如何使用trine处理文件

HowtoHandleFileUploadswithHowtoHandleFileUploadswithHandlingfileuploadswithDoctrineentitiesisnodifferentthanhandlinganyotherfileupload.Inotherwords,you'refreetomovethefileinyourcontrollerafterhandlingaformsubmission.Forexamplesofhowtodothis,seethefiletypereferencepage.Ifyouchooseto,youcanalsointegratethefileuploadintoyourentitylifecycle(i.e.creation,updateandremoval).Inthiscase,asyourentityiscreated,updated,andremovedfromDoctrine,thefileuploadingandremovalprocessingwilltakeplaceautomatically(withoutneedingtodoanythinginyourcontroller).Tomakethiswork,you'llneedtotakecareofanumberofdetails,whichwillbecoveredinthiscookbook使用octne实体处理文件上传与处理任何其他文件上传没有区别。换句话说，你可以在处理过一个表单提交后自由的在控制器里移动这个文件。举例说明怎么做，请看fietpeefeene页面。如果你选择这么做，你也可以整合文件上传到你的实体生命周期里（如，ceaton,upate和emoal）个案例里，一旦你的实体从octne里被创建、更新和移除，文件也会随之自动执行上传和删除动作（不用在控制器里做任何事情）。BasicSetupFirst,createasimpleDoctrineentityclasstowork entityhasanameanditisassociatedwithafile.The propertystorestherelativepathtothefileandispersistedtothedatabase.Theisaconveniencemethodthatreturnstheabsolutepathtothefilewhiletheisaconveniencemethodthatreturnsthewebpath,whichcanbeusedinatemplatetolinktotheuploadedfile.ocumn实体有一个名称，并且它与一个文件联合起来。path属性存储了这个文件的相对路径并存储到数据库了。gtbluteat()是一个便利的方法用来返回这个文件的绝对路径，gbat()wb路径，这个可以用在模板里充当上传文件的链接。Ifyouhavenotdonesoalready,youshouldprobablyreadthefiletypedocumentationfirsttounderstandhowthebasicuploadprocessworks.Ifyou'reusingannotationstospecifyyourvalidationrules(asshowninthisexample),besurethatyou'veenabledvalidationbyannotation(seevalidation（看validationTohandletheactualfileuploadintheform,usea"virtual" field.Forexample,ifyou'rebuildingyourformdirectlyinacontroller,itmightlooklikethis:处理实际的表单文件上传，使用一个虚拟fileNext,createthispropertyon classandaddsomevalidationAsyouareusingthe constraint,Symfonywillautomaticallyguessthattheformfieldisafileuploadinput.That'swhyyoudidnothavetosetitexplicitlywhencreatingtheformabove(ThefollowingcontrollershowsyouhowtohandletheentireThepreviouscontrollerwillautomaticallypersistthe entitywiththesubmittedname,butitwilldonothingaboutthefileandthepropertywillbeblank.Aneasywaytohandlethefileuploadistomoveitjustbeforetheentityispersistedandthenthepropertyaccordingly.Startbycallinganew methodonthe class,whichyou'llcreateinamomenttohandlethefileupload: methodwilltakeadvantageofthe object,whichiswhat'sreturnedafter fieldissubmitted:UsingLifecycleCallbacks¶Usinglifecyclecallbacksisalimitedtechniquethathassomedrawbacks.Ifyouwanttoremovethehardcoded referenceinsidethemethod,thebestwayistostartusingexplicitdoctrinelisteners.Thereyouwillbeabletoinjectkernelparameterssuchas tobeabletobuildabsolutepaths. 的doctrinelisteners.这样你可以注射内核参数，例如用kernel.root_dir构建绝对路径。Evenifthisimplementationworks,itsuffersfromamajorflaw:Whatifthereisaproblemwhentheentityispersisted?Thefilewouldhavealreadymovedtoitsfinallocationeventhoughtheentity'spropertydidn'tpersistcorrectly.Toavoidtheseissues,youshouldchangetheimplementationsothatthedatabaseoperationandthemovingofthefilebecomeatomic:ifthereisaproblempersistingtheentityorifthefilecannotbemoved,thennothingshouldhappen.Todothis,youneedtomovethefilerightasDoctrinepersiststheentitytothedatabase.Thiscanbeaccomplishedbyhookingintoanentitylifecyclecallback:Next,refactor classtotakeadvantageofthese IfchangestoyourentityarehandledbyaDoctrineeventlisteneroreventsubscriber,thecallbackmustnotifyDoctrineaboutthechangesbeingdone.ForfullreferenceonpreUpdateeventrestrictions,seepreUpdateintheDoctrineEventsTheclassnowdoeseverythingyouneed:itgeneratesauniquefilenamebeforepersisting,movesthefileafterpersisting,andremovesthefileiftheentityiseverdeleted.Nowthatthemovingofthefileishandledatomicallybytheentity,thecalltoshouldberemovedfromthecontroller:Theandeventcallbacksaretriggeredbeforeandaftertheentityispersistedtothedatabase.Ontheotherhand,theandeventcallbacksarecalledwhentheentityis callbacksareonlytriggeredifthereisachangeinoneoftheentity'sfieldsthatarepersisted.Thismeansthat,bydefault,ifyoumodifyonly property,theseeventswillnotbetriggered,asthepropertyitselfisnotdirectlypersistedviaDoctrine.Onesolutionwouldbetousean fieldthat'spersistedtoDoctrine,andtomodifyitmanuallywhenchangingthefile.UsingtheidastheFilenameIfyouwanttousethe asthenameofthefile,theimplementationisslightlydifferentasyouneedtosavetheextensionundertheproperty,insteadoftheactualfilename:You'llnoticeinthiscasethatyouneedtodoalittlebitmoreworkinordertoremovethefile.Beforeit'sremov