tomcat8.5.57源码阅读笔记5.1 - 管道
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上一篇终于找到了调用管道方法的地方, 代码片段:
//org/apache/catalina/connector/CoyoteAdapter#service
// Parse and set Catalina and configuration specific
// request parameters 在 Map 中解析请求
postParseSuccess = postParseRequest(req, request, res, response);
if (postParseSuccess) {
//check valves if we support async
//getContainer() -> StandardEngine
request.setAsyncSupported(
connector.getService().getContainer().getPipeline().isAsyncSupported());
// Calling the container
// 调用 StandardEngineValve#invoke(), 开始执行管道方法. (责任链模式)
// 如果有多个 valve , 这里 getFirst() 拿到的就是 first valve,
// 然后在 first valve中, 需要调用 getNext().invoke(request, response) 来传递
connector.getService() // --> StandardService
.getContainer() // --> StandardEngine
.getPipeline() // --> StandardPipeLine
.getFirst() //获取优先级: first > basic
.invoke(request, response);
}
1. 从代码上看, 只获取了 first, 那说好的很多阀门呢? 带着疑问, 只能去看一下 StandardPipeLine 的阀门.
2. 默认情况下, 这里的getFirst() 获取到的是 StandardEngineValve, 其实他是 basic.
StandardPipeLine
他有两个 阀门属性:
1. basic -- 末位阀门
2. first -- 首尾阀门
除此之外, 没找到任何阀门属性了. 没办法, 只能接着看看阀门
Valve
Valve 里面定义了两个方法:
1. public Valve getNext()
2. public void setNext(Valve valve)
看到这里, 总算明白了, 原来阀门本身, 也是一个指针, 指向了下一个阀门的位置. 使用阀门, 可以组成一个单向链表.
addValve()
明白了阀门是指针之后, 还需要知道, 增加阀门时的顺序, 所以必须看一下 addValve() 方法.
/**
* 加入valve时, 会放到basic最近的位子上, 具体分两种情况:
* 1. first为空, 则放在first上 : first -> basic
* 2. first不为空, 则放在离basic最近的位子上
* first -> v1 -> v2 -> basic , 此时要插入 v3, 结果是: first -> v1 -> v2 -> v3 -> basic*/
@Override
public void addValve(Valve valve) {
// Validate that we can add this Valve
if (valve instanceof Contained)
((Contained) valve).setContainer(this.container);
// Start the new component if necessary
if (getState().isAvailable()) {
if (valve instanceof Lifecycle) {
try {
((Lifecycle) valve).start();
} catch (LifecycleException e) {
log.error(sm.getString("standardPipeline.valve.start"), e);
}
}
}
// Add this Valve to the set associated with this Pipeline
if (first == null) {
first = valve;
valve.setNext(basic);
}
else {
Valve current = first;
while (current != null) {
if (current.getNext() == basic) {
current.setNext(valve);
valve.setNext(basic);
break;
}
current = current.getNext();
}
}
container.fireContainerEvent(Container.ADD_VALVE_EVENT, valve);
}
初始状态下, first 是空的, 所有的阀门, 在新增的时候, 都是紧挨着basic的位置放的.
getFirst()
/**
* 拿取优先级:(有头拿头, 没头拿尾)
* 1. first存在, 则返回first
* 2. first不存在, 则返回 basic
* @return
*/
@Override
public Valve getFirst() {
if (first != null) {
return first;
}
return basic;
}
在获取的时候, 当 first 为空时, 直接获取 basic , 说明此时只有一个阀门
当first 不为空时, 则会拿取 first , 然后需要在 调用阀门的时候, 进行传递.
StandardEngineValve
public final void invoke(Request request, Response response)
throws IOException, ServletException {
// Select the Host to be used for this Request
Host host = request.getHost();
if (host == null) {
response.sendError
(HttpServletResponse.SC_BAD_REQUEST,
sm.getString("standardEngine.noHost",
request.getServerName()));
return;
}
if (request.isAsyncSupported()) {
request.setAsyncSupported(host.getPipeline().isAsyncSupported());
}
// Ask this Host to process this request
//调用 StandardHostValve#invoke() 方法
host.getPipeline() //-->StandardPipeline
.getFirst() //--> AccessLogValve --> ErrorReportValve --> StandardHostValve
.invoke(request, response);
}
StandardEngineValve 作为管道的 basic(末位) , 肩负着调用子节点的管道方法. 这里启动了 StandardHostValve
AccessLogValve
//org.apache.catalina.valves.AbstractAccessLogValve#invoke
public void invoke(Request request, Response response) throws IOException,
ServletException {
if (tlsAttributeRequired) {
// The log pattern uses TLS attributes. Ensure these are populated
// before the request is processed because with NIO2 it is possible
// for the connection to be closed (and the TLS info lost) before
// the access log requests the TLS info. Requesting it now causes it
// to be cached in the request.
request.getAttribute(Globals.CERTIFICATES_ATTR);
}
if (cachedElements != null) {
for (CachedElement element : cachedElements) {
element.cache(request);
}
}
getNext().invoke(request, response);
}
ErrorReportValve
public void invoke(Request request, Response response) throws IOException, ServletException {
// Perform the request
getNext().invoke(request, response);
if (response.isCommitted()) {
if (response.setErrorReported()) {
// Error wasn't previously reported but we can't write an error
// page because the response has already been committed. Attempt
// to flush any data that is still to be written to the client.
try {
response.flushBuffer();
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
}
// Close immediately to signal to the client that something went
// wrong
response.getCoyoteResponse().action(ActionCode.CLOSE_NOW,
request.getAttribute(RequestDispatcher.ERROR_EXCEPTION));
}
return;
}
Throwable throwable = (Throwable) request.getAttribute(RequestDispatcher.ERROR_EXCEPTION);
// If an async request is in progress and is not going to end once this
// container thread finishes, do not process any error page here.
if (request.isAsync() && !request.isAsyncCompleting()) {
return;
}
if (throwable != null && !response.isError()) {
// Make sure that the necessary methods have been called on the
// response. (It is possible a component may just have set the
// Throwable. Tomcat won't do that but other components might.)
// These are safe to call at this point as we know that the response
// has not been committed.
response.reset();
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
}
// One way or another, response.sendError() will have been called before
// execution reaches this point and suspended the response. Need to
// reverse that so this valve can write to the response.
response.setSuspended(false);
try {
report(request, response, throwable);
} catch (Throwable tt) {
ExceptionUtils.handleThrowable(tt);
}
}
这里是先进行了传递, 然后根据后面执行的结果, 再进行一些错误处理.
StandardHostValve
public final void invoke(Request request, Response response)
throws IOException, ServletException {
// Select the Context to be used for this Request. context --> StandardContext
Context context = request.getContext();
if (context == null) {
return;
}
if (request.isAsyncSupported()) {
request.setAsyncSupported(context.getPipeline().isAsyncSupported());
}
boolean asyncAtStart = request.isAsync();
try {
context.bind(Globals.IS_SECURITY_ENABLED, MY_CLASSLOADER);
//fireRequestInitEvent 最终会调用 Servlet 监听器 ServletRequestListener#requestInitialized()
if (!asyncAtStart && !context.fireRequestInitEvent(request.getRequest())) {
// Don't fire listeners during async processing (the listener
// fired for the request that called startAsync()).
// If a request init listener throws an exception, the request
// is aborted.
return;
}
// Ask this Context to process this request. Requests that are
// already in error must have been routed here to check for
// application defined error pages so DO NOT forward them to the the
// application for processing.
try {
if (!response.isErrorReportRequired()) {
//StandardContextValve#invoke()
context.getPipeline() //-->StandardPipeline
.getFirst() //--> NonLoginAuthenticator --> StandardContextValve
.invoke(request, response);
}
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
container.getLogger().error("Exception Processing " + request.getRequestURI(), t);
// If a new error occurred while trying to report a previous
// error allow the original error to be reported.
if (!response.isErrorReportRequired()) {
request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, t);
throwable(request, response, t);
}
}
// Now that the request/response pair is back under container
// control lift the suspension so that the error handling can
// complete and/or the container can flush any remaining data
response.setSuspended(false);
Throwable t = (Throwable) request.getAttribute(RequestDispatcher.ERROR_EXCEPTION);
// Protect against NPEs if the context was destroyed during a
// long running request.
if (!context.getState().isAvailable()) {
return;
}
// Look for (and render if found) an application level error page
if (response.isErrorReportRequired()) {
// If an error has occurred that prevents further I/O, don't waste time
// producing an error report that will never be read
AtomicBoolean result = new AtomicBoolean(false);
response.getCoyoteResponse().action(ActionCode.IS_IO_ALLOWED, result);
if (result.get()) {
if (t != null) {
throwable(request, response, t);
} else {
status(request, response);
}
}
}
if (!request.isAsync() && !asyncAtStart) {
//最终会调用 Servlet 监听器 ServletRequestListener#requestDestroyed()
context.fireRequestDestroyEvent(request.getRequest());
}
} finally {
// Access a session (if present) to update last accessed time, based
// on a strict interpretation of the specification
if (ACCESS_SESSION) {
request.getSession(false);
}
context.unbind(Globals.IS_SECURITY_ENABLED, MY_CLASSLOADER);
}
}
StandardHostValve 作为末位valve, 同样的, 肩负着启动子节点的管道.
NonLoginAuthenticator
public void invoke(Request request, Response response) throws IOException, ServletException {
if (log.isDebugEnabled()) {
log.debug("Security checking request " + request.getMethod() + " " +
request.getRequestURI());
}
// Have we got a cached authenticated Principal to record?
if (cache) {
Principal principal = request.getUserPrincipal();
if (principal == null) {
Session session = request.getSessionInternal(false);
if (session != null) {
principal = session.getPrincipal();
if (principal != null) {
if (log.isDebugEnabled()) {
log.debug("We have cached auth type " + session.getAuthType() +
" for principal " + principal);
}
request.setAuthType(session.getAuthType());
request.setUserPrincipal(principal);
}
}
}
}
boolean authRequired = isContinuationRequired(request);
Realm realm = this.context.getRealm();
// Is this request URI subject to a security constraint?
SecurityConstraint[] constraints = realm.findSecurityConstraints(request, this.context);
AuthConfigProvider jaspicProvider = getJaspicProvider();
if (jaspicProvider != null) {
authRequired = true;
}
if (constraints == null && !context.getPreemptiveAuthentication() && !authRequired) {
if (log.isDebugEnabled()) {
log.debug("Not subject to any constraint");
}
getNext().invoke(request, response);
return;
}
// Make sure that constrained resources are not cached by web proxies
// or browsers as caching can provide a security hole
if (constraints != null && disableProxyCaching &&
!"POST".equalsIgnoreCase(request.getMethod())) {
if (securePagesWithPragma) {
// Note: These can cause problems with downloading files with IE
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
} else {
response.setHeader("Cache-Control", "private");
}
response.setHeader("Expires", DATE_ONE);
}
if (constraints != null) {
// Enforce any user data constraint for this security constraint
if (log.isDebugEnabled()) {
log.debug("Calling hasUserDataPermission()");
}
if (!realm.hasUserDataPermission(request, response, constraints)) {
if (log.isDebugEnabled()) {
log.debug("Failed hasUserDataPermission() test");
}
/*
* ASSERT: Authenticator already set the appropriate HTTP status
* code, so we do not have to do anything special
*/
return;
}
}
// Since authenticate modifies the response on failure,
// we have to check for allow-from-all first.
boolean hasAuthConstraint = false;
if (constraints != null) {
hasAuthConstraint = true;
for (int i = 0; i < constraints.length && hasAuthConstraint; i++) {
if (!constraints[i].getAuthConstraint()) {
hasAuthConstraint = false;
} else if (!constraints[i].getAllRoles() &&
!constraints[i].getAuthenticatedUsers()) {
String[] roles = constraints[i].findAuthRoles();
if (roles == null || roles.length == 0) {
hasAuthConstraint = false;
}
}
}
}
if (!authRequired && hasAuthConstraint) {
authRequired = true;
}
if (!authRequired && context.getPreemptiveAuthentication()) {
authRequired =
request.getCoyoteRequest().getMimeHeaders().getValue("authorization") != null;
}
if (!authRequired && context.getPreemptiveAuthentication() &&
HttpServletRequest.CLIENT_CERT_AUTH.equals(getAuthMethod())) {
X509Certificate[] certs = getRequestCertificates(request);
authRequired = certs != null && certs.length > 0;
}
JaspicState jaspicState = null;
if ((authRequired || constraints != null) && allowCorsPreflightBypass(request)) {
if (log.isDebugEnabled()) {
log.debug("CORS Preflight request bypassing authentication");
}
getNext().invoke(request, response);
return;
}
if (authRequired) {
if (log.isDebugEnabled()) {
log.debug("Calling authenticate()");
}
if (jaspicProvider != null) {
jaspicState = getJaspicState(jaspicProvider, request, response, hasAuthConstraint);
if (jaspicState == null) {
return;
}
}
if (jaspicProvider == null && !doAuthenticate(request, response) ||
jaspicProvider != null &&
!authenticateJaspic(request, response, jaspicState, false)) {
if (log.isDebugEnabled()) {
log.debug("Failed authenticate() test");
}
/*
* ASSERT: Authenticator already set the appropriate HTTP status
* code, so we do not have to do anything special
*/
return;
}
}
if (constraints != null) {
if (log.isDebugEnabled()) {
log.debug("Calling accessControl()");
}
if (!realm.hasResourcePermission(request, response, constraints, this.context)) {
if (log.isDebugEnabled()) {
log.debug("Failed accessControl() test");
}
/*
* ASSERT: AccessControl method has already set the appropriate
* HTTP status code, so we do not have to do anything special
*/
return;
}
}
// Any and all specified constraints have been satisfied
if (log.isDebugEnabled()) {
log.debug("Successfully passed all security constraints");
}
getNext().invoke(request, response);
if (jaspicProvider != null) {
secureResponseJspic(request, response, jaspicState);
}
}
这个阀门是进行tomcat身份验证的.
StandardContextValve
public final void invoke(Request request, Response response)
throws IOException, ServletException {
// Disallow any direct access to resources under WEB-INF or META-INF
MessageBytes requestPathMB = request.getRequestPathMB();
if ((requestPathMB.startsWithIgnoreCase("/META-INF/", 0))
|| (requestPathMB.equalsIgnoreCase("/META-INF"))
|| (requestPathMB.startsWithIgnoreCase("/WEB-INF/", 0))
|| (requestPathMB.equalsIgnoreCase("/WEB-INF"))) {
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
// Select the Wrapper to be used for this Request
Wrapper wrapper = request.getWrapper();
if (wrapper == null || wrapper.isUnavailable()) {
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
// Acknowledge the request
try {
response.sendAcknowledgement();
} catch (IOException ioe) {
container.getLogger().error(sm.getString(
"standardContextValve.acknowledgeException"), ioe);
request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, ioe);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
return;
}
if (request.isAsyncSupported()) {
request.setAsyncSupported(wrapper.getPipeline().isAsyncSupported());
}
//StandardWrapperValve#invoke()
wrapper.getPipeline() //-->StandardPipeline
.getFirst() //-->StandardWrapperValve
.invoke(request, response);
}
StandardWrapperValve
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();
//增加请求次数 CAS乐观锁的方式
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
// 创建过滤器链
ApplicationFilterChain filterChain = ApplicationFilterFactory.createFilterChain(request, wrapper, servlet);
// Call the filter chain for this request
// NOTE: This also calls the servlet's service() method
try {
if ((servlet != null) && (filterChain != null)) {
// Swallow output if needed
if (context.getSwallowOutput()) {
try {
SystemLogHandler.startCapture();
if (request.isAsyncDispatching()) {
request.getAsyncContextInternal().doInternalDispatch();
} else {
//执行过滤链
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 {
//执行过滤器链方法, 最终会执行 Servlet 的 service 方法
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) {
//释放过滤链资源
filterChain.release();
}
// Deallocate the allocated servlet instance
try {
if (servlet != null) {
//会受到 Servlet 池例中
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;
}
}
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