1. Educational Tools as Web Services Milena Stanković, Milan Rajković Faculty of Electronic, Niš, Serbia

2. Virual Web Laboratories for permanent Engeenering Education Project suported by Ministry of Technologies and Science of Serbia Set of Virtual Web laboratories for Automatique Control Programing languages Logic Design Image Processing Internet Technologies

3. The Web Services Architecture

4. Web model Web client Web server Web server application Request MIME content via HTTP ISAPI NSAPI CGI Apache module Response Request passing

5. Web model  The most wide spread distributed model  Standardized by W3C consortium  Advantages “Loosely coupled” model HTTP protocol is implemented on all platforms  Disadvantages Applications are browser based, and application to application development is impossible

6. Web Services  The basic idea: Adapting the loosely coupled Web programming model for use in applications that are not browser-based.  Moving from HTML to XML allows structure data descriptions.  Definition: “Web Services are encapsulated, loosely coupled contracted functions offered via standard protocols”

7. Web Service architecture layers  SOAP- communication protocol  WSDL- language for describing Web Services  UDDI- enables finding Web Services on the Internet  XML- fundamental language for the whole architecture UDDI WSDL SOAP XML

8. Using SOAP over the Web SOAP XML messages via HTTP ISAPI NSAPI CGI Apache module Web client Web server Web service application RequestResponse Request passing

9. Web Services for Digital Image Processing

10. DIP++ classes  DIP ++ classes (Digital Image Processing) are developed at Faculty of Electronic Engineering, Niš  These classes can be used for processing various types of images (bmp, jpeg, gif, tiff...)  DIP ++ classes are written in Microsoft Visual C++ 6.0, and they are publicly available in the form of.lib files

11. DIP Web Service architecture Web Service client Web Service application DIP++ functions DLL written using MV C++ CGI created using Delphi 7 PHP script application

12. DIP Web Service application  The Web Service application contains Web Services for digital image processing and exposes them on the Internet  It is a CGI application, written using Delphi 7 and installed on Microsoft IIS 5.0  Base64 encoding used for array of bytes which represents the picture being processed  An example of DIP Web service: function MedianFilter(inBuffer: TByteDynArray; pictureType: String; windowWidth, windowHeight: Integer; token: String): TByteDynArray; stdcall;

13. DIP Web Service client  An example of Web Service client is written in PHP4  NuSOAP classes, by Deitrich Ayala, are used for calling Web Services  For picture data coding and decoding functions base64_encode and base64_decode are used

14. DIP Web Service client