Apress the definitive guide to windows installer apr 2004 ISBN 1590592972

TheDefinitiveGuidetoWindowsInstaller
ISBN:1590592972
byPhilWilson
Apress©2004(302pages)
Thisguidedemonstrateshowtobuildsafeand
secureinstallations,aswellasbuildexample
projectsasVisualStudioSetupand
DeploymentProjects.Itwillshowyouhowyou
needtodesignapplicationstointegrate
properlywithWindowsInstaller.
TableofContents
TheDefinitiveGuidetoWindowsInstaller
Introduction
Chapter1 - InstallationsPast,Present,andFuture
BuildinganMsiFile:VisualStudioand
Chapter2 Orca
Chapter3 - COMintheWindowsInstallerWorld
Chapter4 - SearchesandConditions
Chapter5 - SequencesofEventsandCustomActions
Chapter6 - HowdoYouFixIt?
Chapter7 - ASP.NETSetups
Chapter8 - Installing.NETAssemblies
Chapter9 - InstallationDesign
Chapter10 - WindowsServices
Chapter11 - TheGacandUpdatingAssemblies
Chapter12 - UpdatesusingPatches
Chapter13 - InstallationEnvironments
Chapter14 - How-Tos,Tips,andGotchas


Chapter15 - ExploringtheInstallerAPIs

Chapter16 - ToolsandFutures
Index
ListofFigures


BackCover
Whenacompanybuildsandshipssoftware,the
installationprocessisoftenthefirstopportunityfora
customertoviewtheproductandthecompany—and
theinstallationexperiencecanmakeorbreakalasting
impression.Sothisbookisidealforcompaniesand
developerswhowanttoimpresstheirclientele.
ThisbookcoverseveryaspectofusingtheWindows
Installer—theunderlyinginstallertechnologyin
Windows.Avaluabletoolforyousoftwaredevelopers,
thisbookhelpsensurethoroughandreliable
installationforyourcustomers.Mostotherbooksfor
softwaredevelopersendtooabruptlyandomitcritical
information,likehowtocreatethenecessary
installationsoftware.ButTheDefinitiveGuideto
WindowsInstallerpicksupwheretheotherbookstrail
off.
AbouttheAuthor
PhilWilsongraduatedfromtheUniversityofAston,
Birmingham,England,withabachelor'sdegreein
chemistry,buthepreferredcomputerstotesttubes
andeventuallyworkedfor15yearsondeveloping
operatingsystemsforBurroughsandUnisys
mainframes.PhilstartedprogrammingforWindowsin
theearly1990sandhasdevelopedinMFC,ATLCOM,

VisualBasic,andC#.Hehasbeeninvolvedin
installationdesignandtechnologyforabout8years,
andhebecameaMicrosoftMVPforWindowsInstaller
in2003.Togetawayfromcomputers,heplaysand


recordsguitar,andenjoyscampingintheCalifornia
desert.


TheDefinitiveGuidetoWindowsInstaller
PHILWILSON

Copyright©2004byPhilWilson
Allrightsreserved.Nopartofthisworkmaybereproducedortransmitted
inanyformorbyanymeans,electronicormechanical,including
photocopying,recording,orbyanyinformationstorageorretrieval
system,withoutthepriorwrittenpermissionofthecopyrightownerand
thepublisher.
ISBN(pbk):1-59059-297-2
PrintedandboundintheUnitedStatesofAmerica10987654321
Trademarkednamesmayappearinthisbook.Ratherthanusea
trademarksymbolwitheveryoccurrenceofatrademarkedname,weuse
thenamesonlyinaneditorialfashionandtothebenefitofthetrademark
owner,withnointentionofinfringementofthetrademark.
LeadEditor:DanAppleman
TechnicalReviewers:ChrisGouge,CarolynNapier
EditorialBoard:SteveAnglin,DanAppleman,GaryCornell,James
Cox,TonyDavis,JohnFranklin,JasonGilmore,ChrisMills,Steve
Rycroft,DominicShakeshaft,JimSumser,KarenWatterson,GavinWray,

JohnZukowski
ProjectManager:TracyBrownCollins
CopyManager:NicoleLeClerc
CopyEditor:SusannahPfalzer
ProductionManager:KariBrooks
Compositor:VijayNicoleImprints


Proofreader:LizWelch
Indexer:CarolBurbo
CoverDesigner:KurtKrames
ManufacturingManager:TomDebolski
DistributedtothebooktradeintheUnitedStatesbySpringer-VerlagNew
York,Inc.,175FifthAvenue,NewYork,NY10010andoutsidetheUnited
StatesbySpringer-VerlagGmbH&Co.KG,Tiergartenstr.17,69112
Heidelberg,Germany.
IntheUnitedStates:phone1-800-SPRINGER,e-mail
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Forinformationontranslations,pleasecontactApressdirectlyat2560
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Theinformationinthisbookisdistributedonan"asis"basis,without
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thiswork,neithertheauthor(s)norApressshallhaveanyliabilitytoany
personorentitywithrespecttoanylossordamagecausedorallegedto
becauseddirectlyorindirectlybytheinformationcontainedinthiswork.
Thesourcecodeforthisbookisavailabletoreadersat
intheDownloadssection.

AbouttheAuthor
PhilWilsongraduatedfromtheUniversityofAston,Birmingham,
England,withaBScinchemistry,butpreferredcomputerstotesttubes
andeventuallyworkedfor15yearsondevelopingoperatingsystemsfor
BurroughsandUnisysmainframes.Philstartedprogrammingfor
Windowsintheearly1990sandhasdevelopedinMFC,ATL,COM,


VisualBasic,andC#.Hehasbeeninvolvedininstallationdesignand
technologyforabouteightyears,andbecameaMicrosoftMostValuable
ProfessionalforWindowsInstallerin2003.Togetawayfromcomputers,
heplaysandrecordsguitar,andenjoyscampingintheCaliforniadesert.
PhilworksforUnisysCorporationinMissionViejo,California.
Acknowledgments
ManythankstothepeopleatApressforgivingmethisopportunity,
especiallyDanAppleman.ThankstoTracyBrownCollins,Susannah
Pfalzer,andKariBrooksforgettingmethroughitall.Alotprobablygoes
oninthisprocessthattheykeptmeblissfullyunawareof;allIhadtodo
waskeepwriting.
MyheartfeltthanksgotoChrisGougeandCarolynNapierofMicrosoft
fortheirtechnicalreview.Theypatientlycorrectedmymisunderstandings,
andthebookismuchbetterfortheirreview.Ican'timaginewhatitmust
feelliketohavesomeonewriteabookaboutthesoftwarethatyouwork
oneveryday,sotothemandtherestoftheWindowInstallerteam:I
hopeI'vedoneagoodjob.
ThanksalsotoR.MichaelSanfordforhisearlyreviewwork.
Finally,thankstomyfamilyfortheirpatiencewhileIwasholedup
eveningsandweekendsfortheduration,andthankstomyfriendsM.G.,
A.K.,andV.R.forbelievinginme.

Introduction
Installingnewsoftwareisperhapsthemostadrenalin-inducing
experienceyou'llhaveonacomputer,asidefromwhatevergamesyou
mightplay.It'snothardtoseewhy.Yougiveovercontrolofthesystemto
aprogramthatoftendemandsAdministratorprivilegeandthatthenstarts
updatingsomeofthemostfragilepartsofyoursystem.Youmightknow
theactualproductbeinginstalledquitewell,butthere'srarelyany
documentationaboutwhattheinstallationofitwilldotoyoursystem.It
mightinstallkerneldriversorServices,itmightalteryourpersonal
settingswithoutyourpermission,anditmightresultinotherapplications
onyoursystemnolongerworking.Foracompanybuildingandshipping
software,theinstallationmightbethefirsttimethecustomerhasseen
yourproductoryourcompany,andit'syouropportunitytomakealasting
impressiononewayortheother.Anunreliableinstallationwillaffectthe
customer'simageofyouforalongtime.
Thegoalofthisbookistoshowyouhowtobuildsafeandsecure
installations.ItsfocusisWindowsInstallertechnologyontheWindows
NTseriesofoperatingsystemsforWindows2000andabove,andyou'll
buildexampleprojectsasVisualStudioSetupandDeploymentProjects.
AsidefromtheactualnutsandboltsofbuildingWindowsInstaller-based
installations,I'llofferadviceonhowtobuildareliableinstallationand
whatyoushouldandshouldn'tdo.Theintegrationofinstallertechnology
aspartoftheWindowsoperatingsystemmeansthatthedividingline
betweenanapplicationanditsinstallationhasbecomemuchlesssharp,
andthebookwillcoverhowyouneedtodesignapplicationstointegrate
properlywithWindowsInstaller.
Thebookstartswithbasicprinciplesanddrillsdowndeeperinlater
chapters.Istartwiththeinstallationequivalentofthe"HelloWorld"
program,andthengraduallygetdeeperintothecontentsofinstallerMSI

files,includinginstallationinthe.NETFrameworkworld.AlongthewayI'll
stoptolookatbestpracticesandhowtokeepyourinstallationreliable.
WhereIshowuseoftheinstallerAPIs,I'lluseVBScriptforthesakeof
simplicityandclarity,butI'llalsopointyouattheWin32equivalentsand
showyouacoupleofwaystocallthemfromthe.NETFramework


languageC#.
Asisoftenthecasewhenyoutrytoexplainsomething,youfindthatyou
testyourunderstanding,andifyou'reluckyyoulearnsomethingnewat
thesametime.IhopeyoulearnasmuchfromreadingthisbookasIdid
writingit.


Chapter1:InstallationsPast,Present,and
Future
Itoftenseemsthattheinstallationofaproductisalmostanafterthought.
Developersspendhundredsoflabor-monthsbuildingthatgreatnew
three-tierapplication.However,Iwouldn'tbesurprisedifyou'rereading
thisbookbecauseyou'rethepersonwhohastofigureouthowtoinstall
theapplicationwhileeveryoneelseisoutcelebratingthefactthatthey've
finishedit.Ofcourse,anapplicationisn'tactuallyfinisheduntilyoucan
installitonyourclients'systems.


Background
Manypeopleseeinstallationsasasimpleprocessofcopyingfilestothe
clientsystem,butinreality,copyingfilesisprobablythemost
straightforwardpartofthewholeinstallationprocess.Wheninstallinga
productontheWindowsoperatingsystem(OS),youneedtoconsiderall

thefollowingareas,andthisisnotacompletelistbyanymeans.

WheretheFilesGo
Itisnotalwaysobviouswherefilesshouldactuallybeinstalled.Theusual
conventionisthattheygetcopiedtotheProgramFilesfolderassociated
withyourcompanynameandproductname.Butthisisn'talwaysthe
case.Forexample,ifyourcompanyhasasetofcomponentobjectmodel
(COM)components,thenyoucan'tusuallyhaveyourownprivatecopyin
eachoftheproduct'sfolders.ThereisonlyonesetofCOMregistration
entriesonthesystem.Ifyouinstallthecomponentatonelocationinone
product,thenatanotherlocationfromanotherproduct,thelastcopyof
thecomponentistheonethatalltheclientprogramswilluse.That's
becausetheinstallmarkstheInprocServer32entrytopointtothelast
locationthesharedcomponentwasinstalledto.Uninstallinganyoneof
theproductsbreaksalltheremainingproductsbecausetheuninstall
removestheregistrationdatawhentheprogramisuninstalled.

RedistributingSupportingFiles
Manyproductsalsoneedsupportingsoftwaretobeinstalledbeforethey
willfunctioncorrectly.Sometimesthismeansacollectionofsupporting
DLLsorOCXs,sometimesitmeanssomethingrathercomplicatedsuch
astheMicrosoftDatabaseEngine(MSDE)software.Notonlythat,but
differentoperatingsystemshavedifferentrequirements.Toshowa
coupleofexamples,Windows2000hasmanyoftheVisualStudio6.0
supportDLLsforVisualBasic,ATL,andMFCprojectsaspartofthe
operatingsystem,sotheydon'tneedtobeinstalled.However,ifyou're
supportingWindowsNT4.0,theydo.Microsoft'sVisualStudio.NET


(VS.NET)hasanewsetofredistributables(ATL70.DLL,MFC70.DLL,

MSVCR70.DLL)thatalwaysneedinstalling,evenonWindows2000.This
areacanbeconfusingandcontributestothegeneralexpressionforthis
situation—"DLLHell."

InstallingWindowsServices
WindowsServicessometimesdependonotherServicesthatarealready
onthesystem.InstallingaServicemightthereforerequirestoppingthese
otherServices,installingyours,thenstartinguptheseotherServices,
andfinallystartingyourService.

FilesinUse
Thetypicalproblemwithin-usefilesisthatyou'retryingtoreplacethem
withnewerversions.Itisgoodpracticetoattempttoshutdownthe
applicationusingthesefiles.IftheapplicationisaServiceoran
applicationthathasauserinterface,youmightbeabletosend
messagestocloseitdown(orprompttheusertodoso),butsomeof
thesescenarioscanbecomplex.YoumightbetryingtoregisteraCOM
DLLbycallingitsDllRegisterServerfunction(whichiswhat
REGSVR32.EXEdoes).However,thatDLLmightrequireadependent
DLLthatcouldnotbeinstalledbecauseanolderversionofthat
dependentDLLisinuse.Inthesesituationstheonlyrecourseisto
arrangeareboottogetthefilesreplaced.InthecaseofregisteringCOM
servers,youtypicallyneedtowriteanentrytothesystemRegistry's
RunOncekeytoregistertheDLL,andthenarrangethereboot.

SecurityandtheTargetUser
InstallationsoftenhavetoberunwithAdministratoraccountprivileges
becausetheyupdatepartsofthesystemthatrequireprivilegestocreate
ormodifythem.Ontheotherhand,sayyou'reinstallingonashared
computerandyou'dliketoinstallsomethingonbehalfofanotheruser.

AlthoughyoucouldgoaheadandinstallitwithanAdministrator's
account,it'snotclearthatyouwantthisotherusertohaveAdministrator
privileges.Thereisalsoaprivacyissueonsharedcomputers,perhaps


notsomuchwhenoneindividualinstallssomethingforanother,butinthe
corporateworldwhereseveralusersmightbesharingonecomputer.
Therefore,thereisoftenaconflictbetweenthesecurityrequirementsof
theinstallationandthesecurityrequirementsoftheinstalledproduct.

MaintainingtheProduct
It'saprettysafeassumptionthatsoonerorlateraproductwillneed
updates,whethertheyarebugfixesorfeatureadditions.Youneeda
mechanismthatcanidentifywheretheexistingfilesarelocatedonthe
clientsystemandreplacethemwithnewversions.Thismaintenance
requirementhasallthedrawbacksyoualreadylookedatrelatingtofiles
inuseandsoon,withtheadditionaldifficultiesofworkingoutwhattodo
iftheupdatefails.Thiscanmeanidentifyingthefilesthataretobe
updated,andbackingthemupsomewhere.Thatwaytheusercan
restorethemiftheupdatefailsoriftheuserfindsthattheupdated
productisbrokenandneedstouninstalltheupdate.Thisisthemodel
usedwithWindowsServicePacks.Becauseofthesepossible
requirements,thistypeofservicepackinstallationissometimesdifferent
thantheoriginalinstallation,andyoumayuseadifferenttooltobuildit.It
wouldnotbeunusualforaninstallationdevelopertoneedtounderstand
atleasttwotypesofinstallation—theoriginalproductinstallationandthe
toolsthatbuildit,plusthetoolstobuildservicepacks.

Environments
Forexample,ifaproductconsistsofthreedistincttiers,therearelikelyto

bethreedistinctenvironmentsontowhichyouhavetoinstallsomepiece
oftheapplication.Perhapsyouneedtodividetheproductintoseparate
features,oneperenvironment.Perhapsfilesorprogramsarecommonto
someofthetiers,soyouwouldneedtobreakoutthesecommonfiles
intosomekindofseparatefeature(notvisibletotheuser)thatcanbe
installedonallthetiersbydefault.Eachtiermightalsobeadifferenttype
ofWindowsenvironment.Forexample,theback-endtiermightrequirea
serveroperatingsystem,soyouprobablydon'twanttoallowittobe
installedonaworkstation.Inotherwords,theapplicationneedstobe
brokenupintopiecesandrebuiltasasetoffeaturesthatcanbetargeted


attheappropriateuserorplatform.

TheOne-WayNatureofInstallations
Althoughyouusuallycallaninstallationprograma"program,"it'snotlike
otherprogramsinacoupleofinterestingways.Ifyouhaveanapplication
programthathasabug,youshipafixtoyourclients,whoreplacetheold
versionwiththenewoneandstartrunningthenewversion.Installation
programsaren'tlikethat.Ifyou'veshippedabrokeninstallation,youcan't
justshipacorrectedonetoyourclientsandaskthemtouseit.That's
becausenoprogramontheclient'ssystemcanbereplaced—it'snot
literallyaprograminthatsense.Inreality,aninstallationisaprocess,a
sequenceofactionsthatalterthetargetsystem,andoncetheinstallation
hasdoneitsworkyoucan'tjustreplaceitwithacorrected(updated)
version.Thereisalsotheuninstallprocesstokeepinmind.Oncethe
producthasbeeninstalled,thensohastheuninstallprocess,soit's
essentialthattheuninstallprocessworkproperly.Aproductthatcannot
beuninstalledispotentiallyuselessiffixingorreplacingitrequiresusers
touninstallit.

DevelopmentEaseandtheInstallation
Developmenttoolsmakeiteasytobuildprograms.Youuseawizard,
addsomecode,andyoursystemisalreadysetupwiththesupport
necessaryforyoutotesttheprogram.I'mexaggeratingsomewhat,but
thepointisthatwhenyouinstalltheprogramorapplicationonaclient
system,youneedtoknowabouteachfile,supportingDLL,andRegistry
entrythattheapplicationneedsforittorun.Ifyou'recommunicatingthis
tosomeonewho'sbuildingtheinstallationprogram,detailingeverything
that'sneededisanontrivialtask.

DevelopmentInstallsvs.ProductionInstalls
Developmentenvironmentsanddocumentationfrequentlytalkintermsof
command-lineprogramsthatperforminstallationtasks.InCOM,
developersareusedtotheideaofrunningRegsvr32.exetoregisterCOM
DLLs,ora–Regservercommand-lineargumenttoregisteraCOMlocal


server.Inthe.NETFrameworkworldyouseereferencestorunning
Regasm.exe,Gacutil.exe,andInstallutil.exetoinstallassembliesfor
.NETCOMInterop,toinstallassembliesintotheGlobalAssemblyCache
(theGAC),ortoregisterassembliesas.NETWindowsServices.
However,notoneofthesecommand-lineprogramsisnecessaryfora
WindowsInstaller–basedinstallationbecauseinstallersupportis
providedforthefunctionalityofferedbytheseprograms.


IntroducingWindowsInstaller
BeforeWindowsInstallertherewasnospecificWindowsfunctionality
suppliedtoinstallproducts.(Strictlyspeaking,therehasalwaysbeenthe

SetupAPI,butitsmainfunctionalityisbasedonusingINFfilesto
performinstallations.)TheWindowsprogrammingenvironment
happenedtoberichenoughthatdeveloperscoulduseitsAPIsto
performinstalls.Amajorconsequenceofusingthegeneral-purpose
WindowsAPIswasthattherewasnoconsistentintegrationbetween
Windowsandtheinstalledproduct.Forexample,ifyouwantedto
inventorytheproductsinstalledonasystem,youcouldenumeratethe
contentsoftheRegistryareausedbytheAdd/RemoveProgramsapplet,
butanynumberofdifferenttoolscouldhaveinstalledeachproduct,and
evenasimpletasksuchasfindingwheretheproductwasinstalledwas
nontrivial.
AroundtheWindows2000timeframe,MicrosoftsuppliedWindows
InstallerastheinstallationtechnologyforMicrosoftOffice2000.I'lltakea
brieflookhereattheproblemsithelpssolve,andamorein-depthlookin
laterchapters.WindowsInstallerprovidesastandardwaytoinstall,
maintain,anduninstallsoftware.However,thatbyitselfisnotjustification,
solet'slookatwhatmakesWindowsInstalleruniqueandhowit
addressessomeoftheprecedingtopics.

TransactionalBehavior
Nobodywantsaninstallationtogetpartiallycompletedandthenfailfor
somereason,leavingasysteminsomeindeterminatestate.Windows
Installerturnsproductinstallationsintoanall-or-nothingproposition—the
productiseithersuccessfullyinstalledonthesystem,ortheinstallation
doesnotworkandallthechangesthatmighthavebeenmadetothe
systemarebackedout.
Alargepartofthistransactionalnatureisaconsequenceofeliminating
asmuchcodeaspossiblefromtheinstallationprocess.Asyou'llsee
later,WindowsInstalleroffersfeaturesthatmeanyoudon'tnecessarily
needtoruncustomcodeatinstalltime.Thisisnecessarybecause

otherwiseyou,theinstallationdeveloper,wouldberesponsiblefor
reversinganychangesmadetothesystemduringtheinstallation.
Asanexample,considerCOMserverregistration.AsInotedearlier,a
COMserverhistoricallyrequireditsDllRegisterServerfunctiontobe
called,andlikewisetheuninstallprocesswouldcallDllUnregisterServer.
ThisrequirestheCOMservertoinitialize,whereitmightneeda
dependentDLLthatisn'tonthesystemyet.WindowsInstallerdealswith
thisbystoringCOMregistrationdatainsidetheactualinstallerpackage,
theMSIfile,soitdoesn'tneedtocallorruntheCOMservertoinstallor
uninstalltheRegistryentries.WindowsInstallercanaddorremovethe
COMRegistryentrieswhethertheCOMserveritselfisfunctionalornot.
InstallingtheCOMservermeanscopyingthefiletothesystemand
writingtheRegistryentriesfrominstallertables.
ThesamegeneralideaappliestoWindowsServices(sometimescalled
NTServices).Whentheyareinstalledwithsomethinglikea–Service
command-lineargumenttoarunoftheServiceprogramitself,installand
uninstallaredependentontheServicebeingfunctional.However,
WindowsInstallerhassupportforinstallingServicesdirectlyfromthe
installationpackagewithnorequirementtoruntheServiceexecutableto
installit.Consequently,installationandremovaloftheServiceare
controlledmoresafely.

Repair
It'snotunusualforfilesthatbelongtoaproducttogetaccidentally
deleted.WindowsInstallerhasrepairfeaturesthatrestoreanapplication
thatisbrokenbecauseofmissingfilesorRegistryentries.Ifthe
installationmarksafileoraRegistryentryas"key,"WindowsInstaller
hasthecapabilitytorestorethefileorentryautomaticallyifit'smissing.

WhenyougotoAdd/RemovePrograms,aRepairchoiceisoffered,
alongwithotherchoicestouninstallormodifytheinstalledfeatures.
Repairisprobablythefeaturethatmostoftensurprisesdevelopers.They
aregenerallyfamiliarwiththeideathataproductcanbeinstalledand
thenmanipulatedafterwardsbyaddingnewfilesorremovingunwanted
ones,onlytofindthattherepairmechanismrestoresthefilesorRegistry


keystotheinitialinstallationstate.Userstooaresometimessurprised
whentheyremoveashortcutandmoveittosomeotherlocation,onlyto
findthatWindowsInstallerrestoresitthrougharepair.

64-bit
ThereissupportinWindowsInstallerforinstallingapplicationsonto64bitWindowsoperatingsystems.Thisdoesn'tjustmeanthatyoucan
install32-bitapplicationsonto64-bitsystems,itmeansthatWindows
Installerislikelytobetheonlywaytoinstall64-bitapplicationsontoa64bitsystem.

SharingFiles
Sharinghasalwaysbeenanimportantaspectofinstallations.The
sharingissuesarelargelyresponsibleforthesituationpopularly(or
unpopularly)knownas"DLLHell."YouneedtoworkoutwhichMicrosoft
DLLsneedinstallingtosupportyourproduct,andconsequentlyrunthe
riskofcreatinganincompatiblesetofsystemDLLs.Oryoumighthave
sharedcomponentsinyourcompany'sproductsthatallneedtobe
installedandmanagedcorrectlyonclientsystems.Thisisbecomingless
ofanissuesinceWindows2000introducedWindowsProtectedFiles,a
featurethatpreventsinstallationsfromreplacingcriticalsystemfiles.
WindowsInstallerdoesnotevenattempttoreplacethoseprotectedfiles
thatareconsideredtobepartoftheOS.
SharinginWindowsInstallerusesreferencecountsforeachunique

component.Youstillneedtofollowrules,asyou'llseelater,butthe
WindowsInstallercomponentsharingmechanismismuchmorerobust
thanpreviousschemes.

SystemIntegration
ProductsinstalledwithWindowsInstallerareintegratedintoWindows.
APIsandCOMobjectscanreportinformationaboutinstalledproductsto
adetailedlevel.Inaddition,aWindowsManagementInstrumentation
(WMI)providerreportsthecontentandconfigurationofinstalled


products.Ifyoueverwonderedwhetherthereisawaytodiscover
accuratelywhatproductsareinstalledonasystem,thefactthatthereare
standardAPIcallsisavastimprovementcomparedtoprowlingthe
Registrylookingforproducts.TheseAPIsnotonlyreturndetailabout
potentiallyeveryfileinstalledbyaproduct,theyalsoallowtheapplication
codeitselftointegratewiththeinstallationandmodifyinstalled
componentsonthefly.TheAPIsalsoallowaccesstoinstallation
packages(MSIfiles).Forexample,it'srelativelyeasytoquerythe
contentsofaninstallationpackageandcomparethecontentswitha
versionofthatpackagethatisinstalledonthesystem.

.NET
WindowsInstallerhasbuilt-insupportforinstalling.NETassembliesinto
theGlobalAssemblyCache(GAC).Thisislikelytobetheonlywayyou
shouldinstallassembliesintotheGAC.Yes,Microsoftsuppliesthe
Gacutil.exeutilityinthedevelopmentenvironment,butthisprogram
knowsnothingabouttheWindowsInstallerreference-countingscheme,
sosharedassembliesinstalledintotheGACrequireWindowsInstallerto
maintaincorrectshared-installerreferencecounts.

FortheSystemorforCurrentUser
Whenyoustartinstallingaproductyouareoftenaskedifit'sbeing
installedforyou(privatetoyouraccountonthesystem),orwhetherit's
beinginstalledforeveryone.Thesegenerallyaffectwhether,forexample,
certainRegistryentriesarewrittentotheHKEY_CURRENT_USER
(HKCUarea)ortoHKEY_LOCAL_MACHINE(HKLM).Ifyouassumethat
thetargetuserisinfactthecurrentuserofthesystem,thismeansthat
theapplicationshouldnotbevisibletootherusers.Butthinkaboutthe
mechanicsofCOMregistration,wherecodeintheDllRegisterServer
entrypointcreatesCOMregistrationentriesonthesystem.You'llrealize
thatthereisnowaythatthecodeinDllRegisterServerknowswhetherthe
installationisper-userorper-machine,sotheregistrationcodecannot
knowwhichRegistrylocationisthecorrectone,HKLMorHKCU.The
codeinDllRegisterServerregisterstothelocalmachineRegistrykeys,so
ineffectaninstallforthecurrentuserleavesCOMserversaccessibleto


everyoneonthesystem.ItthereforemakesalotofsensetogetCOM
serversoutofthebusinessofself-registrationandhaveWindows
InstallercreatetheregistrationentriesintheappropriateRegistry
location.

SecurityofInstallationvs.SecurityofProduct
Whentryingtoinstallaproductforauserwhomightnothavethe
securityprivilegestoinstalltheproduct,thereneedstobeawayforthis
usertoinstalltheproductwithoutrequiringthoseelevatedprivilegesona
permanentbasis.WindowsInstallerprovidessomewaystodealwith
theseissues.Onereasonithelpswiththeseissuesisbecauseitrunsas
aWindowsServiceanddoesn'tneedtobeconstrainedbytheprivileges

ofthecurrentuser.Anotherreasonisbecausepoliciescanbeconfigured
soyoucanperformaninstallationwithelevatedprivilegesonbehalfofa
userwhoisnotprivileged.

UpdatingandDeployingNewVersions
BeforeWindowsInstaller,whenyouwantedtoshipcorrectionstoa
product,perhapsyousimplyrebuilttheentireinstallationsetupandsent
ittoyourclients.However,youcan'tjustaskyourclienttoinstallthe
product,becauseyou'dendupwithtwocopiesoftheproductonthe
system.However,ifyou'resupplyingafixoranupdateyouneedto
replacetheexistinginstalledproduct.Generallyspeaking,theincoming
newinstallationwoulddetecttheexistingoneanduninstallit,orperhaps
evenarrangetocompletelyinstallitselfontopoftheexistingproduct.
Anotherchoicewouldbetoproduceaservicepacktoupdatethe
product,oftenrequiringuseofaseparatetooltoinstalltheupdatestothe
clientsystem.Tosummarize,therehavebeenanumberofwaystodeal
withthesemaintenanceissues.WindowsInstallerhassomeformal
mechanismsforinstallingproductupdatesandfixes.

Advertisement
Youcanthinkofadvertisementasinstallation-on-demand.Itcanbe
particularlyusefulincorporateenvironments—youcanhavepractically


everythinginstalled(shortcuts,Registryentries,andsoon)exceptforthe
files.Whenyoureferencetheadvertisedproduct,theinstallationstarts
installingthefilesfromanetworklocationontotheclientsystem.Even
afteraproducthasbeeninstalled,perhapssomeofitsfeatureswillbe
advertised,sothatwhentheadvertisedfeatureisfirstusedthisfeatureis
installed.

Theideaofadvertisedfeaturesisthatyouinstallahookofsomekind,
typicallyashortcut.Usingthisshortcutcausesthefeaturetobeinstalled.
IftheadvertisedfeatureconsistsofoneormoreCOMcomponents,there
isasimilaradvertisementinstallationstepthatcausesthecomponentto
beinstalled.

RunningYourOwnCode
Manyoftheobservationsmadeinthischaptermightgivetheimpression
thatyoucan'taddyourowncodetotheinstallationprocess.Infactyou
can—whenyoudothisit'scalledacustomaction.Manytypesofcustom
actionsallowyoutorunVBScript,executables,andcallintoaDLL,to
quoteafewexamples.Sothatchangestothesystemcanbeprovided
withtransactionalbehaviorinmind,youcanassociatethesecustom
actionswiththeinstall,theuninstall,andalsotherollbackprocessthat
occurswhenaninstallationfailsandeverythingdonetothesystemis
beingundonetorestorethesystemtoitsoriginalstate.


TheTools
WindowsInstallerpackageshavetheMSIfileextension,andthe
WindowsInstallerServiceinstallsthesepackages.YoucanuseanSDK
here,justlikeinmanyotheraspectsofWindowsprogramming.Inthis
case,youusetheWindowsInstallerSDK,whichispartofthePlatform
SDK.Thiscontainsdocumentation,tools,andsamplecodetocreateand
modifyinstallerpackages.VS.NETofferswizardsandadevelopment
environmenttobuildinstallationpackages.
Third-partyvendorswhoprovidetoolstocreateinstallationsetupshave
beenaroundforawhile(forexample,InstallShieldSoftware).These
companies'toolshistoricallyhavebuiltinstallationpackagesthatdiffer
fromoneanother,althoughmostgenerateawizard-basedapproachto

theinstallationprocess.Theinnerworkingsoftheinstall—thecode,the
logfilesandsoon—areallproprietary.
AfterMicrosoftintroducedtheWindowsInstallerService,thesevendors
introducedtoolstocreateinstallerpackages(MSIfiles).Apartfrom
companiesandproductssuchasInstallShield,Wise,OnDemand
Software'sWinINSTALL,ZeroGSoftware'sInstallAnywhere.NET
(formerlyActiveInstall),andCornerHouseSoftware,thereareopen
sourceandfreetoolsthatyoucanusetobuildinstallerpackages.
AlthoughthisbookusesVS.NETextensivelyforitssamples,itis
importanttorealizethatVisualStudioDeploymentProjectsprovidejusta
basicauthoringtoolforcreatingpackagescomparedtosomeofthemore
advancedthird-partyproducts.It'squitelikelythatyouoryourcompany
willwanttobuildinstallerpackagesusingfeaturesthatWindowsInstaller
providesbutthatarebeyondthecapabilitiesofVisualStudioDeployment
Projects.Althoughthisbookwillhelpyoubuildanduseinstaller
packages,you'llfinditmucheasiertobuildmorecomplexinstallation
packagesusingafullyfeaturedtoolwithsupportforyourrequired
functionalitybuiltintoitsIntegratedDevelopmentEnvironment(IDE).
EverythingyoulearninthisbookaboutWindowsInstallerwillbeuseful
nomatterwhichtoolyoueventuallydecidetouse,butyou'llfindthatthe
rightdevelopmenttoolmakestheprocessofbuildinginstallerpackages
easierandfaster.


Summary
Perhapsthemostimportantcharacteristicofaninstallationpackage
(installerterminologyforanMSIfile)isthatitisadatabase.Thisisnot
looseterminology;itreallyisadatabasewithtablesorganizedinto
columnsandrows.Asyou'llseelater,youcanevenuseSQL-like
statementstoqueryorupdatetheinstallationpackage.Thetablesinthe

packagedescribethefiles,features,shortcuts,Registryentries,COM
classes,andyourcustomactioncode,tonamesomeofthecontent.
Eventheorderinwhichactivitiesoccurduringtheinstallationprocessis
determinedbytablesthatcontaineachactionanditsorderrelativeto
otheractions.
Asyou'llseeasyouprogressthroughthefollowingchapters,Windows
Installersuppliesaframeworkforinstallations.Likemostframeworks,it
worksbestwhenyoudon'tbendit.Whenyoudesignanddevelop
applications,you'realmostcertainlyawareofthelimitationsand
capabilitiesoftheimplementationyou'regoingtouse,andyoutakethese
intoaccountwhenyoudesigntheapplication.Thesameistrueof
WindowsInstaller.Ifyoucometodesignaproductinstallation,youmust
beawareofthedirectionthatthetechnologywouldpreferyoutotake.It's
probablynoexaggerationtosaythatmostinstallationproblemsarethe
resultofapreconceiveddesignorimplementationplanthatdoesn'tfitthe
framework.
You'llseehowalltheseexamplesworkusingactualexamplesof
installationpackages,solet'sgetgoingandbuildyourfirstinstallation
package.


Chapter2:BuildinganMsiFile:VisualStudio
andOrca
Inthischapter,you'llbuildaninstallerpackageusingaVS.NETSetup
andDeploymentProjectandlookatitwithatoolcalledOrca,partofthe
WindowsInstallerSDK.


Background
First,somehistoryandanoverviewofVS'scapabilitiesintheinstallation

area.
MicrosofthasoftenaddedcapabilitiesforbuildinginstallationsinVS—
perhapsyou'veusedtheVisualBasicPackageandDeploymentWizard.
Ifyou'veusedVS6.0,youmighthaveusedthefirstversionofVisual
StudioInstaller,whichwasavailableasafreedownloadforVSlicensees.
VS.NETisthefirstreleaseofVSthatintegratestheabilitytobuild
WindowsInstallerpackageswiththeIDE.However,VS.NET'sinstallation
toolcomeswithsomelimitationsandrestrictionsthatbecomeapparent
asyouuseit.Thisdoesn'tmeanthatMicrosoftdidabadjob,butitdoes
meanthatifyouwanttouseasubstantialsetofWindowsInstaller's
features,youshouldlookbeyondVS.NET'sinstallertool.LookinChapter
16foralistofsomeofthevendorsthatsupplyfullyfeaturedtoolsto
createinstallerpackages.
OneofthetoolsthatMicrosoftsuppliestoviewandmodifyinstaller
packagesiscalledOrca.YoucanfinditintheWindowsInstallersection
ofthePlatformSDK;theinstallationpackageis(whatelse?)aninstaller
packagecalledORCA.MSI.Afteryou'veinstalledit,you'llfindthatthe
right-clickcontextmenuonWindowsInstallerfiles(notablypackages,
MSIfilesandmergemodules,MSMfiles)allowsyoutoopenandedit
them.You'llbeusingOrcalatertoviewandmodifyinstallationpackages.
I'lldescribeeverythingIcoverhereregardingWindowsInstallerconcepts
inmoredetailinlaterchapters.Inthischapter,you'llbuildaninstaller
packagesothatyoucanlookinsidetheactualMSIfile;that'swhenyou'll
useOrca.