序代码以处理请求，在开始尝试编写响应之前，它将起作用。您可能需要重新访问代码，但实质上将其更改为可以让您继续：

HttpListenerContext context = listener.GetContext();
HttpListenerRequest request= context.Request;
HttpListenerResponse response = context.Response;

// Process Request **First**
String url = request.RawUrl;
String[] queryStringArray = url.Split('/');
String postedtext = GetPostedText(request);                   

// Process Response **Second**
string html = Properties.Resources.index;
byte[] webPageBuffer = Encoding.UTF8.GetBytes(html);

response.ContentLength64 = webPageBuffer.Length;
ouputStream = response.OutputStream;
ouputStream.Write(webPageBuffer, 0, webPageBuffer.Length);

ouputStream.Flush();

/* etc */

Answer 2

我今天得到了同样的例外，我的理由是在我尝试写HttpResponseStream之前我停止了听众。诀窍是在获得监听器上下文后始终首先编写响应。

尝试对不存在的网络连接执行操作，错误代码为1229

2 个答案: