DEV332Programming for the Middle Tier in Visual Basic .NET

Billy HollisAuthor / Consultant

Agenda

Typical architectural elements in the middle tierWeb Services basics (briefly)Windows servicesPerformance countersEvent logsMessage queues

Typical Architecture ElementsWeb Service Façade Remoting Façade

(Windows Service)

Business rules(Operations with no connection)

Data Access Layer(all connected operations)

MessageQueues

WindowsServices

Remote Web Services

Designing Web ServicesGroup related operations and data into one methodDecide on:

Interface and return dataSecurity

Use output caching to improve performanceDefine your input and output data structures using XSD schemasSeparate XML Web service from underlying business logic

XML Web Services Mapping

DataData

SchemaSchema

ServicesServices

InvocationInvocation

WebWeb

XMLXML

XSDXSD

WSDLWSDL

SOAPSOAP

ApplicationApplicationConceptsConcepts FrameworkFramework

ObjectsObjects

ClassesClasses

MethodsMethods

CallsCalls

The .NET Framework providesThe .NET Framework providesa bi-directional mappinga bi-directional mapping

Returning Data From An XML Web Service

SQL ServerSQL Server

CustomersCustomersDataAdapterDataAdapterXML WebXML Web

serviceservice

DataSetDataSet

IISIIS

OracleOracle

OrdersOrders

XMLXML

DataSetDataSet

Generic ClientGeneric Client

.NET Client.NET Client

DataAdapterDataAdapter

Data Web ServicesData Web Services

demodemo

Binary Data

Web services are not limited to textual data – images, sound files, etcReturn as bytes with Base64 streamUse WS-Attachments (DIME)

Direct Internet Messaging EncapsulationAvailable using WSE toolkit or in Visual Studio .NET 2003Can use over TCP, other protocols

Web Services vs. Remoting

Web Services are easier to create and configureWeb Services can be accessed by non .NET systemsRemoting faster and easier to secureRemoting offers true exceptions

Decision point – if you control both ends, remoting is usually the better choice

Creating A Windows ServiceGreat for non-UI, long-running functionality

MonitoringScheduled ActivityRemoting Host

Respond to eventsTimer tickMessage queue receiveDirectory/file changeEvent log write

Installing Windows Services

Can run under different security contextLocalSystem requires no login

Install using command line utilityinstallutil.exe [projectname.exe]Uninstall usinginstallutil.exe /u [projectname.exe]Custom installer

Service EventsInherits from System.ServiceProcess.ServiceBaseOverride event methods:

Method BehaviorOnStart Set action for when service is started

(thirty seconds maximum!)OnPause Set action for when service is pausedOnStop Set action for when service is stoppedOnContinue Set action for when service is resumed from

pauseOnShutDown Set action for when system is shutting downOnCustomCommand Set action for a custom commandOnPowerEvent Set action for low battery/suspend

Debugging Windows Services

F5 debuggging not availableService must be deployed and installedAttach to the Service’s process

Still set breakpoints for events

Have all errors/exceptions logged to Windows Event Log

Creating Windows ServicesCreating Windows Services

demodemo

Service ControllerService Controller class allows you to stop, start, pause or obtain information about windows servicesNamespace: System.ServiceProcess.ServiceControllerCan only communicate via custom numeric commands

Controlling Windows Controlling Windows ServicesServices

demodemo

Performance CountersPer Application Performance Counters

Enable easily monitoring of individual applications

Custom Performance Counters APIsNow possible to publish unique application-specific performance data Great for real-time application monitoringExample: total orders, orders/sec

Event Logs

Indispensable in the middle tierLog errors and activityDrag and drop programmingCan monitor event log with a Windows Service

Take actionRecord event to database

Message QueueEnables you to connect to, monitor, send/receive/peek and administer message queues Loosely coupled programmingMessageQueue Class

Send/receive/peek messages in the queue

Message ClassConstruct for the message

Namespace: System.Messaging

Performance Counters and Performance Counters and Message QueuesMessage Queues

demodemo

Ask The ExpertsGet Your Questions Answered

Billy will be in the Ask the Experts booth Wednesday afternoon from 2:00 to 4:00

Community Resources

Community Resourceshttp://www.microsoft.com/communities/default.mspx

Most Valuable Professional (MVP)http://www.mvp.support.microsoft.com/

NewsgroupsConverse online with Microsoft Newsgroups, including Worldwidehttp://www.microsoft.com/communities/newsgroups/default.mspx

User GroupsMeet and learn with your peershttp://www.microsoft.com/communities/usergroups/default.mspx

evaluationsevaluations

© 2003 Microsoft Corporation. All rights reserved.© 2003 Microsoft Corporation. All rights reserved.This presentation is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.This presentation is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.