Oregon Delphi User Group September, 2008

What are web services—very briefly Remotely invokable methods with a pre-defined API Parameters (object with properties) Return values (object with properties) SOAP XML via HTTP Another way of saying it… “ Web Services, in the general meaning of the term, are processes offered via the Web. In a typical Web Services scenario, a business application sends a request to a service at a given URL using the SOAP protocol over HTTP. The service receives the request, processes it, and returns a response.” –Harms Software ODUG - Web Services, Sep 2008

What are web services—very briefly

Remotely invokable methods with a pre-defined API

Parameters (object with properties)

Return values (object with properties)

SOAP XML via HTTP

Another way of saying it… “ Web Services, in the general meaning of the term, are processes offered via the Web. In a typical Web Services scenario, a business application sends a request to a service at a given URL using the SOAP protocol over HTTP. The service receives the request, processes it, and returns a response.” –Harms Software

Single store, one database, simple accounting. ODUG - Web Services, Sep 2008

Single store, one database, simple accounting.

Add an ecommerce web site. Two databases—accountant is not happy. Shipping department confused. Customers can “buy” out-of-stock items. ODUG - Web Services, Sep 2008

Add an ecommerce web site.

Two databases—accountant is not happy.

Shipping department confused.

Customers can “buy” out-of-stock items.

Need to merge—but how? ODUG - Web Services, Sep 2008

Need to merge—but how?

The answer of course for today: Web Services! ODUG - Web Services, Sep 2008

The answer of course for today: Web Services!

What is needed here? Web site needs to know what inventory is available Store needs to collect order information Store needs to adjust inventory levels Store needs to ship products Store needs to notify web site of order status Web site needs to display order status ODUG - Web Services, Sep 2008

What is needed here?

Web site needs to know what inventory is available

Store needs to collect order information

Store needs to adjust inventory levels

Store needs to ship products

Store needs to notify web site of order status

Web site needs to display order status

Possible web service methods: UpdateInventory Adds or updates items to web database GetPendingOrders Get list of orders pending from web Get single order details from web UpdateOrderStatus Update status field and tracking number on web ODUG - Web Services, Sep 2008

Possible web service methods:

UpdateInventory

Adds or updates items to web database

GetPendingOrders

Get list of orders pending from web

Get single order details from web

UpdateOrderStatus

Update status field and tracking number on web

File > New Other > Web Services > SOAP Server Application Three types ISAPI .DLL CGI Stand-alone .EXE Web App Debugger Create an interface File > new Other > Web Services > SOAP Server Interface ODUG - Web Services, Sep 2008

File > New

Other > Web Services > SOAP Server Application

Three types

ISAPI .DLL

CGI Stand-alone .EXE

Web App Debugger

Create an interface

File > new

Other > Web Services > SOAP Server Interface

Four modules created __Intf.pas Exposed methods for the web services IMyWebClass = class(Invokable) __Impl.pas Delphi implementation of web services TMyWebClass = class(TInvokableClass, IMyWebClass) Here’s the meat! Data module – web service work horse Main Form – standard application ODUG - Web Services, Sep 2008

Four modules created

__Intf.pas

Exposed methods for the web services

IMyWebClass = class(Invokable)

__Impl.pas

Delphi implementation of web services

TMyWebClass = class(TInvokableClass, IMyWebClass)

Here’s the meat!

Data module – web service work horse

Main Form – standard application

Add interface and implementation Intf and Impl units Build/Run once to register COM object Run Web App Debugger, start server Verify new web service available in browser View WSDL automatically created for us What’s a WSDL? W eb S ervice D escription L anguage XML document describing the web service We’ve Created a Web Service! ODUG - Web Services, Sep 2008

Add interface and implementation

Intf and Impl units

Build/Run once to register COM object

Run Web App Debugger, start server

Verify new web service available in browser

View WSDL automatically created for us

What’s a WSDL?

W eb S ervice D escription L anguage

XML document describing the web service

We’ve Created a Web Service!

Questions? Now on to the Client… ODUG - Web Services, Sep 2008

Questions?

Now on to the Client…

New standard VCL application File > New Other > Web Services > WSDL Importer URL of web service’s WSDL New unit created Full Interface to web service methods! ODUG - Web Services, Sep 2008

New standard VCL application

File > New

Other > Web Services > WSDL Importer

URL of web service’s WSDL

New unit created

Full Interface to web service methods!

Call a method—see the answer—SUCCESS! Web App Debugger View the log See the XML packets Get/Response – general web page requests POST – web service method calls ODUG - Web Services, Sep 2008

Call a method—see the answer—SUCCESS!

Web App Debugger

View the log

See the XML packets

Get/Response – general web page requests

POST – web service method calls

Web Apps –vs- Windows Apps No form Stateless Multi-user Acronymns HTTP – HyperText Transfer Protocol XML – eXtended Markup Language SOAP – Simple Object Access Protocol RIO – Remote Invokable Object WSDL – Web Service Description Language UDDI – Universal Description, Discovery, and Integration ODUG - Web Services, Sep 2008

Web Apps –vs- Windows Apps

No form

Stateless

Multi-user

Acronymns

HTTP – HyperText Transfer Protocol

XML – eXtended Markup Language

SOAP – Simple Object Access Protocol

RIO – Remote Invokable Object

WSDL – Web Service Description Language

UDDI – Universal Description, Discovery, and Integration

Web Service Add(a, b: Double): Double; Subtract(a, b: Double): Double; Client Two edit fields, two buttons, display answer ODUG - Web Services, Sep 2008

Web Service

Add(a, b: Double): Double;

Subtract(a, b: Double): Double;

Client

Two edit fields, two buttons, display answer

Database queries Arrays TRemotable class ODUG - Web Services, Sep 2008

Database queries

Arrays

TRemotable class

Packet Size Server speed Bandwidth bottleneck Trapping XML Logging/modifying XML on-the-fly Use HTTPRIO from WebServices Use TXMLDocument from Internet Tutorial Reference http://exposureroom.com/members/skumar.aspx/tutorials/post/1 ODUG - Web Services, Sep 2008

Packet Size

Server speed

Bandwidth bottleneck

Trapping XML

Logging/modifying XML on-the-fly

Use HTTPRIO from WebServices

Use TXMLDocument from Internet

Tutorial Reference

http://exposureroom.com/members/skumar.aspx/tutorials/post/1

eCommerce Sample packets XML Notepad Google eBay Amazon FedEx CDDB MapPoint More! ODUG - Web Services, Sep 2008

eCommerce

Sample packets

XML Notepad

Google

eBay

Amazon

FedEx

CDDB

MapPoint

More!

ODUG - Web Services, Sep 2008