a natural extension: using the com-plete http server for web-enablement

Moving Beyond Boundaries

A Natural Extension:Using the Com-plete HTTP

Server for Web-EnablementDavid Wimberly

Project/Program Director, University of Arkansas [email protected]


Presentation Overview

The Com-plete HTTP serverA Natural tool for web enablement

Web-Enablement at the University of ArkansasEnhancing existing applications with web

technologies Implementation considerations

Tips and techniquesExamples


The Com-plete HTTP Server

A Natural tool for web-enablementCom-plete 6.1 architectureNatural and the HTTP serverNatural programmer’s viewSystem viewAdvantages of this native MVS web and application

server


Com-plete 6.1 Architecture

VTAMInter-face

Utilities

Spool Telnet

HTTP

CGIapplications

Product X


Natural and the HTTP Server

HTTP

CGIapplications


Natural Programmer’s View

** Read user input from the webCALL ‘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/returnedSEPARATE…FIND EMPLOYEE WITH…

Simple CALL interface


System View

Natural programs:Run in the buffer poolAccess ADABAS and other resourcesCall 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


Native MVS Web and Application Server

NaturalCGI interface(HAANUPR)

HTTP


Web-Enablement with the Com-plete HTTP Server

Enhancing existing applications with web technologiesObjectivesBackgroundWeb session examples


U of A’s Objectives

To enhance and extend our mainframe applicationsReach new audiences

Employees and vendorsEnhance the presentation of information

Consolidate information and dress it upSimplify access for infrequent users

Not to replace all or even most 3270 functions Not to literally move a 3270 application to the web


U of A Background

Natural and ADABAS mainframe shop since 1986 BASIS: Business & Administrative Strategic

Information SystemsCustom inhouse developed applicationsEverything but student systems

Separate groups doing Java web development and screen scraping web deploymentPreference for Natural application code

Timing was right for the Com-plete HTTP Server


Logon


Menu


Browse PO selection screen


Help for Date-Close-Anticipated


Help for PO status, selection


Help for PO status, window


PO status returned


Budgetary Unit help


BU help search


Browse PO for Status and BU by Date


Browse result and PO selection


View of PO, top


View of PO, bottom


Select a PO to Browse Invoices for PO


Browse Invoices for PO


View Invoice


Select a PO to e-mail


E-mail the PO


PO list, vendor help


Vendor name search


Select vendor


PO search by vendor and date, initiated


PO search by vendor and date, results


Main menu, select pay activity


Browse pay activity


View earnings statement


Main menu, select addresses


3270 Addresses, etc. equivalent


Addresses, etc


Enter changes, view errors and previous values


Correct errors and update


Update confirmation screen


Logoff screen


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


How to Maintain State

The web is statelessEach interaction (submission) is self containedNo provision for a continuous user session

To maintain stateUse conversational mode, orCreate a session ID (*TIMESTMP)

Place it on the form as a hidden fieldSave and restore user session information using ADABAS


Back Button

Can subvert your state informationUser reappears not from where you left him

We consideredDisabling itRunning in a window without the toolbar or menubar Issuing errors if they used it

Limit the state information you maintainNot 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”


Back Button vs Return

As1 - 10

Bs1 - 10

Bs11 - 20

Bs21 - 30

Cs1 - 10

Cs11 - 20

Object selection or Paging

Back button

Return

Browse A objects at level 1

Browse B objects at level 2

Browse C objects at level 3


How to Return

Save program hierarchy information in hidden fields Our browse functions stack for each level:

Program IDSearch type in effect ISN and MU/PE occurrence of first record on the

screenWhether page back was valid

A Return Pops one of these from the stackExecutes the program and re-initiates the browse


Data Security

Sensitive data requires encryptionCom-plete HTTP server does not do SSLProxy server introduced to do all encryption and

decryption To avoid mixing document types and client side

warningsStyle sheets and graphics are delivered from a

separate web server using HTTPS


U of A’s Environment

HTTPS HTTP

Client with SSL enabled Web Browser

Proxy Server for SSL encryption

Web Server for *.gif and *.css files

IBM OS/390 running ADABAS, Natural, and Com-plete 6.1


Com-plete HTTP Server Configuration

HAANCONFSERVPOOL=YES

Uses a shared logon or sessionNATLIB=default library

Natural CGI programs in other libraries require an implicit logon

HTTPUSER=default user ID URL processing user exit

Restrict access to specific hosts or domains


Essential JavaScript

Cursor placement Selection processing and linking to different

servicesSet hidden form element to selected valueSubmit form

Window managementOpen and Close windowsPass and return values


Techniques for Generating HTML

Output your HTML to the Source Work Area Use Natural ISPF macros

But macros cannot be invoked directly as a Natural CGI program Use Natural

DEFINE PRINTER (1) OUTPUT 'SOURCE'FORMAT (1) PS=0 LS=133 EJECT OFF (1) SET CONTROL 'Z‘WRITE (1) NOTITLE …

Send the generated HTML to the browser HNANCGIP is provided, but limited to 72 character lines Create your own using longer lines via the USR1035N interface


Coding Tips

Develop an architecture and generate your Natural CGI programs using Natural ISPF macrosFast delivery of new functionsConsistentEasy to implement changes -- REGEN

To simplify making changes in page appearanceUse copy code, subprograms, constants defined in

an LDA, and an external style sheet HTML form fields can have dashes, but javascript

cannot reference themTranslate them to under-scores


HAANUPR Tips

Field namesMust end with a blank character

Field valuesAre not blank filled, reset them before your CALL

Field lengthPassed in: the largest value you will receiveReturned: the actual size of the field entered

CALL ‘HAANUPR’ #CGI-STATUS /* Return 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


Debugging Tips

You can’t sprinkle WRITEs into your code You can’t run the Natural debugger Trap and log errors on a data base file

Note: *ERROR-TA always starts as HNANERR and can only be changed by an assignment statement

Output your debugging information with your web page using HTMLThis may mean holding information until you reach

the page <body>


Code Reuse

Develop a Natural subprogram to output the core HTML document for an object (Purchase Order, Earnings Statement, etc.)Call from your Com-plete web application (Natural

CGI program)Call from online 3270 session to generate an HTML

e-mail attachmentRead the source work area and send to SMTP using ESS’ PROCESS WRITE-SPOOL

Call from batch to generate an HTML e-mail attachment


HTML for UWOMENU, part 1


HTML for UWOMENU, part 2


Natural code, UWCSBH


Natural code, output Action


Natural code, output table of Services


Natural code, read HTML form fields


Enhancement Proposal 958

Efficient browsing of ADABAS data (no wasted I/O)Forward or backward (descending)Possible due to STARTING WITH ISNRegular descriptorsMU type descriptorsUnique PE type descriptors

It is not possible with non-unique PE type descriptors!

Vote for FIND DESCENDING, enhancement proposal 958


Presentation Review

The Com-plete HTTP serverA great run time environment for Natural, and now

an enabler for Natural based web applications Web-Enablement at the University of Arkansas

Examples of what can be done with the Com-plete HTTP server

Implementation considerationsTips and examples from the University of Arkansas


Thank You!

a natural extension: using the com-plete http server for web-enablement

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