Develop Reference

HttpWebRequest random 'request timed out' exception

I am currently developing in Unity (in particular using C#) and I'm stuck with HttpWebRequest - HttpWebResponse random timeouts.
I have some methods that send a POST request to a server I host on my local machine (XAMPP) to use various php scripts which are going to fetch informations from MySQL Database (hosted with XAMPP) and give back those info in JSON format.
Then I handle these JSON informations with my C# scripts.
The problem is that when I run the first test all is good:I can get the JSON data from my Server and show it in the Debug Console.
When I run the second test,a WebException is raised with error:
WebException - The request timed out
After that second test,if I run again and again,the problem keeps presenting in a random way.
I followed all the guidelines I found on the internet on how to setup a webrequest - webresponse properly,in particular I tried to use ServicePoint.DefaultConnectionLimit and ServicePoint.MaxServicePointIdleTime,without any result.
The general structure of my methods (regarding the web request/response part) is something like that:
public void WebMethod(){
string post_url = "http://localhost/service.php?someparam=1&someparam=2";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(post_url);
request.Method = "POST";
request.KeepAlive = false;
request.Timeout = 5000;
request.Proxy = null;
string Response = "";
try
{
using (HttpWebResponse resp = request.GetResponse() as HttpWebResponse)
{
using (Stream objStream = resp.GetResponseStream())
{
using (StreamReader objReader = new StreamReader(objStream, Encoding.UTF8))
{
Response = objReader.ReadToEnd();
objReader.Close();
}
objStream.Flush();
objStream.Close();
}
resp.Close();
}
}catch(WebException e)
{
Debug.Log(e.Message);
}
finally
{
request.Abort();
}
//tried this one after reading some related answers here on StackOverflow,without results
//GC.Collect();
Debug.Log("SERVER RESPONSE:" + Response);
//Response Handling
}
I know that it may be something related to a wrong abort on the HttpWebRequest / Response or maybe related to the HTTP 1.1 connections limit,but I can't figure out any solution at the moment.
Any help is appreciated.

How to Response HTTP 504: Timer Time Out JSON

I'm using https://timercheck.io/YOURTIMERNAME/60 to create timer, and when the timer end the API Manager to return both an error code and some JSON content
This is the JSON data when timer end:
{"errorMessage":"504: timer timed out"}
When the timer still countdown:
{"timer":"neo308CCEACbid","request_id":"e54f484e-1e64-11e6-9552-3950b2ec2d5c","status":"ok","now":1463732937,"start_time":1463732935,"start_seconds":180,"seconds_elapsed":2,"seconds_remaining":178,"message":"Timer still running"}
Because of the error code, i get error on Visual Studio and App force close on my Android. I only want to get the errorMessage in JSON. I'm using Visual Studio 2015 and Xamarin to make this project.
Thanks in advance
UPDATE:
I'm using this to get web response
private async Task<string> FetchUserAsync(string url)
{
// Create an HTTP web request using the URL:
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.ContentType = "application/json";
request.Method = "GET";
// Send the request to the server and wait for the response:
using (WebResponse response = await request.GetResponseAsync())
{
// Get a stream representation of the HTTP web response:
using (var sr = new StreamReader(response.GetResponseStream()))
{
string strContent = sr.ReadToEnd();
return strContent;
}
}
}
And call it like this:
CekTimer dataWaktu = JsonConvert.DeserializeObject<CekTimer>(await FetchUserAsync(url));

I assume you are using HttpClient and GetStringAsync, and that the HttpResponse Status code is a 504 too, like in the Json Content.
The shortcut methods like GetStringAsync all make a call to EnsureSuccessStatusCode, which of cause throws an exception on a 504 (see source here).
You can just make a direct get Request:
var client = new HttpClient();
var response = await client.SendAsync(new HttpRequestMessage(HttpMethod.Get, yourUri));
var json = await response.Content.ReadAsStringAsync();

I found the answer of my problem, because of webservice return error code, just simply use WebException and get the StatusCode like this :
private async Task<string> FetchUserAsync(string url)
{
try
{
// Create an HTTP web request using the URL:
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.ContentType = "application/json";
request.Method = "GET";
// Send the request to the server and wait for the response:
using (WebResponse response = await request.GetResponseAsync())
{
// Get a stream representation of the HTTP web response:
using (var sr = new StreamReader(response.GetResponseStream()))
{
string strContent = sr.ReadToEnd();
return strContent;
}
}
}
catch (WebException e)
{
string a = ((HttpWebResponse)e.Response).StatusCode.ToString();
//Toast.MakeText(this, a, ToastLength.Long).Show();
if (a == "GatewayTimeout")
{
return "{'errorMessage':'504: timer timed out'}";
}
else
{
internetDropDialog();
return "";
}
}
}
I think it isn't the best answer, but it can help you to move on from this problem

401 Unauthorized when calling Stormpath REST API with WebRequest object?

I am using Stormpath for my authentication service. I call the RestAPI of Stormpath by using HttpWebRequest.
I am also using HttpWebRequest to call the RestAPI but it does not work.
private void BtnGetResetApiClick(object sender, EventArgs e)
{
var username = "aaaa";
var password = "bbbb";
ServicePointManager.ServerCertificateValidationCallback = Callback;
var request = WebRequest.Create("https://api.stormpath.com/v1/tenants/current") as HttpWebRequest;
request.UserAgent = ".NET SDK";
request.Method = "GET";
request.Accept = "*/*";
var data = string.Format("{0}:{1}", username, HttpUtility.HtmlEncode(password));
var token = Convert.ToBase64String(Encoding.UTF8.GetBytes(data));
string authHeader = string.Format("Basic {0}", token);
request.Headers.Add("Authorization", authHeader);
request.ServerCertificateValidationCallback = Callback;
using (var response = request.GetResponse())
{
var stream = response.GetResponseStream();
if (stream != null)
{
var streamReader = new StreamReader(stream);
var str = streamReader.ReadToEnd();
streamReader.Close();
stream.Close();
}
}
}
private bool Callback(object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
{
return true;
}
When calling:
var response = request.GetResponse()
I got an exception:
An unhandled exception of type 'System.Net.WebException' occurred in System.dll The remote server returned an error: (401) Unauthorized.
Can you help me to see if my code has something wrong?

Update - use the SDK, it's much easier!
If you're calling the Stormpath API from C# frequently, don't bother with writing requests by hand. Use the Stormpath .NET SDK instead. I'm the author. :)
Install it using install-package Stormpath.SDK from the Package Manager Console. Then, create an IClient object:
// In a production environment, you'll want to load these from
// environment variables or a secure file, instead of hardcoding!
var apiKey = ClientApiKeys.Builder()
.SetId("Your_Stormpath_API_key_ID")
.SetSecret("Your_Stormpath_API_key_secret")
.Build();
var client = Clients.Builder()
.SetApiKey(apiKey)
.Build();
Getting the tenant info is now just a simple call:
var tenant = await client.GetCurrentTenantAsync();
Console.WriteLine($"Current tenant is: {tenant.Name}");
If you really want to make raw requests, you can still do that! I'll explain below.
Constructing the Authorization header
A 401 Unauthorized response means that the API was not able to find a valid Authorization header in your request. To authenticate correctly, you need two things:
An authorization payload in the format apiKeyID:apiKeySecret
An Authorization header with value: Basic base64(payload)
Here's how to construct the complete header:
// API_KEY_ID and API_KEY_SECRET populated elsewhere
var authPayload = string.Format("{0}:{1}", API_KEY_ID, API_KEY_SECRET);
var authPayloadEncoded = Convert.ToBase64String(Encoding.UTF8.GetBytes(authPayload));
request.Headers.Add(HttpRequestHeader.Authorization, "Basic " + authPayloadEncoded);
You don't need the ServerCertificateValidationCallback = Callback stuff. With the above header, the request will be seen by the API as a valid request (assuming your API Key ID and Secret are correct, of course).
Redirection handling
One thing to watch out for (this tripped me up at first!) is that WebRequest will follow HTTP 302 redirects automatically, but will not apply the existing headers to the new request.
The solution is to disable redirect following:
request.AllowAutoRedirect = false;
This means you'll have to handle 302 responses yourself, but it's the only way to correctly apply the Authorization header to each request.
Working example
I created a simple working example in this gist. Since I'll be creating requests multiple times, I wrote a helper function:
private static HttpWebRequest BuildRequest(string method, string uri)
{
var request = WebRequest.Create(uri) as HttpWebRequest;
request.UserAgent = "dotnet/csharp web-request";
request.Method = method;
request.ContentType = "application/json";
// Important, otherwise the WebRequest will try to auto-follow
// 302 redirects without applying the authorization header to the
// subsequent requests.
request.AllowAutoRedirect = false;
// Construct HTTP Basic authorization header
var authPayload = string.Format("{0}:{1}", API_KEY_ID, API_KEY_SECRET);
var authPayloadEncoded = Convert.ToBase64String(Encoding.UTF8.GetBytes(authPayload));
request.Headers.Add(HttpRequestHeader.Authorization, "Basic " + authPayloadEncoded);
return request;
}
And a simple console app to demonstrate getting the current tenant URL and name:
// Get these from the Stormpath admin console
private static string API_KEY_ID = "Your_Stormpath_API_key_ID";
private static string API_KEY_SECRET = "Your_Stormpath_API_key_secret";
static void Main(string[] args)
{
// First, we need to get the current tenant's actual URL
string tenantUrl = null;
var getCurrentTenantRequest = BuildRequest("GET", "https://api.stormpath.com/v1/tenants/current");
try
{
using (var response = getCurrentTenantRequest.GetResponse())
{
tenantUrl = response.Headers["Location"];
}
}
catch (WebException wex)
{
Console.WriteLine("Request failed. {0}", wex.Message);
throw;
}
// Now that we have the real tenant URL, get the tenant info
string tenantData = null;
var getTenantInfoRequest = BuildRequest("GET", tenantUrl);
try
{
using (var response = getTenantInfoRequest.GetResponse())
using (var responseStream = response.GetResponseStream())
using (var reader = new StreamReader(responseStream))
{
tenantData = reader.ReadToEnd();
}
}
catch (WebException wex)
{
Console.WriteLine("Request failed. {0}", wex.Message);
throw;
}
// Use JSON.NET to parse the data and get the tenant name
var parsedData = JsonConvert.DeserializeObject<Dictionary<string, object>>(tenantData);
Console.WriteLine("Current tenant is: {0}", parsedData["name"]);
// Wait for user input
Console.ReadKey(false);
}
The code is pretty verbose because we're making raw requests to the API. Again, if you're making requests frequently, use the SDK instead!

GetWebResponse very slow on windows7

I have tried all the settings, i found on internet to make the C# webclient fast on a Windows7 machine
to no avail. The same exe on Windows XP machine responds in less 100ms for every request.
I have overridden the GetWebRequest function in the derived class of
System.Web.Services.Protocols.SoapHttpClientProtocol
protected override WebRequest GetWebRequest(Uri address)
{
//ServicePointManager.UseNagleAlgorithm = false;
HttpWebRequest.DefaultWebProxy = null;
ServicePointManager.DefaultConnectionLimit = 4096;
ServicePointManager.Expect100Continue = false;
System.Net.ServicePointManager.CheckCertificateRevocationList = false;
HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
request.Proxy = HttpWebRequest.DefaultWebProxy;
return (WebRequest)request;
}
protected override WebResponse GetWebResponse(WebRequest request)
{
HttpWebResponse response = null;
//HttpWebRequest.DefaultWebProxy = null;
//ServicePointManager.Expect100Continue = false;
response = (HttpWebResponse)base.GetWebResponse(request);
return response;
}
I have also added the socket trace settings in the machine.config .Net4.0 folder
and it always waits on the below statement for 7-15 seconds in the output window
System.Net.Sockets Verbose: 0 : [6088] Socket#54042743::Receive()
Hope some champion has resolved this

Try using the GetResponse class and check if you find some difference:
HttpWebRequest wrequest = (HttpWebRequest) WebRequest.Create(objeto.Url);
//Get Response
HttpWebResponse wresp = (HttpWebResponse) wrequest.GetResponse();
//get Response Stream
StreamReader sr = new StreamReader(wresp.GetResponseStream());
//Get string content
string respuestastring = sr.ReadToEnd();

I've had the same issue and it turned out that I didn't close the web request, so when I fired a few in a row, I hit the maximum number of connections allowed by the host and it wouldn't continue until the first requests timed out. So try manually closing your requests or, better, wrap the variable declaration for your request into a using directive.

How do you check if a website is online in C#?

I want my program in C# to check if a website is online prior to executing, how would I make my program ping the website and check for a response in C#?

A Ping only tells you the port is active, it does not tell you if it's really a web service there.
My suggestion is to perform a HTTP HEAD request against the URL
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("your url");
request.AllowAutoRedirect = false; // find out if this site is up and don't follow a redirector
request.Method = "HEAD";
try {
response = request.GetResponse();
// do something with response.Headers to find out information about the request
} catch (WebException wex)
{
//set flag if there was a timeout or some other issues
}
This will not actually fetch the HTML page, but it will help you find out the minimum of what you need to know. Sorry if the code doesn't compile, this is just off the top of my head.

You have use System.Net.NetworkInformation.Ping see below.
var ping = new System.Net.NetworkInformation.Ping();
var result = ping.Send("www.google.com");
if (result.Status != System.Net.NetworkInformation.IPStatus.Success)
return;

Small remark for Digicoder's code and complete example of Ping method:
private bool Ping(string url)
{
try
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.Timeout = 3000;
request.AllowAutoRedirect = false; // find out if this site is up and don't follow a redirector
request.Method = "HEAD";
using (var response = request.GetResponse())
{
return true;
}
}
catch
{
return false;
}
}

if (!NetworkInterface.GetIsNetworkAvailable())
{
// Network does not available.
return;
}
Uri uri = new Uri("http://stackoverflow.com/any-uri");
Ping ping = new Ping();
PingReply pingReply = ping.Send(uri.Host);
if (pingReply.Status != IPStatus.Success)
{
// Website does not available.
return;
}

The simplest way I can think of is something like:
WebClient webClient = new WebClient();
byte[] result = webClient.DownloadData("http://site.com/x.html");
DownloadData will throw an exception if the website is not online.
There is probably a similar way to just ping the site, but it's unlikely that the difference will be noticeable unless you are checking many times a second.