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Posted 13 May 2002

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Webcam Web Service

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4.64/5 (11 votes)
13 May 20022 min read
ASP.NET Web Service written in C# to grab a picture from a webcam

Contents

Introduction

C# Webcam is a port to ASP.NET and C# of the C++ ATL Web Service. It demonstrates the ease of use of C# and ASP.NET to build Web Services compared to ATL Server Web Service.

The project is still based on the Webcam COM component developed in the C++ ATL Web Service. .NET COM Interop is used to import it in the C# project.

Web Service

With Visual Studio, create a new C# ASP.NET Web Service project. Add a reference to 'CamServer 1.0 Type Library' on the COM tab. If 'CamServer 1.0 Type Library' is not in the list, you need to register the Dll CamServer.dll in the 'COM Components' directory. Add this Web Method to the source code obtained by the wizard:

[WebMethod]
public byte[] GrabFrame( short nQuality )
{
    //Shoot a picture from my webcam
    CAMSERVERLib.Camera cam = new CAMSERVERLib.CameraClass();

    return (byte[])cam.GrabFrame( nQuality );
}
Compared to the C++ ATL Web Service we need only three lines of code to get the picture from the COM component and return it to the client.

To have a little more fun coding I decided to add some features. Now it writes to the Windows EventLog the IP and the name of the machine calling it, after a DNS resolution. I have also added the date and hour of the local computer directly in the picture. And at last it increments a system performance counter to keep an eye on the number of people calling it.
[WebMethod]
public byte[] GrabFrame( short nQuality )
{
    //Write to the EventLog the IP and Host name
    string addr = HttpContext.Current.Request.UserHostAddress.Trim();

    string name;

    IPHostEntry host = null;

    try
    {
        host = System.Net.Dns.GetHostByAddress( addr );

        if ( host != null )
        {
            name = host.HostName;
            for( int i = 0; i < host.Aliases.Length; i++ )
                name += "*" + host.Aliases[i];

            eventLog.WriteEntry( addr + " : " + name );
        }
        else
        {
            name = "ERROR";

            eventLog.WriteEntry( name );
        }
    }
    catch( System.Exception error )
    {
        // process the error error.Message
    }

    //Shoot a picture from my webcam
    CAMSERVERLib.Camera cam = new CAMSERVERLib.CameraClass();

    byte[] picture = (byte[])cam.GrabFrame( nQuality );

    //Increments Performance Counter
    performanceCounterShoot.Increment();

    //Add the hour
    MemoryStream ms = new MemoryStream( picture );
    Bitmap bmp = new Bitmap( ms );

    Graphics g = Graphics.FromImage( bmp );

    string strDate = DateTime.Now.ToLongDateString() + 
                     " - " + 
                     DateTime.Now.ToLongTimeString(); 

    g.DrawString(   strDate,
                    new Font( FontFamily.GenericSansSerif, 10 ),
                    new SolidBrush( Color.Black ), 
                    new RectangleF( 1,1,320,240 ) 
                );

    g.DrawString(   strDate,
                    new Font( FontFamily.GenericSansSerif, 10 ),
                    new SolidBrush( Color.White ), 
                    new RectangleF( 0,0,320,240 ) 
                );

    MemoryStream ms2 = new MemoryStream();

    //Get codecs
    ImageCodecInfo[] icf = ImageCodecInfo.GetImageEncoders();

    EncoderParameters encps = new EncoderParameters( 1 );
    EncoderParameter encp = new EncoderParameter( Encoder.Quality, (long) nQuality );

    //Set quality
    encps.Param[0] = encp;

    bmp.Save( ms2, icf[1], encps );
    ms2.Close();

    return ms2.ToArray();
}

Client

The client ActiveX has no need to be modified. It is just needed to change the url of the Web Service, that is now:
http://YOUR_IP/webcamcsharp/service1.asmx?WSDL

Don't forget to register with regsvr32.exe the AxCamClient.dll in the 'COM Components' directory.

Conclusion

With few lines of source code you may obtain the same result then with little more C++ work.

The solution may be better because the COM component pack the picture, we unpack it to add date and hour then we pack again the new picture to send back to the client.

Problems Faced 

  • None.

History

Version 1.00 April 10, 2002
First release.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
Team Leader
France France
I am an experienced Team Leader & Senior Solutions Architect with a passion for shipping high-quality products by empowering development team and culture toward an agile mindset. I bring technical vision and strategy, leading engineering teams to move product, processes and architecture forward.

Comments and Discussions

 
QuestionNot able to download the code Pin
Member 103126722-Oct-13 23:00
MemberMember 103126722-Oct-13 23:00 
BugClass not registered error Pin
ravigpandey5-Aug-13 12:18
Memberravigpandey5-Aug-13 12:18 
GeneralMy vote of 5 Pin
Ashish Rathod14-Dec-12 2:03
MemberAshish Rathod14-Dec-12 2:03 
Question[Ask] why after i register camserver.dll i still cannot find CamServer 1.0 Type Library on COM tab? Pin
oqiee piphi poett2-Nov-11 16:48
Memberoqiee piphi poett2-Nov-11 16:48 
QuestionGrabFrame error Pin
international ninja28-Sep-11 11:16
Memberinternational ninja28-Sep-11 11:16 
Generalhi guys Pin
amiyamohanta29-Jun-10 8:52
Memberamiyamohanta29-Jun-10 8:52 
QuestionVideo in real-time (stream) Pin
lgallogarcia26-Sep-09 5:17
Memberlgallogarcia26-Sep-09 5:17 
AnswerRe: Video in real-time (stream) Pin
anuradha venkatesham2-Aug-12 23:04
Memberanuradha venkatesham2-Aug-12 23:04 
GeneralUnable to select an webcam Pin
Wcverfrisser23-Jul-08 23:25
MemberWcverfrisser23-Jul-08 23:25 
QuestionHow to do with two usb webcams ??? Pin
danieln219-Jun-08 13:41
Memberdanieln219-Jun-08 13:41 
GeneralI Am New to USe Com Component Help Me Pin
123sandip5-Jun-08 19:20
Member123sandip5-Jun-08 19:20 
Generalyou have virus Pin
chemita_cpu30-Aug-07 22:20
Memberchemita_cpu30-Aug-07 22:20 
GeneralAny idea using a pocket pc as webcam Pin
Du Sijun6-Jun-07 22:58
MemberDu Sijun6-Jun-07 22:58 
Generalcannot register CamServer.dll Pin
joejohnholdsworth9-Mar-07 1:34
Memberjoejohnholdsworth9-Mar-07 1:34 
GeneralRe: cannot register CamServer.dll Pin
joejohnholdsworth9-Mar-07 1:44
Memberjoejohnholdsworth9-Mar-07 1:44 
GeneralRe: cannot register CamServer.dll Pin
danieln219-Jun-08 13:37
Memberdanieln219-Jun-08 13:37 
Generalfailure in running webservice service1 Pin
rinal bhogi21-Mar-06 10:24
Memberrinal bhogi21-Mar-06 10:24 
GeneralReload image Pin
frankjonathan816-Feb-06 9:56
Memberfrankjonathan816-Feb-06 9:56 
Generalerror grab frame Pin
fcyjk,kl;25-Aug-05 15:09
Memberfcyjk,kl;25-Aug-05 15:09 
QuestionWhy is it so slow to grab am image and show it? Pin
davezh24-Jul-05 18:05
Memberdavezh24-Jul-05 18:05 
AnswerRe: Why is it so slow to grab am image and show it? Pin
k_catch6-Aug-10 3:55
Memberk_catch6-Aug-10 3:55 
GeneralBlack image Pin
Luan Almeida V.7-Apr-05 17:29
MemberLuan Almeida V.7-Apr-05 17:29 
GeneralRe: Black image Pin
umang551-Apr-06 18:10
Memberumang551-Apr-06 18:10 
QuestionHow to register AxCamClient.dll? Pin
wang896431-Mar-05 19:05
Memberwang896431-Mar-05 19:05 
AnswerRe: How to register AxCamClient.dll? Pin
rukesh12-Jul-05 6:58
Memberrukesh12-Jul-05 6:58 

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