private static async Task ComputationalAsyncCallback(ServerArguments serverArguments,
HttpListenerContext context, CancellationToken cancellationToken)
{
var profiler = Stopwatch.StartNew();
var query = context.Request.QueryString["query"];
if (cancellationToken.IsCancellationRequested)
{
Log.Warn($"Task [{query}] cancelled before computations.");
return;
}
var responseBytes = await ComputeResponseAsync(serverArguments, query, cancellationToken);
await context.Response.OutputStream.WriteAsync(responseBytes, 0, responseBytes.Length, cancellationToken);
if (cancellationToken.IsCancellationRequested)
{
Log.Warn($"Task [{query}] cancelled while or after computing/sending response.");
return;
}
Log.Info($"Request [{query}] processed in {profiler.ElapsedMilliseconds} ms.");
}
private static async Task <byte[]> ComputeResponseAsync(ServerArguments serverArguments, string query,
CancellationToken cancellationToken)
{
await Task.Delay(serverArguments.MethodDuration, cancellationToken);
return(GetBase64HashBytes(query, Encoding.UTF8));
}
/* Two scenarios: 'query'[+'guid'] or 'cancel' requests. */
private static Func <HttpListenerContext, Task> CreateAsyncCallback(ServerArguments serverArguments)
{
return(async context =>
{
var queryString = context.Request.QueryString;
if (queryString["query"] != null)
{
Log.Info($"Receive request [{queryString["query"]}].");
var guidString = queryString["guid"];
if (guidString != null)
{
if (Guid.TryParse(guidString, out var clientGuid))
{
var guidCancellationTokenSource = new CancellationTokenSource();
var guidCancellationToken = guidCancellationTokenSource.Token;
TaskCancellationTokenSources[clientGuid] = guidCancellationTokenSource;
try
{
await ComputationalAsyncCallback(serverArguments, context, guidCancellationToken);
}
catch (OperationCanceledException)
{
Log.Warn($"Task [{queryString["query"]}] cancelled while or after computing/sending response.");
}
catch (HttpListenerException)
{
Log.Warn("Response writing was aborted.");
}
}
else
{
Log.Warn($"Bad request: guid [{guidString}] cannot be parsed.");
}
}
else
{
Log.Warn("Bad request: no guid passed.");
}
}
else if (queryString["cancel"] != null)
{
CancellationAsyncCallback(serverArguments, context);
}
else
{
Log.Warn("Bad request: neither query nor cancel.");
}
});
}
private static void CancellationAsyncCallback(ServerArguments serverArguments, HttpListenerContext context)
{
var cancellationGuidString = context.Request.QueryString["cancel"];
if (!Guid.TryParse(cancellationGuidString, out var cancelGuid))
{
Log.Warn($"Cancellation guid [{cancellationGuidString}] cannot be parsed.");
return;
}
if (!TaskCancellationTokenSources.ContainsKey(cancelGuid))
{
Log.Warn($"Cancellation guid [{cancellationGuidString}] cannot be found.");
return;
}
TaskCancellationTokenSources[cancelGuid].Cancel(false);
TaskCancellationTokenSources[cancelGuid].Dispose();
TaskCancellationTokenSources.TryRemove(cancelGuid, out var _);
}
public static bool TryGetArguments(string[] args, out ServerArguments parsedArguments)
{
var argumentsParser = new FluentCommandLineParser <ServerArguments>();
argumentsParser.Setup(a => a.Port).As('p', "port").Required();
argumentsParser.Setup(a => a.MethodName).As('n', "name").Required();
argumentsParser.Setup(a => a.MethodDuration).As('d', "duration")
.WithDescription("Server will return his response in <duration> ms").Required();
argumentsParser.SetupHelp("?", "h", "help").Callback(text => Console.WriteLine(text));
var parsingResult = argumentsParser.Parse(args);
if (parsingResult.HasErrors)
{
argumentsParser.HelpOption.ShowHelp(argumentsParser.Options);
parsedArguments = null;
return(false);
}
parsedArguments = argumentsParser.Object;
return(!parsingResult.HasErrors);
}
private static void Main(string[] args)
{
XmlConfigurator.Configure();
if (!ServerArguments.TryGetArguments(args, out var arguments))
{
Console.WriteLine("Faulted: Pass arguments to preconfigurate server.");
return;
}
var listener = new HttpListener()
{
Prefixes = { $"http://+:{arguments.Port}/{arguments.MethodName}/" }
};
Log.Info($"Server is starting listening prefixes: {string.Join("; ", listener.Prefixes)}.");
Log.Info("Press <ENTER> to stop listening.");
listener.ProceedRequestsAsync(CreateAsyncCallback(arguments));
Console.ReadLine();
Log.Info("Server stopped.");
}
