Hi I have built a simple threadpool based web crawler within my web application. Its job is to crawl its own application space and build a Lucene index of every valid web page and their meta content. Here's the problem. When I run the crawler from a debug server instance of Visual Studio Express, and provide the starting instance as the IIS url, it works fine. However, when I do not provide the IIS instance and it takes its own url to start the crawl process(ie. crawling its own domain space), I get hit by operation timed out exception on the Webresponse statement. Could someone please guide me into what I should or should not be doing here? Here is my code for fetching the page. It is executed in the multithreaded environment.
private static string GetWebText(string url)
{
string htmlText = "";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.UserAgent = "My Crawler";
using (WebResponse response = request.GetResponse())
{
using (Stream stream = response.GetResponseStream())
{
using (StreamReader reader = new StreamReader(stream))
{
htmlText = reader.ReadToEnd();
}
}
}
return htmlText;
}
And the following is my stacktrace:
at System.Net.HttpWebRequest.GetResponse()
at CSharpCrawler.Crawler.GetWebText(String url) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 366
at CSharpCrawler.Crawler.CrawlPage(String url, List1 threadCityList) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 105
at CSharpCrawler.Crawler.CrawlSiteBuildIndex(String hostUrl, String urlToBeginSearchFrom, List1 threadCityList) in c:\myAppDev\myApp\site\App_Code\CrawlerLibs\Crawler.cs:line 89
at crawler_Default.threadedCrawlSiteBuildIndex(Object threadedCrawlerObj) in c:\myAppDev\myApp\site\crawler\Default.aspx.cs:line 108
at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
Thanks and cheers,
Leon.
