前言
在《Tomcat7.0源码分析——请求原理分析(上)》一文中已经介绍了关于Tomcat7.0处理请求前作的初始化和准备工作,请读者在阅读本文前确保掌握《Tomcat7.0源码分析——请求原理分析(上)》一文中的相关知识以及HTTP协议和TCP协议的一些内容。本文重点讲解Tomcat7.0在准备好接受请求后,请求过程的原理分析。
请求处理架构
在正式开始之前,我们先来看看图1中的Tomcat请求处理架构。
图1 Tomcat请求处理架构
图1列出了Tomcat请求处理架构中的主要组件,这里对它们做个简单介绍:
- Acceptor:负责从ServerSocket中接收新的连接,并将Socket转交给SocketProcessor处理。Acceptor是JIoEndpoint的内部类,其实现已在《Tomcat7.0源码分析——请求原理分析(上)》一文中介绍。Acceptor线程的默认数量为1,我们可以在server.xml的Connector配置中增加acceptorThreadCount的大小。
- SocketProcessor:负责对Acceptor转交的Socket进行处理,包括给Socket设置属性、读取请求行和请求头等,最终将处理交给Engine的Pipeline处理。
- ThreadPool:执行SocketProcessor的线程来自《Tomcat7.0源码分析——请求原理分析(上)》一文中介绍的线程池,此线程池默认的最小线程数minSpareThreads等于10,最大线程数maxThreads等于200,我们可以在server.xml的Connector配置中调整它们的大小。
- Pipeline:SocketProcessor线程最后会将请求进一步交给Engine容器的Pipeline,管道Pipeline包括一系列的valve,如:StandardEngineValve、AccessLogValve、ErrorReportValve、StandardHostValve、 StandardContextValve、 StandardWrapperValve,它们就像地下水管中的一个个阀门,每一个都会对请求数据做不同的处理。
- FilterChain:管道Pipeline的最后一个valve是StandardWrapperValve,它会负责生成Servlet和Filter实例,并将它们组织成对请求处理的链条,这里正是Tomcat与J2EE规范相结合的部分。
默认情况下,Tomcat只有一个Acceptor线程,Acceptor不断循环从ServerSocket中获取Socket,当并发数大的情况下,这里会不会有性能问题?我想说的是,Acceptor的实现非常轻量级,它只负责两个动作:获取Socket和将Socket转交给SocketProcessor线程处理。另外,我们可以通过在server.xml的Connector配置中增加acceptorThreadCount的值,让我们同时可以拥有多个Acceptor线程。虽然我们可以修改maxThreads配置把SocketProcessor的线程数设置的很大,但是我们需要区别对待:
- 如果你部署在Tomcat上的Web服务主要用于计算,那么CPU的开销势必会很大,那么线程数不宜设置的过大,一般以CPU核数*2——CPU核数*3最佳。当然如果计算量非常大,就已经超出了Tomcat的使用范畴,我想此时,选择离线计算框架Hadoop或者实时计算框架Storm、Spark才是更好的选择。
- 如果部署在Tomcat上的Web服务主要是为了提供数据库访问,此时I/O的开销会很大,而CPU利用率反而低,此时应该将线程数设置的大一些,但是如果设置的过大,CPU为了给成百上千个线程分配时间片,造成CPU的精力都分散在线程切换上,反而造成性能下降。具体多大,需要对系统性能调优得出。
原理就讲这么多,下面具体分析下Tomcat处理请求的具体实现。
接收请求
在《Tomcat7.0源码分析——请求原理分析(上)》一文中我们曾经介绍过JIoEndpoint的内部类Acceptor,Acceptor实现了Runnable接口。Acceptor作为后台线程不断循环,每次循环都会接收来自浏览器的Socket连接(用户在浏览器输入HTTP请求地址后,浏览器底层实际使用Socket通信的),最后将Socket交给外部类JIoEndpoint的processSocket方法(见代码清单1)处理。
代码清单1
-
/**
-
* Process given socket.
-
*/
-
protected boolean processSocket(Socket socket) {
-
try {
-
SocketWrapper<Socket> wrapper = new SocketWrapper<Socket>(socket);
-
wrapper.setKeepAliveLeft(getMaxKeepAliveRequests());
-
getExecutor().execute(new SocketProcessor(wrapper));
-
} catch (RejectedExecutionException x) {
-
log.warn("Socket processing request was rejected for:"+socket,x);
-
return false;
-
} catch (Throwable t) {
-
// This means we got an OOM or similar creating a thread, or that
-
// the pool and its queue are full
-
log.error(sm.getString("endpoint.process.fail"), t);
-
return false;
-
}
-
return true;
-
}
根据代码清单1,JIoEndpoint的processSocket方法的处理步骤如下:
- 将Socket封装为SocketWrapper;
- 给SocketWrapper设置连接保持时间keepAliveLeft。这个值是通过调用父类AbstractEndpoint的getMaxKeepAliveRequests方法(见代码清单2)获得的;
- 创建SocketProcessor(此类也是JIoEndpoint的内部类,而且也实现了Runnable接口,见代码清单3),并使用线程池(此线程池已在《Tomcat7.0源码分析——请求原理分析(上)》一文中启动PROTOCOLHANDLER一节介绍)执行。
代码清单2
-
/**
-
* Max keep alive requests
-
*/
-
private int maxKeepAliveRequests=100; // as in Apache HTTPD server
-
public int getMaxKeepAliveRequests() {
-
return maxKeepAliveRequests;
-
}
代码清单3
-
/**
-
* This class is the equivalent of the Worker, but will simply use in an
-
* external Executor thread pool.
-
*/
-
protected class SocketProcessor implements Runnable {
-
-
protected SocketWrapper<Socket> socket = null;
-
protected SocketStatus status = null;
-
-
public SocketProcessor(SocketWrapper<Socket> socket) {
-
if (socket==null) throw new NullPointerException();
-
this.socket = socket;
-
}
-
-
public SocketProcessor(SocketWrapper<Socket> socket, SocketStatus status) {
-
this(socket);
-
this.status = status;
-
}
-
-
public void run() {
-
boolean launch = false;
-
try {
-
-
if (!socket.processing.compareAndSet(false, true)) {
-
log.error("Unable to process socket. Invalid state.");
-
return;
-
}
-
-
SocketState state = SocketState.OPEN;
-
// Process the request from this socket
-
if ( (!socket.isInitialized()) && (!setSocketOptions(socket.getSocket())) ) {
-
state = SocketState.CLOSED;
-
}
-
socket.setInitialized(true);
-
-
if ( (state != SocketState.CLOSED) ) {
-
state = (status==null)?handler.process(socket):handler.process(socket,status);
-
}
-
if (state == SocketState.CLOSED) {
-
// Close socket
-
if (log.isTraceEnabled()) {
-
log.trace("Closing socket:"+socket);
-
}
-
try {
-
socket.getSocket().close();
-
} catch (IOException e) {
-
// Ignore
-
}
-
} else if (state == SocketState.OPEN){
-
socket.setKeptAlive(true);
-
socket.access();
-
//keepalive connection
-
//TODO - servlet3 check async status, we may just be in a hold pattern
-
launch = true;
-
} else if (state == SocketState.LONG) {
-
socket.access();
-
waitingRequests.add(socket);
-
}
-
} finally {
-
socket.processing.set(false);
-
if (launch) getExecutor().execute(new SocketProcessor(socket));
-
socket = null;
-
}
-
// Finish up this request
-
-
}
-
-
}
SocketProcessor线程专门用于处理Acceptor转交的Socket,其执行步骤如下:
- 调用setSocketOptions方法(见代码清单4)给Socket设置属性,从中可以看到设置属性用到了SocketProperties的setProperties方法(见代码清单5),状态更改为初始化完毕;
- 调用handler的process方法处理请求。在《Tomcat7.0源码分析——请求原理分析(上)》一文中我们讲过当处理Http11Protocol协议时,handler默认为Http11Protocol的内部类Http11ConnectionHandler;
- 请求处理完毕后,如果state等于SocketState.CLOSED,则关闭Socket;如果state等于SocketState.OPEN,则保持连接;如果state等于SocketState.LONG,则会作为长连接对待。
代码清单4
-
/**
-
* Set the options for the current socket.
-
*/
-
protected boolean setSocketOptions(Socket socket) {
-
// Process the connection
-
-
try {
-
// 1: Set socket options: timeout, linger, etc
-
socketProperties.setProperties(socket);
-
} catch (SocketException s) {
-
//error here is common if the client has reset the connection
-
if (log.isDebugEnabled()) {
-
log.debug(sm.getString("endpoint.err.unexpected"), s);
-
}
-
// Close the socket
-
return false;
-
} catch (Throwable t) {
-
log.error(sm.getString("endpoint.err.unexpected"), t);
-
// Close the socket
-
return false;
-
}
-
try {
-
// 2: SSL handshake
-
serverSocketFactory.handshake(socket);
-
} catch (Throwable t) {
-
if (log.isDebugEnabled()) {
-
log.debug(sm.getString("endpoint.err.handshake"), t);
-
}
-
// Tell to close the socket
-
return false;
-
}
-
return true;
-
}
代码清单5
-
public void setProperties(Socket socket) throws SocketException{
-
if (rxBufSize != null)
-
socket.setReceiveBufferSize(rxBufSize.intValue());
-
if (txBufSize != null)
-
socket.setSendBufferSize(txBufSize.intValue());
-
if (ooBInline !=null)
-
socket.setOOBInline(ooBInline.booleanValue());
-
if (soKeepAlive != null)
-
socket.setKeepAlive(soKeepAlive.booleanValue());
-
if (performanceConnectionTime != null && performanceLatency != null &&
-
performanceBandwidth != null)
-
socket.setPerformancePreferences(
-
performanceConnectionTime.intValue(),
-
performanceLatency.intValue(),
-
performanceBandwidth.intValue());
-
if (soReuseAddress != null)
-
socket.setReuseAddress(soReuseAddress.booleanValue());
-
if (soLingerOn != null && soLingerTime != null)
-
socket.setSoLinger(soLingerOn.booleanValue(),
-
soLingerTime.intValue());
-
if (soTimeout != null && soTimeout.intValue() >= 0)
-
socket.setSoTimeout(soTimeout.intValue());
-
if (tcpNoDelay != null)
-
socket.setTcpNoDelay(tcpNoDelay.booleanValue());
-
if (soTrafficClass != null)
-
socket.setTrafficClass(soTrafficClass.intValue());
-
}
以Http11ConnectionHandler为例,我们重点分析它是如何进一步处理Socket的。Http11ConnectionHandler的process方法,见代码清单6。
代码清单6
-
public SocketState process(SocketWrapper<Socket> socket) {
-
return process(socket,SocketStatus.OPEN);
-
}
-
-
public SocketState process(SocketWrapper<Socket> socket, SocketStatus status) {
-
Http11Processor processor = connections.remove(socket);
-
boolean recycle = true;
-
try {
-
if (processor == null) {
-
processor = recycledProcessors.poll();
-
}
-
if (processor == null) {
-
processor = createProcessor();
-
}
-
processor.action(ActionCode.ACTION_START, null);
-
-
if (proto.isSSLEnabled() && (proto.sslImplementation != null)) {
-
processor.setSSLSupport
-
(proto.sslImplementation.getSSLSupport(socket.getSocket()));
-
} else {
-
processor.setSSLSupport(null);
-
}
-
-
SocketState state = socket.isAsync()?processor.asyncDispatch(status):processor.process(socket);
-
if (state == SocketState.LONG) {
-
connections.put(socket, processor);
-
socket.setAsync(true);
-
recycle = false;
-
} else {
-
connections.remove(socket);
-
socket.setAsync(false);
-
}
-
return state;
-
} catch(java.net.SocketException e) {
-
// SocketExceptions are normal
-
Http11Protocol.log.debug
-
(sm.getString
-
("http11protocol.proto.socketexception.debug"), e);
-
} catch (java.io.IOException e) {
-
// IOExceptions are normal
-
Http11Protocol.log.debug
-
(sm.getString
-
("http11protocol.proto.ioexception.debug"), e);
-
}
-
// Future developers: if you discover any other
-
// rare-but-nonfatal exceptions, catch them here, and log as
-
// above.
-
catch (Throwable 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.
-
Http11Protocol.log.error
-
(sm.getString("http11protocol.proto.error"), e);
-
} finally {
-
// if(proto.adapter != null) proto.adapter.recycle();
-
// processor.recycle();
-
-
if (recycle) {
-
processor.action(ActionCode.ACTION_STOP, null);
-
recycledProcessors.offer(processor);
-
}
-
}
-
return SocketState.CLOSED;
-
}
根据代码清单6,可见Http11ConnectionHandler的process方法的处理步骤如下:
- 从Socket的连接缓存connections(用于缓存长连接的Socket)中获取Socket对应的Http11Processor;如果连接缓存connections中不存在Socket对应的Http11Processor,则从可以循环使用的recycledProcessors(类型为ConcurrentLinkedQueue)中获取;如果recycledProcessors中也没有可以使用的Http11Processor,则调用createProcessor方法(见代码清单7)创建Http11Processor;
- 如果当前Connector配置了指定了SSLEnabled="true",那么还需要给Http11Processor设置SSL相关的属性;
- 如果Socket是异步的,则调用Http11Processor的asyncDispatch方法,否则调用Http11Processor的process方法;
- 请求处理完毕,如果Socket是长连接的,则将Socket和Http11Processor一起放入connections缓存,否则从connections缓存中移除Socket和Http11Processor。
代码清单7
-
protected Http11Processor createProcessor() {
-
Http11Processor processor =
-
new Http11Processor(proto.getMaxHttpHeaderSize(), (JIoEndpoint)proto.endpoint);
-
processor.setAdapter(proto.adapter);
-
processor.setMaxKeepAliveRequests(proto.getMaxKeepAliveRequests());
-
processor.setKeepAliveTimeout(proto.getKeepAliveTimeout());
-
processor.setTimeout(proto.getTimeout());
-
processor.setDisableUploadTimeout(proto.getDisableUploadTimeout());
-
processor.setCompressionMinSize(proto.getCompressionMinSize());
-
processor.setCompression(proto.getCompression());
-
processor.setNoCompressionUserAgents(proto.getNoCompressionUserAgents());
-
processor.setCompressableMimeTypes(proto.getCompressableMimeTypes());
-
processor.setRestrictedUserAgents(proto.getRestrictedUserAgents());
-
processor.setSocketBuffer(proto.getSocketBuffer());
-
processor.setMaxSavePostSize(proto.getMaxSavePostSize());
-
processor.setServer(proto.getServer());
-
register(processor);
-
return processor;
-
}
根据之前的分析,我们知道Socket的处理方式有异步和同步两种,分别调用Http11Processor的asyncDispatch方法或process方法,我们以同步处理为例,来看看接下来的处理逻辑。
同步处理
Http11Processor的process方法(见代码清单8)用于同步处理,由于其代码很多,所以此处在代码后面追加一些注释,便于读者理解。这里面有一些关键方法重点拿出来解释下:
- InternalInputBuffer的parseRequestLine方法用于读取请求行;
- InternalInputBuffer的parseHeaders方法用于读取请求头;
- prepareRequest用于在正式处理请求之前,做一些准备工作,如根据请求头获取请求的版本号是HTTP/1.1还是HTTP/0.9、keepAlive是否为true等,还会设置一些输入过滤器用于标记请求、压缩等;
- 调用CoyoteAdapter的service方法处理请求。
代码清单8
-
RequestInfo rp = request.getRequestProcessor();
-
rp.setStage(org.apache.coyote.Constants.STAGE_PARSE);
-
this.socket = socketWrapper;
-
inputBuffer.setInputStream(socket.getSocket().getInputStream());//设置输入流
-
outputBuffer.setOutputStream(socket.getSocket().getOutputStream());//设置输出流
-
int keepAliveLeft = maxKeepAliveRequests>0?socketWrapper.decrementKeepAlive():-1;//保持连接递减
-
int soTimeout = endpoint.getSoTimeout();//socket超时时间
-
socket.getSocket().setSoTimeout(soTimeout);//设置超时时间
-
boolean keptAlive = socketWrapper.isKeptAlive();//是否保持连接
-
while (started && !error && keepAlive) {
-
-
// Parsing the request header
-
try {
-
//TODO - calculate timeout based on length in queue (System.currentTimeMills() - wrapper.getLastAccess() is the time in queue)
-
if (keptAlive) {//是否保持连接
-
if (keepAliveTimeout > 0) {
-
socket.getSocket().setSoTimeout(keepAliveTimeout);
-
}
-
else if (soTimeout > 0) {
-
socket.getSocket().setSoTimeout(soTimeout);
-
}
-
}
-
inputBuffer.parseRequestLine(false);//读取请求行
-
request.setStartTime(System.currentTimeMillis());
-
keptAlive = true;
-
if (disableUploadTimeout) {
-
socket.getSocket().setSoTimeout(soTimeout);
-
} else {
-
socket.getSocket().setSoTimeout(timeout);
-
}
-
inputBuffer.parseHeaders();//解析请求头
-
} catch (IOException e) {
-
error = true;
-
break;
-
} catch (Throwable t) {
-
if (log.isDebugEnabled()) {
-
log.debug(sm.getString("http11processor.header.parse"), t);
-
}
-
// 400 - Bad Request
-
response.setStatus(400);
-
adapter.log(request, response, 0);
-
error = true;
-
}
-
-
if (!error) {
-
// Setting up filters, and parse some request headers
-
rp.setStage(org.apache.coyote.Constants.STAGE_ENDED);
-
try {
-
prepareRequest();//对请求内容增加过滤器——协议、方法、请求头、host等
-
} catch (Throwable t) {
-
if (log.isDebugEnabled()) {
-
log.debug(sm.getString("http11processor.request.prepare"), t);
-
}
-
// 400 - Internal Server Error
-
response.setStatus(400);
-
adapter.log(request, response, 0);
-
error = true;
-
}
-
}
-
-
if (maxKeepAliveRequests > 0 && keepAliveLeft == 0)
-
keepAlive = false;
-
// Process the request in the adapter
-
if (!error) {
-
try {
-
rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
-
adapter.service(request, response); //将进一步处理交给CoyoteAdapter
-
// 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 && !error) { // Avoid checking twice.
-
error = response.getErrorException() != null ||
-
statusDropsConnection(response.getStatus());
-
}
-
-
} catch (InterruptedIOException e) {
-
error = true;
-
} catch (Throwable t) {
-
log.error(sm.getString("http11processor.request.process"), t);
-
// 500 - Internal Server Error
-
response.setStatus(500);
-
adapter.log(request, response, 0);
-
error = true;
-
}
-
}
-
-
// Finish the handling of the request
-
try {
-
rp.setStage(org.apache.coyote.Constants.STAGE_ENDINPUT);
-
// If we know we are closing the connection, don't drain input.
-
// This way uploading a 100GB file doesn't tie up the thread
-
// if the servlet has rejected it.
-
-
if(error && !async)
-
inputBuffer.setSwallowInput(false);
-
if (!async)
-
endRequest();
-
} catch (Throwable t) {
-
log.error(sm.getString("http11processor.request.finish"), t);
-
// 500 - Internal Server Error
-
response.setStatus(500);
-
adapter.log(request, response, 0);
-
error = true;
-
}
-
try {
-
rp.setStage(org.apache.coyote.Constants.STAGE_ENDOUTPUT);
-
} catch (Throwable t) {
-
log.error(sm.getString("http11processor.response.finish"), t);
-
error = true;
-
}
-
-
// If there was an error, make sure the request is counted as
-
// and error, and update the statistics counter
-
if (error) {
-
response.setStatus(500);
-
}
-
request.updateCounters();
-
-
rp.setStage(org.apache.coyote.Constants.STAGE_KEEPALIVE);
-
-
// Don't reset the param - we'll see it as ended. Next request
-
// will reset it
-
// thrA.setParam(null);
-
// Next request
-
if (!async || error) {
-
inputBuffer.nextRequest();
-
outputBuffer.nextRequest();
-
}
-
-
//hack keep alive behavior
-
break;
-
}
-
-
rp.setStage(org.apache.coyote.Constants.STAGE_ENDED);
-
if (error) {
-
recycle();
-
return SocketState.CLOSED;
-
} else if (async) {
-
return SocketState.LONG;
-
} else {
-
if (!keepAlive) {
-
recycle();
-
return SocketState.CLOSED;
-
} else {
-
return SocketState.OPEN;
-
}
-
}
从代码清单8可以看出,最后的请求处理交给了CoyoteAdapter,CoyoteAdapter的service方法(见代码清单9)用于真正处理请求。
代码清单9
-
/**
-
* Service method.
-
*/
-
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().setQueryStringEncoding
-
(connector.getURIEncoding());
-
-
}
-
-
if (connector.getXpoweredBy()) {
-
response.addHeader("X-Powered-By", POWERED_BY);
-
}
-
-
boolean comet = false;
-
boolean async = false;
-
-
try {
-
-
// Parse and set Catalina and configuration specific
-
// request parameters
-
req.getRequestProcessor().setWorkerThreadName(Thread.currentThread().getName());
-
if (postParseRequest(req, request, res, response)) {
-
//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.isComet()) {
-
if (!response.isClosed() && !response.isError()) {
-
if (request.getAvailable() || (request.getContentLength() > 0 && (!request.isParametersParsed()))) {
-
// Invoke a read event right away if there are available bytes
-
if (event(req, res, SocketStatus.OPEN)) {
-
comet = true;
-
res.action(ActionCode.ACTION_COMET_BEGIN, null);
-
}
-
} else {
-
comet = true;
-
res.action(ActionCode.ACTION_COMET_BEGIN, null);
-
}
-
} else {
-
// Clear the filter chain, as otherwise it will not be reset elsewhere
-
// since this is a Comet request
-
request.setFilterChain(null);
-
}
-
}
-
-
}
-
AsyncContextImpl asyncConImpl = (AsyncContextImpl)request.getAsyncContext();
-
if (asyncConImpl!=null && asyncConImpl.getState()==AsyncContextImpl.AsyncState.STARTED) {
-
res.action(ActionCode.ACTION_ASYNC_START, request.getAsyncContext());
-
async = true;
-
} else if (request.isAsyncDispatching()) {
-
asyncDispatch(req, res, SocketStatus.OPEN);
-
if (request.isAsyncStarted()) {
-
async = true;
-
res.action(ActionCode.ACTION_ASYNC_START, request.getAsyncContext());
-
}
-
} else if (!comet) {
-
response.finishResponse();
-
req.action(ActionCode.ACTION_POST_REQUEST , null);
-
}
-
-
} catch (IOException e) {
-
// Ignore
-
} catch (Throwable t) {
-
log.error(sm.getString("coyoteAdapter.service"), t);
-
} finally {
-
req.getRequestProcessor().setWorkerThreadName(null);
-
// Recycle the wrapper request and response
-
if (!comet && !async) {
-
request.recycle();
-
response.recycle();
-
} else {
-
// Clear converters so that the minimum amount of memory
-
// is used by this processor
-
request.clearEncoders();
-
response.clearEncoders();
-
}
-
}
-
-
}
从代码清单9可以看出,CoyoteAdapter的service方法的执行步骤如下:
- 创建Request与Response对象并且关联起来;
- 调用postParseRequest方法(见代码清单10)对请求进行解析;
- 将真正的请求处理交给Engine的Pipeline去处理,代码:connector.getService().getContainer().getPipeline().getFirst().invoke(request, response);
代码清单10
-
/**
-
* Parse additional request parameters.
-
*/
-
protected boolean postParseRequest(org.apache.coyote.Request req,
-
Request request,
-
org.apache.coyote.Response res,
-
Response response)
-
throws Exception {
-
// 省略前边的次要代码
-
parsePathParameters(req, request);
-
-
// URI decoding
-
// %xx decoding of the URL
-
try {
-
req.getURLDecoder().convert(decodedURI, false);
-
} catch (IOException ioe) {
-
res.setStatus(400);
-
res.setMessage("Invalid URI: " + ioe.getMessage());
-
connector.getService().getContainer().logAccess(
-
request, response, 0, true);
-
return false;
-
}
-
// Normalization
-
if (!normalize(req.decodedURI())) {
-
res.setStatus(400);
-
res.setMessage("Invalid URI");
-
connector.getService().getContainer().logAccess(
-
request, response, 0, true);
-
return false;
-
}
-
// Character decoding
-
convertURI(decodedURI, request);
-
// Check that the URI is still normalized
-
if (!checkNormalize(req.decodedURI())) {
-
res.setStatus(400);
-
res.setMessage("Invalid URI character encoding");
-
connector.getService().getContainer().logAccess(
-
request, response, 0, true);
-
return false;
-
}
-
-
// Set the remote principal
-
String principal = req.getRemoteUser().toString();
-
if (principal != null) {
-
request.setUserPrincipal(new CoyotePrincipal(principal));
-
}
-
-
// Set the authorization type
-
String authtype = req.getAuthType().toString();
-
if (authtype != null) {
-
request.setAuthType(authtype);
-
}
-
-
// Request mapping.
-
MessageBytes serverName;
-
if (connector.getUseIPVHosts()) {
-
serverName = req.localName();
-
if (serverName.isNull()) {
-
// well, they did ask for it
-
res.action(ActionCode.ACTION_REQ_LOCAL_NAME_ATTRIBUTE, null);
-
}
-
} else {
-
serverName = req.serverName();
-
}
-
if (request.isAsyncStarted()) {
-
//TODO SERVLET3 - async
-
//reset mapping data, should prolly be done elsewhere
-
request.getMappingData().recycle();
-
}
-
connector.getMapper().map(serverName, decodedURI,
-
request.getMappingData());
-
request.setContext((Context) request.getMappingData().context);
-
request.setWrapper((Wrapper) request.getMappingData().wrapper);
-
-
// 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 (int i=0; i<methods.length; i++) {
-
if ("TRACE".equals(methods[i])) {
-
continue;
-
}
-
if (header == null) {
-
header = methods[i];
-
} else {
-
header += ", " + methods[i];
-
}
-
}
-
}
-
}
-
res.setStatus(405);
-
res.addHeader("Allow", header);
-
res.setMessage("TRACE method is not allowed");
-
request.getContext().logAccess(request, response, 0, true);
-
return false;
-
}
-
-
// 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
-
if (request.getServletContext().getEffectiveSessionTrackingModes()
-
.contains(SessionTrackingMode.URL)) {
-
-
// Get the session ID if there was one
-
String sessionID = request.getPathParameter(
-
ApplicationSessionCookieConfig.getSessionUriParamName(
-
request.getContext()));
-
if (sessionID != null) {
-
request.setRequestedSessionId(sessionID);
-
request.setRequestedSessionURL(true);
-
}
-
}
-
-
// Possible redirect
-
MessageBytes redirectPathMB = request.getMappingData().redirectPath;
-
if (!redirectPathMB.isNull()) {
-
String redirectPath = urlEncoder.encode(redirectPathMB.toString());
-
String query = request.getQueryString();
-
if (request.isRequestedSessionIdFromURL()) {
-
// This is not optimal, but as this is not very common, it
-
// shouldn't matter
-
redirectPath = redirectPath + ";" +
-
ApplicationSessionCookieConfig.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;
-
}
-
-
// Finally look for session ID in cookies and SSL session
-
parseSessionCookiesId(req, request);
-
parseSessionSslId(request);
-
return true;
-
}
从代码清单10可以看出,postParseRequest方法的执行步骤如下:
- 解析请求url中的参数;
- URI decoding的转换(为了保证URL的可移植、完整性、可读性,通过ASCII字符集的有限子集对任意字符或数据进行编码、解码);
- 调用normalize方法判断请求路径中是否存在"\", "//", "/./"和"/../",如果存在则处理结束;
- 调用convertURI方法将字节转换为字符;
- 调用checkNormalize方法判断uri是否存在"\", "//", "/./"和"/../",如果存在则处理结束;
- 调用Connector的getMapper方法获取Mapper(已在《Tomcat7.0源码分析——请求原理分析(上)》一文中介绍),然后调用Mapper的map方法(见代码清单11)对host和context进行匹配(比如http://localhost:8080/manager/status会匹配host:localhost,context:/manager),其实质是调用internalMap方法;
- 使用ApplicationSessionCookieConfig.getSessionUriParamName获取sessionid的key,然后获取sessionid;
- 调用parseSessionCookiesId和parseSessionSslId方法查找cookie或者SSL中的sessionid。
代码清单11
-
public void map(MessageBytes host, MessageBytes uri,
-
MappingData mappingData)
-
throws Exception {
-
-
if (host.isNull()) {
-
host.getCharChunk().append(defaultHostName);
-
}
-
host.toChars();
-
uri.toChars();
-
internalMap(host.getCharChunk(), uri.getCharChunk(), mappingData);
-
-
}
CoyoteAdapter的service方法最后会将请求交给Engine的Pipeline去处理,我将在《Tomcat7.0源码分析——请求原理分析(下)》一文中具体讲解。