NPE occur when request body is empty. (TomcatService)

[be-hase]

Hi.

I am using armeria-tomcat with spring-mvc.
For example, controller is like the following code.

@RestController
public static class MyController {

    @PostMapping("/hoge")
    public String hoge(
            @RequestBody String body
    ) {
        return "POST";
    }
}

NPE occur when request body is empty.
Stack trace is like the following.

java.lang.NullPointerException: null
        at org.apache.coyote.Request.doRead(Request.java:511)
        at org.apache.catalina.connector.InputBuffer.realReadBytes(InputBuffer.java:318)
        at org.apache.tomcat.util.buf.ByteChunk.checkEof(ByteChunk.java:397)
        at org.apache.tomcat.util.buf.ByteChunk.substract(ByteChunk.java:363)
        at org.apache.catalina.connector.InputBuffer.readByte(InputBuffer.java:329)
        at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:93)
        at java.io.FilterInputStream.read(FilterInputStream.java:83)
        at java.io.PushbackInputStream.read(PushbackInputStream.java:139)
        at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver$EmptyBodyCheckingHttpInputMessage.<init>(AbstractMessageConverterMethodArgumentResolver.java:311)
        at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:185)
        at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:149)
        at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:127)
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:160)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:129)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
        at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:164)
        at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:80)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
        at com.linecorp.armeria.server.http.tomcat.TomcatService.lambda$null$4(TomcatService.java:407)
        at com.linecorp.armeria.common.AbstractRequestContext.lambda$makeContextAware$1(AbstractRequestContext.java:59)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
        at java.lang.Thread.run(Thread.java:745)

It seems to be null because it is not set here when content is empty.

https://github.com/line/armeria/blob/master/tomcat/src/main/java/com/linecorp/armeria/server/http/tomcat/TomcatService.java#L467-L469

Can I send PR ?

@@ -464,9 +464,7 @@ public final class TomcatService implements HttpService {
 
         // Set the content.
         final HttpData content = req.content();
-        if (!content.isEmpty()) {
-            coyoteReq.setInputBuffer(new InputBufferImpl(content));
-        }
+        coyoteReq.setInputBuffer(new InputBufferImpl(content));
 
         return coyoteReq;
     }
@@ -574,7 +572,7 @@ public final class TomcatService implements HttpService {
 
         @Override
         public int doRead(ByteChunk chunk) {
-            if (read) {
+            if (read || content.isEmpty()) {
                 // Read only once.
                 return -1;
             }

[trustin]

@be-hase The proposed fix sounds good to me. Yes, please send a PR! Thanks. 👍

[be-hase]

@trustin
thanks.
I will send the PR.