queryrecord.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;

namespace SECompare.Structure
{
	/// <summary>
	/// Class QueryRecord is used to store a query result record, including title, URL, snippet etc.
	/// The directory structure is following:
	/// -----[DataRoot]
	///    |_____[A]~[Z]: Hash mapping. The first letter of query string.
	///        |_____[Query words] : for example, "cnn.com","CSU" etc.
	///            |_____[Google/Yahoo/MSN]: Search Engine name.
	///                |_____"info.txt": record information about result records (differs from query and engine, has not been completed yet).
	///                |_____"1","2",...,"1000": (Rank number) Files that store search result records.
	///                |_____"1.html","2.html",...,"1000.html": (Rank number.html) Files that store HTML code of corresponding URL.
	///                
	///The format of the files (like "1","2",...,"1000") is following:
	///--------------------------------------------------------
	///*Title
	///[Title: Store title of result.]
	///*URL
	///[URL  : Store URL of result.]
	///*Snippet
	///[Snippet: Store Snippet of result.]
	///--------------------------------------------------------
	///
	///NOTICE:
	///1. Seperate line is started with "*" and description of next row. 
	///2. HTML code of taget page is saved as "1.html","2.html"...,"1000.html".
	///
	/// </summary>
	public class QueryRecord
	{
		private String mQuery;
		private String mEngine;
		private String mRank;   //Rank index number
		private String mURL;
		private String mSnippet;
		private String mTitle;
		private String mHTML;

		public String URL
		{
			get
			{
				return this.mURL;
			}
		}

		public String Title
		{
			get
			{
				return this.mTitle;
			}
		}

		public String Snippet
		{
			get
			{
				return this.mSnippet;
			}
		}

		public int Rank
		{
			set
			{
				this.mRank = value.ToString();
			}
			get
			{
				return Convert.ToInt32(this.mRank);
			}
		}

		public String HTML
		{
			get
			{
				return this.mHTML;
			}
		}

		/// <summary>
		/// Initial a record of query results.
		/// </summary>
		/// <param name="query">Query words</param>
		/// <param name="engine">Search engine name</param>
		/// <param name="rank">Rank number</param>
		/// <param name="title">Title of the page</param>
		/// <param name="url">URL of the page</param>
		/// <param name="snippet">Snippet of the page</param>
		public QueryRecord(String query,String engine,String rank,String title,String url,String snippet)
		{
			this.mQuery   = query;
			this.mEngine  = engine;
			this.mRank    = rank;
			this.mTitle   = title;
			this.mURL     = url;
			this.mSnippet = snippet;
		}

		public QueryRecord(String query,EngineSet engine,String rank,String title,String url,String snippet)
		{
			this.mQuery   = query;
			this.mEngine  = EngineSetting.GetName(engine);
			this.mRank    = rank;
			this.mTitle   = title;
			this.mURL     = url;
			this.mSnippet = snippet;
		}

		/// <summary>
		/// Get stored file name according to the directory naming standard
		/// </summary>
		/// <param name="query">Query Words</param>
		/// <param name="engine">Engine Name</param>
		/// <param name="rank">Rank number</param>
		/// <returns></returns>
		public static String GetPath(String query,String engine,String rank)
		{
			return QueryRecord.GetPath(query,engine) + "\\" + rank;
		}

		public static String GetPathOfHTML(String query,String engine,String rank)
		{
			return QueryRecord.GetPath(query,engine) + "\\" + rank + ".html";
		}

		private static String GetPath(String query,String engine)
		{
			StringBuilder path = new StringBuilder((new Config.Config()).DataRoot);
			path.Append("\\" + QueryRecord.FilenameEncode(query.Substring(0,1)));
			path.Append("\\" + QueryRecord.FilenameEncode(query));
			path.Append("\\" + engine);
			return path.ToString();
		}

		
		/// <summary>
		/// Encode the words to a string, which could be a standard file name.
		/// </summary>
		/// <param name="originalName"></param>
		/// <returns></returns>
		public static String FilenameEncode(String originalName)
		{
			StringBuilder Words = new StringBuilder(originalName);
			//use '0' as ESC
			Words = Words.Replace("0", "00");  //This line must be run at first, before following replacements.
			Words = Words.Replace(@"\","01");
			Words = Words.Replace(@"/","02");
			Words = Words.Replace(":", "03");
			Words = Words.Replace("*", "04");
			Words = Words.Replace("?", "05");
			Words = Words.Replace("\"","06");
			Words = Words.Replace("<", "07");
			Words = Words.Replace(">", "08");
			Words = Words.Replace("|", "09");
			return Words.ToString();
		}

		/// <summary>
		/// Check if the result of search (query,engine,rank) exists.
		/// </summary>
		/// <param name="query"></param>
		/// <param name="engine"></param>
		/// <param name="rank"></param>
		/// <returns></returns>
		public static bool Exists(String query,String engine,int rank)
		{
			if(query==null||query.Equals(""))
				return false;
			String file = QueryRecord.GetPath(query,engine,rank.ToString());
			if(!File.Exists(file))
				return false;
			else
				return true;
		} 


		/// <summary>
		/// Check if HTML code of search (query,engine,rank) exists.
		/// </summary>
		/// <param name="query"></param>
		/// <param name="engine"></param>
		/// <param name="rank"></param>
		/// <returns></returns>
		public static bool ExistsHTML(String query,String engine,int rank)
		{
			String html = QueryRecord.GetPathOfHTML(query,engine,rank.ToString());
			if(!File.Exists(html))
				return false;
			else
				return true;
		}

		/// <summary>
		/// Load a record.
		/// </summary>
		/// <param name="query">Query Words</param>
		/// <param name="engine">Engine Name</param>
		/// <param name="rank">Rank number</param>
		/// <returns>Loaded QueryRecord</returns>
		public static QueryRecord Load(String query,String engine,int rank)
		{
			if(QueryRecord.Exists(query,engine,rank)==false)
				return null;

			//Get File Path
			String file = QueryRecord.GetPath(query,engine,rank.ToString());
			StreamReader reader = new StreamReader(file);
			String line;
			line = reader.ReadLine();

			//Read Title
			StringBuilder title = new StringBuilder(64);

			while(line!=null&&line.StartsWith("*"))
			{
				line = reader.ReadLine();
			}

			while(line!=null&&!line.StartsWith("*"))
			{
				title.Append(line);
				//read next line until read "*" line
				line = reader.ReadLine();
			}

			//Read URL
			StringBuilder URL = new StringBuilder(64);

			while(line!=null&&line.StartsWith("*"))
			{
				line = reader.ReadLine();
			}

			while(line!=null&&!line.StartsWith("*"))
			{
				URL.Append(line);
				//read next line until read "*" line
				line = reader.ReadLine();
			}

			//Read Snippet
			StringBuilder snippet = new StringBuilder(512);

			while(line!=null&&line.StartsWith("*"))
			{
				line = reader.ReadLine();
			}

			while(line!=null&&!line.StartsWith("*"))
			{
				snippet.Append(line);
				//read next line until read the end
				line = reader.ReadLine();
			}
			reader.Close();

			//Return value
			return new QueryRecord(query,engine,rank.ToString(),title.ToString().Trim(),URL.ToString().Trim(),snippet.ToString());
		}

		/// <summary>
		/// Load HTML code.
		/// Because this function will cost some time, it is not contained in constructor function.
		/// If you want to load HTML, you should call this function after "new QueryRecord()".
		/// </summary>
		public void LoadHTML()
		{
			//Read HTML
			StringBuilder HTML = new StringBuilder(4096);
			String path = QueryRecord.GetPathOfHTML(this.mQuery,this.mEngine,this.mRank);
			StreamReader reader = new StreamReader(path,System.Text.Encoding.UTF8);

			String line = reader.ReadLine();
			while(line!=null)
			{
				HTML.Append(line);
				//read next line until read the end
				line = reader.ReadLine();
			}
			reader.Close();

			this.mHTML = HTML.ToString();
		}

		/// <summary>
		/// Check if QueryRecord obj equals to QueryRecord this.
		/// </summary>
		/// <param name="obj"></param>
		/// <returns></returns>
		public override bool Equals(object obj)
		{
			if (obj == null || GetType() != obj.GetType()) 
				return false;

			if(  ((QueryRecord)obj).mURL.Equals(this.mURL)  )
				return true;
			
			return false;
		}

		public override int GetHashCode() 
		{
			return this.Rank * base.GetHashCode();
		}

		/// <summary>
		/// Save Record As new rank, where the older record will be overwrited.
		/// If the record has not been saved yet, do nothing.
		/// </summary>
		/// <param name="NewRank">new rank number</param>
		public void SaveAsNewRank(int NewRank)
		{
			if(!QueryRecord.Exists(this.mQuery,this.mEngine,Convert.ToInt32(this.mRank)))
				return;
			if(this.mRank.Equals(NewRank.ToString()))
                return;

			String OldFile = QueryRecord.GetPath(this.mQuery,this.mEngine,this.mRank);
			String NewFile = QueryRecord.GetPath(this.mQuery,this.mEngine,NewRank.ToString());

			if(File.Exists(NewFile))
				File.Delete(NewFile);

			File.Move(OldFile,NewFile);
			this.mRank = NewRank.ToString();
		}

		/// <summary>
		/// Delete this record from hard disk forever.
		/// </summary>
		public void Delete()
		{
			QueryRecord.Delete(this.mQuery,this.mEngine,this.mRank);
		}

		public static void Delete(String Query,String Engine,String Rank)
		{
			String file = QueryRecord.GetPath(Query,Engine,Rank);
			if(File.Exists(file))
				File.Delete(file);
			file = QueryRecord.GetPathOfHTML(Query,Engine,Rank);
			if(File.Exists(file))
				File.Delete(file);
		}

		public static void Delete(String Query,String Engine)
		{
			String path = QueryRecord.GetPath(Query,Engine);
			if(Directory.Exists(path))
				Directory.Delete(path,true);
		}

		/// <summary>
		/// Save the record to file. 
		/// If the record exists, it will be overwrite.
		/// </summary>
		public void Save()
		{
			String filepath = QueryRecord.GetPath(this.mQuery,this.mEngine,this.mRank);
    			
			//Save Title, URL and Snippet
			FileInfo file = new FileInfo(filepath);
			if(!file.Exists)
			{
				file.Directory.Create();
				FileStream fs = file.Create();
				fs.Close();
			}
			
			StreamWriter w = new StreamWriter(file.FullName,false);
			w.WriteLine("*Title");
			w.WriteLine(this.Title);
			w.WriteLine("*URL");
			w.WriteLine(this.URL);
			w.WriteLine("*Snippet");
			w.WriteLine(this.Snippet);
			w.Close();
		}


		/// <summary>
		/// Save HTML code.
		/// Because this function will cost some time and may be not necessary, it is not contained in Save().
		/// If you want to save HTML, you should call this function.
		/// </summary>
		/// <param name="HTML">HTML code to save.</param>
		public void SaveHTML(String HTML)
		{
			String filepath = QueryRecord.GetPathOfHTML(this.mQuery,this.mEngine,this.mRank);
			
			//Write file
			FileInfo file = new FileInfo(filepath);
			if(!file.Exists)
			{
				FileStream fs = file.Create();
				fs.Close();
			}
			
			StreamWriter w = new StreamWriter(file.FullName,false,System.Text.Encoding.UTF8);
			w.Write(HTML);
			w.Close();
		}

		public override String ToString()
		{
			StringBuilder sb = new StringBuilder(4096);
			sb.Append(this.mRank+". ");
			sb.Append(this.mTitle+"\n");
			sb.Append(this.mSnippet+"\n");
			sb.Append("[URL] "+this.mURL+" \r\n\r\n");
			return sb.ToString();
		}
	}
}