A Natural Extension: Using the Com-plete HTTP Server for Web-Enablement

1. A Natural Extension:Using the Com-plete HTTP Server for Web-Enablement David Wimberly Project/Program Director, University of Arkansas wdw@uark.edu

2. Presentation Overview • The Com-plete HTTP server • A Natural tool for web enablement • Web-Enablement at the University of Arkansas • Enhancing existing applications with web technologies • Implementation considerations • Tips and techniques • Examples

3. The Com-plete HTTP Server • A Natural tool for web-enablement • Com-plete 6.1 architecture • Natural and the HTTP server • Natural programmer’s view • System view • Advantages of this native MVS web and application server

4. VTAM Inter- face CGI applications Product X Utili ties Spool Telnet Natural HTTP HLLI Posix RTS Com-plete 6.1 Architecture

5. CGI applications Natural HTTP HLLI Posix RTS Natural and the HTTP Server

6. Natural Programmer’s View • Simple CALL interface ** Read user input from the web CALL ‘HAANUPR’ #CGI-STATUS /* Return code and reason code #CGI-ACTION /* GET-DATA or PUT-DATA #FIELD-NAME /* HTML form field name #FIELD-VALUE /* User input value #FIELD-LENGTH /* Length anticipated/returned SEPARATE… FIND EMPLOYEE WITH…

7. System View • Natural programs: • Run in the buffer pool • Access ADABAS and other resources • Call external module HAANUPR • To read HTML form inputs and controls (GET or POST) • To send dynamically generated HTML to the browser • Configuration parameters for default user ID, library, buffer sizes, etc. • Automatic EBCDIC/ASCII translations and url encoding/decoding

8. Com-plete v6.1 Natural HLLI Posix TCP/IP ESX TCP/IP ADABAS Natural CGI interface (HAANUPR) HTTP Operating System Native MVS Web and Application Server

9. Web-Enablement with the Com-plete HTTP Server • Enhancing existing applications with web technologies • Objectives • Background • Web session examples

10. U of A’s Objectives • To enhance and extend our mainframe applications • Reach new audiences • Employees and vendors • Enhance the presentation of information • Consolidate information and dress it up • Simplify access for infrequent users • Not to replace all or even most 3270 functions • Not to literally move a 3270 application to the web

11. U of A Background • Natural and ADABAS mainframe shop since 1986 • BASIS: Business & Administrative Strategic Information Systems • Custom inhouse developed applications • Everything but student systems • Separate groups doing Java web development and screen scraping web deployment • Preference for Natural application code • Timing was right for the Com-plete HTTP Server

12. Logon

13. Menu

14. Browse PO selection screen

15. Help for Date-Close-Anticipated

16. Help for PO status, selection

17. Help for PO status, window

18. PO status returned

19. Budgetary Unit help

20. BU help search

21. Browse PO for Status and BU by Date

22. Browse result and PO selection

23. View of PO, top

24. View of PO, bottom

25. Select a PO to Browse Invoices for PO

26. Browse Invoices for PO

27. View Invoice

28. Select a PO to e-mail

29. E-mail the PO

30. PO list, vendor help

31. Vendor name search

32. Select vendor

33. PO search by vendor and date, initiated

34. PO search by vendor and date, results

35. Main menu, select pay activity

36. Browse pay activity

37. View earnings statement

38. Main menu, select addresses

39. 3270 Addresses, etc. equivalent

40. Addresses, etc

41. Enter changes, view errors and previous values

42. Correct errors and update

43. Update confirmation screen

44. Logoff screen

45. Implementation Considerations • How to maintain state • Back button • Back button vs Return • Data security • Configuration • Essential JavaScript • Techniques for generating HTML • Coding tips, debugging tips, and more • Example HTML and Natural code

46. How to Maintain State • The web is stateless • Each interaction (submission) is self contained • No provision for a continuous user session • To maintain state • Use conversational mode, or • Create a session ID (*TIMESTMP) • Place it on the form as a hidden field • Save and restore user session information using ADABAS

47. Back Button • Can subvert your state information • User reappears not from where you left him • We considered • Disabling it • Running in a window without the toolbar or menubar • Issuing errors if they used it • Limit the state information you maintain • Not the active position within a READ loop • Instead, hide the first and last ISN on a page • Have one entry point -- a dispatcher program • action=“uwowdis”

48. Back Button vs Return Browse A objects at level 1 Browse B objects at level 2 Browse C objects at level 3 As 1 - 10 Bs 1 - 10 Cs 1 - 10 Object selection or Paging Cs 11 - 20 Bs 11 - 20 Back button Return Bs 21 - 30

49. How to Return • Save program hierarchy information in hidden fields • Our browse functions stack for each level: • Program ID • Search type in effect • ISN and MU/PE occurrence of first record on the screen • Whether page back was valid • A Return • Pops one of these from the stack • Executes the program and re-initiates the browse

50. Data Security • Sensitive data requires encryption • Com-plete HTTP server does not do SSL • Proxy server introduced to do all encryption and decryption • To avoid mixing document types and client side warnings • Style sheets and graphics are delivered from a separate web server using HTTPS