tomcat9源码阅读2接收http请求

tomcat9源码阅读2接收http请求

0 官方文档

链接1: https://tomcat.apache.org/tomcat-9.0-doc/architecture/requestProcess/request-process.png.
链接2: https://tomcat.apache.org/tomcat-9.0-doc/architecture/requestProcess/authentication-process.png.

1 Acceptor

1.1 Acceptor主要功能

1.响应服务器的pause和stop。
2.调用endPoint中的connectionLimitLatch,来控制连接的数量
3.调用endPoint,创建socket。调用endPoint,处理socket。调用endPoint,关闭socket。

1.2 Acceptor工作机制

acceptor作为守护线程。在其run方法中,一直循环,通过endPoint.serverSocketAccept()来创建socket,通过endPoint.setSocketOptions()来处理socket,关闭socket。如果接收到pause,则会休眠一阵子。如果收到stop则跳出主循环,结束线程。
下面是主要的run方法

    @Override
    public void run() {

        int errorDelay = 0;

        try {
            // Loop until we receive a shutdown command
            while (!stopCalled) {

                // Loop if endpoint is paused
                while (endpoint.isPaused() && !stopCalled) {
                    state = AcceptorState.PAUSED;
                    try {
                        Thread.sleep(50);
                    } catch (InterruptedException e) {
                        // Ignore
                    }
                }

                if (stopCalled) {
                    break;
                }
                state = AcceptorState.RUNNING;

                try {
                    //if we have reached max connections, wait
                    endpoint.countUpOrAwaitConnection();

                    // Endpoint might have been paused while waiting for latch
                    // If that is the case, don't accept new connections
                    if (endpoint.isPaused()) {
                        continue;
                    }

                    U socket = null;
                    try {
                        // Accept the next incoming connection from the server
                        // socket
                        socket = endpoint.serverSocketAccept();
                    } catch (Exception ioe) {
                        // We didn't get a socket
                        endpoint.countDownConnection();
                        if (endpoint.isRunning()) {
                            // Introduce delay if necessary
                            errorDelay = handleExceptionWithDelay(errorDelay);
                            // re-throw
                            throw ioe;
                        } else {
                            break;
                        }
                    }
                    // Successful accept, reset the error delay
                    errorDelay = 0;

                    // Configure the socket
                    if (!stopCalled && !endpoint.isPaused()) {
                        // setSocketOptions() will hand the socket off to
                        // an appropriate processor if successful
                        if (!endpoint.setSocketOptions(socket)) {
                            endpoint.closeSocket(socket);
                        }
                    } else {
                        endpoint.destroySocket(socket);
                    }
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    String msg = sm.getString("endpoint.accept.fail");
                    // APR specific.
                    // Could push this down but not sure it is worth the trouble.
                    if (t instanceof Error) {
                        Error e = (Error) t;
                        if (e.getError() == 233) {
                            // Not an error on HP-UX so log as a warning
                            // so it can be filtered out on that platform
                            // See bug 50273
                            log.warn(msg, t);
                        } else {
                            log.error(msg, t);
                        }
                    } else {
                            log.error(msg, t);
                    }
                }
            }
        } finally {
            stopLatch.countDown();
        }
        state = AcceptorState.ENDED;
    }

2 AbstractEndpoint,NioEndpoint

2.1 NioEndpoint主要功能

1.NioEndpoint的poller线程消费acceptor生产的socket将socket包装成socketWrapper,并把socketWrapper扔到线程池中去执行
2.NioEndpoint的线程池执行的时候,通过调用NioEndpoint.SocketProcessor来最终调用AbstractProtocol进一步处理socketWrapper

2.2 NioEndpoint工作机制

1.NioEndpoint.setSocketOptions():将socket包装成socketWrapper并调用poller.register(socketWrapper)将socketWrapper注册到pooler
2.NioEndpoint.Poller.register(final NioSocketWrapper socketWrapper):将socketWrapper包装成PollerEvent并调用NioEndpoint.Poller.addEvent(PollerEvent event)将事件加入到事件队列中
3.NioEndpoint.Poller.run():响应关闭事件。寻循环从事件队列中获取事件,调用NioEndpoint.Poller.events(),判定是否有新的事件,将socketChannel注册到selector上。调用NioEndpoint.Poller.processKey(SelectionKey sk, NioSocketWrapper socketWrapper)进一步处理socketWrapper。调用NioEndpoint.Poller.timeout(int keyCount, boolean hasEvents)判定事件处理是否超时
4.NioEndpoint.Poller.processKey(SelectionKey sk, NioSocketWrapper socketWrapper): 响应关闭事件。根据是读事件还是写事件,最终调用NioEndpoint.processSocket(SocketWrapperBase socketWrapper, SocketEvent event, boolean dispatch)把,socketWrapperf封装成NioEndpoint.SocketProcessor最终提交给先endpoint中的线程池进行处理。
5.线程池执行最重是调用NioEndpoint.SocketProcessor.doRun()方法,等待网络协议握手之后,调用:AbstractProtocol.ConnectionHandler.process(SocketWrapperBase wrapper, SocketEvent status)进一步处理socketWrapper。

    @Override
    protected boolean setSocketOptions(SocketChannel socket) {
        NioSocketWrapper socketWrapper = null;
        try {
            // Allocate channel and wrapper
            NioChannel channel = null;
            if (nioChannels != null) {
                channel = nioChannels.pop();
            }
            if (channel == null) {
                SocketBufferHandler bufhandler = new SocketBufferHandler(
                        socketProperties.getAppReadBufSize(),
                        socketProperties.getAppWriteBufSize(),
                        socketProperties.getDirectBuffer());
                if (isSSLEnabled()) {
                    channel = new SecureNioChannel(bufhandler, selectorPool, this);
                } else {
                    channel = new NioChannel(bufhandler);
                }
            }
            NioSocketWrapper newWrapper = new NioSocketWrapper(channel, this);
            channel.reset(socket, newWrapper);
            connections.put(socket, newWrapper);
            socketWrapper = newWrapper;

            // Set socket properties
            // Disable blocking, polling will be used
            socket.configureBlocking(false);
            socketProperties.setProperties(socket.socket());

            socketWrapper.setReadTimeout(getConnectionTimeout());
            socketWrapper.setWriteTimeout(getConnectionTimeout());
            socketWrapper.setKeepAliveLeft(NioEndpoint.this.getMaxKeepAliveRequests());
            poller.register(socketWrapper);
            return true;
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            try {
                log.error(sm.getString("endpoint.socketOptionsError"), t);
            } catch (Throwable tt) {
                ExceptionUtils.handleThrowable(tt);
            }
            if (socketWrapper == null) {
                destroySocket(socket);
            }
        }
        // Tell to close the socket if needed
        return false;
    }
        /**
         * The background thread that adds sockets to the Poller, checks the
         * poller for triggered events and hands the associated socket off to an
         * appropriate processor as events occur.
         */
        @Override
        public void run() {
            // Loop until destroy() is called
            while (true) {

                boolean hasEvents = false;

                try {
                    if (!close) {
                        hasEvents = events();
                        if (wakeupCounter.getAndSet(-1) > 0) {
                            // If we are here, means we have other stuff to do
                            // Do a non blocking select
                            keyCount = selector.selectNow();
                        } else {
                            keyCount = selector.select(selectorTimeout);
                        }
                        wakeupCounter.set(0);
                    }
                    if (close) {
                        events();
                        timeout(0, false);
                        try {
                            selector.close();
                        } catch (IOException ioe) {
                            log.error(sm.getString("endpoint.nio.selectorCloseFail"), ioe);
                        }
                        break;
                    }
                    // Either we timed out or we woke up, process events first
                    if (keyCount == 0) {
                        hasEvents = (hasEvents | events());
                    }
                } catch (Throwable x) {
                    ExceptionUtils.handleThrowable(x);
                    log.error(sm.getString("endpoint.nio.selectorLoopError"), x);
                    continue;
                }

                Iterator<SelectionKey> iterator =
                    keyCount > 0 ? selector.selectedKeys().iterator() : null;
                // Walk through the collection of ready keys and dispatch
                // any active event.
                while (iterator != null && iterator.hasNext()) {
                    SelectionKey sk = iterator.next();
                    iterator.remove();
                    NioSocketWrapper socketWrapper = (NioSocketWrapper) sk.attachment();
                    // Attachment may be null if another thread has called
                    // cancelledKey()
                    if (socketWrapper != null) {
                        processKey(sk, socketWrapper);
                    }
                }

                // Process timeouts
                timeout(keyCount,hasEvents);
            }

            getStopLatch().countDown();
        }
        protected void processKey(SelectionKey sk, NioSocketWrapper socketWrapper) {
            try {
                if (close) {
                    cancelledKey(sk, socketWrapper);
                } else if (sk.isValid() && socketWrapper != null) {
                    if (sk.isReadable() || sk.isWritable()) {
                        if (socketWrapper.getSendfileData() != null) {
                            processSendfile(sk, socketWrapper, false);
                        } else {
                            unreg(sk, socketWrapper, sk.readyOps());
                            boolean closeSocket = false;
                            // Read goes before write
                            if (sk.isReadable()) {
                                if (socketWrapper.readOperation != null) {
                                    if (!socketWrapper.readOperation.process()) {
                                        closeSocket = true;
                                    }
                                } else if (!processSocket(socketWrapper, SocketEvent.OPEN_READ, true)) {
                                    closeSocket = true;
                                }
                            }
                            if (!closeSocket && sk.isWritable()) {
                                if (socketWrapper.writeOperation != null) {
                                    if (!socketWrapper.writeOperation.process()) {
                                        closeSocket = true;
                                    }
                                } else if (!processSocket(socketWrapper, SocketEvent.OPEN_WRITE, true)) {
                                    closeSocket = true;
                                }
                            }
                            if (closeSocket) {
                                cancelledKey(sk, socketWrapper);
                            }
                        }
                    }
                } else {
                    // Invalid key
                    cancelledKey(sk, socketWrapper);
                }
            } catch (CancelledKeyException ckx) {
                cancelledKey(sk, socketWrapper);
            } catch (Throwable t) {
                ExceptionUtils.handleThrowable(t);
                log.error(sm.getString("endpoint.nio.keyProcessingError"), t);
            }
        }
public boolean processSocket(SocketWrapperBase<S> socketWrapper,
            SocketEvent event, boolean dispatch) {
        try {
            if (socketWrapper == null) {
                return false;
            }
            SocketProcessorBase<S> sc = null;
            if (processorCache != null) {
                sc = processorCache.pop();
            }
            if (sc == null) {
                sc = createSocketProcessor(socketWrapper, event);
            } else {
                sc.reset(socketWrapper, event);
            }
            Executor executor = getExecutor();
            if (dispatch && executor != null) {
                executor.execute(sc);
            } else {
                sc.run();
            }
        } catch (RejectedExecutionException ree) {
            getLog().warn(sm.getString("endpoint.executor.fail", socketWrapper) , ree);
            return false;
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            // This means we got an OOM or similar creating a thread, or that
            // the pool and its queue are full
            getLog().error(sm.getString("endpoint.process.fail"), t);
            return false;
        }
        return true;
    }

线程池执行:

@Override
        protected void doRun() {
            /*
             * Do not cache and re-use the value of socketWrapper.getSocket() in
             * this method. If the socket closes the value will be updated to
             * CLOSED_NIO_CHANNEL and the previous value potentially re-used for
             * a new connection. That can result in a stale cached value which
             * in turn can result in unintentionally closing currently active
             * connections.
             */
            Poller poller = NioEndpoint.this.poller;
            if (poller == null) {
                socketWrapper.close();
                return;
            }

            try {
                int handshake = -1;
                try {
                    if (socketWrapper.getSocket().isHandshakeComplete()) {
                        // No TLS handshaking required. Let the handler
                        // process this socket / event combination.
                        handshake = 0;
                    } else if (event == SocketEvent.STOP || event == SocketEvent.DISCONNECT ||
                            event == SocketEvent.ERROR) {
                        // Unable to complete the TLS handshake. Treat it as
                        // if the handshake failed.
                        handshake = -1;
                    } else {
                        handshake = socketWrapper.getSocket().handshake(event == SocketEvent.OPEN_READ, event == SocketEvent.OPEN_WRITE);
                        // The handshake process reads/writes from/to the
                        // socket. status may therefore be OPEN_WRITE once
                        // the handshake completes. However, the handshake
                        // happens when the socket is opened so the status
                        // must always be OPEN_READ after it completes. It
                        // is OK to always set this as it is only used if
                        // the handshake completes.
                        event = SocketEvent.OPEN_READ;
                    }
                } catch (IOException x) {
                    handshake = -1;
                    if (log.isDebugEnabled()) log.debug("Error during SSL handshake",x);
                } catch (CancelledKeyException ckx) {
                    handshake = -1;
                }
                if (handshake == 0) {
                    SocketState state = SocketState.OPEN;
                    // Process the request from this socket
                    if (event == null) {
                        state = getHandler().process(socketWrapper, SocketEvent.OPEN_READ);
                    } else {
                        state = getHandler().process(socketWrapper, event);
                    }
                    if (state == SocketState.CLOSED) {
                        poller.cancelledKey(getSelectionKey(), socketWrapper);
                    }
                } else if (handshake == -1 ) {
                    getHandler().process(socketWrapper, SocketEvent.CONNECT_FAIL);
                    poller.cancelledKey(getSelectionKey(), socketWrapper);
                } else if (handshake == SelectionKey.OP_READ){
                    socketWrapper.registerReadInterest();
                } else if (handshake == SelectionKey.OP_WRITE){
                    socketWrapper.registerWriteInterest();
                }
            } catch (CancelledKeyException cx) {
                poller.cancelledKey(getSelectionKey(), socketWrapper);
            } catch (VirtualMachineError vme) {
                ExceptionUtils.handleThrowable(vme);
            } catch (Throwable t) {
                log.error(sm.getString("endpoint.processing.fail"), t);
                poller.cancelledKey(getSelectionKey(), socketWrapper);
            } finally {
                socketWrapper = null;
                event = null;
                //return to cache
                if (running && !paused && processorCache != null) {
                    processorCache.push(this);
                }
            }
        }

3 AbstractProtocol,Http11NioProtocol

主要根据不同的协议创建具体的processor,并把socketWrapper交给具体的Processor处理

        @Override
        public SocketState process(SocketWrapperBase<S> wrapper, SocketEvent status) {
            if (getLog().isDebugEnabled()) {
                getLog().debug(sm.getString("abstractConnectionHandler.process",
                        wrapper.getSocket(), status));
            }
            if (wrapper == null) {
                // Nothing to do. Socket has been closed.
                return SocketState.CLOSED;
            }

            S socket = wrapper.getSocket();

            Processor processor = (Processor) wrapper.getCurrentProcessor();
            if (getLog().isDebugEnabled()) {
                getLog().debug(sm.getString("abstractConnectionHandler.connectionsGet",
                        processor, socket));
            }

            // Timeouts are calculated on a dedicated thread and then
            // dispatched. Because of delays in the dispatch process, the
            // timeout may no longer be required. Check here and avoid
            // unnecessary processing.
            if (SocketEvent.TIMEOUT == status &&
                    (processor == null ||
                    !processor.isAsync() && !processor.isUpgrade() ||
                    processor.isAsync() && !processor.checkAsyncTimeoutGeneration())) {
                // This is effectively a NO-OP
                return SocketState.OPEN;
            }

            if (processor != null) {
                // Make sure an async timeout doesn't fire
                getProtocol().removeWaitingProcessor(processor);
            } else if (status == SocketEvent.DISCONNECT || status == SocketEvent.ERROR) {
                // Nothing to do. Endpoint requested a close and there is no
                // longer a processor associated with this socket.
                return SocketState.CLOSED;
            }

            ContainerThreadMarker.set();

            try {
                if (processor == null) {
                    String negotiatedProtocol = wrapper.getNegotiatedProtocol();
                    // OpenSSL typically returns null whereas JSSE typically
                    // returns "" when no protocol is negotiated
                    if (negotiatedProtocol != null && negotiatedProtocol.length() > 0) {
                        UpgradeProtocol upgradeProtocol = getProtocol().getNegotiatedProtocol(negotiatedProtocol);
                        if (upgradeProtocol != null) {
                            processor = upgradeProtocol.getProcessor(wrapper, getProtocol().getAdapter());
                            if (getLog().isDebugEnabled()) {
                                getLog().debug(sm.getString("abstractConnectionHandler.processorCreate", processor));
                            }
                        } else if (negotiatedProtocol.equals("http/1.1")) {
                            // Explicitly negotiated the default protocol.
                            // Obtain a processor below.
                        } else {
                            // TODO:
                            // OpenSSL 1.0.2's ALPN callback doesn't support
                            // failing the handshake with an error if no
                            // protocol can be negotiated. Therefore, we need to
                            // fail the connection here. Once this is fixed,
                            // replace the code below with the commented out
                            // block.
                            if (getLog().isDebugEnabled()) {
                                getLog().debug(sm.getString("abstractConnectionHandler.negotiatedProcessor.fail",
                                        negotiatedProtocol));
                            }
                            return SocketState.CLOSED;
                            /*
                             * To replace the code above once OpenSSL 1.1.0 is
                             * used.
                            // Failed to create processor. This is a bug.
                            throw new IllegalStateException(sm.getString(
                                    "abstractConnectionHandler.negotiatedProcessor.fail",
                                    negotiatedProtocol));
                            */
                        }
                    }
                }
                if (processor == null) {
                    processor = recycledProcessors.pop();
                    if (getLog().isDebugEnabled()) {
                        getLog().debug(sm.getString("abstractConnectionHandler.processorPop", processor));
                    }
                }
                if (processor == null) {
                    processor = getProtocol().createProcessor();
                    register(processor);
                    if (getLog().isDebugEnabled()) {
                        getLog().debug(sm.getString("abstractConnectionHandler.processorCreate", processor));
                    }
                }

                processor.setSslSupport(
                        wrapper.getSslSupport(getProtocol().getClientCertProvider()));

                // Associate the processor with the connection
                wrapper.setCurrentProcessor(processor);

                SocketState state = SocketState.CLOSED;
                do {
                    state = processor.process(wrapper, status);

                    if (state == SocketState.UPGRADING) {
                        // Get the HTTP upgrade handler
                        UpgradeToken upgradeToken = processor.getUpgradeToken();
                        // Retrieve leftover input
                        ByteBuffer leftOverInput = processor.getLeftoverInput();
                        if (upgradeToken == null) {
                            // Assume direct HTTP/2 connection
                            UpgradeProtocol upgradeProtocol = getProtocol().getUpgradeProtocol("h2c");
                            if (upgradeProtocol != null) {
                                // Release the Http11 processor to be re-used
                                release(processor);
                                // Create the upgrade processor
                                processor = upgradeProtocol.getProcessor(wrapper, getProtocol().getAdapter());
                                wrapper.unRead(leftOverInput);
                                // Associate with the processor with the connection
                                wrapper.setCurrentProcessor(processor);
                            } else {
                                if (getLog().isDebugEnabled()) {
                                    getLog().debug(sm.getString(
                                        "abstractConnectionHandler.negotiatedProcessor.fail",
                                        "h2c"));
                                }
                                // Exit loop and trigger appropriate clean-up
                                state = SocketState.CLOSED;
                            }
                        } else {
                            HttpUpgradeHandler httpUpgradeHandler = upgradeToken.getHttpUpgradeHandler();
                            // Release the Http11 processor to be re-used
                            release(processor);
                            // Create the upgrade processor
                            processor = getProtocol().createUpgradeProcessor(wrapper, upgradeToken);
                            if (getLog().isDebugEnabled()) {
                                getLog().debug(sm.getString("abstractConnectionHandler.upgradeCreate",
                                        processor, wrapper));
                            }
                            wrapper.unRead(leftOverInput);
                            // Associate with the processor with the connection
                            wrapper.setCurrentProcessor(processor);
                            // Initialise the upgrade handler (which may trigger
                            // some IO using the new protocol which is why the lines
                            // above are necessary)
                            // This cast should be safe. If it fails the error
                            // handling for the surrounding try/catch will deal with
                            // it.
                            if (upgradeToken.getInstanceManager() == null) {
                                httpUpgradeHandler.init((WebConnection) processor);
                            } else {
                                ClassLoader oldCL = upgradeToken.getContextBind().bind(false, null);
                                try {
                                    httpUpgradeHandler.init((WebConnection) processor);
                                } finally {
                                    upgradeToken.getContextBind().unbind(false, oldCL);
                                }
                            }
                            if (httpUpgradeHandler instanceof InternalHttpUpgradeHandler) {
                                if (((InternalHttpUpgradeHandler) httpUpgradeHandler).hasAsyncIO()) {
                                    // The handler will initiate all further I/O
                                    state = SocketState.UPGRADED;
                                }
                            }
                        }
                    }
                } while ( state == SocketState.UPGRADING);

                if (state == SocketState.LONG) {
                    // In the middle of processing a request/response. Keep the
                    // socket associated with the processor. Exact requirements
                    // depend on type of long poll
                    longPoll(wrapper, processor);
                    if (processor.isAsync()) {
                        getProtocol().addWaitingProcessor(processor);
                    }
                } else if (state == SocketState.OPEN) {
                    // In keep-alive but between requests. OK to recycle
                    // processor. Continue to poll for the next request.
                    wrapper.setCurrentProcessor(null);
                    release(processor);
                    wrapper.registerReadInterest();
                } else if (state == SocketState.SENDFILE) {
                    // Sendfile in progress. If it fails, the socket will be
                    // closed. If it works, the socket either be added to the
                    // poller (or equivalent) to await more data or processed
                    // if there are any pipe-lined requests remaining.
                } else if (state == SocketState.UPGRADED) {
                    // Don't add sockets back to the poller if this was a
                    // non-blocking write otherwise the poller may trigger
                    // multiple read events which may lead to thread starvation
                    // in the connector. The write() method will add this socket
                    // to the poller if necessary.
                    if (status != SocketEvent.OPEN_WRITE) {
                        longPoll(wrapper, processor);
                        getProtocol().addWaitingProcessor(processor);
                    }
                } else if (state == SocketState.SUSPENDED) {
                    // Don't add sockets back to the poller.
                    // The resumeProcessing() method will add this socket
                    // to the poller.
                } else {
                    // Connection closed. OK to recycle the processor.
                    // Processors handling upgrades require additional clean-up
                    // before release.
                    wrapper.setCurrentProcessor(null);
                    if (processor.isUpgrade()) {
                        UpgradeToken upgradeToken = processor.getUpgradeToken();
                        HttpUpgradeHandler httpUpgradeHandler = upgradeToken.getHttpUpgradeHandler();
                        InstanceManager instanceManager = upgradeToken.getInstanceManager();
                        if (instanceManager == null) {
                            httpUpgradeHandler.destroy();
                        } else {
                            ClassLoader oldCL = upgradeToken.getContextBind().bind(false, null);
                            try {
                                httpUpgradeHandler.destroy();
                            } finally {
                                try {
                                    instanceManager.destroyInstance(httpUpgradeHandler);
                                } catch (Throwable e) {
                                    ExceptionUtils.handleThrowable(e);
                                    getLog().error(sm.getString("abstractConnectionHandler.error"), e);
                                }
                                upgradeToken.getContextBind().unbind(false, oldCL);
                            }
                        }
                    }
                    release(processor);
                }
                return state;
            } catch(java.net.SocketException e) {
                // SocketExceptions are normal
                getLog().debug(sm.getString(
                        "abstractConnectionHandler.socketexception.debug"), e);
            } catch (java.io.IOException e) {
                // IOExceptions are normal
                getLog().debug(sm.getString(
                        "abstractConnectionHandler.ioexception.debug"), e);
            } catch (ProtocolException e) {
                // Protocol exceptions normally mean the client sent invalid or
                // incomplete data.
                getLog().debug(sm.getString(
                        "abstractConnectionHandler.protocolexception.debug"), e);
            }
            // Future developers: if you discover any other
            // rare-but-nonfatal exceptions, catch them here, and log as
            // above.
            catch (OutOfMemoryError oome) {
                // Try and handle this here to give Tomcat a chance to close the
                // connection and prevent clients waiting until they time out.
                // Worst case, it isn't recoverable and the attempt at logging
                // will trigger another OOME.
                getLog().error(sm.getString("abstractConnectionHandler.oome"), oome);
            } catch (Throwable e) {
                ExceptionUtils.handleThrowable(e);
                // any other exception or error is odd. Here we log it
                // with "ERROR" level, so it will show up even on
                // less-than-verbose logs.
                getLog().error(sm.getString("abstractConnectionHandler.error"), e);
            } finally {
                ContainerThreadMarker.clear();
            }

            // Make sure socket/processor is removed from the list of current
            // connections
            wrapper.setCurrentProcessor(null);
            release(processor);
            return SocketState.CLOSED;
        }

4 AbstractProcessorLight,Http11Processor

1.初步从socketWrapper的缓冲中读取报文。通过Http11InputBuffer.parseRequestLine(boolean keptAlive, int connectionTimeout, int keepAliveTimeout)读取http header的头报文。
2.设计具体的http协议版本
3.设置request的filter
4.把已经解析了httpheader的 request 交个 CoyoteAdapter进一步处理。

    @Override
    public SocketState process(SocketWrapperBase<?> socketWrapper, SocketEvent status)
            throws IOException {

        SocketState state = SocketState.CLOSED;
        Iterator<DispatchType> dispatches = null;
        do {
            if (dispatches != null) {
                DispatchType nextDispatch = dispatches.next();
                if (getLog().isDebugEnabled()) {
                    getLog().debug("Processing dispatch type: [" + nextDispatch + "]");
                }
                state = dispatch(nextDispatch.getSocketStatus());
                if (!dispatches.hasNext()) {
                    state = checkForPipelinedData(state, socketWrapper);
                }
            } else if (status == SocketEvent.DISCONNECT) {
                // Do nothing here, just wait for it to get recycled
            } else if (isAsync() || isUpgrade() || state == SocketState.ASYNC_END) {
                state = dispatch(status);
                state = checkForPipelinedData(state, socketWrapper);
            } else if (status == SocketEvent.OPEN_WRITE) {
                // Extra write event likely after async, ignore
                state = SocketState.LONG;
            } else if (status == SocketEvent.OPEN_READ) {
                state = service(socketWrapper);
            } else if (status == SocketEvent.CONNECT_FAIL) {
                logAccess(socketWrapper);
            } else {
                // Default to closing the socket if the SocketEvent passed in
                // is not consistent with the current state of the Processor
                state = SocketState.CLOSED;
            }

            if (getLog().isDebugEnabled()) {
                getLog().debug("Socket: [" + socketWrapper +
                        "], Status in: [" + status +
                        "], State out: [" + state + "]");
            }

            if (isAsync()) {
                state = asyncPostProcess();
                if (getLog().isDebugEnabled()) {
                    getLog().debug("Socket: [" + socketWrapper +
                            "], State after async post processing: [" + state + "]");
                }
            }

            if (dispatches == null || !dispatches.hasNext()) {
                // Only returns non-null iterator if there are
                // dispatches to process.
                dispatches = getIteratorAndClearDispatches();
            }
        } while (state == SocketState.ASYNC_END ||
                dispatches != null && state != SocketState.CLOSED);

        return state;
    }
    @Override
    public SocketState service(SocketWrapperBase<?> socketWrapper)
        throws IOException {
        RequestInfo rp = request.getRequestProcessor();
        rp.setStage(org.apache.coyote.Constants.STAGE_PARSE);

        // Setting up the I/O
        setSocketWrapper(socketWrapper);

        // Flags
        keepAlive = true;
        openSocket = false;
        readComplete = true;
        boolean keptAlive = false;
        SendfileState sendfileState = SendfileState.DONE;

        while (!getErrorState().isError() && keepAlive && !isAsync() && upgradeToken == null &&
                sendfileState == SendfileState.DONE && !protocol.isPaused()) {

            // Parsing the request header
            try {
                if (!inputBuffer.parseRequestLine(keptAlive, protocol.getConnectionTimeout(),
                        protocol.getKeepAliveTimeout())) {
                    if (inputBuffer.getParsingRequestLinePhase() == -1) {
                        return SocketState.UPGRADING;
                    } else if (handleIncompleteRequestLineRead()) {
                        break;
                    }
                }

                // Process the Protocol component of the request line
                // Need to know if this is an HTTP 0.9 request before trying to
                // parse headers.
                prepareRequestProtocol();

                if (protocol.isPaused()) {
                    // 503 - Service unavailable
                    response.setStatus(503);
                    setErrorState(ErrorState.CLOSE_CLEAN, null);
                } else {
                    keptAlive = true;
                    // Set this every time in case limit has been changed via JMX
                    request.getMimeHeaders().setLimit(protocol.getMaxHeaderCount());
                    // Don't parse headers for HTTP/0.9
                    if (!http09 && !inputBuffer.parseHeaders()) {
                        // We've read part of the request, don't recycle it
                        // instead associate it with the socket
                        openSocket = true;
                        readComplete = false;
                        break;
                    }
                    if (!protocol.getDisableUploadTimeout()) {
                        socketWrapper.setReadTimeout(protocol.getConnectionUploadTimeout());
                    }
                }
            } catch (IOException e) {
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("http11processor.header.parse"), e);
                }
                setErrorState(ErrorState.CLOSE_CONNECTION_NOW, e);
                break;
            } catch (Throwable t) {
                ExceptionUtils.handleThrowable(t);
                UserDataHelper.Mode logMode = userDataHelper.getNextMode();
                if (logMode != null) {
                    String message = sm.getString("http11processor.header.parse");
                    switch (logMode) {
                        case INFO_THEN_DEBUG:
                            message += sm.getString("http11processor.fallToDebug");
                            //$FALL-THROUGH$
                        case INFO:
                            log.info(message, t);
                            break;
                        case DEBUG:
                            log.debug(message, t);
                    }
                }
                // 400 - Bad Request
                response.setStatus(400);
                setErrorState(ErrorState.CLOSE_CLEAN, t);
            }

            // Has an upgrade been requested?
            if (isConnectionToken(request.getMimeHeaders(), "upgrade")) {
                // Check the protocol
                String requestedProtocol = request.getHeader("Upgrade");

                UpgradeProtocol upgradeProtocol = protocol.getUpgradeProtocol(requestedProtocol);
                if (upgradeProtocol != null) {
                    if (upgradeProtocol.accept(request)) {
                        response.setStatus(HttpServletResponse.SC_SWITCHING_PROTOCOLS);
                        response.setHeader("Connection", "Upgrade");
                        response.setHeader("Upgrade", requestedProtocol);
                        action(ActionCode.CLOSE,  null);
                        getAdapter().log(request, response, 0);

                        InternalHttpUpgradeHandler upgradeHandler =
                                upgradeProtocol.getInternalUpgradeHandler(
                                        socketWrapper, getAdapter(), cloneRequest(request));
                        UpgradeToken upgradeToken = new UpgradeToken(upgradeHandler, null, null, requestedProtocol);
                        action(ActionCode.UPGRADE, upgradeToken);
                        return SocketState.UPGRADING;
                    }
                }
            }

            if (getErrorState().isIoAllowed()) {
                // Setting up filters, and parse some request headers
                rp.setStage(org.apache.coyote.Constants.STAGE_PREPARE);
                try {
                    prepareRequest();
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    if (log.isDebugEnabled()) {
                        log.debug(sm.getString("http11processor.request.prepare"), t);
                    }
                    // 500 - Internal Server Error
                    response.setStatus(500);
                    setErrorState(ErrorState.CLOSE_CLEAN, t);
                }
            }

            int maxKeepAliveRequests = protocol.getMaxKeepAliveRequests();
            if (maxKeepAliveRequests == 1) {
                keepAlive = false;
            } else if (maxKeepAliveRequests > 0 &&
                    socketWrapper.decrementKeepAlive() <= 0) {
                keepAlive = false;
            }

            // Process the request in the adapter
            if (getErrorState().isIoAllowed()) {
                try {
                    rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
                    getAdapter().service(request, response);
                    // Handle when the response was committed before a serious
                    // error occurred.  Throwing a ServletException should both
                    // set the status to 500 and set the errorException.
                    // If we fail here, then the response is likely already
                    // committed, so we can't try and set headers.
                    if(keepAlive && !getErrorState().isError() && !isAsync() &&
                            statusDropsConnection(response.getStatus())) {
                        setErrorState(ErrorState.CLOSE_CLEAN, null);
                    }
                } catch (InterruptedIOException e) {
                    setErrorState(ErrorState.CLOSE_CONNECTION_NOW, e);
                } catch (HeadersTooLargeException e) {
                    log.error(sm.getString("http11processor.request.process"), e);
                    // The response should not have been committed but check it
                    // anyway to be safe
                    if (response.isCommitted()) {
                        setErrorState(ErrorState.CLOSE_NOW, e);
                    } else {
                        response.reset();
                        response.setStatus(500);
                        setErrorState(ErrorState.CLOSE_CLEAN, e);
                        response.setHeader("Connection", "close"); // TODO: Remove
                    }
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    log.error(sm.getString("http11processor.request.process"), t);
                    // 500 - Internal Server Error
                    response.setStatus(500);
                    setErrorState(ErrorState.CLOSE_CLEAN, t);
                    getAdapter().log(request, response, 0);
                }
            }

            // Finish the handling of the request
            rp.setStage(org.apache.coyote.Constants.STAGE_ENDINPUT);
            if (!isAsync()) {
                // If this is an async request then the request ends when it has
                // been completed. The AsyncContext is responsible for calling
                // endRequest() in that case.
                endRequest();
            }
            rp.setStage(org.apache.coyote.Constants.STAGE_ENDOUTPUT);

            // If there was an error, make sure the request is counted as
            // and error, and update the statistics counter
            if (getErrorState().isError()) {
                response.setStatus(500);
            }

            if (!isAsync() || getErrorState().isError()) {
                request.updateCounters();
                if (getErrorState().isIoAllowed()) {
                    inputBuffer.nextRequest();
                    outputBuffer.nextRequest();
                }
            }

            if (!protocol.getDisableUploadTimeout()) {
                int connectionTimeout = protocol.getConnectionTimeout();
                if(connectionTimeout > 0) {
                    socketWrapper.setReadTimeout(connectionTimeout);
                } else {
                    socketWrapper.setReadTimeout(0);
                }
            }

            rp.setStage(org.apache.coyote.Constants.STAGE_KEEPALIVE);

            sendfileState = processSendfile(socketWrapper);
        }

        rp.setStage(org.apache.coyote.Constants.STAGE_ENDED);

        if (getErrorState().isError() || (protocol.isPaused() && !isAsync())) {
            return SocketState.CLOSED;
        } else if (isAsync()) {
            return SocketState.LONG;
        } else if (isUpgrade()) {
            return SocketState.UPGRADING;
        } else {
            if (sendfileState == SendfileState.PENDING) {
                return SocketState.SENDFILE;
            } else {
                if (openSocket) {
                    if (readComplete) {
                        return SocketState.OPEN;
                    } else {
                        return SocketState.LONG;
                    }
                } else {
                    return SocketState.CLOSED;
                }
            }
        }
    }
    private void prepareRequestProtocol() {

        MessageBytes protocolMB = request.protocol();
        if (protocolMB.equals(Constants.HTTP_11)) {
            http09 = false;
            http11 = true;
            protocolMB.setString(Constants.HTTP_11);
        } else if (protocolMB.equals(Constants.HTTP_10)) {
            http09 = false;
            http11 = false;
            keepAlive = false;
            protocolMB.setString(Constants.HTTP_10);
        } else if (protocolMB.equals("")) {
            // HTTP/0.9
            http09 = true;
            http11 = false;
            keepAlive = false;
        } else {
            // Unsupported protocol
            http09 = false;
            http11 = false;
            // Send 505; Unsupported HTTP version
            response.setStatus(505);
            setErrorState(ErrorState.CLOSE_CLEAN, null);
            if (log.isDebugEnabled()) {
                log.debug(sm.getString("http11processor.request.prepare")+
                          " Unsupported HTTP version \""+protocolMB+"\"");
            }
        }
    
    /**
     * After reading the request headers, we have to setup the request filters.
     */
    private void prepareRequest() throws IOException {

        contentDelimitation = false;

        if (protocol.isSSLEnabled()) {
            request.scheme().setString("https");
        }

        MimeHeaders headers = request.getMimeHeaders();

        // Check connection header
        MessageBytes connectionValueMB = headers.getValue(Constants.CONNECTION);
        if (connectionValueMB != null && !connectionValueMB.isNull()) {
            Set<String> tokens = new HashSet<>();
            TokenList.parseTokenList(headers.values(Constants.CONNECTION), tokens);
            if (tokens.contains(Constants.CLOSE)) {
                keepAlive = false;
            } else if (tokens.contains(Constants.KEEP_ALIVE_HEADER_VALUE_TOKEN)) {
                keepAlive = true;
            }
        }

        if (http11) {
            MessageBytes expectMB = headers.getValue("expect");
            if (expectMB != null && !expectMB.isNull()) {
                if (expectMB.toString().trim().equalsIgnoreCase("100-continue")) {
                    inputBuffer.setSwallowInput(false);
                    request.setExpectation(true);
                } else {
                    response.setStatus(HttpServletResponse.SC_EXPECTATION_FAILED);
                    setErrorState(ErrorState.CLOSE_CLEAN, null);
                }
            }
        }

        // Check user-agent header
        Pattern restrictedUserAgents = protocol.getRestrictedUserAgentsPattern();
        if (restrictedUserAgents != null && (http11 || keepAlive)) {
            MessageBytes userAgentValueMB = headers.getValue("user-agent");
            // Check in the restricted list, and adjust the http11
            // and keepAlive flags accordingly
            if(userAgentValueMB != null && !userAgentValueMB.isNull()) {
                String userAgentValue = userAgentValueMB.toString();
                if (restrictedUserAgents.matcher(userAgentValue).matches()) {
                    http11 = false;
                    keepAlive = false;
                }
            }
        }


        // Check host header
        MessageBytes hostValueMB = null;
        try {
            hostValueMB = headers.getUniqueValue("host");
        } catch (IllegalArgumentException iae) {
            // Multiple Host headers are not permitted
            badRequest("http11processor.request.multipleHosts");
        }
        if (http11 && hostValueMB == null) {
            badRequest("http11processor.request.noHostHeader");
        }

        // Check for an absolute-URI less the query string which has already
        // been removed during the parsing of the request line
        ByteChunk uriBC = request.requestURI().getByteChunk();
        byte[] uriB = uriBC.getBytes();
        if (uriBC.startsWithIgnoreCase("http", 0)) {
            int pos = 4;
            // Check for https
            if (uriBC.startsWithIgnoreCase("s", pos)) {
                pos++;
            }
            // Next 3 characters must be "://"
            if (uriBC.startsWith("://", pos)) {
                pos += 3;
                int uriBCStart = uriBC.getStart();

                // '/' does not appear in the authority so use the first
                // instance to split the authority and the path segments
                int slashPos = uriBC.indexOf('/', pos);
                // '@' in the authority delimits the userinfo
                int atPos = uriBC.indexOf('@', pos);
                if (slashPos > -1 && atPos > slashPos) {
                    // First '@' is in the path segments so no userinfo
                    atPos = -1;
                }

                if (slashPos == -1) {
                    slashPos = uriBC.getLength();
                    // Set URI as "/". Use 6 as it will always be a '/'.
                    // 01234567
                    // http://
                    // https://
                    request.requestURI().setBytes(uriB, uriBCStart + 6, 1);
                } else {
                    request.requestURI().setBytes(uriB, uriBCStart + slashPos, uriBC.getLength() - slashPos);
                }

                // Skip any user info
                if (atPos != -1) {
                    // Validate the userinfo
                    for (; pos < atPos; pos++) {
                        byte c = uriB[uriBCStart + pos];
                        if (!HttpParser.isUserInfo(c)) {
                            // Strictly there needs to be a check for valid %nn
                            // encoding here but skip it since it will never be
                            // decoded because the userinfo is ignored
                            badRequest("http11processor.request.invalidUserInfo");
                            break;
                        }
                    }
                    // Skip the '@'
                    pos = atPos + 1;
                }

                if (http11) {
                    // Missing host header is illegal but handled above
                    if (hostValueMB != null) {
                        // Any host in the request line must be consistent with
                        // the Host header
                        if (!hostValueMB.getByteChunk().equals(
                                uriB, uriBCStart + pos, slashPos - pos)) {
                            if (protocol.getAllowHostHeaderMismatch()) {
                                // The requirements of RFC 2616 are being
                                // applied. If the host header and the request
                                // line do not agree, the request line takes
                                // precedence
                                hostValueMB = headers.setValue("host");
                                hostValueMB.setBytes(uriB, uriBCStart + pos, slashPos - pos);
                            } else {
                                // The requirements of RFC 7230 are being
                                // applied. If the host header and the request
                                // line do not agree, trigger a 400 response.
                                badRequest("http11processor.request.inconsistentHosts");
                            }
                        }
                    }
                } else {
                    // Not HTTP/1.1 - no Host header so generate one since
                    // Tomcat internals assume it is set
                    try {
                        hostValueMB = headers.setValue("host");
                        hostValueMB.setBytes(uriB, uriBCStart + pos, slashPos - pos);
                    } catch (IllegalStateException e) {
                        // Edge case
                        // If the request has too many headers it won't be
                        // possible to create the host header. Ignore this as
                        // processing won't reach the point where the Tomcat
                        // internals expect there to be a host header.
                    }
                }
            } else {
                badRequest("http11processor.request.invalidScheme");
            }
        }

        // Validate the characters in the URI. %nn decoding will be checked at
        // the point of decoding.
        for (int i = uriBC.getStart(); i < uriBC.getEnd(); i++) {
            if (!httpParser.isAbsolutePathRelaxed(uriB[i])) {
                badRequest("http11processor.request.invalidUri");
                break;
            }
        }

        // Input filter setup
        InputFilter[] inputFilters = inputBuffer.getFilters();

        // Parse transfer-encoding header
        if (http11) {
            MessageBytes transferEncodingValueMB = headers.getValue("transfer-encoding");
            if (transferEncodingValueMB != null) {
                List<String> encodingNames = new ArrayList<>();
                if (TokenList.parseTokenList(headers.values("transfer-encoding"), encodingNames)) {
                    for (String encodingName : encodingNames) {
                        // "identity" codings are ignored
                        addInputFilter(inputFilters, encodingName);
                    }
                } else {
                    // Invalid transfer encoding
                    badRequest("http11processor.request.invalidTransferEncoding");
                }
            }
        }

        // Parse content-length header
        long contentLength = -1;
        try {
            contentLength = request.getContentLengthLong();
        } catch (NumberFormatException e) {
            badRequest("http11processor.request.nonNumericContentLength");
        } catch (IllegalArgumentException e) {
            badRequest("http11processor.request.multipleContentLength");
        }
        if (contentLength >= 0) {
            if (contentDelimitation) {
                // contentDelimitation being true at this point indicates that
                // chunked encoding is being used but chunked encoding should
                // not be used with a content length. RFC 2616, section 4.4,
                // bullet 3 states Content-Length must be ignored in this case -
                // so remove it.
                headers.removeHeader("content-length");
                request.setContentLength(-1);
            } else {
                inputBuffer.addActiveFilter(inputFilters[Constants.IDENTITY_FILTER]);
                contentDelimitation = true;
            }
        }

        // Validate host name and extract port if present
        parseHost(hostValueMB);

        if (!contentDelimitation) {
            // If there's no content length
            // (broken HTTP/1.0 or HTTP/1.1), assume
            // the client is not broken and didn't send a body
            inputBuffer.addActiveFilter(inputFilters[Constants.VOID_FILTER]);
            contentDelimitation = true;
        }

        if (!getErrorState().isIoAllowed()) {
            getAdapter().log(request, response, 0);
        }
    }

5 CoyoteAdapter

1.从request中取出httpRequest或者根据request生成httpRequest;从response中取出httpResponse或者根据response生成httpResponse
2.设置requestURI的编码
3.进一步解析http报文,解析uri,解析pathParameter,解析host信息,解析或者生成sessionID,设置或者生成userPrincipal
4.根据uri找到对应Host,context(war包),wrapper(servlet)
5.httpReques和httpResponse,交给容器StandardService处理
6.完成httpReques和httpResponse

    @Override
    public void service(org.apache.coyote.Request req, org.apache.coyote.Response res)
            throws Exception {

        Request request = (Request) req.getNote(ADAPTER_NOTES);
        Response response = (Response) res.getNote(ADAPTER_NOTES);

        if (request == null) {
            // Create objects
            request = connector.createRequest();
            request.setCoyoteRequest(req);
            response = connector.createResponse();
            response.setCoyoteResponse(res);

            // Link objects
            request.setResponse(response);
            response.setRequest(request);

            // Set as notes
            req.setNote(ADAPTER_NOTES, request);
            res.setNote(ADAPTER_NOTES, response);

            // Set query string encoding
            req.getParameters().setQueryStringCharset(connector.getURICharset());
        }

        if (connector.getXpoweredBy()) {
            response.addHeader("X-Powered-By", POWERED_BY);
        }

        boolean async = false;
        boolean postParseSuccess = false;

        req.getRequestProcessor().setWorkerThreadName(THREAD_NAME.get());

        try {
            // Parse and set Catalina and configuration specific
            // request parameters
            postParseSuccess = postParseRequest(req, request, res, response);
            if (postParseSuccess) {
                //check valves if we support async
                request.setAsyncSupported(
                        connector.getService().getContainer().getPipeline().isAsyncSupported());
                // Calling the container
                connector.getService().getContainer().getPipeline().getFirst().invoke(
                        request, response);
            }
            if (request.isAsync()) {
                async = true;
                ReadListener readListener = req.getReadListener();
                if (readListener != null && request.isFinished()) {
                    // Possible the all data may have been read during service()
                    // method so this needs to be checked here
                    ClassLoader oldCL = null;
                    try {
                        oldCL = request.getContext().bind(false, null);
                        if (req.sendAllDataReadEvent()) {
                            req.getReadListener().onAllDataRead();
                        }
                    } finally {
                        request.getContext().unbind(false, oldCL);
                    }
                }

                Throwable throwable =
                        (Throwable) request.getAttribute(RequestDispatcher.ERROR_EXCEPTION);

                // If an async request was started, is not going to end once
                // this container thread finishes and an error occurred, trigger
                // the async error process
                if (!request.isAsyncCompleting() && throwable != null) {
                    request.getAsyncContextInternal().setErrorState(throwable, true);
                }
            } else {
                request.finishRequest();
                response.finishResponse();
            }

        } catch (IOException e) {
            // Ignore
        } finally {
            AtomicBoolean error = new AtomicBoolean(false);
            res.action(ActionCode.IS_ERROR, error);

            if (request.isAsyncCompleting() && error.get()) {
                // Connection will be forcibly closed which will prevent
                // completion happening at the usual point. Need to trigger
                // call to onComplete() here.
                res.action(ActionCode.ASYNC_POST_PROCESS,  null);
                async = false;
            }

            // Access log
            if (!async && postParseSuccess) {
                // Log only if processing was invoked.
                // If postParseRequest() failed, it has already logged it.
                Context context = request.getContext();
                Host host = request.getHost();
                // If the context is null, it is likely that the endpoint was
                // shutdown, this connection closed and the request recycled in
                // a different thread. That thread will have updated the access
                // log so it is OK not to update the access log here in that
                // case.
                // The other possibility is that an error occurred early in
                // processing and the request could not be mapped to a Context.
                // Log via the host or engine in that case.
                long time = System.currentTimeMillis() - req.getStartTime();
                if (context != null) {
                    context.logAccess(request, response, time, false);
                } else if (response.isError()) {
                    if (host != null) {
                        host.logAccess(request, response, time, false);
                    } else {
                        connector.getService().getContainer().logAccess(
                                request, response, time, false);
                    }
                }
            }

            req.getRequestProcessor().setWorkerThreadName(null);

            // Recycle the wrapper request and response
            if (!async) {
                updateWrapperErrorCount(request, response);
                request.recycle();
                response.recycle();
            }
        }
    }

    /**
     * Perform the necessary processing after the HTTP headers have been parsed
     * to enable the request/response pair to be passed to the start of the
     * container pipeline for processing.
     *
     * @param req      The coyote request object
     * @param request  The catalina request object
     * @param res      The coyote response object
     * @param response The catalina response object
     *
     * @return <code>true</code> if the request should be passed on to the start
     *         of the container pipeline, otherwise <code>false</code>
     *
     * @throws IOException If there is insufficient space in a buffer while
     *                     processing headers
     * @throws ServletException If the supported methods of the target servlet
     *                          cannot be determined
     */
    protected boolean postParseRequest(org.apache.coyote.Request req, Request request,
            org.apache.coyote.Response res, Response response) throws IOException, ServletException {

        // If the processor has set the scheme (AJP does this, HTTP does this if
        // SSL is enabled) use this to set the secure flag as well. If the
        // processor hasn't set it, use the settings from the connector
        if (req.scheme().isNull()) {
            // Use connector scheme and secure configuration, (defaults to
            // "http" and false respectively)
            req.scheme().setString(connector.getScheme());
            request.setSecure(connector.getSecure());
        } else {
            // Use processor specified scheme to determine secure state
            request.setSecure(req.scheme().equals("https"));
        }

        // At this point the Host header has been processed.
        // Override if the proxyPort/proxyHost are set
        String proxyName = connector.getProxyName();
        int proxyPort = connector.getProxyPort();
        if (proxyPort != 0) {
            req.setServerPort(proxyPort);
        } else if (req.getServerPort() == -1) {
            // Not explicitly set. Use default ports based on the scheme
            if (req.scheme().equals("https")) {
                req.setServerPort(443);
            } else {
                req.setServerPort(80);
            }
        }
        if (proxyName != null) {
            req.serverName().setString(proxyName);
        }

        MessageBytes undecodedURI = req.requestURI();

        // Check for ping OPTIONS * request
        if (undecodedURI.equals("*")) {
            if (req.method().equalsIgnoreCase("OPTIONS")) {
                StringBuilder allow = new StringBuilder();
                allow.append("GET, HEAD, POST, PUT, DELETE, OPTIONS");
                // Trace if allowed
                if (connector.getAllowTrace()) {
                    allow.append(", TRACE");
                }
                res.setHeader("Allow", allow.toString());
                // Access log entry as processing won't reach AccessLogValve
                connector.getService().getContainer().logAccess(request, response, 0, true);
                return false;
            } else {
                response.sendError(400, "Invalid URI");
            }
        }

        MessageBytes decodedURI = req.decodedURI();

        if (undecodedURI.getType() == MessageBytes.T_BYTES) {
            // Copy the raw URI to the decodedURI
            decodedURI.duplicate(undecodedURI);

            // Parse (and strip out) the path parameters
            parsePathParameters(req, request);

            // URI decoding
            // %xx decoding of the URL
            try {
                req.getURLDecoder().convert(decodedURI.getByteChunk(), connector.getEncodedSolidusHandlingInternal());
            } catch (IOException ioe) {
                response.sendError(400, "Invalid URI: " + ioe.getMessage());
            }
            // Normalization
            if (normalize(req.decodedURI())) {
                // Character decoding
                convertURI(decodedURI, request);
                // Check that the URI is still normalized
                // Note: checkNormalize is deprecated because the test is no
                //       longer required in Tomcat 10 onwards and has been
                //       removed
                if (!checkNormalize(req.decodedURI())) {
                    response.sendError(400, "Invalid URI");
                }
            } else {
                response.sendError(400, "Invalid URI");
            }
        } else {
            /* The URI is chars or String, and has been sent using an in-memory
             * protocol handler. The following assumptions are made:
             * - req.requestURI() has been set to the 'original' non-decoded,
             *   non-normalized URI
             * - req.decodedURI() has been set to the decoded, normalized form
             *   of req.requestURI()
             */
            decodedURI.toChars();
            // Remove all path parameters; any needed path parameter should be set
            // using the request object rather than passing it in the URL
            CharChunk uriCC = decodedURI.getCharChunk();
            int semicolon = uriCC.indexOf(';');
            if (semicolon > 0) {
                decodedURI.setChars(uriCC.getBuffer(), uriCC.getStart(), semicolon);
            }
        }

        // Request mapping.
        MessageBytes serverName;
        if (connector.getUseIPVHosts()) {
            serverName = req.localName();
            if (serverName.isNull()) {
                // well, they did ask for it
                res.action(ActionCode.REQ_LOCAL_NAME_ATTRIBUTE, null);
            }
        } else {
            serverName = req.serverName();
        }

        // Version for the second mapping loop and
        // Context that we expect to get for that version
        String version = null;
        Context versionContext = null;
        boolean mapRequired = true;

        if (response.isError()) {
            // An error this early means the URI is invalid. Ensure invalid data
            // is not passed to the mapper. Note we still want the mapper to
            // find the correct host.
            decodedURI.recycle();
        }

        while (mapRequired) {
            // This will map the the latest version by default
            connector.getService().getMapper().map(serverName, decodedURI,
                    version, request.getMappingData());

            // If there is no context at this point, either this is a 404
            // because no ROOT context has been deployed or the URI was invalid
            // so no context could be mapped.
            if (request.getContext() == null) {
                // Allow processing to continue.
                // If present, the rewrite Valve may rewrite this to a valid
                // request.
                // The StandardEngineValve will handle the case of a missing
                // Host and the StandardHostValve the case of a missing Context.
                // If present, the error reporting valve will provide a response
                // body.
                return true;
            }

            // Now we have the context, we can parse the session ID from the URL
            // (if any). Need to do this before we redirect in case we need to
            // include the session id in the redirect
            String sessionID;
            if (request.getServletContext().getEffectiveSessionTrackingModes()
                    .contains(SessionTrackingMode.URL)) {

                // Get the session ID if there was one
                sessionID = request.getPathParameter(
                        SessionConfig.getSessionUriParamName(
                                request.getContext()));
                if (sessionID != null) {
                    request.setRequestedSessionId(sessionID);
                    request.setRequestedSessionURL(true);
                }
            }

            // Look for session ID in cookies and SSL session
            try {
                parseSessionCookiesId(request);
            } catch (IllegalArgumentException e) {
                // Too many cookies
                if (!response.isError()) {
                    response.setError();
                    response.sendError(400);
                }
                return true;
            }
            parseSessionSslId(request);

            sessionID = request.getRequestedSessionId();

            mapRequired = false;
            if (version != null && request.getContext() == versionContext) {
                // We got the version that we asked for. That is it.
            } else {
                version = null;
                versionContext = null;

                Context[] contexts = request.getMappingData().contexts;
                // Single contextVersion means no need to remap
                // No session ID means no possibility of remap
                if (contexts != null && sessionID != null) {
                    // Find the context associated with the session
                    for (int i = contexts.length; i > 0; i--) {
                        Context ctxt = contexts[i - 1];
                        if (ctxt.getManager().findSession(sessionID) != null) {
                            // We found a context. Is it the one that has
                            // already been mapped?
                            if (!ctxt.equals(request.getMappingData().context)) {
                                // Set version so second time through mapping
                                // the correct context is found
                                version = ctxt.getWebappVersion();
                                versionContext = ctxt;
                                // Reset mapping
                                request.getMappingData().recycle();
                                mapRequired = true;
                                // Recycle cookies and session info in case the
                                // correct context is configured with different
                                // settings
                                request.recycleSessionInfo();
                                request.recycleCookieInfo(true);
                            }
                            break;
                        }
                    }
                }
            }

            if (!mapRequired && request.getContext().getPaused()) {
                // Found a matching context but it is paused. Mapping data will
                // be wrong since some Wrappers may not be registered at this
                // point.
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // Should never happen
                }
                // Reset mapping
                request.getMappingData().recycle();
                mapRequired = true;
            }
        }

        // Possible redirect
        MessageBytes redirectPathMB = request.getMappingData().redirectPath;
        if (!redirectPathMB.isNull()) {
            String redirectPath = URLEncoder.DEFAULT.encode(
                    redirectPathMB.toString(), StandardCharsets.UTF_8);
            String query = request.getQueryString();
            if (request.isRequestedSessionIdFromURL()) {
                // This is not optimal, but as this is not very common, it
                // shouldn't matter
                redirectPath = redirectPath + ";" +
                        SessionConfig.getSessionUriParamName(
                            request.getContext()) +
                    "=" + request.getRequestedSessionId();
            }
            if (query != null) {
                // This is not optimal, but as this is not very common, it
                // shouldn't matter
                redirectPath = redirectPath + "?" + query;
            }
            response.sendRedirect(redirectPath);
            request.getContext().logAccess(request, response, 0, true);
            return false;
        }

        // Filter trace method
        if (!connector.getAllowTrace()
                && req.method().equalsIgnoreCase("TRACE")) {
            Wrapper wrapper = request.getWrapper();
            String header = null;
            if (wrapper != null) {
                String[] methods = wrapper.getServletMethods();
                if (methods != null) {
                    for (String method : methods) {
                        if ("TRACE".equals(method)) {
                            continue;
                        }
                        if (header == null) {
                            header = method;
                        } else {
                            header += ", " + method;
                        }
                    }
                }
            }
            if (header != null) {
                res.addHeader("Allow", header);
            }
            response.sendError(405, "TRACE method is not allowed");
            // Safe to skip the remainder of this method.
            return true;
        }

        doConnectorAuthenticationAuthorization(req, request);

        return true;
    }

6 StandardService StandardWrapperValve ApplicationFilterChain

1.执行完所有的Valve和filter后再执行servlet的service方法,并根据http报文中的方法具体执行get,post,put等等方法。

    public final void invoke(Request request, Response response)
        throws IOException, ServletException {

        // Initialize local variables we may need
        boolean unavailable = false;
        Throwable throwable = null;
        // This should be a Request attribute...
        long t1=System.currentTimeMillis();
        requestCount.incrementAndGet();
        StandardWrapper wrapper = (StandardWrapper) getContainer();
        Servlet servlet = null;
        Context context = (Context) wrapper.getParent();

        // Check for the application being marked unavailable
        if (!context.getState().isAvailable()) {
            response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardContext.isUnavailable"));
            unavailable = true;
        }

        // Check for the servlet being marked unavailable
        if (!unavailable && wrapper.isUnavailable()) {
            container.getLogger().info(sm.getString("standardWrapper.isUnavailable",
                    wrapper.getName()));
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
                response.setDateHeader("Retry-After", available);
                response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                        sm.getString("standardWrapper.isUnavailable",
                                wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
                response.sendError(HttpServletResponse.SC_NOT_FOUND,
                        sm.getString("standardWrapper.notFound",
                                wrapper.getName()));
            }
            unavailable = true;
        }

        // Allocate a servlet instance to process this request
        try {
            if (!unavailable) {
                servlet = wrapper.allocate();
            }
        } catch (UnavailableException e) {
            container.getLogger().error(
                    sm.getString("standardWrapper.allocateException",
                            wrapper.getName()), e);
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
                response.setDateHeader("Retry-After", available);
                response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardWrapper.isUnavailable",
                                        wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
                response.sendError(HttpServletResponse.SC_NOT_FOUND,
                           sm.getString("standardWrapper.notFound",
                                        wrapper.getName()));
            }
        } catch (ServletException e) {
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), StandardWrapper.getRootCause(e));
            throwable = e;
            exception(request, response, e);
        } catch (Throwable e) {
            ExceptionUtils.handleThrowable(e);
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
            servlet = null;
        }

        MessageBytes requestPathMB = request.getRequestPathMB();
        DispatcherType dispatcherType = DispatcherType.REQUEST;
        if (request.getDispatcherType()==DispatcherType.ASYNC) dispatcherType = DispatcherType.ASYNC;
        request.setAttribute(Globals.DISPATCHER_TYPE_ATTR,dispatcherType);
        request.setAttribute(Globals.DISPATCHER_REQUEST_PATH_ATTR,
                requestPathMB);
        // Create the filter chain for this request
        ApplicationFilterChain filterChain =
                ApplicationFilterFactory.createFilterChain(request, wrapper, servlet);

        // Call the filter chain for this request
        // NOTE: This also calls the servlet's service() method
        Container container = this.container;
        try {
            if ((servlet != null) && (filterChain != null)) {
                // Swallow output if needed
                if (context.getSwallowOutput()) {
                    try {
                        SystemLogHandler.startCapture();
                        if (request.isAsyncDispatching()) {
                            request.getAsyncContextInternal().doInternalDispatch();
                        } else {
                            filterChain.doFilter(request.getRequest(),
                                    response.getResponse());
                        }
                    } finally {
                        String log = SystemLogHandler.stopCapture();
                        if (log != null && log.length() > 0) {
                            context.getLogger().info(log);
                        }
                    }
                } else {
                    if (request.isAsyncDispatching()) {
                        request.getAsyncContextInternal().doInternalDispatch();
                    } else {
                        filterChain.doFilter
                            (request.getRequest(), response.getResponse());
                    }
                }

            }
        } catch (ClientAbortException | CloseNowException e) {
            if (container.getLogger().isDebugEnabled()) {
                container.getLogger().debug(sm.getString(
                        "standardWrapper.serviceException", wrapper.getName(),
                        context.getName()), e);
            }
            throwable = e;
            exception(request, response, e);
        } catch (IOException e) {
            container.getLogger().error(sm.getString(
                    "standardWrapper.serviceException", wrapper.getName(),
                    context.getName()), e);
            throwable = e;
            exception(request, response, e);
        } catch (UnavailableException e) {
            container.getLogger().error(sm.getString(
                    "standardWrapper.serviceException", wrapper.getName(),
                    context.getName()), e);
            //            throwable = e;
            //            exception(request, response, e);
            wrapper.unavailable(e);
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
                response.setDateHeader("Retry-After", available);
                response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardWrapper.isUnavailable",
                                        wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
                response.sendError(HttpServletResponse.SC_NOT_FOUND,
                            sm.getString("standardWrapper.notFound",
                                        wrapper.getName()));
            }
            // Do not save exception in 'throwable', because we
            // do not want to do exception(request, response, e) processing
        } catch (ServletException e) {
            Throwable rootCause = StandardWrapper.getRootCause(e);
            if (!(rootCause instanceof ClientAbortException)) {
                container.getLogger().error(sm.getString(
                        "standardWrapper.serviceExceptionRoot",
                        wrapper.getName(), context.getName(), e.getMessage()),
                        rootCause);
            }
            throwable = e;
            exception(request, response, e);
        } catch (Throwable e) {
            ExceptionUtils.handleThrowable(e);
            container.getLogger().error(sm.getString(
                    "standardWrapper.serviceException", wrapper.getName(),
                    context.getName()), e);
            throwable = e;
            exception(request, response, e);
        } finally {
            // Release the filter chain (if any) for this request
            if (filterChain != null) {
                filterChain.release();
            }

            // Deallocate the allocated servlet instance
            try {
                if (servlet != null) {
                    wrapper.deallocate(servlet);
                }
            } catch (Throwable e) {
                ExceptionUtils.handleThrowable(e);
                container.getLogger().error(sm.getString("standardWrapper.deallocateException",
                                 wrapper.getName()), e);
                if (throwable == null) {
                    throwable = e;
                    exception(request, response, e);
                }
            }

            // If this servlet has been marked permanently unavailable,
            // unload it and release this instance
            try {
                if ((servlet != null) &&
                    (wrapper.getAvailable() == Long.MAX_VALUE)) {
                    wrapper.unload();
                }
            } catch (Throwable e) {
                ExceptionUtils.handleThrowable(e);
                container.getLogger().error(sm.getString("standardWrapper.unloadException",
                                 wrapper.getName()), e);
                if (throwable == null) {
                    exception(request, response, e);
                }
            }
            long t2=System.currentTimeMillis();

            long time=t2-t1;
            processingTime += time;
            if( time > maxTime) maxTime=time;
            if( time < minTime) minTime=time;
        }
    }

    /**
     * Invoke the next filter in this chain, passing the specified request
     * and response.  If there are no more filters in this chain, invoke
     * the <code>service()</code> method of the servlet itself.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet exception occurs
     */
    @Override
    public void doFilter(ServletRequest request, ServletResponse response)
        throws IOException, ServletException {

        if( Globals.IS_SECURITY_ENABLED ) {
            final ServletRequest req = request;
            final ServletResponse res = response;
            try {
                java.security.AccessController.doPrivileged(
                    new java.security.PrivilegedExceptionAction<Void>() {
                        @Override
                        public Void run()
                            throws ServletException, IOException {
                            internalDoFilter(req,res);
                            return null;
                        }
                    }
                );
            } catch( PrivilegedActionException pe) {
                Exception e = pe.getException();
                if (e instanceof ServletException)
                    throw (ServletException) e;
                else if (e instanceof IOException)
                    throw (IOException) e;
                else if (e instanceof RuntimeException)
                    throw (RuntimeException) e;
                else
                    throw new ServletException(e.getMessage(), e);
            }
        } else {
            internalDoFilter(request,response);
        }
    }
private void internalDoFilter(ServletRequest request,
                                  ServletResponse response)
        throws IOException, ServletException {

        // Call the next filter if there is one
        if (pos < n) {
            ApplicationFilterConfig filterConfig = filters[pos++];
            try {
                Filter filter = filterConfig.getFilter();

                if (request.isAsyncSupported() && "false".equalsIgnoreCase(
                        filterConfig.getFilterDef().getAsyncSupported())) {
                    request.setAttribute(Globals.ASYNC_SUPPORTED_ATTR, Boolean.FALSE);
                }
                if( Globals.IS_SECURITY_ENABLED ) {
                    final ServletRequest req = request;
                    final ServletResponse res = response;
                    Principal principal =
                        ((HttpServletRequest) req).getUserPrincipal();

                    Object[] args = new Object[]{req, res, this};
                    SecurityUtil.doAsPrivilege ("doFilter", filter, classType, args, principal);
                } else {
                    filter.doFilter(request, response, this);
                }
            } catch (IOException | ServletException | RuntimeException e) {
                throw e;
            } catch (Throwable e) {
                e = ExceptionUtils.unwrapInvocationTargetException(e);
                ExceptionUtils.handleThrowable(e);
                throw new ServletException(sm.getString("filterChain.filter"), e);
            }
            return;
        }

        // We fell off the end of the chain -- call the servlet instance
        try {
            if (ApplicationDispatcher.WRAP_SAME_OBJECT) {
                lastServicedRequest.set(request);
                lastServicedResponse.set(response);
            }

            if (request.isAsyncSupported() && !servletSupportsAsync) {
                request.setAttribute(Globals.ASYNC_SUPPORTED_ATTR,
                        Boolean.FALSE);
            }
            // Use potentially wrapped request from this point
            if ((request instanceof HttpServletRequest) &&
                    (response instanceof HttpServletResponse) &&
                    Globals.IS_SECURITY_ENABLED ) {
                final ServletRequest req = request;
                final ServletResponse res = response;
                Principal principal =
                    ((HttpServletRequest) req).getUserPrincipal();
                Object[] args = new Object[]{req, res};
                SecurityUtil.doAsPrivilege("service",
                                           servlet,
                                           classTypeUsedInService,
                                           args,
                                           principal);
            } else {
                servlet.service(request, response);
            }
        } catch (IOException | ServletException | RuntimeException e) {
            throw e;
        } catch (Throwable e) {
            e = ExceptionUtils.unwrapInvocationTargetException(e);
            ExceptionUtils.handleThrowable(e);
            throw new ServletException(sm.getString("filterChain.servlet"), e);
        } finally {
            if (ApplicationDispatcher.WRAP_SAME_OBJECT) {
                lastServicedRequest.set(null);
                lastServicedResponse.set(null);
            }
        }
    }
    /**
     * Receives standard HTTP requests from the public
     * <code>service</code> method and dispatches
     * them to the <code>do</code><i>Method</i> methods defined in
     * this class. This method is an HTTP-specific version of the
     * {@link javax.servlet.Servlet#service} method. There's no
     * need to override this method.
     *
     * @param req   the {@link HttpServletRequest} object that
     *                  contains the request the client made of
     *                  the servlet
     *
     * @param resp  the {@link HttpServletResponse} object that
     *                  contains the response the servlet returns
     *                  to the client
     *
     * @exception IOException   if an input or output error occurs
     *                              while the servlet is handling the
     *                              HTTP request
     *
     * @exception ServletException  if the HTTP request
     *                                  cannot be handled
     *
     * @see javax.servlet.Servlet#service
     */
    protected void service(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {

        String method = req.getMethod();

        if (method.equals(METHOD_GET)) {
            long lastModified = getLastModified(req);
            if (lastModified == -1) {
                // servlet doesn't support if-modified-since, no reason
                // to go through further expensive logic
                doGet(req, resp);
            } else {
                long ifModifiedSince;
                try {
                    ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);
                } catch (IllegalArgumentException iae) {
                    // Invalid date header - proceed as if none was set
                    ifModifiedSince = -1;
                }
                if (ifModifiedSince < (lastModified / 1000 * 1000)) {
                    // If the servlet mod time is later, call doGet()
                    // Round down to the nearest second for a proper compare
                    // A ifModifiedSince of -1 will always be less
                    maybeSetLastModified(resp, lastModified);
                    doGet(req, resp);
                } else {
                    resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                }
            }

        } else if (method.equals(METHOD_HEAD)) {
            long lastModified = getLastModified(req);
            maybeSetLastModified(resp, lastModified);
            doHead(req, resp);

        } else if (method.equals(METHOD_POST)) {
            doPost(req, resp);

        } else if (method.equals(METHOD_PUT)) {
            doPut(req, resp);

        } else if (method.equals(METHOD_DELETE)) {
            doDelete(req, resp);

        } else if (method.equals(METHOD_OPTIONS)) {
            doOptions(req,resp);

        } else if (method.equals(METHOD_TRACE)) {
            doTrace(req,resp);

        } else {
            //
            // Note that this means NO servlet supports whatever
            // method was requested, anywhere on this server.
            //

            String errMsg = lStrings.getString("http.method_not_implemented");
            Object[] errArgs = new Object[1];
            errArgs[0] = method;
            errMsg = MessageFormat.format(errMsg, errArgs);

            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg);
        }
    }
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