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This article mainly shows you the "SpringCloud zuul source code example analysis", the content is easy to understand, clear, hope to help you solve doubts, the following let the editor lead you to study and learn "SpringCloud zuul source code example analysis" this article.

There are some slight changes in the implementation of each version of zuul, and the overall implementation idea has not changed. Take spring-cloud-netflix-core-1.3.6.RELEASE as an example.

1. Important initialization classes of zuul

Org.springframework.cloud.netflix.zuul.ZuulServerAutoConfiguration

Org.springframework.cloud.netflix.zuul.ZuulProxyAutoConfiguration

Org.springframework.cloud.netflix.zuul.ZuulFilterInitializer

Org.springframework.cloud.netflix.zuul.RibbonCommandFactoryConfiguration

ZuulServerAutoConfiguration

Initialize routing rules

Initialize some important filter such as PreDecorationFilter,RibbonRoutingFilter

Initialize ZuulFilterInitializer

Initialize ZuulHandlerMapping

The code is as follows

/ / routing rule @ Bean @ ConditionalOnMissingBean (DiscoveryClientRouteLocator.class) public DiscoveryClientRouteLocator discoveryRouteLocator () {return new DiscoveryClientRouteLocator (this.server.getServletPrefix (), this.discovery, this.zuulProperties, this.serviceRouteMapper);} / / pre filters @ Bean public PreDecorationFilter preDecorationFilter (RouteLocator routeLocator, ProxyRequestHelper proxyRequestHelper) {return new PreDecorationFilter (routeLocator, this.server.getServletPrefix (), this.zuulProperties, proxyRequestHelper);} / / route filters @ Bean public RibbonRoutingFilter ribbonRoutingFilter (ProxyRequestHelper helper, RibbonCommandFactory ribbonCommandFactory) {RibbonRoutingFilter filter = new RibbonRoutingFilter (helper, ribbonCommandFactory, this.requestCustomizers) Return filter;} @ Configuration protected static class ZuulFilterConfiguration {@ Autowired private Map filters; @ Bean public ZuulFilterInitializer zuulFilterInitializer (CounterFactory counterFactory, TracerFactory tracerFactory) {FilterLoader filterLoader = FilterLoader.getInstance (); FilterRegistry filterRegistry = FilterRegistry.instance (); return new ZuulFilterInitializer (this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry);} @ Bean public ZuulController zuulController () {return new ZuulController ();} @ Bean public ZuulHandlerMapping zuulHandlerMapping (RouteLocator routes) {ZuulHandlerMapping mapping = new ZuulHandlerMapping (routes, zuulController ()); mapping.setErrorController (this.errorController) Return mapping;}

ZuulProxyAutoConfiguration

ZuulProxAutoConfiguration inherits ZuulServerAutoConfiguration functions and zuulServerAutoConfiguration

The main function is to add the configuration of RibbonCommandFactoryConfiguration and initialize all the ways to implement ribbon, such as apache,okhttp.

ZuulFilterInitializer

The main purpose of this class is to register the initialized filter with zuul's FilterRegistry,FilterRegistry is a singleton used to initialize routing information, used in ZuulRunner

RibbonCommandFactoryConfiguration

The main function is to configure the implementation of forwarding, and the main implementation is apache,okhttp

Second, the forwarding implementation of zuul

First, go to the lookupHandler method in ZuulHandlerMapping and transfer the forwarding to zuulController.

@ Override protected Object lookupHandler (String urlPath, HttpServletRequest request) throws Exception {if (this.errorController! = null & & urlPath.equals (this.errorController.getErrorPath () {return null;} String [] ignored = this.routeLocator.getIgnoredPaths () .toArray (new String [0]); if (PatternMatchUtils.simpleMatch (ignored, urlPath)) {return null;} RequestContext ctx = RequestContext.getCurrentContext (); if (ctx.containsKey ("forward.to")) {return null } if (this.dirty) {synchronized (this) {if (this.dirty) {registerHandlers (); this.dirty = false;} return super.lookupHandler (urlPath, request);}

When dirty is true for the first visit, the rule for initializing a request is as follows

Private void registerHandlers () {Collection routes = this.routeLocator.getRoutes (); if (routes.isEmpty ()) {this.logger.warn ("No routes found from RouteLocator");} else {for (Route route: routes) {registerHandler (route.getFullPath (), this.zuul);}

The second step is that ZuulController inherits ServletWrappingController and transfers the request to ZuulServlet as follows

/ * * @ author Spencer Gibb * / public class ZuulController extends ServletWrappingController {public ZuulController () {setServletClass (ZuulServlet.class); setServletName ("zuul"); setSupportedMethods ((String []) null); / / Allow all} @ Override public ModelAndView handleRequest (HttpServletRequest request, HttpServletResponse response) throws Exception {try {/ / We don't care about the other features of the base class, just want to / / handle the request return super.handleRequestInternal (request, response) } finally {/ @ see com.netflix.zuul.context.ContextLifecycleFilter.doFilter RequestContext.getCurrentContext () .unset ();}

In the third step, the service method of ZuulServlet is as follows to execute pre,route,postRoute three kinds of routers

@ Override public void service (javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse) throws ServletException, IOException {try {init ((HttpServletRequest) servletRequest, (HttpServletResponse) servletResponse); / / Marks this request as having passed through the "Zuul engine", as opposed to servlets / / explicitly bound in web.xml, for which requests will not have the same data attached RequestContext context = RequestContext.getCurrentContext (); context.setZuulEngineRan (); try {preRoute () } catch (ZuulException e) {error (e); postRoute (); return;} try {route ();} catch (ZuulException e) {error (e); postRoute (); return;} try {postRoute ();} catch (ZuulException e) {error (e); return }} catch (Throwable e) {error (new ZuulException (e500,500, "UNHANDLED_EXCEPTION_" + e.getClass (). GetName ());} finally {RequestContext.getCurrentContext (). Unset ();}}

4. Finally, the SendResponseFilter executes and returns the result. The filterOrder is 1000, so it is best that the filter of the post should not exceed 1000, otherwise the returned result will be affected.

The above is all the contents of this article "sample Analysis of zuul Source Code of SpringCloud". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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