聊聊springboot tomcat的maxHttpFormPostSize

序

本文主要研究一下spring boot tomcat的maxHttpFormPostSize参数

parseParameters

tomcat-embed-core-9.0.37-sources.jar!/org/apache/catalina/connector/Request.java

    /**
     * Parse request parameters.
     */
    protected void parseParameters() {

        parametersParsed = true;

        Parameters parameters = coyoteRequest.getParameters();
        boolean success = false;
        try {
            // Set this every time in case limit has been changed via JMX
            parameters.setLimit(getConnector().getMaxParameterCount());

            // getCharacterEncoding() may have been overridden to search for
            // hidden form field containing request encoding
            Charset charset = getCharset();

            boolean useBodyEncodingForURI = connector.getUseBodyEncodingForURI();
            parameters.setCharset(charset);
            if (useBodyEncodingForURI) {
                parameters.setQueryStringCharset(charset);
            }
            // Note: If !useBodyEncodingForURI, the query string encoding is
            //       that set towards the start of CoyoyeAdapter.service()

            parameters.handleQueryParameters();

            if (usingInputStream || usingReader) {
                success = true;
                return;
            }

            String contentType = getContentType();
            if (contentType == null) {
                contentType = "";
            }
            int semicolon = contentType.indexOf(';');
            if (semicolon >= 0) {
                contentType = contentType.substring(0, semicolon).trim();
            } else {
                contentType = contentType.trim();
            }

            if ("multipart/form-data".equals(contentType)) {
                parseParts(false);
                success = true;
                return;
            }

            if( !getConnector().isParseBodyMethod(getMethod()) ) {
                success = true;
                return;
            }

            if (!("application/x-www-form-urlencoded".equals(contentType))) {
                success = true;
                return;
            }

            int len = getContentLength();

            if (len > 0) {
                int maxPostSize = connector.getMaxPostSize();
                if ((maxPostSize >= 0) && (len > maxPostSize)) {
                    Context context = getContext();
                    if (context != null && context.getLogger().isDebugEnabled()) {
                        context.getLogger().debug(
                                sm.getString("coyoteRequest.postTooLarge"));
                    }
                    checkSwallowInput();
                    parameters.setParseFailedReason(FailReason.POST_TOO_LARGE);
                    return;
                }
                byte[] formData = null;
                if (len < CACHED_POST_LEN) {
                    if (postData == null) {
                        postData = new byte[CACHED_POST_LEN];
                    }
                    formData = postData;
                } else {
                    formData = new byte[len];
                }
                try {
                    if (readPostBody(formData, len) != len) {
                        parameters.setParseFailedReason(FailReason.REQUEST_BODY_INCOMPLETE);
                        return;
                    }
                } catch (IOException e) {
                    // Client disconnect
                    Context context = getContext();
                    if (context != null && context.getLogger().isDebugEnabled()) {
                        context.getLogger().debug(
                                sm.getString("coyoteRequest.parseParameters"), e);
                    }
                    parameters.setParseFailedReason(FailReason.CLIENT_DISCONNECT);
                    return;
                }
                parameters.processParameters(formData, 0, len);
            } else if ("chunked".equalsIgnoreCase(
                    coyoteRequest.getHeader("transfer-encoding"))) {
                byte[] formData = null;
                try {
                    formData = readChunkedPostBody();
                } catch (IllegalStateException ise) {
                    // chunkedPostTooLarge error
                    parameters.setParseFailedReason(FailReason.POST_TOO_LARGE);
                    Context context = getContext();
                    if (context != null && context.getLogger().isDebugEnabled()) {
                        context.getLogger().debug(
                                sm.getString("coyoteRequest.parseParameters"),
                                ise);
                    }
                    return;
                } catch (IOException e) {
                    // Client disconnect
                    parameters.setParseFailedReason(FailReason.CLIENT_DISCONNECT);
                    Context context = getContext();
                    if (context != null && context.getLogger().isDebugEnabled()) {
                        context.getLogger().debug(
                                sm.getString("coyoteRequest.parseParameters"), e);
                    }
                    return;
                }
                if (formData != null) {
                    parameters.processParameters(formData, 0, formData.length);
                }
            }
            success = true;
        } finally {
            if (!success) {
                parameters.setParseFailedReason(FailReason.UNKNOWN);
            }
        }

    }

tomcat request解析表单参数

maxPostSize

主要是下面这段

                if ((maxPostSize >= 0) && (len > maxPostSize)) {
                    Context context = getContext();
                    if (context != null && context.getLogger().isDebugEnabled()) {
                        context.getLogger().debug(
                                sm.getString("coyoteRequest.postTooLarge"));
                    }
                    checkSwallowInput();
                    parameters.setParseFailedReason(FailReason.POST_TOO_LARGE);
                    return;
                }

如果大于maxPostSize，则会设置FailReason.POST_TOO_LARGE，如果开启debug日志则会打印coyoteRequest.postTooLarge的内容

postTooLarge

coyoteRequest.postTooLarge=Parameters were not parsed because the size of the posted data was too big. Use the maxPostSize attribute of the connector to resolve this if the application should accept large POSTs.

400

对于spring boot来说，请求会报400，也就是参数丢失的错误，比如

org.springframework.web.bind.MissingServletRequestParameterException: Required String parameter 'arg1' is not present
    at org.springframework.web.method.annotation.RequestParamMethodArgumentResolver.handleMissingValue(RequestParamMethodArgumentResolver.java:204)
    at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:114)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:92)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at net.rakugakibox.spring.boot.logback.access.tomcat.LogbackAccessTomcatValve.invoke(LogbackAccessTomcatValve.java:91)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:833)

TomcatWebServerFactoryCustomizer

spring-boot-autoconfigure-2.3.3.RELEASE-sources.jar!/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizer.java

    public void customize(ConfigurableTomcatWebServerFactory factory) {
        ServerProperties properties = this.serverProperties;
        ServerProperties.Tomcat tomcatProperties = properties.getTomcat();
        PropertyMapper propertyMapper = PropertyMapper.get();
        propertyMapper.from(tomcatProperties::getBasedir).whenNonNull().to(factory::setBaseDirectory);
        propertyMapper.from(tomcatProperties::getBackgroundProcessorDelay).whenNonNull().as(Duration::getSeconds)
                .as(Long::intValue).to(factory::setBackgroundProcessorDelay);
        customizeRemoteIpValve(factory);
        ServerProperties.Tomcat.Threads threadProperties = tomcatProperties.getThreads();
        propertyMapper.from(threadProperties::getMax).when(this::isPositive)
                .to((maxThreads) -> customizeMaxThreads(factory, threadProperties.getMax()));
        propertyMapper.from(threadProperties::getMinSpare).when(this::isPositive)
                .to((minSpareThreads) -> customizeMinThreads(factory, minSpareThreads));
        propertyMapper.from(this.serverProperties.getMaxHttpHeaderSize()).whenNonNull().asInt(DataSize::toBytes)
                .when(this::isPositive)
                .to((maxHttpHeaderSize) -> customizeMaxHttpHeaderSize(factory, maxHttpHeaderSize));
        propertyMapper.from(tomcatProperties::getMaxSwallowSize).whenNonNull().asInt(DataSize::toBytes)
                .to((maxSwallowSize) -> customizeMaxSwallowSize(factory, maxSwallowSize));
        propertyMapper.from(tomcatProperties::getMaxHttpFormPostSize).asInt(DataSize::toBytes)
                .when((maxHttpFormPostSize) -> maxHttpFormPostSize != 0)
                .to((maxHttpFormPostSize) -> customizeMaxHttpFormPostSize(factory, maxHttpFormPostSize));
        propertyMapper.from(tomcatProperties::getAccesslog).when(ServerProperties.Tomcat.Accesslog::isEnabled)
                .to((enabled) -> customizeAccessLog(factory));
        propertyMapper.from(tomcatProperties::getUriEncoding).whenNonNull().to(factory::setUriEncoding);
        propertyMapper.from(tomcatProperties::getConnectionTimeout).whenNonNull()
                .to((connectionTimeout) -> customizeConnectionTimeout(factory, connectionTimeout));
        propertyMapper.from(tomcatProperties::getMaxConnections).when(this::isPositive)
                .to((maxConnections) -> customizeMaxConnections(factory, maxConnections));
        propertyMapper.from(tomcatProperties::getAcceptCount).when(this::isPositive)
                .to((acceptCount) -> customizeAcceptCount(factory, acceptCount));
        propertyMapper.from(tomcatProperties::getProcessorCache)
                .to((processorCache) -> customizeProcessorCache(factory, processorCache));
        propertyMapper.from(tomcatProperties::getRelaxedPathChars).as(this::joinCharacters).whenHasText()
                .to((relaxedChars) -> customizeRelaxedPathChars(factory, relaxedChars));
        propertyMapper.from(tomcatProperties::getRelaxedQueryChars).as(this::joinCharacters).whenHasText()
                .to((relaxedChars) -> customizeRelaxedQueryChars(factory, relaxedChars));
        customizeStaticResources(factory);
        customizeErrorReportValve(properties.getError(), factory);
    }

customizeMaxHttpFormPostSize

    private void customizeMaxHttpFormPostSize(ConfigurableTomcatWebServerFactory factory, int maxHttpFormPostSize) {
        factory.addConnectorCustomizers((connector) -> connector.setMaxPostSize(maxHttpFormPostSize));
    }

tomcat-embed-core-9.0.37-sources.jar!/org/apache/catalina/connector/Connector.java

    /**
     * Set the maximum size of a POST which will be automatically
     * parsed by the container.
     *
     * @param maxPostSize The new maximum size in bytes of a POST which will
     * be automatically parsed by the container
     */
    public void setMaxPostSize(int maxPostSize) {
        this.maxPostSize = maxPostSize;
        setProperty("maxPostSize", String.valueOf(maxPostSize));
    }

The maximum size in bytes of the POST which will be handled by the container FORM URL parameter parsing. The limit can be disabled by setting this attribute to a value less than zero. If not specified, this attribute is set to 2097152 (2 megabytes). Note that the FailedRequestFilter can be used to reject requests that exceed this limit.

customizeMaxSwallowSize

    private void customizeMaxSwallowSize(ConfigurableTomcatWebServerFactory factory, int maxSwallowSize) {
        factory.addConnectorCustomizers((connector) -> {
            ProtocolHandler handler = connector.getProtocolHandler();
            if (handler instanceof AbstractHttp11Protocol) {
                AbstractHttp11Protocol<?> protocol = (AbstractHttp11Protocol<?>) handler;
                protocol.setMaxSwallowSize(maxSwallowSize);
            }
        });
    }

tomcat-embed-core-9.0.37-sources.jar!/org/apache/coyote/http11/AbstractHttp11Protocol.java

    /**
     * Maximum amount of request body to swallow.
     */
    private int maxSwallowSize = 2 * 1024 * 1024;
    public int getMaxSwallowSize() { return maxSwallowSize; }
    public void setMaxSwallowSize(int maxSwallowSize) {
        this.maxSwallowSize = maxSwallowSize;
    }

The maximum number of request body bytes (excluding transfer encoding overhead) that will be swallowed by Tomcat for an aborted upload. An aborted upload is when Tomcat knows that the request body is going to be ignored but the client still sends it. If Tomcat does not swallow the body the client is unlikely to see the response. If not specified the default of 2097152 (2 megabytes) will be used. A value of less than zero indicates that no limit should be enforced.

小结

tomcat提供了maxPostSize及maxSwallowSize两个参数，其中maxPostSize用于限制post表单请求大小，默认2M，而maxSwallowSize用于限制aborted upload能够swallowed的大小。在springboot的2.3.3版本的话，通过server.tomcat.max-http-form-post-size来指定maxPostSize大小。

doc

• tomcat config http