public override PageCrawl InsertPageCrawl(PageCrawl crawl)
{
Console.WriteLine("Logger database crawl insert:");
Console.WriteLine(crawl.Page.Uri.ToString());
Console.WriteLine(crawl.Content.Length + " bytes");
Console.WriteLine(crawl.CrawlTime);
Console.WriteLine();
return(crawl);
}
public PageCrawl InsertPageCrawl(PageCrawl crawl)
{
Console.WriteLine("FILE DB");
string crawlPath = GetPageCrawlPath(crawl);
// Ensure contains no invalid chars
foreach (char invalidChar in Path.GetInvalidFileNameChars().Concat(Path.GetInvalidPathChars()))
{
if (invalidChar == '/' || invalidChar == '\\')
{
continue; // leaves slashes to preserve file path
}
crawlPath = crawlPath.Replace(invalidChar, '_');
}
if (String.IsNullOrWhiteSpace(crawlPath) || String.IsNullOrEmpty(crawlPath))
{
crawlPath = "%20";
}
// creating an existing directory has no effect so we can do that every time
try
{
Directory.CreateDirectory(Path.GetDirectoryName(crawlPath));
StreamWriter streamWriter = File.CreateText(crawlPath);
streamWriter.Write(crawl.Page.Uri.ToString());
streamWriter.Write(DATA_SEPARATOR);
streamWriter.Write(crawl.Page.LinkedFrom);
streamWriter.Write(DATA_SEPARATOR);
streamWriter.Write(crawl.CrawlTime);
streamWriter.Write(DATA_SEPARATOR);
streamWriter.Write(crawl.Content);
streamWriter.Close();
}
catch (Exception ex)
{
string errMsg = "Failed to save crawl to disk - " + crawl.Page.Uri.ToString() + " at " + crawlPath;
Console.WriteLine(errMsg);
throw new IOException(errMsg, ex);
}
Console.WriteLine("Saved crawl to " + crawlPath);
return(crawl);
}
public IEnumerable <PageCrawl> Start()
{
while (frontier.Count > 0)
{
Console.WriteLine("Frontier size: " + frontier.Count);
Page currentCrawlPage = frontier.Dequeue();
if (ShouldSkip(currentCrawlPage.Uri))
{
continue;
}
latestCrawl = Browser.Crawl(currentCrawlPage);
currentCrawlPage.Crawl = latestCrawl;
visited.Add(currentCrawlPage.ToString());
// Ensure crawl didn't fail
if (latestCrawl == null)
{
continue;
}
Uri[] newLinks = LinkParser.Parse(latestCrawl.Content, latestCrawl.Page.Uri);
// Add links and new crawl
foreach (Uri uri in newLinks)
{
if (!visited.Contains(uri.ToString()))
{
frontier.Enqueue(new Page(uri, currentCrawlPage));
}
}
yield return(latestCrawl);
int millisecondDelay = robots[currentCrawlPage.Uri.Authority].CrawlDelay * 1000;
millisecondDelay = (int)Math.Max(0, millisecondDelay - (DateTime.Now - latestCrawl.CrawlTime).TotalMilliseconds);
Console.WriteLine("Waiting for " + millisecondDelay + "ms");
Thread.Sleep(millisecondDelay);
}
}
public virtual PageCrawl InsertPageCrawl(PageCrawl crawl)
{
throw new NotImplementedException();
}
protected string GetPageCrawlPath(PageCrawl crawl)
{
return(GetHostPath(crawl) + crawl.Page.Uri.AbsolutePath + "-" + crawl.CrawlTime.ToString("yyyy'-'MM'-'dd-HH'-'mm'-'ss") + ".txt");
}
protected string GetHostPath(PageCrawl crawl)
{
return(GetDatabaseDir() + "/" + crawl.Page.Uri.Host);
}
