Author: Stevan Rodrigues Email: stevanrin@hotmail.comDownload versions
The Search Engine module will search an entire page also dynamic pages for matching keyword(s) or a phrase and will count how many times the keyword(s) or phrase are found on the page, and display the results with the highest matches first. The module will search all files with the extensions that you can easily place the extension name into the web.config file where indicated. Files or folders that you don't want searched can be placed in the web.config where indicated, so these files and folders are not searched. Also now you can choose the encoding of your choice.
This updated article contains tips to globalize and enhance the code.
Note: It is best suited for small sites. Also you can modify this code to crawl pages internally by using regular expressions. For larger site you will need to write to XML file once periodically and then read from XML file. I have offered tips at the end of the section to do so.
Site Search Engine helps a user to trace the pages of his interest. When I was working on an ASP.NET project, I had to add the site search module. I had one in ASP but not in .NET. Hence the birth of this site search engine. My first version was just a single web form and I had not exploited the full features of the object oriented .NET language. In my spare time, I reworked my code to make the maximum use of the object oriented language. For this article, I further enhanced my design on the basis of the experience and the good practices suggested by different authors.
Mr. Song Tao from Beijing, China approached me with queries how to convert the module to Chinese. With his help I enhanced the code to support other languages. Also a few users encountered article errors when the SiteSearch.aspx was placed in the root. I modified the code to rectify the error.
The structure of the Site Search Engine is as follows:
The ability to define a class and create instances of classes is one of the most important capabilities of any object-oriented language. In the coming section, we see the classes that we have used in the search module.
| Class Name | Description |
SiteSearch |
Class for the web form where the user can search the site for certain words. |
Searches.CleanHtml |
Class to clean the HTMl content |
Searches.FileContent |
Class to get the content form the HTML File |
Searches.Page |
Class to store data of the pages |
Searches.PagesDataset |
Class to create and store results in dataset |
Searches.Site |
Class to read the configurations of the site |
Searches.UserSearch |
Class to store the search information per user |
Web Forms are one of the new, exciting features in Microsoft's .NET initiative. SiteSearch.aspx is a web form which is also the start page for the search module.
A Web Forms page consists of a page (ASPX file) and a code behind file (.aspx.cs file or .aspx.vb file). Our web form consists of SiteSearch.aspx and SiteSearch.aspx.vb. I will be treating them simultaneously touching on the main elements of the web form.
ASP.NET is an event-driven programming environment. We will see some event handlers and methods in the coming section.
The server controls are loaded on the Page object and the view
state information is available at this point. The Page_Load event checks if
sSite is nothing and assigns the Session("Site") variable to it.
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
If IsNothing(sSite) Then
sSite = Session("Site")
End If
End Sub
The search button event is fired when the search button is clicked. Here we put the code to change control settings or display text on the page. Here we check if the search contains text and then call the SearchSite method. DisplayContent() is called to assign values to different controls in the web page.
'*********************************************************************
'
' srchbtn_Click event
'
' Add code to this event.
'
'*********************************************************************
Private Sub srchbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles srchbtn.Click
Dim strSearchWords As String
'If there is no words entered by the user to search for then dont carryout the file search routine
pnlSearchResults.Visible = False
strSearchWords = Trim(Request.Params("search"))
If Not strSearchWords.Equals("") Then
Searchs.Site.ApplicationPath = String.Format("http://{0}{1}", Request.ServerVariables("HTTP_HOST"), Request.ApplicationPath)
sSite = SearchSite(strSearchWords)
Session("Site") = sSite
dgrdPages.CurrentPageIndex = 0
DisplayContent()
End If
End Sub
DisplayContent() is called to assign values to different controls in the web page. The DataGrid content is set by calling the BindDataGrid method. ViewState("SortExpression") is used to store the sort expression.
'*********************************************************************
'
' DisplayContent method
'
' The data is bound to the respective fields.
'
'*********************************************************************
Private Sub DisplayContent()
If Not IsNothing(sSite.PageDataset) Then
pnlSearchResults.Visible = True
lblSearchWords.Text = sSite.SearchWords
If ViewState("SortExpression") Is Nothing Then
ViewState("SortExpression") = "MatchCount Desc"
End If
BindDataGrid(ViewState("SortExpression"))
lblTotalFiles.Text = sSite.TotalFilesSearched
lblFilesFound.Text = sSite.TotalFilesFound
End If
End Sub
The main call to the search takes place in this method. UserSearch class which we will cover shortly stores the entire search information and the result of the search. UserSearch object, i.e. srchSite is created and its properties like SearchWords and SearchCriteria assigned. Also srchSite.Search method is called.
'************************************************************
'
' SearchSite method
'
' The sSite.PageDataset is used to populate the datagrid.
'
'************************************************************
Private Function SearchSite(ByVal strSearch_
As String) As Searchs.UserSearch
Dim srchSite As Searchs.UserSearch
srchSite = New Searchs.UserSearch()
'Read in all the search words into one variable
srchSite.SearchWords = strSearch
If Phrase.Checked Then
srchSite.SearchCriteria = Searchs.SearchCriteria.Phrase
ElseIf AllWords.Checked Then
srchSite.SearchCriteria = Searchs.SearchCriteria.AllWords
ElseIf AnyWords.Checked Then
srchSite.SearchCriteria = Searchs.SearchCriteria.AnyWords
End If
srchSite.Search(Server.MapPath("./"))
Return srchSite
End Function
The DataGrid control renders a multi-column, fully templated grid and is by far the most versatile of all data bound controls. Moreover the DataGrid control is the ASP.NET control of choice for data reporting. Hence, I have used it to display the search results. Since the focus of the article is the internal search engine, I will just give a brief overview of the features of the DataGrid used here.
Data binding is the process of retrieving data from a source and dynamically associating it to a property of a visual element. Because a DataGrid handles (or at least has in memory) more items simultaneously, you should associate the DataGrid explicitly with a collection of data—that is, the data source.
The content of a DataGrid is set by using its DataSource property. The entire search result is stored in the sSite.PageDataset.Tables("Pages"). Hence the content of the DataGrid is set to dvwPages i.e. sSite.PageDataset.Tables("Pages").DefaultView. BindDataGrid method is called every time the page loads.
'************************************************************
'
' BindDataGrid method
'
' The sSite.PageDataset is used to populate the datagrid.
'
'************************************************************
Private Sub BindDataGrid(ByVal strSortField As String)
Dim dvwPages As DataView
dvwPages = sSite.PageDataset.Tables("Pages").DefaultView
dvwPages.Sort = strSortField
dgrdPages.DataSource = dvwPages
dgrdPages.DataBind()
End Sub
The control has the ability to automatically generate columns that are based on the structure of the data source. Auto-generation is the default behavior of DataGrid, but you can manipulate that behavior by using a Boolean property named AutoGenerateColumns. Set the property to False when you want the control to display only the columns you explicitly add to the Columns collection. Set it to True (the default) when you want the control to add as many columns as is required by the data source. Auto-generation does not let you specify the header text, nor does it provide text formatting. Hence, here I have set it to False. You typically bind columns using the <columns> tag in the body of the <asp:datagrid> server control.
<Columns>
<asp:TemplateColumn>
<ItemTemplate>
<%# DisplayTitle(Container.DataItem( "Title" ), _
Container.DataItem( "Path" )) %>
<br>
<%# Container.DataItem( "Description" ) %>
<br>
<span class="Path">
<%# String.Format("{0} - {1}kb", DisplayPath(Container.DataItem( "Path" )) ,Container.DataItem( "Size" ))%>
</span>
<br>
<br>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
DisplayTitle method and DisplayPath method are used to display customized information to the columns in the DataGrid.
'****************************************
'
' DisplayTitle method
'
' Display title of searched pages
'
'****************************************
Protected Function DisplayTitle(ByVal Title _
As String, ByVal Path As String) As String
Return String.Format("<A href="{1}">{0}</A>", Title, Path)
End Function
'****************************************
'
' DisplayPath method
'
' Path of the file is returned
'
'****************************************
Protected Function DisplayPath(ByVal Path As String) As String
Return String.Format("{0}{1}/{2}", _
Request.ServerVariables("HTTP_HOST"), _
Request.ApplicationPath, Path)
End Function
Unlike the DataList control, the DataGrid control supports data pagination, that is, the ability to divide the displayed data source rows into pages. The size of our data source easily exceeds the page real estate. So to preserve scalability on the server and to provide a more accessible page to the user, you display only a few rows at a time. To enable pagination of the DataGrid control, you need to tell the control about it. You do this through the AllowPaging property.
The pager bar is an interesting and complimentary feature offered by the DataGrid control to let users easily move from page to page. The pager bar is a row displayed at the bottom of the DataGrid control that contains links to available pages. When you click any of these links, the control automatically fires the PageIndexChanged event and updates the page index accordingly. dgrdPages_PageIndexChanged is called when the page index changes.
'*****************************************************************
'
' dgrdPages_PageIndexChanged event
'
' The CurrentPageIndex is Assigned the page index value.
' The datagrid is then populated using the BindDataGrid function.
'
'*****************************************************************
Protected Sub dgrdPages_PageIndexChanged(ByVal s As Object, _
ByVal e As DataGridPageChangedEventArgs) _
Handles dgrdPages.PageIndexChanged
dgrdPages.CurrentPageIndex = e.NewPageIndex
DisplayContent()
End Sub
You control the pager bar by using the PagerStyle property’s Mode attribute. Values for the Mode attribute come from the PagerMode enumeration. Here we have chosen a detailed series of numeric buttons, each of which points to a particular page.
<PagerStyle CssClass="GridPager" Mode="NumericPages"></PagerStyle>
The DataGrid control does not actually sort rows, but it provides good support for sorting as long as the sorting capabilities of the underlying data source are adequate. The data source is always responsible for returning a sorted set of records based on the sort expression selected by the user through the DataGrid control’s user interface. The built-in sorting mechanism is triggered by setting the AllowSorting property to True.
dgrdPages_SortCommand is called to sort the DataGrid. The SortCommand event handler knows about the sort expression through the SortExpression property, which is provided by the DataGridSortCommandEventArgs class. In our code, the sort information is persisted because it is stored in a slot in the page’s ViewState collection.
Note: In my pages, I have disabled the header but if the header is shown, you can use it to sort the DataGrid.
'*****************************************************************
'
' dgrdAdditionalItems_SortCommand event
'
' The ViewState( "SortExpression" ) is Assigned
' the sort expression value.
' The datagrid is then populated using the BindDataGrid function.
'
'*****************************************************************
Protected Sub dgrdPages_SortCommand(ByVal s As Object, _
ByVal e As DataGridSortCommandEventArgs) _
Handles dgrdPages.SortCommand
ViewState("SortExpression") = e.SortExpression
DisplayContent()
End Sub
The role of the Page object is to store the data related to each page of the site.
The Page class defines the following properties
Path |
Stores the path of the file |
Title |
Stores the text in HTML title tag |
Keywords |
Stores the text in HTML meta keywords tags |
Description |
Stores the text in HTML meta description tags |
Contents |
Stores the text in HTML page |
Matchcount |
Stores the matches found in HTML page |
'***************************************************
'
' Size Property
'
' Assign and retrieve size of the file
'
'***********************************************
Public Property Size() As Decimal
Get
Return m_size
End Get
Set(ByVal Value As Decimal)
m_size = Value
End Set
End Property
'***************************************************
'
' Path Property
'
' Assign and retrieve path of the file
'
'***********************************************
Public Property Path() As String
Get
Return m_path
End Get
Set(ByVal Value As String)
m_path = Value
End Set
End Property
'***********************************************
'
' Title Property
'
'Assign and retrieve title of the file
'
'***********************************************
Public Property Title() As String
Get
Return m_title
End Get
Set(ByVal Value As String)
m_title = Value
End Set
End Property
'***********************************************
'
' Keywords Property
'
' Assign and retrieve Keywords
' (meta tags) of the file
'
'***********************************************
Public Property Keywords() As String
Get
Return m_keywords
End Get
Set(ByVal Value As String)
m_keywords = Value
End Set
End Property
'***********************************************
'
' Description Property
'
' Assign and retrieve description
' (meta tags) of the file
'
'***********************************************
Public Property Description() As String
Get
Return m_description
End Get
Set(ByVal Value As String)
m_description = Value
End Set
End Property
'***********************************************
'
' Contents Property
'
' Assign and retrieve contents of the file
'
'***********************************************
Public Property Contents() As String
Get
Return m_contents
End Get
Set(ByVal Value As String)
m_contents = Value
End Set
End Property
'***********************************************
'
' Contents Property
'
' Assign and retrieve MatchCount of the file
'
'***********************************************
Public Property MatchCount() As Integer
Get
Return m_matchcount
End Get
Set(ByVal Value As Integer)
m_matchcount = Value
End Set
End Property
The Page class has two private methods and two public methods. It defines the following methods:
It is a public method which checks if title, description and content exists. If the text for title is empty then it assigns the default value "No Title". If the text for description is empty then it either assigns the contents of the file or default value "There is no description available for this page".
'*************************************************
'
' CheckFileInfo method
'
' Subroutine to the check the file contains
' title and decription
'
'*************************************************
Public Sub CheckFileInfo()
'If the page contains no title then Page Title
' variable the appropriate message to display
If IsNothing(m_title) Or m_title.Trim().Equals("") Then
m_title = "No Title"
End If
'If the page contains no title then Page Description
'variable the appropriate message to display
If IsNothing(m_description) Or m_description.Trim().Equals("") Then
If IsNothing(m_contents) Or m_contents.Trim().Equals("") Then
m_description = _
"There is no description available for this page"
Else
If m_contents.Length > 200 Then
m_description = m_contents.Substring(0, 200)
Else
m_description = m_contents
End If
End If
End If
End Sub
Search method is a public method which calls SearchPhrase
and SearchWords methods depending on the search criteria. SearchPhrase
method searches for phrases while SearchWords searches for all
or any words. Both these methods calls SearchPattern metod which uses regular
expressions to search the files.
'*******************************************
'
' Search method
'
' Subroutine to the search file
'
'*******************************************
Public Sub Search(ByVal strSearchWords As String, _
ByVal SrchCriteria As SearchCriteria)
'If the user has choosen to search by phrase
If SrchCriteria = SearchCriteria.Phrase Then
SearchPhrase(strSearchWords)
'Else the search is either by all or any words
Else
SearchWords(strSearchWords, SrchCriteria)
End If
End Sub
'*********************************************************************
'
' SearchPhrase method
'
' Subroutine to the search file
'
'*********************************************************************
Private Sub SearchPhrase(ByVal strSearchWords As String)
Dim mtches As MatchCollection
mtches = SearchPattern(strSearchWords)
'Check to see if the phrase has been found
If mtches.Count > 0 Then
'Get the number of times the phrase is matched
m_matchcount = mtches.Count
End If
End Sub
'*********************************************************************
'
' SearchWords method
'
' Subroutine to the search file
'
'*********************************************************************
Private Sub SearchWords(ByVal strSearchWords As String, ByVal SrchCriteria As SearchCriteria)
Dim intSearchLoopCounter As Integer
Dim sarySearchWord As String() 'Array to hold the words to be searched for
Dim mtches As MatchCollection
'Split each word to be searched up and place in an array
sarySearchWord = Split(Trim(strSearchWords), " ")
'Loop round to search for each word to be searched
For intSearchLoopCounter = 0 To UBound(sarySearchWord)
'Set the pattern to search for
mtches = SearchPattern(sarySearchWord(intSearchLoopCounter))
If SrchCriteria = SearchCriteria.AnyWords Then
m_matchcount = m_matchcount + mtches.Count
ElseIf SrchCriteria = SearchCriteria.AllWords Then
'Check to see if any of the words have been found
If mtches.Count > 0 Then
'Get the number of times the search word is matched
If m_matchcount = 0 Or (m_matchcount > 0 And m_matchcount > mtches.Count) Then
m_matchcount = mtches.Count
End If
Else
'If the search word is not found then set the search found variable back to false as one of the words has not been found
m_matchcount = 0
Exit Sub
End If
End If
Next
End Sub
The escaped character \b is a special case. In a regular expression, \b denotes
a word boundary (between \w and \W characters) except within a [] character
class, where \b refers to the backspace character. In a replacement pattern,
\b always denotes a backspace.
We might need to drop the word boundary when your are using encoding other than UTF-8.
'*********************************************************************
'
' SearchPattern method
'
' Subroutine to the search file
'
'*********************************************************************
Private Function SearchPattern(ByVal strSearchWord As String) As MatchCollection
Dim regexp As Regex
Dim strPattern
'Set the pattern to search for
regexp = New Regex("", RegexOptions.IgnoreCase)
'Search the file for the phrase
If Searchs.Site.Encoding.Equals("utf-8") Then
strPattern = "\b{0}\b"
Else
strPattern = "{0}"
End If
Return regexp.Matches(m_contents, String.Format(strPattern, strSearchWord), RegexOptions.IgnoreCase)
End Function
It contains the following properties:
SearchCriteria |
The user choice of search is stored and retrieved from here |
SearchWords |
The search words used by the user is stored and retrieved from here |
TotalFilesSearched |
Total Files Searched is read from here |
TotalFilesFound |
Total Files Searched found is read from here |
'**********************************************************
'
' SearchCriteria Property
'
' Assign and retrieve SearchCriteria of the site
'
'**********************************************************
Public Property SearchCriteria() As Searchs.SearchCriteria
Get
Return m_searchCriteria
End Get
Set(ByVal Value As Searchs.SearchCriteria)
m_searchCriteria = Value
End Set
End Property
'**********************************************************
'
' SearchWords Property
'
'Assign and retrieve SearchWords of the site
'
'**********************************************************
Public Property SearchWords() As String
Get
Return m_searchWords
End Get
Set(ByVal Value As String)
m_searchWords = Value
End Set
End Property
'**********************************************************
'
' TotalFilesSearched Property
'
' Retrieve TotalFilesSearched of the site
'
'**********************************************************
Public ReadOnly Property TotalFilesSearched() As Integer
Get
Return m_totalFilesSearched
End Get
End Property
'**********************************************************
'
' TotalFilesFound Property
'
' Retrieve TotalFilesFound of the site
'
'**********************************************************
Public ReadOnly Property TotalFilesFound() As Integer
Get
Return m_totalFilesFound
End Get
End Property
'**********************************************************
'
' PageDataset Shared Property
'
' Retrieve data of the entire site of the site
'
'**********************************************************
Public ReadOnly Property PageDataset() As DataSet
Get
Return m_dstPages
End Get
End Property
Actual processing of the search begins here. DataSet to store the search results is created here and ProcessDirectory method is called.
'********************************************
'
' Search Method
'
' Search the entire site
'
'********************************************
Public Function Search(ByVal targetDirectory As String) As DataSet
'If the site is in English then use the server HTML encode method
If Searchs.Site.EnglishLanguage = True Then
'Replace any HTML tags with the HTML codes
'for the same characters (stops people entering HTML tags)
m_searchWords = m_page.Server.HtmlEncode(m_searchWords)
'If the site is not english just change the script tags
Else
'Just replace the script tag <> with HTML encoded < and >
m_searchWords = Replace(m_searchWords, "<", "<", 1, -1, 1)
m_searchWords = Replace(m_searchWords, ">", ">", 1, -1, 1)
End If
If m_dstPages Is Nothing Then
m_dstPages = Searchs.PagesDataset.Create()
End If
ProcessDirectory(targetDirectory)
Return m_dstPages
End Function
The ProcessDirectory loops through all the files and calls the ProcessFile method. Later, it also loops through the subdirectories and calls itself.
'*********************************************
'
' ProcessDirectory Method
'
' Files in the directories are searched
'
'********************************************
Private Sub ProcessDirectory(ByVal targetDirectory As String)
Dim fileEntries As String()
Dim subdirectoryEntries As String()
Dim filePath As String
Dim subdirectory As String
fileEntries = Directory.GetFiles(targetDirectory)
' Process the list of files found in the directory
For Each filePath In fileEntries
m_totalFilesSearched += 1
ProcessFile(filePath)
Next filePath
subdirectoryEntries = Directory.GetDirectories(targetDirectory)
' Recurse into subdirectories of this directory
For Each subdirectory In subdirectoryEntries
'Check to make sure the folder about to be searched
'is not a barred folder if it is then don't search
If Not InStr(1, Searchs.Site.BarredFolders, _
Path.GetFileName(subdirectory), vbTextCompare) > 0 Then
'Call the search sub prcedure to search the web site
ProcessDirectory(subdirectory)
End If
Next subdirectory
End Sub 'ProcessDirectory
The ProcessFile calls the GetInfo which returns the Searchs.Page object which contains all the information of the particular file. Later, it checks if the matchcount is greater than 0 and calls the CheckFileInfo to clean up the information stored in the Page object. It then stores the file in the PagesDataset.
'*******************************************************
'
' ProcessFile Method
'
' Real logic for processing found files would go here.
'
'*******************************************************
Private Sub ProcessFile(ByVal FPath As String)
Dim srchFile As Searchs.Page
srchFile = GetInfo(FPath)
If Not IsNothing(srchFile) Then
srchFile.Search(m_searchWords, m_searchCriteria)
If srchFile.MatchCount > 0 Then
m_totalFilesFound += 1
'Response.Write(srchFile.Contents)
srchFile.CheckFileInfo()
Searchs.PagesDataset.StoreFile(m_dstPages, srchFile)
End If
End If
End Sub 'ProcessFile
The GetInfo method's main task is to get the data of the file. It calls the shared method Searchs.FileContent.GetFileInfo where much of the work is done.
'*****************************************************************
'
' GetInfo Method
'
' File data is picked in this method
'
'*****************************************************************
Private Function GetInfo(ByVal FPath As String) As Searchs.Page
Dim fileInform As New FileInfo(FPath)
Dim sr As StreamReader
Dim srchFile As New Searchs.Page()
Dim strBldFile As New StringBuilder()
Dim strFileURL As String 'Holds the path to the file on the site
'Check the file extension to make sure the file
'is of the extension type to be searched
If InStr(1, Searchs.Site.FilesTypesToSearch, _
fileInform.Extension, vbTextCompare) > 0 Then
'm_page.Trace.Warn("File ext.", fileInform.Extension)
'Check to make sure the file about to be searched
'is not a barred file if it is don't search the file
If Not InStr(1, Searchs.Site.BarredFiles, _
Path.GetFileName(FPath), vbTextCompare) > 0 Then
'm_page.Trace.Warn("File", FPath)
If Not File.Exists(FPath) Then
'm_page.Trace.Warn("Error", _
'String.Format("{0} does not exist.", FPath))
'Add throw excetion here
'
'
Return Nothing
End If
Searchs.FileContent.GetFileInfo(FPath, srchFile)
Return srchFile
End If
End If
Return Nothing
End Function
Here the chunk of the data in the page is retrieved. The file content is either
read from the source if the files are static using the GetStaticFileContent
method. If the files are dynamic then content is retreived from server using
the GetDynamicFileContent method. Title information is retrieved
from the title tags, and description and keywords from meta tags by calling
the GetMetaContent method. Contents of the file is stripped from
the HTML page by calling Searchs.CleanHtml.Clean method.
'**********************************************
'
' GetFileInfo Method
'
' File data is picked in this method
'
'**********************************************
Public Shared Sub GetFileInfo(ByVal FPath As String, _
ByVal srchFile As Searchs.Page)
Dim fileInform As New FileInfo(FPath)
Dim strBldFile As New StringBuilder()
Dim fileSize As Decimal = fileInform.Length \ 1024
srchFile.Size = fileSize
GetFilePath(FPath, srchFile)
If InStr(1, Searchs.Site.DynamicFilesTypesToSearch, fileInform.Extension, vbTextCompare) > 0 Then
m_page.Trace.Warn("Path", String.Format("{0}/{1}", "", srchFile.Path))
GetDynamicFileContent(srchFile)
Else
GetStaticFileContent(FPath, srchFile)
End If
If Not srchFile.Contents.Equals("") Then
srchFile.Contents = sr.ReadToEnd()
'Read in the title of the file
srchFile.Title = GetMetaContent(srchFile.Contents,_
"<title>", "</title>")
'm_page.Trace.Warn("Page Title", strPageTitle)
'Read in the description meta tag of the file
srchFile.Description = GetMetaContent(srchFile.Contents,_
"<meta name=""description"" content=""", ",""">")
'm_page.Trace.Warn("Page Desc", strPageDescription)
'Read in the keywords of the file
srchFile.Keywords = GetMetaContent(srchFile.Contents,_
"<meta name=""keywords"" content=""", ",""">")
'm_page.Trace.Warn("Page Keywords", strPageKeywords)
srchFile.Contents = _
Searchs.CleanHtml.Clean(srchFile.Contents)
srchFile.Contents = _
strBldFile.AppendFormat("{0} {1} {2} {3}", _
srchFile.Contents, srchFile.Description, _
srchFile.Keywords, srchFile.Title).ToString.Trim()
'm_page.Trace.Warn("File Info", strBldFile.ToString)
End If
End Sub
'*********************************************************************
'
' GetStaticFileContent Method
'
' File Content is picked in this method
'
'*********************************************************************
Private Shared Sub GetStaticFileContent(ByVal FPath As String, ByVal srchFile As Searchs.Page)
Dim sr As StreamReader
sr = File.OpenText(FPath)
Try
srchFile.Contents = sr.ReadToEnd()
sr.Close()
Catch ex As Exception
m_page.Trace.Warn("Error", ex.Message)
srchFile.Contents = ex.Message
End Try
End Sub
GetDynamicFileContent branches into two method viz GetDynamicFileContentOther
or GetDynamicFileContentUTF depending on the encoding.
'*********************************************************************
'
' GetDynamicFileContent Method
'
' File Content is picked in this method
'
'*********************************************************************
Private Shared Sub GetDynamicFileContent(ByVal srchFile As Searchs.Page)
Dim wcMicrosoft As System.Net.WebClient
If Searchs.Site.Encoding.Equals("utf-8") Then
GetDynamicFileContentUTF(srchFile)
Else
GetDynamicFileContentOther(srchFile)
End If
End Sub
System.Net.WebClient provides common methods for sending data
to and receiving data from a resource identified by a URI. We make use of the DownloadData
which downloads data from a resource and returns a byte array.
Applications that target the common language runtime use encoding to map character representations from the native character scheme (Unicode) to other schemes. Applications use decoding to map characters from nonnative schemes (non-Unicode) to the native scheme. The System.Text Namespace provides classes that allow you to encode and decode characters.
'*********************************************************************
'
' GetDynamicFileContentOther Method
'
' File Content is picked in this method according to the encoding provided
'
'*********************************************************************
Private Shared Sub GetDynamicFileContentOther(ByVal srchFile As Searchs.Page)
Dim wcMicrosoft As System.Net.WebClient
Dim fileEncoding As System.Text.Encoding
Try
fileEncoding = System.Text.Encoding.GetEncoding(Searchs.Site.Encoding)
srchFile.Contents = fileEncoding.GetString( _
wcMicrosoft.DownloadData(String.Format("{0}/{1}", Searchs.Site.ApplicationPath, srchFile.Path)))
Catch ex As System.Net.WebException
m_page.Trace.Warn("Error", ex.Message)
srchFile.Contents = ex.Message
Catch ex As System.Exception
m_page.Trace.Warn("Error", ex.Message)
srchFile.Contents = ex.Message
End Try
End Sub
UTF8Encoding class encodes Unicode characters using UCS Transformation Format, 8-bit form (UTF-8). This encoding supports all Unicode character values and surrogates.
'*********************************************************************
'
' GetDynamicFileContentUTF Method
'
' File Content is picked in this method according to the utf-8 encoding
'
'*********************************************************************
Private Shared Sub GetDynamicFileContentUTF(ByVal srchFile As Searchs.Page)
Dim wcMicrosoft As System.Net.WebClient
Dim objUTF8Encoding As UTF8Encoding
Try
wcMicrosoft = New System.Net.WebClient()
objUTF8Encoding = New UTF8Encoding()
srchFile.Contents = objUTF8Encoding.GetString( _
wcMicrosoft.DownloadData(String.Format("{0}/{1}", Searchs.Site.ApplicationPath, srchFile.Path)))
Catch ex As System.Net.WebException
m_page.Trace.Warn("Error", ex.Message)
srchFile.Contents = ex.Message
Catch ex As System.Exception
m_page.Trace.Warn("Error", ex.Message)
srchFile.Contents = ex.Message
End Try
End Sub
The GetFilePath method coverts local folder path to reflect the URL of the site.
'*****************************************
'
' GetFilePath Method
'
' File path is modfied to be displayed
' as hyperlink in this method
'
'*****************************************
Private Shared Sub GetFilePath(ByVal strFileURL As String,_
ByVal srchFile As Searchs.Page)
'Turn the server path to the file into a URL path to the file
strFileURL = Replace(strFileURL, m_page.Server.MapPath("./"), "")
'Replace the NT backslash with the internet
'forward slash in the URL to the file
strFileURL = Replace(strFileURL, "\", "/")
'Encode the file name and path into the URL code method
strFileURL = m_page.Server.UrlEncode(strFileURL)
'Just incase it's encoded any backslashes
strFileURL = Replace(strFileURL.Trim(), _
"%2f", "/", vbTextCompare)
srchFile.Path = strFileURL
m_page.Trace.Warn("Url", srchFile.Path)
End Sub
GetMetaContent method uses regular expressions to strip the tags and get the required information.
'************************************************
'
' GetMetaContent Method
'
' Metacontent is stripped in this method
'
'************************************************
Private Shared Function GetMetaContent(ByVal strFile As String, _
ByVal strMetaStart As String, ByVal strMetaEnd As String) As String
'List the text between the title tags:
Dim regexp As Regex
Dim strMeta As String
Dim strPattern As String
Dim strInPattern As String
'If no description or keywords are found then you may be
'using http-equiv= instead of name= in your meta tags
If InStr(1, LCase(strFile), strMetaStart, 1) = 0 _
And InStr(strMetaStart, "name=") Then
'Swap name= for http-equiv=
strMetaStart = Replace(strMetaStart, "name=", "http-equiv=")
End If
'Build Pattern
strInPattern = "((.|\n)*?)"
strPattern = String.Format("{0}{1}{2}", _
strMetaStart, strInPattern, strMetaEnd)
regexp = New Regex(strPattern, RegexOptions.IgnoreCase)
'Match Pattern
strMeta = regexp.Match(strFile).ToString
'Build Pattern
strInPattern = "(.*?)"
strPattern = String.Format("{0}{1}{2}", _
strMetaStart, strInPattern, strMetaEnd)
'Get Pattern content
strMeta = regexp.Replace(strMeta, strPattern,_
"$1", RegexOptions.IgnoreCase)
Return strMeta
End Function
This class is used to create and build the DataSet. It consists of two methods StoreFile. Create method creates the DataSet to store the searched results and the Storefile is responsible for adding records to DataTable in the DataSet.
'*******************************************************
'
' Create Method - Shared method
'
' Creates a datset for the pages and returns the result
'
'********************************************************
Public Shared Function Create() As DataSet
'Objects are defined
Dim pgDataSet As New DataSet()
Dim keys(1) As DataColumn
'Table is created and added to table collection
pgDataSet.Tables.Add(New DataTable("Pages"))
'Schema of table is defined
pgDataSet.Tables("Pages").Columns.Add("PageId", _
System.Type.GetType("System.Int32"))
pgDataSet.Tables("Pages").Columns.Add("Title",_
System.Type.GetType("System.String"))
pgDataSet.Tables("Pages").Columns.Add("Description", _
System.Type.GetType("System.String"))
pgDataSet.Tables("Pages").Columns.Add("Path", _
System.Type.GetType("System.String"))
pgDataSet.Tables("Pages").Columns.Add("MatchCount", _
System.Type.GetType("System.Int32"))
pgDataSet.Tables("Pages").Columns.Add("Size", _
System.Type.GetType("System.Decimal"))
'PageId is defined as indentity
pgDataSet.Tables("Pages").Columns("PageID").AutoIncrement = True
pgDataSet.Tables("Pages").Columns("PageID").AutoIncrementSeed = 1
'PageId is defined as the primary key
keys(0) = pgDataSet.Tables("Pages").Columns("PageId")
pgDataSet.Tables("Pages").PrimaryKey = keys
Return pgDataSet
End Function
'********************************************************
'
' StoreFile Method - Shared method
'
' Creates a datset for the pages and returns the result
'
'********************************************************
Public Shared Sub StoreFile(ByVal dstPgs As DataSet,_
ByVal srchPg As Searchs.Page)
'Objects are defined
Dim pageRow As DataRow
'New row is created
pageRow = dstPgs.Tables("Pages").NewRow()
'Data is added
pageRow("Title") = srchPg.Title
pageRow("Description") = srchPg.Description
pageRow("Path") = srchPg.Path
pageRow("MatchCount") = srchPg.MatchCount
pageRow("Size") = srchPg.Size
'Row is added to the dataset
dstPgs.Tables("Pages").Rows.Add(pageRow)
End Sub
CleanHtml class contains a single public shared method which uses regular expressions to clean the HTML content.
'*****************************************************
'
' CleanFileContent Method
'
' Subroutine to the clean the file of html content
'
'*****************************************************
Public Shared Function Clean(ByVal Contents As String) As String
Dim regexp As Regex
Dim strPattern As String
strPattern = ""
regexp = New Regex(strPattern, RegexOptions.IgnoreCase)
Contents = regexp.Replace(Contents, _
"<(select|option|script|style|title)(.*?)" & _
">((.|\n)*?)</(SELECT|OPTION|SCRIPT|STYLE|TITLE)>",_
" ", RegexOptions.IgnoreCase)
Contents = regexp.Replace(Contents, "&(nbsp|quot|copy);", "")
'Contents = regexp.Replace(Contents, "<[^>]*>", "")
Contents = regexp.Replace(Contents, "<([\s\S])+?>",_
" ", RegexOptions.IgnoreCase).Replace(" ", " ")
'Contents = regexp.Replace(Contents, "<[^<>]+>",_
" ", RegexOptions.IgnoreCase)
'Contents = regexp.Replace("(<(\w+)[^>]*?>(.*?)</\1>", "$1")
Contents = regexp.Replace(Contents, "\W", " ")
'Trace.Warn("File Contents", Contents)
Return Contents
End Function
Site class consists of shared properties which store the configurations
of the entire site. These properties get their values from the web.config
file using the ConfigurationSettings.AppSettings.
Following are the properties of the site class:
FilesTypesToSearch |
Returns the files types you want to search |
DynamicFilesTypesToSearch |
Returns dynamic files to search |
BarredFolders |
Returns the barred folders |
EnglishLanguage |
Returns a Boolean value whether the language is English
or not. |
Encoding |
Returns the encoding for the site |
BarredFiles |
Returns barred files |
ApplicationPath |
Assign and returns the path of the application |
'*************************************************
'
' FilesTypesToSearch ReadOnly Property
'
' Retrieve FilesTypesToSearch of the site
'
'*************************************************
Public Shared ReadOnly Property FilesTypesToSearch() As String
Get
Return ConfigurationSettings.AppSettings("FilesTypesToSearch")
End Get
End Property
'*************************************************
'
' DynamicFilesTypesToSearch ReadOnly Property
'
' Retrieve FilesTypesToSearch of the site
'
'*************************************************
Public Shared ReadOnly Property DynamicFilesTypesToSearch() As String
Get
Return ConfigurationSettings.AppSettings("DynamicFilesTypesToSearch")
End Get
End Property
'*************************************************
'
' BarredFolders ReadOnly Property
'
' Retrieve BarredFolders of the site
'
'*************************************************
Public Shared ReadOnly Property BarredFolders() As String
Get
Return ConfigurationSettings.AppSettings("BarredFolders")
End Get
End Property
'*************************************************
'
' BarredFiles ReadOnly Property
'
' Retrieve BarredFiles of the site
'
'*************************************************
Public Shared ReadOnly Property BarredFiles() As String
Get
Return ConfigurationSettings.AppSettings("BarredFiles")
End Get
End Property
'*************************************************
'
' EnglishLanguage Property
'
' Retrieve EnglishLanguage of the site
'
'*************************************************
Public Shared ReadOnly Property EnglishLanguage() As String
Get
Return ConfigurationSettings.AppSettings("EnglishLanguage")
End Get
End Property
'*********************************************************************
'
' Encoding Property
'
' Retreive Encoding of the site
'
'*********************************************************************
Public Shared ReadOnly Property Encoding() As String
Get
Return ConfigurationSettings.AppSettings("Encoding")
End Get
End Property
'**********************************************************
'
' ApplicationPath Property
'
'Assign and retrieve ApplicationPath of the site
'
'**********************************************************
Public Property ApplicationPath() As String
Get
Return m_ApplicationPath
End Get
Set(ByVal Value As String)
m_ApplicationPath = Value
End Set
End Property
The ASP.NET configuration system features an extensible infrastructure that enables you to define configuration settings at the time your ASP.NET applications are first deployed, so that you can add or revise configuration settings at any time, with minimal impact on operational Web applications and servers. Multiple configuration files, all named Web.config, can appear in multiple directories on an ASP.NET Web application server. Each Web.config file applies configuration settings to its own directory and all child directories below it. As mentioned earlier, the site configurations can be assigned in the web.config file.
<appSettings>
<!-- Place the names of the files types you want searching
in the following line separated by commas -->
<add key="FilesTypesToSearch" value=".htm,.html,.asp,.shtml,.aspx"
/>
<!-- Place the names of the dynamic files types you want
searching in the following line separated by commas -->
<add key="DynamicFilesTypesToSearch" value=".asp,.shtml,.aspx" />
<!-- Place the names of the folders you don't
want searched in the following line separated by commas-->
<add key="BarredFolders"
value="aspnet_client,_private,_vti_cnf,_vti_log,_vti_pvt,_vti_script,_vti_txt,cgi_bin,_bin,bin,_notes,images,scripts"
/>
<!-- Place the names of the files you don't want searched in the
following line separated by commas include the file extension-->
<add key="BarredFiles"
value="localstart.asp,iisstart.asp,AssemblyInfo.vb,
Global.asax,Global.asax.vb,SiteSearch.aspx"
/>
<!-- Set this boolean to False if you are not using
an English language web site-->
<add key="EnglishLanguage" value="True" />
<!-- Set this to the Encoding of the web site-->
<add key="Encoding" value="utf-8" />
</appSettings>
The application has been tested with the web form SiteSearch.aspx in the root directory. So my suggestion is that you do the same. Later on, you can try moving it to any subfolder. All my classes I have placed in components folder. You can move them to any folder of your choice.
When the application is place in the root you may get the following errors.
The remote server returned an error: (401) Unauthorized.
OR
The remote server returned an error: (500) Internal Server Error.
This error is caused because
1)If server returns (401) Unauthorized, the application is unable to read the file beacuse of right access.
2)If server returns (500) Internal Server Error, the page that it was trying to read returned an error. The page that application was trying to read either has an error or requires parameters because of which it returns error
Follow the steps to rectify the error
1)In the Web.config ensure that the BarredFolders list is comprehensive
aspnet_client,_private,_vti_cnf,_vti_log,_vti_pvt,_vti_script,_vti_txt,cgi_bin,_bin,bin,_notes,images,scripts
2)Ensure that the BarredFiles list is comprehensive and contains localstart.asp,iisstart.asp
The Search Engine module can be easily globalize. For this purpose we will see how to convert it into Chinese language.
The XML declaration must appear as the first line of the document without other content, including white space, in front of the start <.
The XML declaration in the document map consists of the following:<?xml version="1.0" encoding="Your Encoding" ?>. By default the visual studio uses the utf-8 encoding this needs to be changed to encoding that you want to use. Here we will change to gb2312. Hence the XML Declaration needs to be modified as follows.
<?xml version="1.0" encoding="utf-8" ?>
<?xml version="1.0" encoding="gb2312" ?>
The requestEncoding and responseEncoding specifies
the assumed encoding of each incoming request and outgoing response. The default
encoding is UTF-8, specified in the <globalization> tag included in the
Machine.config file created when the .NET Framework is installed. If encoding
is not specified in a Machine.config or Web.config file, encoding defaults to
the computer's Regional Options locale setting. We will need to change requestEncoding and responseEncoding
to reflect the change in encoding.
<globalization requestEncoding="utf-8" responseEncoding="utf-8" />
<globalization requestEncoding="gb2312" responseEncoding="gb2312" />
In order to avoid building the code when the encoding changes we need to add
the encoding key to the appsettings.
<!-- Set this to the Encoding of the web site--> <add key="Encoding" value="gb2312" />
Also change the English Language key to false.
<!-- Set this boolean to False if you are not using an English language web site--> <add key="EnglishLanguage" value="True" />
Last but not the least, the codepage attribute has to be added in the page
directive.
<%@ Page Language="vb" Trace="False" AutoEventWireup="false" Codebehind="SiteSearch.aspx.vb" Inherits="SearchDotnet.SiteSearch" debug="false" %>
<%@ Page Language="vb" Trace="False" AutoEventWireup="false" Codebehind="SiteSearch.aspx.vb" Inherits="SearchDotnet.SiteSearch" debug="false" codePage="936" %>
The application is meant for small sites. For bigger sites, the code can be further enhanced. Infact you will need to write to database say XML file periodically and then read from it. I will offer a few tips to do so.
1)In my code I search and filter the data using regular expression. Instead of this you will have to write entire data (not filtered data) to XML file using the following method.
Private Shared Sub WriteXmlToFile(ByVal thisDataSet As DataSet)
If thisDataSet Is Nothing Then
Return
End If
thisDataSet.WriteXml(XMLFile)
End Sub
2)Later you will need to read the xml from file save it to the shared dataset say Searchs.Site.PageDataset.Tables("Pages").
Private Shared Function ReadXmlFromFile() As DataSet
' Create a new DataSet.
Dim newDataSet As New DataSet("New DataSet")
' Read the XML document back in.
' Create new FileStream to read schema with.
Dim fsReadXml As New System.IO.FileStream(XMLFile, System.IO.FileMode.Open)
' Create an XmlTextReader to read the file.
Dim myXmlReader As New System.Xml.XmlTextReader(fsReadXml)
' Read the XML document into the DataSet.
newDataSet.ReadXml(myXmlReader)
' Close the XmlTextReader
myXmlReader.Close()
Return newDataSet
End Function
3)For each search you will later need use the Select method of PageDataset.Tables to filter it according to search results. Filter dataset might look like this. FillDataset method contains logic to create and add search results (array of DataRow) to database.
Private Sub FiterPagesDatset()
Dim strExpr As String
Dim foundRows As DataRow()
Dim Field() As String = {"Title", "Description", "Keywords", "Contents"}
strExpr = SomeFunction 'Your function to build the query.
foundRows = Searchs.Site.PageDataset.Tables("Pages").Select(strExpr)
FillDataset(foundRows)
End Sub
4)The filtered result store it into another dataset and use it to display results
When I was working on the project, the question was how to display the results. DataGrid was my choice as we can exploit a lot of its features which are not present in other list controls. Once my question was solved, the next was how to pass content to the DataGrid. DataSet was the only alternative. As I worked further before storing the information in DataSet, I had to move to and fro with bulk information about the page. I decided to use site object to store the information.
One of the authors suggested the following best practices:
After carefully analyzing the code and keeping the best practices in mind, I redesigned the code to what it is now.
Modified the code to read dynamic pages.
Enhanced the code to support globalization.