php和mysql web开发外文翻译 2.docx

php和mysql web开发外文翻译 2.docx

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php和mysqlweb开发外文翻译2

外文翻译-原文部分

LauraThomsonphpandmysqlwebdevelop

PHPisascriptinglanguageoriginallydesignedforproducingdynamicwebpagesIthasevolvedtoincludeacommandlineinterfacecapabilityandcanbeusedinstandalonegraphicalapplications.

WhilePHPwasoriginallycreatedbyRasmusLerdorfin1995,themainimplementationofPHPisnowproducedbyThePHPGroupandservesasthedefactostandiirdforPHPasthereisnoformalspecification.PHPisfreesoftwarereleasedunderthePHPLicense,howeveritisincompatiblewiththeGNUGeneralPublicLicense（GPL）,duetorestrictionsontheusageofthetermPHP.

PHPisawidely-usedgeneral-purposescriptinglanguagethatisespeciallysuitedforwebdevelopmentandcanbeembeddedintoHTML.Itgenerallyrunsonawebserver,takingPHPcodeasitsinputandcreatingwebpagesasoutput.Itcanbemillionwebsitesand1millionwebservers.

PHPoriginallystoodforPersonalHomePage,Itbeganin1994asasetofCommonGatewayInterfacebinarieswrittenintheCprogramminglanguagebytheDanish/GreenlandicprogrammerRasmusLerdorf.LerdorfinitiallycreatedthesePersonalHomePageToolstoreplaceasmallsetofPerlscriptshehadbeenusingtomaintainhispersonalhomepage.Thetoolswereusedtoperformtaskssuchasdisplayinghisrdsum^andrecordinghowmuchtraffichispagewasreceiving.HecombinedthesebinarieswithhisFonnInterpretertocreatePHP/FI,whichhadmorefunctionality.PHP/FIincludedalargerimplementationfortheCprogramminglanguageandcouldcommunicatewithdatabases,enablingthebuildingofsimple,dynamicwebapplications.lerdorfreleasedPHPpubliclyonJune8，1995toacceleratebuglocationandimprovethecode.ThisreleasewasnamedPHPversion2andalreadyhadthebasicfunctionalitythatPHPhastoday.ThisincludedPerl-likevariables,formhandling,andtheabilitytoembedHTML.ThesyntaxwassimilartoPerlbutwasmorelimited,simpler,andlessconsistent.

ZeevSuraskiandAndiGutmans，twoIsraelidevelopersattheTechnionIIT，rewrotetheparserin1997andformedthebaseofPHP3,changingthelanguage'snametotherecursiveinitialismPHP:

HypertextPreprocessor.ThedevelopmentteamofficiallyreleasedPHP/FI2inNovember1997aftermonthsofbetatesting.Afterwards,publictestingofPHP3began,andtheofficiallaunchcameinJune1998.wSuraskiandGutmansthenstartedanewrewriteofPHP'score,producingtheZendEnginein1999.TheyalsofoundedZendTechnologiesinRamatGan,Israel.

OnMay22,2000,PHP4,poweredbytheZendEngine1•0,wasreleased.OnJuly13,2004,PHP5wasreleased,poweredbythenewZendEngineII.PHP5includednewfeaturessuchasimprovedsupportforobject-orientedprogramming,thePHPData

Objectsextension（whichdefinesalightweightandconsistentinterfaceforaccessingdatabases）,andnumerousperformanceenhancements.ThemostrecentupdatereleasedbyThePHPGroupisfortheolderPHPversion4codebranch.AsofAugust,2008thisbranchisuptoversion4.4.9.PHP4isnolongerunderdevelopmentnorwillanysecurityupdatesbereleased.

In2008,PHP5becametheonlystableversionunderdevelopment.LatestaticbindinghasbeenmissingfromPHPandwillbeaddedinversion5.3.PHP6isunderdevelopmentalongsidePHP5.Majorchangesincludetheremovalofregister_globals，magicquotes,andsafemode.Thereasonfortheremovalswasbecauseregister_globalshadgivenwaytosecurityholes，andmagicquoteshadanunpredictablenature,andwasbestavoided.Instead,toescapecharacters,magicquotesmaybesubstitutedwiththeaddslashes（）function,ormoreappropriatelyanescapemechanismspecifictothedatabasevendoritselflikemysql_rcal_escape_string（）forMySQL.

PHPdoesnothavecompletenativesupportforUnicodeormultibytestrings;UnicodesupportwillbeincludedinPHP6.ManyhighprofileopensourceprojectsceasedtosupportPHP4innewcodeasofFebruary5,2008,duetotheGoPHP5initiative,providedbyaconsortiumofPHPdeveloperspromotingthetransitionfromPHP4toPHP1397Itrunsinboth32-bitand64-bitenvironments,butonWindowstheonlyofficialdistributionis32-bit,requiringWindows32-bitcompatibilitymodetobeenabledwhileusingIISina64-bitWindowsenvironment.Thereisathird-partydistributionavailablefor64-bitWindows.

PHPisageneral-purposescriptinglanguagethatisespeciallysuitedforwebdevelopment.PHPgenerallyrunsonawebserver,takingPHPcodeasitsinputandcreatingwebpagesasoutput.Itcanalsobeusedforcommand-linescriptingandclient-sideGUIapplications.PHPcanbedeployedonmostwebservers,manyoperatingsystemsandplatforms,andcanbeusedwithmanyrelationaldatabasemanagementsystems.Itisavailablefreeofcharge,andthePHPGroupprovidesthecompletesourcecodeforuserstobuild,customizeandextendfortheirownuse.

PHPprimarilyactsasafilter,takinginputfromafileorstreamcontainingtextand/orPHPinstructionsandoutputsanotherstreamofdata;mostcommonlytheoutputwillbeHTML.Itcanautomaticallydetectthelanguageoftheuser.FromPHP4,thePHPparsercompilesinputtoproducebylecodeforprocessingbytheZendEngine,givingimprovedperformanceoveritsinterpreterpredecessor.

Originallydesignedtocreatedynamicwebpages，PHP’sprincipalfocusisserver-sidescripting,anditissimilartootherserver-sidescriptinglanguagesthatprovidedynamiccontentfromawebservertoaclient,suchasMicrosoft’sActiveServerPages,SunMicrosystems1JavaServerPages,andmod_perl.PHPhasalsoattractedthedevelopmentofmanyframeworksthatprovidebuildingblocksandadesignstructuretopromoterapidapplicationdevelopment（RAD）.SomeoftheseincludeCakePHP,Symfony,Codeigniter,andZendFramework,offeringfeaturessimilartootherwebapplicationframeworks-

TheLAMParchitecturehasbecomepopularinthewebindustryasawayofdeployingvvebapplications.PHPiscommonlyusedasthePinthisbundlealongsideLinux,ApacheandMySQL,althoughthePmayalsorefertoPythonorPerl.

AsofApril2007,over20millionInternetdomainswerehostedonserverswithPHPinstalled,andPHPwasrecordedasthemostpopularApachemodule.SignificantwebsitesarcwritteninPHPincludingtheuser-facingportionofFaccbook,Wikipedia,PHPcanbeusedtocreatestand-alone,compiledapplicationsandlibraries,itcanbeusedforshellscripting,andthePHPbinariescanbecalledfromthecommandline.

Aswithmanyscriptinglanguages，PHPscriptsarenormallykeptashuman-readablesourcecode,evenonproductionwebservers.Inthiscase,PHPscriptswillhecompiledatruntimebythePHPengine,whichincreasestheirexecutiontime.PHPscriptsareabletobecompiledbeforeruntimeusingPHPcompilersaswithotherprogramminglanguagessuchasC（thelanguagePHPanditsextensionsarewrittenin）.

Codeoptimizersaimtoreducethecomputationalcomplexityofthecompiledcodebyreducingitssizeandmakingotherchangesthatcanreducetheexecutiontimewiththeoverallgoalofimprovingperformance.ThenatureofthePHPcompilerissuchthatthereareoftenopportunitiesforcodeoptimization,andanexampleofacodeoptimizeristheZendOptimizerPHPextension.

AnotherapproachforreducingoverheadforhighloadPHPserversisusingPHPaccelerators.ThesecanoffersignificantperformancegainsbycachingthecompiledformofaPHPscriptinsharedmemorytoavoidtheoverheadofparsingandcompilingthecodeeverytimethescriptruns.

TheNationalVulnerabilityDatabasestoresallvulnerabilitiesfoundincomputersoftware.TheoverallproportionofPHP-relatedvulnerabilitiesonthedatabaseamountedto:

12%in2003,20%in2004,28%in2005,43%in2006,36%in2007,and35%in2008.MostofthesePHP-relatedvulnerabilitiescanbeexploitedremotely:

theyallowhackerstostealordestroydatafromdatasourceslinkedtotheWebserver（suchasanSQLdatabase），sendspamorcontributetoDOSattacksusingmalware，whichitselfcanbeinstalledonthevulnerableservers.

Thesevulnerabilitiesarccausedmostlybynotfollowingbestpracticeprogrammingrules:

technicalsecurityflawsofthelanguageitselforofitscorelibrariesarenotfrequent.Recognizingthatprogrammerscannotbetrusted,somelanguagesincludetaintcheckingtodetectautomaticallythelackofinputvalidationwhichinducesmanyissues.SuchafeatureisbeingdevelopedforPHP.AllhoughitmaybeincludedinmainstreamPHPinafuturerelease,itsinclusionhasbeenrejectedseveraltimesinthepast.

HostingPHPapplicationsonaserverrequiresacarefulandconstantattentiontodealwiththesesecurityrisks.ThereareadvancedprotectionpatchessuchasvSuhosinandHardening-Patch,especiallydesignedforwebhostingenvironments.InstallingPHPasaCGIbinaryratherthanasanApachemoduleisthepreferredmethodforaddedsecurity.

Withrespecttosecuringthecodeitself,PHPcodecanbeobfuscatedtomakeitdifficulttoreadwhileremainingfunctional.

Syntax-highlightedPHPcodeembeddedwithinHTMLPHPonlyparsescodewithinitsdelimiters.AnythingoutsideitsdelimitersissentdirectlytotheoutputandisnotparsedbyPHP.Themostcommondelimitersare

phpand?

>,whichareopenandclosedelimitersrespectively.〈scriptlanguage="php">anddelimitersarealsoavailable.ShorttagscanbeusedtostartPHPcode,

or

=（whichisusedtoechobackastringorvariable）andthetagtoendPHPcode,?

>.Thesetagsarccommonlyused，butlikeASP-styletags（<%or<%=and%>），theyarelessportableastheycanbedisabledinthePHPconfiguration.Forthisreason,theuseofshorttagsandASP-styletagsisdiscouraged.Thepuipo