private void IndexWords(string[] words, UrlAndIndex newPage)
{
MySqlTransaction sqlTran = myConnection.BeginTransaction ();
var uniqueWords = new List<string> ();
try {
//int position = 0;
for (int i=0; i<words.Length; i++) {
MySqlCommand setWord = myConnection.CreateCommand ();
//MySqlCommand setPosition = myConnection.CreateCommand ();
if (words [i] != "") {
if (!uniqueWords.Contains (words [i])) {//Adds word if it's the first time it appears
setWord.CommandText =
"Insert into words_rel_page (word,p_id) values (@word,@p_id);";
if (newPage.Url.Contains (words [i])) {//if the word is in the url
setWord.Parameters.AddWithValue ("@word", words[i]);
setWord.Parameters.AddWithValue ("@p_id", newPage.Index);
} else {
setWord.Parameters.AddWithValue ("@word", words[i]);
setWord.Parameters.AddWithValue ("@p_id", newPage.Index);
}
setWord.ExecuteNonQuery ();
uniqueWords.Add (words [i]);
}
//setPosition.CommandText =
// "Insert into positions (position,word,p_id) values (@position,@word,@p_id);";
//setPosition.Parameters.AddWithValue ("@word", words[i]);
//setPosition.Parameters.AddWithValue ("@p_id", newPage.Index);
//setPosition.Parameters.AddWithValue ("@position", position);
//setPosition.ExecuteNonQuery();
//position++;
}
}
sqlTran.Commit ();
} catch (Exception e) {
Console.Error.WriteLine ("Could not commit words from " + newPage.Url + " continuing");
sqlTran.Rollback ();
}
}
/// <summary>
/// Adds the new downloaded url to the database.
/// </summary>
/// <param name="i">To define the url index, and make easier the conversion to a matrix when calculating pagerank.</param>
private void AddUrlToDb(UrlAndIndex newPage)
{
MySqlTransaction sqlTran = myConnection.BeginTransaction ();
MySqlCommand createPage = myConnection.CreateCommand ();
try {
createPage.CommandText =
"Insert into pages (url,p_id,pagerank) values (@url,@ID,@pagerank);";
createPage.Parameters.AddWithValue ("@url", newPage.Url);
createPage.Parameters.AddWithValue ("@ID", newPage.Index);
createPage.Parameters.AddWithValue ("@pagerank", 0);
createPage.ExecuteNonQuery ();
// Commit the transaction.
sqlTran.Commit ();
numberPages++;
PagesInDatabase.Add (newPage);
CrawlQueue.Enqueue (newPage);
} catch (Exception e) {
Console.Error.WriteLine ("Could not commit insert {0},skipping page ", newPage.Url);
sqlTran.Rollback ();
throw (e);
}
}
/// <summary>
/// Finds the links among the webpage using regular expressions. Adds those not visited to the queue. In this version only root
/// links are evaluated.
/// </summary>
/// <param name="pageContents"> String containing the contents of the webpage</param>
private void FindNewPages(string pageContents, UrlAndIndex newPage)
{
MatchCollection links = Regex.Matches (pageContents, "href=\".*?\"", RegexOptions.Singleline);//find new links
//"<a href=.^>"
foreach (Match element in links) {
//Extract the link part
//This version only parses the root of each webpage.
String linkString = Regex.Match (element.ToString (), "https?://www\\..*?\\.(com|es|org|edu|uk|de)", RegexOptions.Singleline).ToString ();
linkString = linkString.Replace ("https://", "http://");
UrlAndIndex link = new UrlAndIndex (linkString, numberPages);
if (link.Url != "") {
UrlAndIndex linkInDb = PagesInDatabase.Find (page => page.Url.Equals (link.Url));
if (linkInDb == null) {//if we havent visited the link yet we add it.
try {
AddUrlToDb (link);
} catch (Exception ex) {
continue;
}
} else {// We use the link already in db, or we would get a wrong p_id
link = linkInDb;
}
//Add link relationship to db
MySqlTransaction sqlTran = myConnection.BeginTransaction ();
MySqlCommand createLink = myConnection.CreateCommand ();
try {
//Can link to itself
createLink.CommandText =
"Insert IGNORE into links (p_id_linker,p_id_reciever) values (@Linker,@Reciever);";
createLink.Parameters.AddWithValue ("@Linker", newPage.Index);
createLink.Parameters.AddWithValue ("@Reciever", link.Index);
createLink.ExecuteNonQuery ();
// Commit the transaction.
sqlTran.Commit ();
} catch (Exception e) {
Console.Error.WriteLine ("Could not commit link " + link + "from " + newPage + " continuing");
sqlTran.Rollback ();
}
}
}
}
void AddCrawledPage(UrlAndIndex newPage, string pageContents, string content,string title)
{
MySqlTransaction sqlTran = myConnection.BeginTransaction ();
MySqlCommand createCrawledPage = myConnection.CreateCommand ();
try {
createCrawledPage.CommandText = "Insert into crawled_pages (p_id,words,content,title) values (@ID,@words,@content,@title);";
createCrawledPage.Parameters.AddWithValue ("@ID", newPage.Index);
createCrawledPage.Parameters.AddWithValue ("@words", pageContents);
createCrawledPage.Parameters.AddWithValue ("@title", title);
createCrawledPage.Parameters.AddWithValue ("@content", content);
createCrawledPage.ExecuteNonQuery ();
// Commit the transaction.
sqlTran.Commit ();
}
catch (Exception e) {
Console.Error.WriteLine ("Could not commit insert {0} into crawled, fatal error for now ", newPage.Url);
sqlTran.Rollback ();
System.Environment.Exit(1);
}
}
