public void DownloadAndEnqueue(string seed)
{
//validate
try
{
var validate = ValidateUrl.Validate(seed);
if (!validate.Item1)
{
return;
}
//if is in hashset
if (CrawledUrls.Contains(validate.Item2.AbsoluteUri))
{
return;
}
CrawledUrls.Add(validate.Item2.AbsoluteUri);
//download and save html file
var html = new HtmlDownloader(validate.Item2).Load();
if (html == null)
{
return;
}
//parse html file to get urls
var linkedPages = Parser.Parse(html, validate.Item2);
foreach (string linkedPage in linkedPages)
{
Queue.Enqueue(linkedPage);
}
}
catch (Exception ex) { }
}
private List <UrlLink> GetChildren(string startingUrlAddress)
{
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
var html = new HtmlDownloader(startingUrlAddress).HtmlText;
//WriteToFile.WriteTextToFile(html, "BeforeMod.txt");
// Restrictions for the Pcmag website -> CANNOT use links that are in elements with id beggining with comment-
if (startingUrlAddress.Contains("konkurs.pcmagbg.net"))
{
html = RemoveTags(html, "id=\"comment-");
html = RemoveTags(html, "id=\"recentcomments");
}
// Restrictions for TelerikAcademy website -> CANNOT use links that are in elements with attribute:
// id="fb0021a1c"
// id="RecentVideoHeader"
// id="ForumPostsHeader"
// id="BlogPostsHeader"
// id="IndexCalendarHeader"
if (startingUrlAddress.Contains("telerikacademy.com"))
{
html = RemoveTags(html, "id=\"f202640e64");
html = RemoveTags(html, "id=\"RecentVideos");
html = RemoveTags(html, "id=\"LatestForumPosts");
html = RemoveTags(html, "id=\"BlogPosts");
html = RemoveTags(html, "id=\"Calendar");
}
// Restrictions for youtube website -> can ONLY use links that are in elements with attribute:
// id="eow-description"
// class="primary-pane"
if (startingUrlAddress.Contains("youtube.com"))
{
html = RetriveTags(html, "eow-description", "primary-pane");
}
//WriteToFile.WriteTextToFile(html, "AfterMod.txt");
// Extract the anchor tags from text
var tags = new LinkFilter(html).AnchorTags;
//WriteToFile.WriteTextToFile(tags, "tags.txt");
// Extract the href links from the anchor tags
var hrefs = new LinkFilter(tags).LinksFromHrefs;
//WriteToFile.WriteTextToFile(hrefs, "hrefs.txt");
// Links can be only from the following sites:
// http://academy.telerik.com
// http://telerikacademy.com
// http://konkurs.pcmagbg.net
// http://www.youtube.com/playlist?list=
// http://www.youtube.com/watch?v=
// If NO protocol or server is present in the link -> relative link
// All relative links are equal to the current website plus relative link
// Current site is always Correct!
// The resulting links are the allowed children links of the initial url address
List <UrlLink> linksList = new List <UrlLink>();
var links = hrefs.Split(new char[] { '\n' }, StringSplitOptions.RemoveEmptyEntries);
for (int index = 0; index < links.Length; index++)
{
UrlLink validUrl;
links[index] = links[index].Trim();
links[index] = links[index].Trim('\r');
if (!links[index].StartsWith("http"))
{
if (startingUrlAddress[startingUrlAddress.Length - 1] == '/')
{
validUrl = new UrlLink(startingUrlAddress + links[index], links[index]);
}
else
{
validUrl = new UrlLink(startingUrlAddress + "/" + links[index], links[index]);
}
linksList.Add(validUrl);
}
else
{
if (links[index].StartsWith("http://academy.telerik.com") ||
links[index].StartsWith("http://telerikacademy.com") ||
links[index].StartsWith("http://konkurs.pcmagbg.net") ||
links[index].StartsWith("http://www.youtube.com/playlist?list=") ||
links[index].StartsWith("http://www.youtube.com/watch?v=")
)
{
validUrl = new UrlLink(links[index], links[index]);
linksList.Add(validUrl);
}
}
}
//StringBuilder sb = new StringBuilder();
//foreach (var l in linksList)
//{
// sb.AppendLine(l.ToString());
//}
//WriteToFile.WriteTextToFile(sb.ToString(), "links.txt");
//Process.Start(Environment.CurrentDirectory + "\\" + "BeforeMod.txt");
//Process.Start(Environment.CurrentDirectory + "\\" + "AfterMod.txt");
//Process.Start(Environment.CurrentDirectory + "\\" + "tags.txt");
//Process.Start(Environment.CurrentDirectory + "\\" + "hrefs.txt");
//Process.Start(Environment.CurrentDirectory + "\\" + "links.txt");
//stopwatch.Stop();
ColorConsole.Write(string.Format("FINISHED with {0} in {1:0.00} seconds.\n", startingUrlAddress, stopwatch.Elapsed.TotalSeconds), ConsoleColor.Green);
return(linksList);
}
