® IBM Software Group © 2009 IBM Corporation Web Services – An Introduction Leigh Compton – Certified IT Specialist – CICS, Web Services and Java David

®

IBM Software Group

© 2009 IBM Corporation

Web Services – An IntroductionWeb Services – An Introduction

Leigh Compton – Certified IT Specialist – CICS, Web Services and JavaDavid Myers – RDz PLM

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IBM Trademarks and Copyrights

© Copyright IBM Corporation 2007, 2008, 2009, 2010. All rights reserved.

The information contained in these materials is provided for informational purposes only, and is provided AS IS without warranty of any kind, express or implied. IBM shall not be responsible for any damages arising out of the use of, or otherwise related to, these materials. Nothing contained in these materials is intended to, nor shall have the effect of, creating any warranties or representations from IBM or its suppliers or licensors, or altering the terms and conditions of the applicable license agreement governing the use of IBM software. References in these materials to IBM products, programs, or services do not imply that they will be available in all countries in which IBM operates.

This information is based on current IBM product plans and strategy, which are subject to change by IBM without notice. Product release dates and/or capabilities referenced in these materials may change at any time at IBM’s sole discretion based on market opportunities or other factors, and are not intended to be a commitment to future product or feature availability in any way.

IBM, the IBM logo, the on-demand business logo, Rational, the Rational logo, and other IBM Rational products and services are trademarks or registered trademarks of the International Business Machines Corporation, in the United States, other countries or both. Other company, product, or service names may be trademarks or service marks of others.

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Services are the driving business system design paradigm of the day.

Services – Generated by RDz provide a cross platform language for business oriented development

Services and SOA are based on the concept of “Service Oriented Design”

ExternalWebService

WSDLRDz

Records

RDz Service

RDz Service

WSDL

RDz Interface

RDz Interface

RDz SOA for WAS, CICS, System i

At development time… Focus on the business logic Implement SOA design elements: services and interfaces Leverage existing business developers for new SOA

development Ignore deployment targets/technology while coding/testing

Deploy Web Services…To any platform Java to WAS/Tomcat/etc. COBOL to CICS, iSeries

As… A Web Service (uses SOAP) A private service (uses CICS ECI, J2C, or TCP) Other SOA runtimes when they reach critical mass

Leverage external web services… Service Interfaces

Represent external web services Are created via import from WSDL Allow the RDz developer to stay within the context of the RDz programming model

External Applications

Deploy Services as Web ServicesDeploy Services as Web Services

Consume external servicesConsume external services

The Promise of Services and SOA (Service Oriented Architecture)

© 2008 IBM Corporation4

At a Very High LevelAt a Very High Level

What we’re ultimately getting at here is a decoupling of application requester from the application provider. And the placement of an intermediary function to make things more flexible and dynamic:

Intermediary Function

Simple forwarding

or

Complex message transformation and protocol remapping

Passing of an agreed-to request in

message format

Return of information in the form of an agreed-to message response


What’s Behind This … Why Are We Talking About ThisWhat’s Behind This … Why Are We Talking About ThisOver the years our application systems have become very complicated, with tightly-coupled relationships that are often little understood.

Actual application architecture Actual application architecture map from real-life customer map from real-life customer

Changes to any part of this are …

• Difficult to determine what impact there is on other components

• Expensive to analyze, often expensive to implement

• Delays often result in missed opportunities

Two objectives: eliminate tight (hard-coded) interconnections, and create a way for one program to dynamically seek, find, and bind to another.

Two basic problems:

1. Inflexible connectivity definitions (hard-coded, deeply imbedded in code)

2. Knowledge of relationships lost over time

Possible third: duplication of resources because reuse

difficult in this environment


A “Service” – Conceptual DefinitionA “Service” – Conceptual DefinitionA discrete set of business or technical functionality that can be identified, has a defined set of input and outputs, and is reusable

User“Consumer”

Service“Producer”Input

Output

Discrete – can be contained within a definite and known “fence”Identified -- it’s recognized as a service and people acknowledge it as a serviceDefined – the input and the outputs are known and understoodReusable – is not just a one-time thing

There’s nothing revolutionary about this. What’s different is that we’re coming to a point where improvements in technology have allowed us to do this better than before:

• Settled on a universal and common networking protocol -- TCP/IP• Networking bandwidth is increasingly available, cheap and reliable• The idea of “industry standards” has matured and is embraced rather than resisted• Java as a platform-unaware language has opened up a new world of interoperability

Inte

rfac

eImplementation

Exactly how the service is implemented behind the interface doesn’t really matter to the

consumer of the service


An Example - Currency ExchangeAn Example - Currency Exchange

IBM’s Travel Expense Reimbursement application does not do its own foreign currency conversions … it uses an external service for that:

Currency = $US?

Inte

rfac

e

Implementation$US

No

YesInternet

[ £100,$US,15-June ]

[ $196.00 ]

For this to work, several things need to be in place:• IBM application needs to know about the service and where it is located• IBM application needs to know the interface requirements: parameters, sequence, format

Could IBM have coded an internal subroutine to do currency conversions? Sure. But very good converters exist on the web and in this case IBM took advantage of them.

Understanding what services are available, where they’re located and what interface requirements they have is a key aspect of SOA.


Another Example - CICS Web ServiceAnother Example - CICS Web ServiceWe’ve not really defined what a “web service” is … but for now be aware that CICS has the ability to front-end existing CICS programs with a web service interface … “exposing” the CICS program as a service:

CICS Web Service

Front-End

Existing CICS

Program

CICS V3.1

NetworkWeb Service

Client Program

CICS program unchanged

Appl

3270EXCI

Traditional access unaffected

New front-end allows service

oriented invocation

SOAP/HTTP

Key point is that a traditional CICS program can be turned into a message based “service” which can then be used by “service consumers” in your network

Inte

rfac

e


Service Oriented ArchitectureService Oriented Architecture

Service oriented architecture Service oriented architecture (SOA) is a business-driven IT (SOA) is a business-driven IT architectural approach that architectural approach that supports integrating the supports integrating the business as linked, repeatable business as linked, repeatable business tasks, or services.business tasks, or services.

From www.ibm.com

An exact definition is probably not all that important. It's more important to understand:

• The concept of a “service”

• The implied value of a loosely coupled “service” rather than a tightly coupled connection to another application’s interface … flexibility

• That “SOA” is a path towards the use of more and more services in your I/T architecture … not a “thing” or an “all-at-once” proposition

• That there’s more to it than just services.


CICS is an Application CICS is an Application ServerServerCICS is a system that hosts applications, and provides a rich set of “services” which the applications may make use of:

CICS Services

External Data Resources“EXEC CICS” API C++ classes for CICS JCICS classes for Java

“CICS Programs”COBOL

C/C++

PL/I

AssemblerJava EJBs

CICS EJB Support(transparent mapping)

CICS

ProgramAccess

JVMs

There are many ways to access programs running in CICS -- 3270 terminal, EXCI or EPI, RMI/IIOP, MQ, HTTP. Our focus here is going to be accessing via Web Services.

These are the “existing assets” we’re looking to “expose” as services


Provider vs. Requester -- CICS Can Do BothProvider vs. Requester -- CICS Can Do Both

CICS as a Web Service Provider …

We typically consider CICS as a provider of web services:

Web Service Client

Appl

CICS

But it can also be a consumer (or requester) of web services:

Appl

CICS

Web Service Client

This web service could be anywhere accessible to CICS -- inside your company or outside

We’ll focus on the top one for the most part. The concepts you’ll see are mostly applicable to both environments. See “CICS Web Services Guide” (SC34-6458) for more.

The case where existing (or new) CICS applications are exposed as reusable services.

External Service


CICS as a Web Services ProviderCICS as a Web Services Provider

Three basic requirements of being a Web Services provider:

Ability to receive the SOAP request

Standard ways: SOAP/HTTP or SOAP/JMS

Ability to read and understand the contents of the SOAP request

XML parser along with implementation of the “WS-basic” standards

Ability to act upon the request

This is the “behind the interface” implementation we’ve shown before

HTTP

MQ

Built-in SOAP Handler

Custom Program

CICS Transaction

CICS

This is defined within something called a “Pipeline,” which is a structure within CICS that invokes your customized program(s).

This is what does the mapping of XML to application data structure and invokes the CICS transaction.


CICS Web Services Development ToolsCICS Web Services Development Tools

There are two primary tools used to develop CICS web services:

1. CICS Web Service AssistantConsists of a set of JCL batch utilities that generate program components

DFHLS2WS – Transforms a language structure into a Web Service Binding File and a Web Service Description (WSDL). Use this to put a web service front end on an existing application.

DFHWS2LS - Generates a Web Service binding file from a Web Service description (WSDL). This utility also generates a language structure that you can use in your application programs. Use this to create a new CICS application based on a WSDL, or to enable CICS to be a web service requester

2. Rational Developer for System z (RDz)2. Rational Developer for System z (RDz)An Eclipse-based tool for zSeries development (not just web services), it does what CICS Web Service Assistant does with additional flexibility and capabilities.

RDz is the more powerful alternative.

CICS Web Service Assistant should only be used for basic web services enablement and when Eclipse expertise is lacking


What’s Produced by RDz for Web ServicesWhat’s Produced by RDz for Web Services

The process of creating and defining a Web Service to CICS

z/OS System

COBOL source, including COPYBOOK of existing

CICS application

COBOL source to our new handler, which converts SOAP XML-to-COMMAREA and vice-versa

WSBINDWSBIND file, which is a binary file that contains information about the service, including the “URI MapURI Map” that triggers the execution of the pipeline and web service

RDz

Import into RDz

Run through the creation

wizardsCompile this into the CICS LOADLIB

Optional used to define the CICS pipeline entriesMore complex scenarios can

occur, of course. But this illustrates some essential elements of the process

Transfer down to RDz

Using simple drag-and-drop capability

Transferback

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The Importance of XML in Web Services

You will see that XML is the common mechanism to exchange information in a web services environment. What is XML, and why is it valuable?What is XML, and why is it valuable?

<SOAP-ENV:Envelope>

<SOAP-ENV:Body>

<q0:DFHCOMMAREA>

<CustNo>3</CustNo>

</q0:DFHCOMMAREA>

</SOAP-ENV:Body>

</SOAP-ENV:Envelope>

A series of “tags” that mark the beginning and end of blocks of XML

It holds both the data, as well as description of the data<CustNo> provides an indicator of what the data is; “3” is the actual data.

It is both machine readable and human readable, which makes things relatively easy to understand

Contrast with bit-format protocols, where bits within bytes meant certain things. Machine readable yes; human readable less so.

Characters use “Unicode” encoding, which means it’s universally understood

As opposed to the old EBCDIC vs. ASCII debatesExample of XML SOAP envelope

we’ll use in one of the labs

XML can be “parsed”XML is “Self Describing”Something called a “Schema Definition” (XSD) is used to tell a program what XML tags to expect.

The WSDL file (more in moment) has XSD information

If a program knows what tags to expect (the WSDL supplies this),

then the program can “parse” (extract) information from the XML.

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“SOAP over HTTP”

The Web Service Description Language (WSDL) file …

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:q0="http://www.WBCSCUSTI.com/schemas/WBCSCUSTIInterface" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <SOAP-ENV:Body> <q0:DFHCOMMAREA> <CustNo>3</CustNo> </q0:DFHCOMMAREA> </SOAP-ENV:Body></SOAP-ENV:Envelope>

You’ll frequently hear this phrase. What it’s referring to is the passing of an XML document -- a SOAP “envelope” -- using the HTTP protocol

Web Service Client

Web Service Provider

HTTP Protocol(TCP/IP Network)

XML File

The key is that the client program knew what the provider expected -- what data elements and what XML tags to use. How did it know that? It had the WSDL file.

The SOAP input for our CICS lab

Knowing the layout is not that important to us at this point

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The WSDL File

Where does WSDL come from? …

WSDL contains information about the service -- where it’s located, what parameters it takes as input, what it gives back as output, what XML tags to use, etc. It is sometimes known as a “bindings file”.

It can be long and complicated … what follows is a boiled-down snippet to show essence

<SOAP-ENV:Body> <q0:DFHCOMMAREA> <CustNo>3</CustNo> </q0:DFHCOMMAREA></SOAP-ENV:Body>

Web Service Client

<complexType name="DFHCOMMAREA"> <sequence> <element name="CustNo"> <simpleType> <restriction base="int"/> </simpleType> </element> </sequence></complexType>

<wsdl:service name="WBCSCUSService"> <wsdl:port binding="tns:WBCSCUSBinding" name="WBCSCUSPort"> <soap:address location="http://mig.null.washington.ibm.com:12301/WBCSCUST"/> </wsdl:port></wsdl:service>

What service will return was here … removed to save space

Web Service Provider

Client knows input XML and data requirements based on this

Client knows where service is located based on this

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WSDL File is a Product of RDz

You could hand-code the WSDL.

More likely you’ll use a development tool (in our case, RDz) to create the web service, and RDz will also produce the WSDL.

Web Service Client

Web Service ProviderService Program

WSDL File• Rational Application Developer• WebSphere Developer for zSeries• Other Development Tools

With WSDL, client knows where service is and how to drive it

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That's all well and good, but what about performance?

http://listserv.uga.edu/cgi-bin/wa?A2=ind0908&L=CICS-L&D=0&P=30338

That’s .1 secondThat’s .1 second1/10th of a second1/10th of a second

Any other questions about "Why Web Services"?Any other questions about "Why Web Services"?

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Legacy

Data Abstraction

Data Services/Messaging

Services

Process/Orchestration

Monitoring/Event Management

Security

Governance

RepData

SQL/XQuery/XML

J2EE/JCA (EJB)

Source: Linthicum Group

IMSAppIMSAppIMSApp

J2EE/JCA(EJB)

SOAP/J2EEIMS Database Web Services

IMSDB

Service Oriented Architecture Model – and IMS

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IMS On Demand Overview

Web

Serv

ice

.NET Client

Client Developer

Application developer

SAP Client

Web service clients

Java/J2EE Client

Java dev

Direct Database access

Developers

Java /J2EE Developer

CICS Developer

DB2 Developer

Java class Library

Direct SOAP

IMS SOAP Gateway

WDz

Solutions

WID RAD

IMS TM Resource Adapter

MFS Web Services

WebSphere

Solutions

DLI Model Utility

DLI Model Utility

DB2 SP/CICS

Java class

Library

Java class

Library

WebSphere

IMS DB Resource Adapter

IMS

Database

IMS

Co

nn

ect

OD

BA

/DR

ASQL

XQueryDL/I

DL/ISOAPTCP/IP

Java class Library

Transaction manager

IMS APP

Database manager

DLI Model Utility

22

App

IMSTM

CO

NN

EC

T

IMSDB CTRL

z/OS

TCP/IP Access to IMS

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Architecture Foundation - IMS Connect

A capability that provides connectivity support between TCP/IP applications and IMS transactions – Integrated into IMS V9

Configured on a z/OS server

Benefits and Value Supports TCP/IP sockets access to IMS transactions and commands Provides a general purpose and structured interface Provides a strategic base for new connection technologies:

Operations Manager – IMS Control Center IMS SOAP Gateway MFS Web Services

IMSAIMS Connect

IMSB

VTAM

TCP/IP

Java Applet

BROWSER

Web Server

COMTIVisual BasicPowerBuilder...

Web Server program

Websphere

CobolAssemblerC/C++Java

24

App

IMSTM

CO

NN

EC

T

IMSDB CTRL

z/OS

App

TM RA

WebSphere

IMS TM Resource Adapter

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J2EE/JCA Architecture

ApplicationComponent

Security Management

Transaction Management

Connection Management

J2EE Application Server

EIS

Application Contract

EIS-specific interface

System Contracts

Container-ComponentContract

SPI (service provider interface)

CCI (common client Interface)

ResourceAdapter

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PLI

IMS TM Resource Adapter …

Supports the development of J2EE applications, Web services, and business processes that can interface with IMS Connect

Development component– Rational Developer for System z – RDz

Runtime component – Must be installed into an application server, e.g., WebSphere

WebSphereUnit Test

Environment

IMS RESOURCEADAPTER

IMS SERVICE

DEPLOY& TEST

IMPORTC

COBOL

RDz

IMS RESOURCEADAPTER

imsico.RAR

Appl.EARJ2CConnectionFactory

IMS

IMSConnect

InstalledApplications

TCP/IP

WebSphere Application Server

Export

(supplied with IMS Connect)

Toolkits that generate web services, EJBs, JSP, etc. for IMS, CICS, DB2

Java Applet

BROWSER

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© Copyright IBM Corporation 2010. All rights reserved. The information contained in these materials is provided for informational purposes only, and is provided AS IS without warranty of any kind, express or implied. IBM shall not be responsible for any damages arising out of the use of, or otherwise related to, these materials. Nothing contained in these materials is intended to, nor shall have the effect of, creating any warranties or representations from IBM or its suppliers or licensors, or altering the terms and conditions of the applicable license agreement governing the use of IBM software. References in these materials to IBM products, programs, or services do not imply that they will be available in all countries in which IBM operates. Product release dates and/or capabilities referenced in these materials may change at any time at IBM’s sole discretion based on market opportunities or other factors, and are not intended to be a commitment to future product or feature availability in any way. IBM, the IBM logo, Rational, the Rational logo, Telelogic, the Telelogic logo, and other IBM products and services are trademarks of the International Business Machines Corporation, in the United States, other countries or both. Other company, product, or service names may be trademarks or service marks of others.

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® IBM Software Group © 2009 IBM Corporation Web Services – An Introduction Leigh Compton – Certified IT Specialist – CICS, Web Services and Java David