Spring源代码解析(十)：Spring Acegi框架授权的实现(6页).doc

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1、-Spring源代码解析(十)：Spring Acegi框架授权的实现-第 7 页Spring源代码解析（十）：Spring Acegi框架授权的实现我们从FilterSecurityInterceptor我们从入手看看怎样进行授权的： Java代码 1. /这里是拦截器拦截HTTP请求的入口 2. publicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,FilterChainchain) 3. throwsIOException,ServletException 4. FilterInvocationfi=newFil

2、terInvocation(request,response,chain); 5. invoke(fi); 6. /这是具体的拦截调用 7. publicvoidinvoke(FilterInvocationfi)throwsIOException,ServletException 8. if(fi.getRequest()!=null)&(fi.getRequest().getAttribute(FILTER_APPLIED)!=null) 9. &observeOncePerRequest) 10. /在第一次进行过安全检查之后就不会再做了 11. fi.getChain().doFilt

3、er(fi.getRequest(),fi.getResponse(); 12. else 13. /这是第一次收到相应的请求，需要做安全检测，同时把标志为设置好-FILTER_APPLIED，下次就再有请求就不会作相同的安全检查了 14. if(fi.getRequest()!=null) 15. fi.getRequest().setAttribute(FILTER_APPLIED,Boolean.TRUE); 16. /这里是做安全检查的地方 17. InterceptorStatusTokentoken=super.beforeInvocation(fi); 18. /接着向拦截器链执

4、行 19. try 20. fi.getChain().doFilter(fi.getRequest(),fi.getResponse(); 21. finally 22. super.afterInvocation(token,null); TTP请求的入口 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException FilterInvocation fi = new FilterInvocation

5、(request, response, chain); invoke(fi);/这是具体的拦截调用 public void invoke(FilterInvocation fi) throws IOException, ServletException if (fi.getRequest() != null) & (fi.getRequest().getAttribute(FILTER_APPLIED) != null) & observeOncePerRequest) /在第一次进行过安全检查之后就不会再做了 fi.getChain().doFilter(fi.getRequest(), f

6、i.getResponse(); else /这是第一次收到相应的请求，需要做安全检测，同时把标志为设置好 - FILTER_APPLIED，下次就再有请求就不会作相同的安全检查了 if (fi.getRequest() != null) fi.getRequest().setAttribute(FILTER_APPLIED, Boolean.TRUE); /这里是做安全检查的地方 InterceptorStatusToken token = super.beforeInvocation(fi); /接着向拦截器链执行 try fi.getChain().doFilter(fi.getRequ

7、est(), fi.getResponse(); finally super.afterInvocation(token, null);我们看看在AbstractSecurityInterceptor是怎样对HTTP请求作安全检测的： Java代码 1. protectedInterceptorStatusTokenbeforeInvocation(Objectobject) 2. Assert.notNull(object,Objectwasnull); 3. if(!getSecureObjectClass().isAssignableFrom(object.getClass() 4. t

8、hrownewIllegalArgumentException(Securityinvocationattemptedforobject5. +object.getClass().getName() 6. +butAbstractSecurityInterceptoronlyconfiguredtosupportsecureobjectsoftype:7. +getSecureObjectClass(); 8. /这里读取配置FilterSecurityInterceptor的ObjectDefinitionSource属性，这些属性配置了资源的安全设置 9. ConfigAttributeD

9、efinitionattr=this.obtainObjectDefinitionSource().getAttributes(object); 10. if(attr=null) 11. if(rejectPublicInvocations) 12. thrownewIllegalArgumentException( 13. NopublicinvocationsareallowedviathisAbstractSecurityInterceptor.14. +Thisindicatesaconfigurationerrorbecausethe15. +AbstractSecurityInt

10、erceptor.rejectPublicInvocationspropertyissettotrue); 16. if(logger.isDebugEnabled() 17. logger.debug(Publicobject-authenticationnotattempted); 18. publishEvent(newPublicInvocationEvent(object); 19. returnnull;/nofurtherworkpost-invocation 20. if(logger.isDebugEnabled() 21. logger.debug(Secureobject

11、:+object.toString()+;ConfigAttributes:+attr.toString(); 22. /这里从SecurityContextHolder中去取Authentication对象，一般在登录时会放到SecurityContextHolder中去 23. if(SecurityContextHolder.getContext().getAuthentication()=null) 24. credentialsNotFound(messages.getMessage(AbstractSecurityInterceptor.authenticationNotFound

12、, 25. AnAuthenticationobjectwasnotfoundintheSecurityContext),object,attr); 26. /如果前面没有处理鉴权，这里需要对鉴权进行处理 27. Authenticationauthenticated; 28. if(!SecurityContextHolder.getContext().getAuthentication().isAuthenticated()|alwaysReauthenticate) 29. try/调用配置好的AuthenticationManager处理鉴权，如果鉴权不成功，抛出异常结束处理 30.

13、authenticated=this.authenticationManager.authenticate(SecurityContextHolder.getContext() 31. .getAuthentication(); 32. catch(AuthenticationExceptionauthenticationException) 33. throwauthenticationException; 34. /Wedontauthenticated.setAuthentication(true),becauseeachprovidershoulddothat 35. if(logge

14、r.isDebugEnabled() 36. logger.debug(SuccessfullyAuthenticated:+authenticated.toString(); 37. /这里把鉴权成功后得到的Authentication保存到SecurityContextHolder中供下次使用 38. SecurityContextHolder.getContext().setAuthentication(authenticated); 39. else/这里处理前面已经通过鉴权的请求，先从SecurityContextHolder中去取得Authentication 40. authen

15、ticated=SecurityContextHolder.getContext().getAuthentication(); 41. if(logger.isDebugEnabled() 42. logger.debug(PreviouslyAuthenticated:+authenticated.toString(); 43. /这是处理授权的过程 44. try 45. /调用配置好的AccessDecisionManager来进行授权 46. this.accessDecisionManager.decide(authenticated,object,attr); 47. catch(

16、AccessDeniedExceptionaccessDeniedException) 48. /授权不成功向外发布事件 49. AuthorizationFailureEventevent=newAuthorizationFailureEvent(object,attr,authenticated, 50. accessDeniedException); 51. publishEvent(event); 52. throwaccessDeniedException; 53. if(logger.isDebugEnabled() 54. logger.debug(Authorizationsu

17、ccessful); 55. AuthorizedEventevent=newAuthorizedEvent(object,attr,authenticated); 56. publishEvent(event); 57. /这里构建一个RunAsManager来替代当前的Authentication对象，默认情况下使用的是NullRunAsManager会把SecurityContextHolder中的Authentication对象清空 58. AuthenticationrunAs=this.runAsManager.buildRunAs(authenticated,object,att

18、r); 59. if(runAs=null) 60. if(logger.isDebugEnabled() 61. logger.debug(RunAsManagerdidnotchangeAuthenticationobject); 62. /nofurtherworkpost-invocation 63. returnnewInterceptorStatusToken(authenticated,false,attr,object); 64. else 65. if(logger.isDebugEnabled() 66. logger.debug(SwitchingtoRunAsAuthe

19、ntication:+runAs.toString(); 67. SecurityContextHolder.getContext().setAuthentication(runAs); 68. /reverttotoken.Authenticatedpost-invocation 69. returnnewInterceptorStatusToken(authenticated,true,attr,object); protected InterceptorStatusToken beforeInvocation(Object object) Assert.notNull(object, O

20、bject was null); if (!getSecureObjectClass().isAssignableFrom(object.getClass() throw new IllegalArgumentException(Security invocation attempted for object + object.getClass().getName() + but AbstractSecurityInterceptor only configured to support secure objects of type: + getSecureObjectClass(); /这里

21、读取配置FilterSecurityInterceptor的ObjectDefinitionSource属性，这些属性配置了资源的安全设置 ConfigAttributeDefinition attr = this.obtainObjectDefinitionSource().getAttributes(object); if (attr = null) if(rejectPublicInvocations) throw new IllegalArgumentException( No public invocations are allowed via this AbstractSecuri

22、tyInterceptor. + This indicates a configuration error because the + AbstractSecurityInterceptor.rejectPublicInvocations property is set to true); if (logger.isDebugEnabled() logger.debug(Public object - authentication not attempted); publishEvent(new PublicInvocationEvent(object); return null; / no

23、further work post-invocation if (logger.isDebugEnabled() logger.debug(Secure object: + object.toString() + ; ConfigAttributes: + attr.toString(); /这里从SecurityContextHolder中去取Authentication对象，一般在登录时会放到SecurityContextHolder中去 if (SecurityContextHolder.getContext().getAuthentication() = null) credentia

24、lsNotFound(messages.getMessage(AbstractSecurityInterceptor.authenticationNotFound, An Authentication object was not found in the SecurityContext), object, attr); / 如果前面没有处理鉴权，这里需要对鉴权进行处理 Authentication authenticated; if (!SecurityContextHolder.getContext().getAuthentication().isAuthenticated() | alw

25、aysReauthenticate) try /调用配置好的AuthenticationManager处理鉴权，如果鉴权不成功，抛出异常结束处理 authenticated = this.authenticationManager.authenticate(SecurityContextHolder.getContext() .getAuthentication(); catch (AuthenticationException authenticationException) throw authenticationException; / We dont authenticated.set

26、Authentication(true), because each provider should do that if (logger.isDebugEnabled() logger.debug(Successfully Authenticated: + authenticated.toString(); /这里把鉴权成功后得到的Authentication保存到SecurityContextHolder中供下次使用 SecurityContextHolder.getContext().setAuthentication(authenticated); else /这里处理前面已经通过鉴权

27、的请求，先从SecurityContextHolder中去取得Authentication authenticated = SecurityContextHolder.getContext().getAuthentication(); if (logger.isDebugEnabled() logger.debug(Previously Authenticated: + authenticated.toString(); / 这是处理授权的过程 try /调用配置好的AccessDecisionManager来进行授权 this.accessDecisionManager.decide(aut

28、henticated, object, attr); catch (AccessDeniedException accessDeniedException) /授权不成功向外发布事件 AuthorizationFailureEvent event = new AuthorizationFailureEvent(object, attr, authenticated, accessDeniedException); publishEvent(event); throw accessDeniedException; if (logger.isDebugEnabled() logger.debug(

29、Authorization successful); AuthorizedEvent event = new AuthorizedEvent(object, attr, authenticated); publishEvent(event); / 这里构建一个RunAsManager来替代当前的Authentication对象，默认情况下使用的是NullRunAsManager会把SecurityContextHolder中的Authentication对象清空 Authentication runAs = this.runAsManager.buildRunAs(authenticated,

30、 object, attr); if (runAs = null) if (logger.isDebugEnabled() logger.debug(RunAsManager did not change Authentication object); / no further work post-invocation return new InterceptorStatusToken(authenticated, false, attr, object); else if (logger.isDebugEnabled() logger.debug(Switching to RunAs Aut

31、hentication: + runAs.toString(); SecurityContextHolder.getContext().setAuthentication(runAs); / revert to token.Authenticated post-invocation return new InterceptorStatusToken(authenticated, true, attr, object);到这里我们假设配置AffirmativeBased作为AccessDecisionManager： Java代码 1. /这里定义了决策机制，需要全票才能通过 2. public

32、voiddecide(Authenticationauthentication,Objectobject,ConfigAttributeDefinitionconfig) 3. throwsAccessDeniedException 4. /这里取得配置好的迭代器集合 5. Iteratoriter=this.getDecisionVoters().iterator(); 6. intdeny=0; 7. /依次使用各个投票器进行投票，并对投票结果进行计票 8. while(iter.hasNext() 9. AccessDecisionVotervoter=(AccessDecisionVo

33、ter)iter.next(); 10. intresult=voter.vote(authentication,object,config); 11. /这是对投票结果进行处理，如果遇到其中一票通过，那就授权通过，如果是弃权或者反对，那就继续投票 12. switch(result) 13. caseAccessDecisionVoter.ACCESS_GRANTED: 14. return; 15. caseAccessDecisionVoter.ACCESS_DENIED: 16. /这里对反对票进行计数 17. deny+; 18. break; 19. default: 20. br

34、eak; 21. /如果有反对票，抛出异常，整个授权不通过 22. if(deny0) 23. thrownewAccessDeniedException(messages.getMessage(AbstractAccessDecisionManager.accessDenied, 24. Accessisdenied); 25. /这里对弃权票进行处理，看看是全是弃权票的决定情况，默认是不通过，由allowIfAllAbstainDecisions变量控制 26. checkAllowIfAllAbstainDecisions(); 27. 具体的投票由投票器进行，我们这里配置了RoleVo

35、ter来进行投票： 28. publicintvote(Authenticationauthentication,Objectobject,ConfigAttributeDefinitionconfig) 29. intresult=ACCESS_ABSTAIN; 30. /这里取得资源的安全配置 31. Iteratoriter=config.getConfigAttributes(); 32. while(iter.hasNext() 33. ConfigAttributeattribute=(ConfigAttribute)iter.next(); 34. if(this.support

36、s(attribute) 35. result=ACCESS_DENIED; 36. /这里对资源配置的安全授权级别进行判断，也就是匹配ROLE为前缀的角色配置 37. /遍历每个配置属性，如果其中一个匹配该主体持有的GrantedAuthority,则访问被允许。 38. for(inti=0;iauthentication.getAuthorities().length;i+) 39. if(attribute.getAttribute().equals(authentication.getAuthorities()i.getAuthority() 40. returnACCESS_GRA

37、NTED; 41. returnresult; /这里定义了决策机制，需要全票才能通过 public void decide(Authentication authentication, Object object, ConfigAttributeDefinition config) throws AccessDeniedException /这里取得配置好的迭代器集合 Iterator iter = this.getDecisionVoters().iterator(); int deny = 0; /依次使用各个投票器进行投票，并对投票结果进行计票 while (iter.hasNext() AccessDecisionVoter voter = (AccessDecisionVoter) i