/SHFB/Source/PresentationStyles/LegacyWeb/SearchHelp.aspx

<%@ Page Language="C#" EnableViewState="False" %>



<script runat="server">

//===============================================================================================================

// System  : Sandcastle Help File Builder

// File    : SearchHelp.aspx

// Author  : Eric Woodruff  (Eric@EWoodruff.us)

// Updated : 04/09/2014

// Note    : Copyright 2007-2014, Eric Woodruff, All rights reserved

// Compiler: Microsoft C#

//

// This file contains the code used to search for keywords within the help topics using the full-text index

// files created by the help file builder.

//

// This code is published under the Microsoft Public License (Ms-PL).  A copy of the license should be

// distributed with the code.  It can also be found at the project website: http://SHFB.CodePlex.com.  This

// notice, the author's name, and all copyright notices must remain intact in all applications, documentation,

// and source files.

//

//    Date     Who  Comments

// ==============================================================================================================

// 06/24/2007  EFW  Created the code

// 02/17/2012  EFW  Switched to JSON serialization to support websites that use something other than ASP.NET

//                  such as PHP.

//===============================================================================================================



/// <summary>

/// This class is used to track the results and their rankings

/// </summary>

private class Ranking

{

    public string Filename, PageTitle;

    public int Rank;



    public Ranking(string file, string title, int rank)

    {

        Filename = file;

        PageTitle = title;

        Rank = rank;

    }

}



/// <summary>

/// Render the search results

/// </summary>

/// <param name="writer">The writer to which the results are written</param>

protected override void Render(HtmlTextWriter writer)

{

    JavaScriptSerializer jss = new JavaScriptSerializer();

    string searchText, ftiFile;

    char letter;

    bool sortByTitle = false;



    jss.MaxJsonLength = Int32.MaxValue;



    // The keywords for which to search should be passed in the query string

    searchText = this.Request.QueryString["Keywords"];



    if(String.IsNullOrEmpty(searchText))

    {

        writer.Write("<b class=\"PaddedText\">Nothing found</b>");

        return;

    }



    // An optional SortByTitle option can also be specified

    if(this.Request.QueryString["SortByTitle"] != null)

        sortByTitle = Convert.ToBoolean(this.Request.QueryString["SortByTitle"]);



    List<string> keywords = this.ParseKeywords(searchText);

    List<char> letters = new List<char>();

    List<string> fileList;

    Dictionary<string, List<long>> ftiWords, wordDictionary =

        new Dictionary<string,List<long>>();



    // Load the file index

    using(StreamReader sr = new StreamReader(Server.MapPath("fti/FTI_Files.json")))

    {

        fileList = jss.Deserialize<List<string>>(sr.ReadToEnd());

    }



    // Load the required word index files

    foreach(string word in keywords)

    {

        letter = word[0];



        if(!letters.Contains(letter))

        {

            letters.Add(letter);

            ftiFile = Server.MapPath(String.Format(CultureInfo.InvariantCulture,

                "fti/FTI_{0}.json", (int)letter));



            if(File.Exists(ftiFile))

            {

                using(StreamReader sr = new StreamReader(ftiFile))

                {

                    ftiWords = jss.Deserialize<Dictionary<string, List<long>>>(sr.ReadToEnd());

                }



                foreach(string ftiWord in ftiWords.Keys)

                    wordDictionary.Add(ftiWord, ftiWords[ftiWord]);

            }

        }

    }



    // Perform the search and return the results as a block of HTML

    writer.Write(this.Search(keywords, fileList, wordDictionary, sortByTitle));

}



/// <summary>

/// Split the search text up into keywords

/// </summary>

/// <param name="keywords">The keywords to parse</param>

/// <returns>A list containing the words for which to search</returns>

private List<string> ParseKeywords(string keywords)

{

    List<string> keywordList = new List<string>();

    string checkWord;

    string[] words = Regex.Split(keywords, @"\W+");



    foreach(string word in words)

    {

        checkWord = word.ToLower(CultureInfo.InvariantCulture);

        

        if(checkWord.Length > 2 && !Char.IsDigit(checkWord[0]) &&

          !keywordList.Contains(checkWord))

            keywordList.Add(checkWord);

    }



    return keywordList;

}



/// <summary>

/// Search for the specified keywords and return the results as a block of

/// HTML.

/// </summary>

/// <param name="keywords">The keywords for which to search</param>

/// <param name="fileInfo">The file list</param>

/// <param name="wordDictionary">The dictionary used to find the words</param>

/// <param name="sortByTitle">True to sort by title, false to sort by

/// ranking</param>

/// <returns>A block of HTML representing the search results.</returns>

private string Search(List<string> keywords, List<string> fileInfo,

    Dictionary<string, List<long>> wordDictionary, bool sortByTitle)

{

    StringBuilder sb = new StringBuilder(10240);

    Dictionary<string, List<long>> matches = new Dictionary<string, List<long>>();

    List<long> occurrences;

    List<int> matchingFileIndices = new List<int>(),

        occurrenceIndices = new List<int>();

    List<Ranking> rankings = new List<Ranking>();



    string filename, title;

    string[] fileIndex;

    bool isFirst = true;

    int idx, wordCount, matchCount;



    foreach(string word in keywords)

    {

        if(!wordDictionary.TryGetValue(word, out occurrences))

            return "<b class=\"PaddedText\">Nothing found</b>";



        matches.Add(word, occurrences);

        occurrenceIndices.Clear();



        // Get a list of the file indices for this match

        foreach(long entry in occurrences)

            occurrenceIndices.Add((int)(entry >> 16));

            

        if(isFirst)

        {

            isFirst = false;

            matchingFileIndices.AddRange(occurrenceIndices);

        }

        else

        {

            // After the first match, remove files that do not appear for

            // all found keywords.

            for(idx = 0; idx < matchingFileIndices.Count; idx++)

                if(!occurrenceIndices.Contains(matchingFileIndices[idx]))

                {

                    matchingFileIndices.RemoveAt(idx);

                    idx--;

                }

        }

    }



    if(matchingFileIndices.Count == 0)

        return "<b class=\"PaddedText\">Nothing found</b>";



    // Rank the files based on the number of times the words occurs

    foreach(int index in matchingFileIndices)

    {

        // Split out the title, filename, and word count

        fileIndex = fileInfo[index].Split('\x0');



        title = fileIndex[0];

        filename = fileIndex[1];

        wordCount = Convert.ToInt32(fileIndex[2]);

        matchCount = 0;

        

        foreach(string word in keywords)

        {

            occurrences = matches[word];



            foreach(long entry in occurrences)

                if((int)(entry >> 16) == index)

                    matchCount += (int)(entry & 0xFFFF);

        }



        rankings.Add(new Ranking(filename, title, matchCount * 1000 / wordCount));

    }



    // Sort by rank in descending order or by page title in ascending order

    rankings.Sort(delegate (Ranking x, Ranking y)

    {

        if(!sortByTitle)

            return y.Rank - x.Rank;



        return x.PageTitle.CompareTo(y.PageTitle);

    });



    // Format the file list and return the results

    foreach(Ranking r in rankings)

        sb.AppendFormat("<div class=\"TreeItem\">\r\n<img src=\"Item.gif\"/>" +

            "<a class=\"UnselectedNode\" target=\"TopicContent\" " +

            "href=\"{0}\" onclick=\"javascript: SelectSearchNode(this);\">" +

            "{1}</a>\r\n</div>\r\n", r.Filename, r.PageTitle);



    // Return the keywords used as well in a hidden span

    sb.AppendFormat("<span id=\"SearchKeywords\" style=\"display: none\">{0}</span>",

        String.Join(" ", keywords.ToArray()));



    return sb.ToString();

}



</script>