HTTPWebRequest&过了一会儿,400(错误请求)启动

Question

我有一个后台工作线程,它不断地将数据同步到远程服务器或从远程服务器同步数据.当我第一次运行应用程序时,一切似乎都正常.它每30秒发出一次Web请求,数据返回成功.

如果我让模拟器长时间运行,最终请求将因(400)错误请求而失败.所有后续请求都做同样的事情.如果我杀了应用程序并重新启动它...一切都很好.

有人有主意吗？代码如下.

public RestResponse<T> Execute<T>(RestRequest request) {
    var restResponse = new RestResponse<T>();
    var serializer = new JavaScriptSerializer();
    var urlPath = baseUrl + "/" + request.Resource;
    Console.WriteLine("Requesting: " + urlPath);
    var httpRequest = (HttpWebRequest)HttpWebRequest.Create(new Uri(urlPath));

    httpRequest.Headers = request.Headers;
    foreach (string key in clientHeaders.Keys)
        httpRequest.Headers.Add(key, clientHeaders[key]);
    httpRequest.Headers.Add("Accept-Encoding", "gzip,deflate");

    Authenticator.Authenticate(httpRequest);
    httpRequest.Method = request.Method.ToString();       
    HttpWebResponse httpResponse = null;
    try {
        if ((request.Method == Method.POST) && (!request.IsJsonPost))
            SetPostData(httpRequest, request);

        if ((request.Method == Method.POST) && (request.IsJsonPost)){
            SetJsonPostData(httpRequest, request);
        }

        httpResponse = (HttpWebResponse)httpRequest.GetResponse();
        var reader = new StreamReader(GetStreamForResponse(httpResponse));
        var responseString = reader.ReadToEnd();
        Console.WriteLine(responseString);
        reader.Close();
        restResponse.StatusCode = httpResponse.StatusCode;
        restResponse.Headers = httpResponse.Headers;
        restResponse.Data = serializer.Deserialize<T>(responseString);
        restResponse.ResponseStatus = ResponseStatus.Completed;
        httpResponse.Close();
    } catch (WebException e) {
        restResponse.ResponseStatus = ResponseStatus.Error;
        restResponse.ErrorMessage = e.Message;
        restResponse.ErrorException = e;
        var webResponse = (HttpWebResponse)e.Response;
        if (webResponse != null) {
            restResponse.StatusCode = webResponse.StatusCode;
            restResponse.Headers = webResponse.Headers;
        }
        if (restResponse.StatusCode != HttpStatusCode.NotModified)
            Console.WriteLine("An exception occured:\r\n " + request.Resource + "\r\n" + e + "\r\n");
    } catch (Exception ex) {
        restResponse.ResponseStatus = ResponseStatus.Error;
        restResponse.ErrorMessage = ex.Message;
        restResponse.ErrorException = ex;
    }

    if (httpResponse != null)
        httpResponse.Close();

    return restResponse;
}

它失败了:

httpResponse = (HttpWebResponse)httpRequest.GetResponse();

堆栈跟踪:

System.Net.WebException: The remote server returned an error: (400) Bad Request.
  at System.Net.HttpWebRequest.CheckFinalStatus (System.Net.WebAsyncResult result) [0x002f2] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/HttpWebRequest.cs:1477 
  at System.Net.HttpWebRequest.SetResponseData (System.Net.WebConnectionData data) [0x00141] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/HttpWebRequest.cs:1300 

请求永远不会到达远程服务器.

Answer 1

问题出在clientHeaders集合上。该类RESTClient在应用程序生命周期中实例化一次。我一遍又一遍地添加标题，而不是先清除它们。一段时间后，标头变得太大并且发出了错误的请求。