yahoo.cs

用C#编写的一个款搜索engine的源代码！摘自<Visual c#2005 程序设计>

using System;
using System.IO;
using System.Text;
using System.Collections;
using SECompare.Config;
using SECompare.Structure;

namespace SECompare.SearchAPI
{
	/// <summary>
	/// Summary description for Yahoo.
	/// </summary>
	public class Yahoo
	{
		public Yahoo()
		{
			//
			// TODO: Add constructor logic here
			//
		}

		/// <summary>
		/// Crawl and save results.
		/// </summary>
		/// <param name="words"></param>
		/// <param name="start"></param>
		/// <param name="maxResults"></param>
		/// <returns></returns>
		public static bool Crawl(String words,int start,int maxResults)
		{
			ArrayList results = YahooParser.Parser.Run(words,start,maxResults);
			//If no returns, there is no results.
			if(results==null||results.Count==0)
				return false;
			//If returned results is too little, there are no more results.
			if(results.Count<(maxResults*0.9)&&start>10) 
				return false; 
			for(int i=0;i<results.Count;i++)
			{
				YahooParser.Parser.Record record = (YahooParser.Parser.Record)results[i];
				QueryRecord r = new QueryRecord(words,EngineSet.Yahoo,(start+i).ToString(),
					record.Title,record.URL,record.Snippet);
				r.Save();
			}
			
			//Write Log file
			Log.Append("Yahoo Saved:" + words + "[" + start.ToString() + "-" + (start+results.Count-1).ToString() + "]");		
			return true;
		}

		public static QueryRecord[] Parse(String html,String words,int start)
		{
			ArrayList results = YahooParser.Parser.Run(html);
			//If no returns, there is no results.
			if(results==null||results.Count==0)
				return null;
			//Construct return value
			QueryRecord[] ret = new QueryRecord[results.Count];
			for(int i=0;i<results.Count;i++)
			{
				YahooParser.Parser.Record record = (YahooParser.Parser.Record)results[i];
				ret[i] = new QueryRecord(words,EngineSet.Yahoo,(start+i).ToString(),
					record.Title,record.URL,record.Snippet);
			}
			return ret;
		}

	}
}