public async Task <FetchResult> FetchDom(Uri uri, bool isJsonContainer = false, bool returnNull = false)
{
var fetchResult = new FetchResult();
var domainRequestAssistant = _requestResetEvents.GetOrAdd(uri.Host, s => new DomainRequestAssistant());
var timeBeforeWait = DateTime.Now;
Console.WriteLine("Waiting before call");
domainRequestAssistant.ResetEvent.WaitOne(2000);
Console.WriteLine("Waited '{0}' before call", (DateTime.Now - timeBeforeWait).TotalMilliseconds);
if (domainRequestAssistant.FrequentTotalRequestCounter > 0 &&
domainRequestAssistant.FrequentTotalRequestCounter % NumberOfSequenctialRequests == 0)
{
Console.WriteLine("Reseting the domain request assistant");
domainRequestAssistant.ResetEvent.Reset();
Console.WriteLine("Delaying request... ({0})", uri.OriginalString);
await Task.Delay(1000);
Console.WriteLine("Setting the domain request assistant");
domainRequestAssistant.ResetEvent.Set();
}
_requestResetEvents.AddOrUpdate(uri.Host, s => new DomainRequestAssistant(), (s, assistant) =>
{
if ((DateTime.UtcNow - domainRequestAssistant.UpdatedTime).TotalMilliseconds <
MaxGoodGapBetweenCalls)
{
assistant.FrequentTotalRequestCounter++;
}
else
{
assistant.FrequentTotalRequestCounter = 0;
}
assistant.UpdatedTime = DateTime.UtcNow;
assistant.TotalRequestCounter++;
return(assistant);
});
try
{
if (isJsonContainer)
{
fetchResult = await FetchJsonData(uri);
}
else
{
fetchResult = await FetchData(uri);
}
Console.WriteLine("Handling result from: {0}", uri.PathAndQuery);
if (!string.IsNullOrWhiteSpace(fetchResult.RawPage))
{
fetchResult.HtmlDocument = BuildDom(fetchResult.RawPage, returnNull);
}
else
{
fetchResult.HtmlDocument = null;
}
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
if (!returnNull && fetchResult.HtmlDocument == null)
{
fetchResult.HtmlDocument = new HtmlDocument();
}
return(fetchResult);
}
private async Task <FetchResult> FetchData(Uri uri)
{
var originalUri = uri;
var fetchResult = new FetchResult();
var tryCount = 3;
var isSuccess = false;
var failed = false;
var rndTime = new Random((int)DateTime.Now.Ticks & 0x0000FFFF);
while (tryCount > 0 && !isSuccess)
{
tryCount--;
try
{
if (failed)
{
failed = false;
fetchResult.UsedProxy = true;
uri = new Uri(string.Format(ProxyPath, System.Web.HttpUtility.UrlEncode(originalUri.OriginalString)));
var domainRequestAssistant = _requestResetEvents.GetOrAdd(originalUri.Host,
s => new DomainRequestAssistant());
Console.WriteLine("Reseting the domain request assistant");
domainRequestAssistant.ResetEvent.Reset();
Console.WriteLine("Delaying request (after error)... ({0})", originalUri);
await Task.Delay(rndTime.Next(MinGoodGapBetweenCalls, MaxGoodGapBetweenCalls));
Console.WriteLine("Setting the domain request assistant");
domainRequestAssistant.ResetEvent.Set();
}
var httpClient = _bypassCache ? new HttpClient(new BypassCacheHttpRequestHandler(_noCacheUri), true) : new HttpClient();
httpClient.Timeout = this.Timeout;
Console.WriteLine("Requesting: {0}", uri.PathAndQuery);
fetchResult.RawPage = await httpClient.GetStringAsync(uri);
isSuccess = true;
}
catch (ArgumentNullException aex)
{
Console.WriteLine(aex);
}
catch (WebException wex)
{
var res = (HttpWebResponse)wex.Response;
Console.WriteLine(wex);
int statusCode;
int.TryParse(res.StatusCode.ToString(), out statusCode);
if (res != null && statusCode == 429 || statusCode == 503 || statusCode == 500)
{
failed = true;
}
}
catch (HttpRequestException exception)
{
Console.WriteLine(exception);
if (exception.Message.Contains("429") || exception.Message.Contains("503") || exception.Message.Contains("500"))
{
failed = true;
}
}
catch (TaskCanceledException exception)
{
Console.WriteLine(exception);
failed = true;
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
}
if (tryCount == 0 && !isSuccess)
{
var msg = string.Format("Failed all attempts to get url: {0}", originalUri.OriginalString);
Console.WriteLine(msg);
}
return(fetchResult);
}
