/// <summary>
/// Evaluates if the current document must be added or if it can be skipped
/// </summary>
/// <param name="propertyBag"></param>
/// <param name="updateCrawler"></param>
/// <param name="id"></param>
/// <param name="message"></param>
/// <returns></returns>
protected bool EvaluateSkipConditions(PropertyBag propertyBag, UpdateContextAwareCrawler updateCrawler, string id, out String message)
{
message = String.Empty;
var htmlDocProp = propertyBag["HtmlDoc"];
if (htmlDocProp != null && htmlDocProp.Value != null)
{
var htmlDoc = htmlDocProp.Value as HtmlDocument;
if (htmlDoc != null)
{
//Raise a custom event indicating that a document is analysed
var args = new CrawlDocumentAnalyseEventArgs(updateCrawler, htmlDoc);
Event.RaiseEvent("SiteCrawler:DocumentAnalyse", args);
//When the Skip field is set the event handlers have indicated that this document should be skipped
if (args.Skip)
{
message = "CrawlDocumentAnalyse Skip = true";
return(true);
}
if (EvaluateSkipConditions(htmlDoc, id, out message))
{
return(true);
}
}
}
return(false);
}
private void Crawl(IndexUpdateContext context)
{
if (_isrunning)
{
_logger.InfoFormat("Crawler is already running, aborting");
return;
}
lock (_runninglock)
{
if (_isrunning)
{
_logger.InfoFormat("Crawler is already running, aborting");
return;
}
_isrunning = true;
var dir = _directoryHelper.GetDirectoryName(_index);
_cancelled = false;
try
{
_directoryHelper.CreateDirectoryBackup(dir);
GetIndexWriter(context).DeleteDocuments(new Term(BuiltinFields.Tags, ValueOrEmpty(Tags)));
var runningContextId = ShortID.NewId();
var urls = GetTransformedUrls().ToList();
if (_logger != null)
{
urls.ForEach(url => _logger.InfoFormat("Starting url: {0}", url));
}
var documentProcessor = (_logger != null && _logger.IsDebugEnabled)
? new LogHtmlDocumentProcessor(_logger, _indexFilters, _followFilters)
: new HtmlDocumentProcessor(_indexFilters, _followFilters);
using (var c = new UpdateContextAwareCrawler(context, runningContextId, urls, new LogLoggerBridge(_logger), documentProcessor, this))
{
if (_logger != null)
{
_logger.Info(String.Format("Crawler started: Using {0} threads", MaximumThreadCount));
}
c.AdhereToRobotRules = AdhereToRobotRules;
c.MaximumThreadCount = MaximumThreadCount;
c.UriSensitivity = UriSensitivity;
if (MaximumCrawlDepth > 0)
{
c.MaximumCrawlDepth = MaximumCrawlDepth;
}
if (MaximumDocuments > 0)
{
c.MaximumCrawlCount = MaximumDocuments;
}
if (MaximumCrawlTime.TotalMinutes > 0)
{
c.MaximumCrawlTime = MaximumCrawlTime;
}
c.UseCookies = UseCookies;
c.ExcludeFilter = new[]
{
new RegexFilter(new Regex(RegexExcludeFilter))
};
c.AfterDownload += CrawlerAfterDownload;
c.PipelineException += CrawlerPipelineException;
c.DownloadException += CrawlerDownloadException;
c.Cancelled += CrawlerCancelled;
Event.RaiseEvent("SiteCrawler:Started", new CrawlStartedEventArgs(c));
c.Crawl();
Event.RaiseEvent("SiteCrawler:Finished", new CrawlFinishedEventArgs(c));
}
}
catch (Exception crawlException)
{
if (_logger != null)
{
_logger.Error(GetExceptionLog(crawlException).ToString());
}
if (_directoryHelper.RestoreDirectoryBackup(dir))
{
_cancelled = false;
}
}
finally
{
if (_logger != null)
{
_logger.Info("Crawler finished");
}
_isrunning = false;
if (!_cancelled)
{
_directoryHelper.DeleteBackupDirectory(dir);
}
}
}
}
