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Get HTML Source from User Defined Web Address

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31 Jul 2009CPOL2 min read 53.3K   2.4K   38   7
A very easy way to get HTML source from user defined web address

GetHtml

Figure 1: HTML Source

WebBrowser

Figure 2: Web Browser

Introduction

Give me your web address, I will return to you the HTML source. This article will demonstrate to you a very effortless way to do this.

Background

HTTP post & HTTP reply are very common concepts. Some time ago, I had a little interest in that, so I tried to understand the features of .NET framework library. It was an excellent experience, it’s huge! & my interest went up. All of a sudden, I understand the use of the classes, HttpWebRequest & HttpWebResponse, which will be found at System.Net namespace & I tried to implement this idea.

Using the Code

This is a very simple method. I just use the following classes:

  1. HttpWebRequest 
  2. HttpWebResponse 
  3. StreamReader

HttpWebRequest  

Provides an HTTP-specific implementation of the WebRequest class. The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.

More details can be found at this link.

HttpWebResponse

Provides an HTTP-specific implementation of the WebResponse class. This class contains support for HTTP-specific uses of the properties and methods of the WebResponse class. The HttpWebResponse class is used to build HTTP stand-alone client applications that send HTTP requests and receive HTTP responses.

More details can be found at this link.

StreamReader

Implements a TextReader that reads characters from a byte stream in a particular encoding.
StreamReader is designed for character input in a particular encoding, whereas the Stream class is designed for byte input and output. Use StreamReader for reading lines of information from a standard text file. 

StreamReader defaults to UTF-8 encoding unless specified otherwise, instead of defaulting to the ANSI code page for the current system. UTF-8 handles Unicode characters correctly and provides consistent results on localized versions of the operating system.
By default, a StreamReader is not thread safe. See TextReader..::.Synchronized for a thread-safe wrapper.

The Read(array<Char>[]()[], Int32, Int32) and Write(array<Char>[]()[], Int32, Int32) method overloads read and write the number of characters specified by the count parameter. These are to be distinguished from BufferedStream..::.Read and BufferedStream..::.Write , which read and write the number of bytes specified by the count parameter. Use the BufferedStream methods only for reading and writing an integral number of byte array elements.

More details can be found at this link.

Sample Code Example

VB.NET
// Button event
Private Sub ButtonGet_Click(ByVal sender As System.Object, _
	ByVal e As System.EventArgs) Handles ButtonGet.Click
        Dim objGetSource As GetSource = New GetSource()
        Try
            If Me.TextBoxWebAddress.Text.Trim <> vbNullString Then
                Me.RichTextBoxHTMLSource.Text = _
                    objGetSource.GetHTML(Me.TextBoxWebAddress.Text.Trim())
                Me.WebBrowser1.Navigate(Me.TextBoxWebAddress.Text.Trim)
                Me.WebBrowser1.Refresh()
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message.ToString)
        End Try
End Sub 
VB.NET
// Get HTML Source class 
Imports System
Imports System.IO
Imports System.Web

Public Class GetSource
    Function GetHTML(ByVal strPage As String) As String
        Dim strReply As String = "NULL"
        'Dim objErr As ErrObject

        Try
            Dim objHttpRequest As System.Net.HttpWebRequest
            Dim objHttpResponse As System.Net.HttpWebResponse
            objHttpRequest = System.Net.HttpWebRequest.Create(strPage)
            objHttpResponse = objHttpRequest.GetResponse
            Dim objStrmReader As New StreamReader(objHttpResponse.GetResponseStream)

            strReply = objStrmReader.ReadToEnd()

        Catch ex As Exception
            strReply = "ERROR! " + ex.Message.ToString
        End Try

        Return strReply

    End Function
End Class

Conclusion

I hope that you will like it. Enjoy!

History

  • 1st August, 2009: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)



Comments and Discussions

 
QuestionGetting HTML Source from a webpage in VB.Net Pin
aarvee53 from Bangalore2-Jun-23 19:52
aarvee53 from Bangalore2-Jun-23 19:52 
QuestionHttpGET Pin
Member 1189363814-Mar-23 5:30
Member 1189363814-Mar-23 5:30 
GeneralWebClient Pin
tomas.hubelbauer1-Aug-09 4:39
tomas.hubelbauer1-Aug-09 4:39 
GeneralRe: WebClient Pin
Md. Marufuzzaman1-Aug-09 6:25
professionalMd. Marufuzzaman1-Aug-09 6:25 
GeneralRe: WebClient Pin
Md. Marufuzzaman1-Aug-09 7:43
professionalMd. Marufuzzaman1-Aug-09 7:43 
GeneralNice! Pin
rspercy6531-Jul-09 10:41
rspercy6531-Jul-09 10:41 
GeneralRe: Nice! Pin
Md. Marufuzzaman31-Jul-09 10:50
professionalMd. Marufuzzaman31-Jul-09 10:50 

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