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Async web request with timeout for web errors [duplicate]

This question already has answers here:
Timeout behaviour in HttpWebRequest.GetResponse() vs GetResponseAsync()
(2 answers)
Closed 7 years ago.
I've been going at this all day. I am creating web requests using
public async static Task<string> FetchString(string Url)
{
HttpWebRequest Request = (HttpWebRequest)WebRequest.Create(Url);
Request.Proxy = null;
WebResponse Response = await Request.GetResponseAsync();
Stream DataStream = Response.GetResponseStream();
if (DataStream == null) return String.Empty;
StreamReader DataReader = new StreamReader(DataStream);
return await DataReader.ReadToEndAsync();
}
which works great. The problem is, though, is that sometimes it hangs on HTTP 504, gateway timeout. Using Request.Timeout (or any of the three variants) does not time the method out for when my method hangs on 504 (edit: timeout doesn't reply to async methods, great). To combat this, I've tried to create a timer that would kill the thread the request was running on, but had no luck doing that, though it felt like a working concept.
How would I be able to asynchronously get the contents of a URL in string form, while still being abe to time the request out after say five seconds?

In my research, I found this is a duplicate question (sorry, i dunno how this works)
Timeout behaviour in HttpWebRequest.GetResponse() vs GetResponseAsync()
Timeout does not apply to asynchronous HttpWebRequest requests. To
quote the docs:
The Timeout property has no effect on asynchronous requests
I recommend you use HttpClient instead, which was designed with
asynchronous requests in mind.
-Stephen Cleary

Ftp requests in Windows Service Timing out

I have windows service that periodically upload file upload file on an FTP server. I have set,
ServicePointManager.DefaultConnectionLimit = 100;
and I have,
public void MyMethod(string url,
string userName,
string password)
{
try
{
var request = (FtpWebRequest) WebRequest.Create(url);
request.Timeout = GetFtpTimeoutInMinutes()*60*1000;
request.Credentials = new NetworkCredential(userName, password);
request.Method = method;
request.UseBinary = true;
request.UsePassive = true;
request.KeepAlive = false;
request.GetResponse();
}
catch (Exception ex)
{
_logger.Log(ex);
}
Its work fine for 100 or more request but after 100 or more I am continuously getting,
System.Net.WebException: The operation has timed out.
at System.Net.FtpWebRequest.CheckError()
at System.Net.FtpWebRequest.GetResponse()
Why this is happening.
Update: I am thinking to move in http

request.GetResponse();
Your snippet is very incomplete, but surely the problem started here. GetResponse() returns an FtpWebResponse object, it is crucial that your code calls Close() or disposes it to ensure that the Ftp connection is closed.
If you forget then you will have 100 active connections after downloading 100 files and trip the ServicePointManager.DefaultConnectionLimit. The garbage collector doesn't run often enough to keep you out of trouble. After which any subsequent downloads will die with a timeout. Fix:
using (var response = request.GetResponse()) {
// Do stuff
//...
}
Which uses the reliable way to ensure that the connection will be closed, even if the code falls over with an exception. If you still have trouble then diagnose with, say, SysInternals' TcpView utility. It is a good way to see active connections.

wowza streaming c# HTTP get method for livestreamrecord

Hello I need some help with livestreamrecord recording via http url c# calls,
I can start and stop a stream recording using:
http://[username]:[password]#[wowza-ip-address]:8086/livestreamrecord?app=live&streamname=myStream&action=startRecording
When inputting it directly in to a browser or when I redirect my webpage to it from code, but when I try to do the same from c# on a webpage nothing happens.
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://[username]:[password]#[wowza-ip-address]:8086/livestreamrecord?app=live&streamname=myStream&action=startRecording);
request.Method = "GET";
request.Proxy = new WebProxy("[wowza-ip-address]", 8086);
request.Credentials = new NetworkCredential("[username]", "[password]");
request.ContentType = "application/x-www-form-urlencoded";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream stm = response.GetResponseStream();
When I first tried to set it up I kept getting 401 unauthorized error which the code above no long throws, but now I'm stuck as no error is thrown and still no recording is started.
The response returns:
<html><head><title>Wowza Streaming Engine 4 Perpetual Edition 4.0.1 build10615</title></head><body>Wowza Streaming Engine 4 Perpetual Edition 4.0.1 build10615</body></html>
Which indicates it is not reaching the livestreamrecord page.
Ben

Sovled the problem, thier was a 302 redirect on the request which was producing the 401 unauthorized responses. Adding:
request.AllowAutoRedirect = false;
and removing:
request.Proxy = new WebProxy("[wowza-ip-address]", 8086);
Resolved the problem.
With Proxy in, it didn't throw an error but also didn't record. Removing Proxy allowed the record command to work but throw the 401 response which was then resolved by setting AllowAutoRedirect to false.

How do I resend a "failed" WebRequest?

I send POST and GET WebRequest that should support longer periods of internet being down. The idea is to queue the failed (timedout) webrequest and to try to resend them periodically until the internet is up again and all queued WebRequests are sent.
However, I seems that I cannot just reuse the old WebRequest. Do I need to set it up again?
IAsyncResult result = request.BeginGetResponse (o => {
callCallback (o);
}, state);
When request is just setup using:
var request = HttpWebRequest.Create (String.Format (#"{0}/{1}", baseServiceUrl, path));
request.Method = "GET";
request.ContentType = "application/xml; charset=UTF-8";
request.Headers.Add ("Authority", account.Session);
return request;
it works fine. But after a timeout (and request.Abort ();) and calling BeginGetResponse() on the same webrequest just freezes.

You cannot call BeginGetResponse() multiple times on the same HttpWebRequest. I'm not sure whether that's support on .NET, but it's not possible with Mono's implementation (and not something that'd be easy to change).
See also Can I reuse HttpWebRequest without disconnecting from the server? - the underlying network connection will be reused.

Cancel HTTPWebRequest when server goes down

I have created a Windows Service that calls a API (that returns JSON) with HTTPWebRequest.
The API doesn't return anything until it has something to "deliver". So I set the timeout quite high and lets the request wait until it receivs a response.
The problem is that when I test to turn off or disconnect the server running the API. The HTTPWebRequest doesn't stop the request. So I can't know if the API server has gone down.
The request code:
HttpWebRequest Request = (HttpWebRequest)HttpWebRequest.Create(Url);
Request.Method = "POST";
Request.ContentType = "application/x-www-form-urlencoded";
Request.ContentLength = PostData.Length;
Request.Timeout = Timeout;
Request.KeepAlive = true;
using (StreamWriter sw = new StreamWriter(Request.GetRequestStream()))
{
sw.Write(PostData);
}
using (HttpWebResponse Response = (HttpWebResponse)Request.GetResponse())
{
using (StreamReader sr = new StreamReader(Response.GetResponseStream()))
{
ResponseText = sr.ReadToEnd();
}
}
Is there anyway to "break" the request when the requested server goes down?
I have tried using the webbrowser to call the API server and after a while disconnect it and that return an error to the webpage.

you could use a background worker only cecking if the server is online. It has some disatvantages but may work fine.

It is always good to keep the requests asynchronous (See the BeginXXX methods in HttpWebRequest - http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx).
Using the asynchronous APIs ensures that you are not blocked until you get a response from the server.
In addition to using the asynchronous APIs, you can have a heart-beat requests (that could be just a HEAD HTTP request to a ping service on the server, which returns an empty body and HTTP 200 status), to keep track that the server is alive. If this request times out, then server is not alive - in which case, you can cancel / just 'forget' that the request has been made.