我有一个构建HttpWebRequest的服务,并使用JSON字符串设置其主体以发送到系统的API。在调用请求流时,我偶尔会收到WebException超时错误。为什么在这一点上会出错?在继续之前是否测试连接到其他系统?
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();
}
}
答案 0 :(得分:0)
一种选择是增加时间限制。
https://msdn.microsoft.com/pt-br/library/system.net.httpwebrequest.timeout(v=vs.110).aspx
webRequest.Timeout=2000; (2 seconds)
另一种是在超时后重复执行,等待x秒。
任何连接都可能遇到问题,您的代码需要为此做好准备。
我希望它在某种程度上有所帮助。