Parsing information from a webpage

**madwolf32** · Jun 15th, 2006, 07:22 AM

Hello:
I want to know how to parse(read) the information contained in a web page, using a VB applet that will refresh this information every 2 or 3 seconds. The web page is very simple, does not contain images and only a marquee (which can be eliminated), it only contaings text that displays temperature readings etcetera.
I know that i have to use the webbrowser control, and after the document has loaded i have to parse it, what i dont know is how to parse it.
Thanks

**Static** · Jun 15th, 2006, 07:29 AM

whats the URL? (or is it a local page)

We will need to see the source to be able to give u some code to do this.

if this page is online, the 2 to 3 seconds may not be possible with the webbrowser control. but what can be done is reload as soon as its done parsing which should still be very fast.

**madwolf32** · Jun 15th, 2006, 07:34 AM

The webpage is local (its being generated by a microcontroller board), i dont really have that much of a source code, but i have read some. I also want to know if it is possible to just extract the information, ignoring a marquee thats on the page.
thanks

**Static** · Jun 15th, 2006, 07:36 AM

Yes. but I need to see the full source and what u want to get from it.
Using the webbrowser control combined with a reference to the HTML Object Library..
it should be a snap.

Can u post the full source? (or attach the page)

Thanks!

**madwolf32** · Jun 15th, 2006, 07:39 AM

ok
i will post the full source

**shirazamod** · Jun 15th, 2006, 07:43 AM

It would be easiest using the webbrowser control, but I suggest you use the Inet control to increase the speed of the download (if that is a priority to you).

Post the source code of the page as Static said, and we will be able to help you generate code to parse it.

**madwolf32** · Jun 15th, 2006, 07:45 AM

Web Server for Embedded Applications\
</I>\r\n\
<BR>\
<A HREF=http://www.violasystems.com>\
www.violasystems.com - Embedding The Internet</A>\
</BODY>";

char Https_TestIndexPage[] = "HTTP/1.0 200 OK\r\n\
Last-modified: Fri, 18 Oct 2002 12:04:32 GMT\r\n\
Server: ESERV-10/1.0\nContent-type: text/html\r\n\
Content-length: 400\r\n\
\r\n\
<HEAD>\
<TITLE>UPRB Sistema de monitoreo de Sensores</TITLE></HEAD>\
<BODY>\
<DIV align=center>\
<H2><MARQUEE behavior=scroll direction=right width=500> MCF5282 Microcontroller</DIV></MARQUEE></H2>\
<BR>\
<DIV align=center>\
UPRB Salón 121 \
<HR>\
<BR> Temperatura Fahrenh = \
<I>\r\n\
<BR> Humedad Relativa = \
<BR> Intensidad de luz = \
<BR> Sensor de Humo = \
<BR> Sensor de Movimiento = \
<BR> Sensor de Puerta = \
<BR> Servidor WEB <BR></I>\r\n\
<BR>\
<A HREF=http://www.uprb.edu>\
www.uprb.edu</A>\
<BR><BR>\
<HR>\
</DIV>\
</BODY>";

**madwolf32** · Jun 15th, 2006, 07:46 AM

this the part of the C code that generates the web page

**Static** · Jun 15th, 2006, 07:47 AM

we need just the final result (the HTML) with data included for testing

**madwolf32** · Jun 15th, 2006, 07:50 AM

the thing is that the variables that are displayed are made in another section of the microcontroller, can u suggest any code with what you have up until now and i will fill in the gaps
where it says
<BR> Temperatura Fahrenh = \
<I>\r\n\
<BR> Humedad Relativa = \
<BR> Intensidad de luz = \
<BR> Sensor de Humo = \
<BR> Sensor de Movimiento = \
<BR> Sensor de Puerta = \

this is the part of the html that i want to read (its in spanish)

**madwolf32** · Jun 15th, 2006, 08:22 AM

ok i have been able to parse the inner text out of the web-page,now i have another problem:
when i try to reload the page after a variable(im controlling) changes, the information "read" by the program is not updated, and i know its a problem with the cache.
Any Info on this i will post the source code following this

**madwolf32** · Jun 15th, 2006, 08:23 AM

Option Explicit

Private Sub cmdExit_Click()
If MsgBox("Are you sure?", vbYesNo, "Exiting the application") = vbYes Then
Unload Me
End If
End Sub

Private Sub cmdGo_Click()
Dim objLink As HTMLLinkElement
Dim objMSHTML As New MSHTML.HTMLDocument
Dim objDocument As MSHTML.HTMLDocument

lblStatus.Caption = "Gettting document via HTTP"

' This function is only available with Internet Explorer 5

Set objDocument = objMSHTML.createDocumentFromUrl(txtURL.Text, vbNullString)

lblStatus.Caption = "Getting and parsing HTML document"

' Tricky, to make the function wait for the document to complete, usually
' the transfer is asynchronus. Note that this string might be different if
' you have another language than english for Internet Explorer on the
' machine where the code is executed.

While objDocument.readyState <> "complete"
DoEvents
Wend

lblStatus.Caption = "Document completed"

' Copying the source to the text box

txtSource.Text = objDocument.documentElement.innerText

DoEvents

' Copying the title of the page to the label

lblTitle.Caption = "Title : " & objDocument.Title

DoEvents

lblStatus.Caption = "Extracting links"

' Processing the link collection of the HTMLDocument object

For Each objLink In objDocument.links
lstLinks.AddItem objLink
lblStatus.Caption = "Extracted " & objLink
DoEvents
Next

lblStatus.Caption = "Done"

Beep

End Sub

**madwolf32** · Jun 15th, 2006, 08:26 AM

is there a way to make the program always look on the web page for the document instead of the cache?

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