public WebSpider()
{
LoadBlackList(DataFilePath + @"\BlackList.txt");
WebData.CreateDBFile();
connection = WebData.ConnectDB();
connection.Open();
WebData.CreateWebTable(connection, "webs");
if (Count > 0)
{
globalUniqueIndex = WebData.GetIntByExecution(connection, "select max(idx) from webs") + 1;
}
}
public void ReadDBIndex()
{
SQLiteDataReader reader = WebData.GetReaderByExecution(connection, "select url, idx from webs");
string url;
int idx;
url2idx.Clear();
idx2url.Clear();
while (reader.Read())
{
url = reader.GetString(0);
idx = reader.GetInt32(1);
url2idx.Add(url, idx);
idx2url.Add(idx, url);
}
}
public WEBPAGE SingleStep()
{
if (to_visit_links.Count <= 0)
{
return(null);
}
string link = to_visit_links.Dequeue();
Console.WriteLine(String.Format("{0} visited.", link));
string content = "";
if (!isLegal(link))
{
Console.WriteLine("Failed in visit {0}, because it is illegal", link);
return(null);
}
else if (!DownloadHtml(link, out content))
{
Console.WriteLine("Failed in visit {0}, error: {1}", link, content);
return(null);
}
WEBPAGE page = new WEBPAGE(link, content);
if (!WebData.ContainsRecord(connection, link))
{
page.id = globalUniqueIndex++;
WebData.SaveToLocal(page.id, content);
WebData.LoadFromLocal(page.id, out content);
WebData.SaveToDB(connection, link, content.GetMD5(), content.Length, page.id);
}
pages.Add(link, page);
foreach (string next_link in page.LINKS)
{
next_link.Trim('/');
if (!url_visited.Contains(next_link))
{
to_visit_links.Enqueue(next_link);
url_visited.Add(next_link);
}
}
return(page);
}
public int ReadDBContent()
{
SQLiteDataReader reader = WebData.GetReaderByExecution(connection, "select url, md5 from webs");
string url, md5;
url2page.Clear();
while (reader.Read())
{
url = reader.GetString(0);
md5 = reader.GetString(1);
int idx = url2idx[url];
if (WebData.LoadFromLocal(idx, out string content))
{
if (content.GetMD5() == md5)
{
url2page.Add(url, new WEBPAGE(url, content));
}
else
{
Console.WriteLine("File at index {0} has different md5, md5 of content is {1}, but in db is {2}", idx, content.GetMD5(), md5);
}
}
else
{
Console.WriteLine("Failed to load file at index {0}", idx);
}
}
foreach (string src in url2idx.Keys)
{
foreach (string key in url2page[src].LINKS)
{
if (url2idx.ContainsKey(key))
{
url2page[src].point_id.Add(url2idx[key]);
}
}
}
return(url2page.Count);
}
public DBReader()
{
connection = WebData.ConnectDB();
connection.Open();
}
