IBM Tivoli Web Access for Information Management

4 IBM Tivoli Web Access for Information Management

1.1 Data flow

Your Web browser clients and your server machines communicate using TCP/IP protocol and

must be part of the same IP network. This network could either be the Internet itself or a

private network (intranet) that has no external connections or is connected to the Internet

through a firewall.

Web browser transactions are received by TCP/IP and queued for processing by the HTTP

Server. The HTTP Server Go Webserver API (GWAPI) REXX interface is used to process

Web browser transactions. The HTTP Server invokes the GWAPI REXX DLL, which

establishes a REXX environment and invokes the REXX programs in the Web Access

application.

Requests for static HTML are served immediately by reading the information either from the

HTML UNIX System Services directory (/usr/lpp/InfoMan/web/html) or from an internal cache.

If access to the Information Management for z/OS database is required, the Web Access

REXX programs use HLAPI/REXX calls to communicate with the database, formatting data

they receive into HTML code that they pass back to the HTTP Server to be returned to the

client.

1.1.1 The details

Figure 1-1 depicts the components of the Web Access application.

Figure 1-1 Web Access application flow

HTTP Server for z/OS

Caches

HTML

User data

P-class

HLAPI env

SRL

BLQPARMs

Session data

(cached record)

Session data

(cached record)

Core REXX

BLQWSWRT

BLQWRGET

BLQWRVAL

BLQWRUPD

BLQWRNEW

BLQWRUPD

BLQWRINQ

...

Business

Logic

BLQUXPRE

BLQUXFIL

BLQUXVAL

TSXs

Tables

(PIDT and alias)

Tivoli Web Access

Information

Management

Home Page

BLQHOME

TCP/IP Network

z/OS

HTML

Directory

httpd.envvars

httpd.conf

SAF/LDAP

Database

HLAPI/REXX

Database,

Data Model

Records

HLAPI/REXX

Chapter 1. Overview 5

The HTTP Server for z/OS, Information Management for z/OS, and Web Access, along with

your existing TCP/IP network and workstations, work together to enable a user to work with

records in your Information Management for z/OS database using a Web browser. Accessing

the Information Management for z/OS database in this way is done using a URL that can

either be typed into the browser’s address box or (more likely) hyperlinked from an existing

HTML page that your users frequent. When a Web user addresses the HTTP Server for

z/OS, it authenticates that user using either SAF (RACF) or Lightweight Directory Access

Protocol (LDAP) directories. If the user cannot be authenticated, processing stops and the

user is not allowed access to the Information Management for z/OS database. After the Web

user has been authenticated, the HTTP Server calls Web Access to process the request.

Web Access performs the request and returns HTML to the HTTP Server, which then sends

the HTML over your TCP/IP network to the Web browser to display to the user.

To process requests, Web Access interacts with your Information Management for z/OS

database using the Information Management HLAPI/REXX interface and the HTTP Server for

z/OS GWAPI, both of which are documented and supported general application programming

interfaces.

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Following is a breakdown of the components and functionality of the HTTP Server, Web

Access, and Information Management for z/OS:

HTTP Server for z/OS

The HTTP Server for z/OS does the following:

򐂰 Authenticates the Web user.

򐂰 Serves up static HTML directly from files stored in UNIX System Services directories in the

Hierarchical File System (HFS).

򐂰 Sends requests for dynamic HTML (any record display, search, update, or create) to Web

Access using the GWAPI.

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Web Access

Web Access provides the infrastructure required to display, update, create, or search for

records stored in the Information Management for z/OS database. This infrastructure consists

of the following:

򐂰 Core REXX—Modules that are executed to process the requests, including:

–

BLQWSWRT:

• Parses and translates the HTTP protocol request.

• Calls Web Access routines to process the request.

• Manages each Web user’s profile (user data cache).

• Obtains and frees a HLAPI session for each request.

• Manages the HLAPI environment cache.

• Handles error recovery.

–

BLQWRGET:

• Using HLAPI/REXX, reads a record from the Information Management for z/OS

database.

• Loads the record data into the user’s session data cache.

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4

No undocumented or unsupported interfaces are used by Web Access.

5

A Common Gateway Interface (CGI)-like interface.

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A cached copy of the record data for use by other Web Access routines and business logic user exits.