HttpWebRequest.GetRequestStream() Timeout

Question

J'ai un service qui construit un HttpWebRequest et définit son corps avec une chaîne JSON à envoyer à l'API d'un système. Au moment de l'appel du flux de requêtes, je reçois occasionnellement une erreur de délai d'attente WebException. Pourquoi aurait-il commis une erreur à ce stade? Teste-t-il la connexion à l'autre système avant de continuer?

try 
{ 
    //Get default request data 
    if (requestObj == null) 
     requestObj = new ApiRequest(); 

    //Convert request info to json+bytes 
    string url = _baseUrl + path; 
    string requestStr = JsonConvert.SerializeObject(requestObj, _jsonSettings); 
    requestObjJson = requestStr; 

    byte[] data = Encoding.UTF8.GetBytes(requestStr); 

    //Post to SystemX 
    webRequest = (HttpWebRequest)WebRequest.Create(url); 
    webRequest.ContentType = "application/json;charset=UTF-8"; 
    webRequest.Headers.Add("access_token", _accessToken); 
    webRequest.Method = "POST"; 
    webRequest.ContentLength = data.Length; 

    webRequestJson = JsonConvert.SerializeObject(webRequest, Formatting.Indented); 

    using (Stream dataStream = webRequest.GetRequestStream()) 
    { 
     dataStream.Write(data, 0, data.Length); 
     dataStream.Close(); 
    } 

    webRequestJson = JsonConvert.SerializeObject(webRequest, Formatting.Indented); 

    LogMessage("SystemXApiAdapter._request() Request", "Information only. Not an error.", webRequestJson + ";" + requestObjJson, connectionString, customerName, licenseInfoID); 

    //Get response 
    string responseString = null; 
    HttpStatusCode status; 
    using (HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse()) 
    { 
     if (response != null) 
     { 
      using (Stream stream = response.GetResponseStream()) 
      using (StreamReader sr = new StreamReader(stream)) 
      { 
       responseString = sr.ReadToEnd(); 
       status = response.StatusCode; 
      } 

      response.Close(); 
     } 
     else 
     { 
      status = HttpStatusCode.NoContent; 
     } 
    } 
    T responseObj = null; 

    LogMessage("SystemXApiAdapter._request() Response", "Information only. Not an error.", responseString, connectionString, customerName, licenseInfoID); 

    if (typeof(T) == typeof(EmptyApiResponse)) 
     return null; 

    if (string.IsNullOrEmpty(responseString)) 
     throw new Exception("Empty response for non-empty request"); 

    responseObj = JsonConvert.DeserializeObject<T>(responseString); 

    if (callback != null) 
     callback(responseObj); 

    //Get next page of data if needed 
    if (handlePaging && status == HttpStatusCode.PartialContent) 
    { 
     //Move to next page and recursively make more requests until we've got everything 
     requestObj.page_num++; 
     T moreData = _request<T>(path, connectionString, customerName, licenseInfoID, true, requestObj, callback); 
     if (moreData != null) 
      responseObj = (T)(responseObj).AppendResponseData(moreData); 
    } 

    return responseObj; 
} 
catch (Exception ex) 
{ 
    SystemXApiException SystemXEx = new SystemXApiException(requestObj, ex, webRequestJson); 

    if (!bIsRetry && SystemXEx.StatusCode.HasValue && retryOnStatuses.Contains(SystemXEx.StatusCode.Value)) 
    { 
     return _request<T>(path, connectionString, customerName, licenseInfoID, handlePaging, requestObj, callback, true); 
    } 
    else 
    { 
     throw SystemXEx; 
    } 

    if (ex is WebException) 
    { 
     WebException webEx = (WebException)ex; 
     HttpStatusCode? StatusCode = null; 
     string responseBody = null; 

     //Read Status Code 
     if (webEx.Status == WebExceptionStatus.ProtocolError) 
     { 
      var response = webEx.Response as HttpWebResponse; 
      if (response != null) 
      { 
       StatusCode = response.StatusCode; 
      } 
     } 

     //Retry once on applicable status code 
     if (!bIsRetry && StatusCode.HasValue && retryOnStatuses.Contains(StatusCode.Value)) 
      return _request<T>(path, connectionString, customerName, licenseInfoID, handlePaging, requestObj, callback, true); 

     //Read response Body 
     if (webEx.Response != null) 
     { 
      using (Stream responseStream = webEx.Response.GetResponseStream()) 
      using (StreamReader sr = new StreamReader(responseStream, Encoding.Default)) 
      { 
       responseBody = sr.ReadToEnd(); 
      } 
     } 
     else 
     { 
      responseBody = "Empty response body."; 
     } 

     string message = null; 

     //Format new Exception 
     if (StatusCode.HasValue) 
      message = string.Format("{0} {1}: {2}: {3}: {4}", (int)StatusCode, StatusCode.ToString(), responseBody, requestObjJson, webRequestJson); 
     else 
      message = string.Format("{0} {1}: {2}: {3}: {4}", "No status code", "No status code", responseBody, requestObjJson, webRequestJson); 

     throw new Exception(message, ex); 
    } 
    else 
     throw; 
} 
finally 
{ 
    if (webRequest != null) 
    { 
     webRequest.Abort(); 
    } 
} 

Answer 1

Une option consiste à augmenter la limite de temps.

https://msdn.microsoft.com/pt-br/library/system.net.httpwebrequest.timeout(v=vs.110).aspx

webRequest.Timeout=2000; (2 seconds) 

Une autre consiste à répéter l'exécution après un délai d'attente, d'attente x secondes.

Toute connexion peut rencontrer des problèmes, votre code doit être préparé pour cela.

J'espère que cela a aidé en quelque sorte.