com.lark.oapi.core.exception.IncorrectSignatureException: The result of signature verification failed

oapi-sdk调用报错：

com.lark.oapi.core.exception.IncorrectSignatureException: The result of signature verification failed
	at com.lark.oapi.event.EventDispatcher.handle(EventDispatcher.java:200) [oapi-sdk-2.0.2.jar:2.0.2]
	at com.lark.oapi.sdk.servlet.ext.ServletAdapter.handleEvent(ServletAdapter.java:31) [oapi-sdk-servlet-ext-1.0.0-rc2.jar:1.0.0-rc2]
	at cn.healthlink.devops.web.controller.EventController.event(EventController.java:73) [classes/:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_221]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_221]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_221]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_221]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) [spring-web-5.3.23.jar:5.3.23]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) [spring-web-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1071) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:964) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.3.23.jar:5.3.23]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) [spring-webmvc-5.3.23.jar:5.3.23]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:517) [jakarta.servlet-api-4.0.4.jar:4.0.4]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.3.23.jar:5.3.23]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:584) [jakarta.servlet-api-4.0.4.jar:4.0.4]
	at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at cn.springsoter.core.log4j2.filter.LogMDCFilter.doFilter(LogMDCFilter.java:24) [springsoter-core-log4j2-1.0.31.jar:1.0.31]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) [spring-web-5.3.23.jar:5.3.23]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) [spring-web-5.3.23.jar:5.3.23]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) [spring-web-5.3.23.jar:5.3.23]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) [spring-web-5.3.23.jar:5.3.23]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) [spring-boot-actuator-2.6.12.jar:2.6.12]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) [spring-web-5.3.23.jar:5.3.23]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) [spring-web-5.3.23.jar:5.3.23]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) [spring-web-5.3.23.jar:5.3.23]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:117) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:275) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:79) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:134) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:131) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:255) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:79) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:100) [undertow-servlet-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852) [undertow-core-2.2.19.Final.jar:2.2.19.Final]
	at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) [jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019) [jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558) [jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1423) [jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282) [xnio-api-3.8.7.Final.jar:3.8.7.Final]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_221]

pom依赖：

<dependency>
  <groupId>com.larksuite.oapi</groupId>
  <artifactId>oapi-sdk</artifactId>
  <version>2.0.2</version>
</dependency>

原因：
com.lark.oapi.event.EventDispatcher类的verifySign(EventReq eventReq)方法，获取timestamp、nonce、sourceSign的值为空。因为eventReq.getHeaderFirstValue(String name)方法参数name被转化成小写了，导致Map<String, List<String>> headers = new HashMap();headers里获取不到值。

希望能尽快解决这个bug，谢谢！

Start with com.lark.oapi.event.EventDispatcher.verifySign(EventReq) and inspect EventReq.getHeaderFirstValue(String name), focusing on how header names are normalized and looked up. Reproduce the reported failure with the servlet event path shown in the stack trace; done means timestamp, nonce, and sourceSign are retrieved and signature verification no longer fails for valid requests.