zuul两个重要功能，一个是路由转发，另一个就是过滤器。路由转发上一篇随笔已经写了，这一个写过滤器的实例。
spring cloud zuul 实现的过滤器需要包含4个基本特征：过滤类型、执行顺序、执行条件、具体操作。也就是zuulFilter接口的4个抽象方法。
ZuulFilter源码
/*
* Copyright 2013 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.netflix.zuul;
import com.netflix.config.DynamicBooleanProperty;
import com.netflix.config.DynamicPropertyFactory;
import com.netflix.zuul.monitoring.MonitoringHelper;
import com.netflix.zuul.monitoring.Tracer;
import com.netflix.zuul.monitoring.TracerFactory;
import org.junit.Before;
import org.junit.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Collections;
import java.util.concurrent.atomic.AtomicReference;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertSame;
import static org.mockito.Mockito.*;
/**
* Base abstract class for ZuulFilters. The base class defines abstract methods to define:
* filterType() - to classify a filter by type. Standard types in Zuul are "pre" for pre-routing filtering,
* "route" for routing to an origin, "post" for post-routing filters, "error" for error handling.
* We also support a "static" type for static responses see StaticResponseFilter.
* Any filterType made be created or added and run by calling FilterProcessor.runFilters(type)
* <p/>
* filterOrder() must also be defined for a filter. Filters may have the same filterOrder if precedence is not
* important for a filter. filterOrders do not need to be sequential.
* <p/>
* ZuulFilters may be disabled using Archius Properties.
* <p/>
* By default ZuulFilters are static; they don't carry state. This may be overridden by overriding the isStaticFilter() property to false
*
* @author Mikey Cohen
* Date: 10/26/11
* Time: 4:29 PM
*/
public abstract class ZuulFilter implements IZuulFilter, Comparable<ZuulFilter> {
private final AtomicReference<DynamicBooleanProperty> filterDisabledRef = new AtomicReference<>();
/**
* to classify a filter by type. Standard types in Zuul are "pre" for pre-routing filtering,
* "route" for routing to an origin, "post" for post-routing filters, "error" for error handling.
* We also support a "static" type for static responses see StaticResponseFilter.
* Any filterType made be created or added and run by calling FilterProcessor.runFilters(type)
*
* @return A String representing that type
*/
abstract public String filterType();
/**
* filterOrder() must also be defined for a filter. Filters may have the same filterOrder if precedence is not
* important for a filter. filterOrders do not need to be sequential.
*
* @return the int order of a filter
*/
abstract public int filterOrder();
/**
* By default ZuulFilters are static; they don't carry state. This may be overridden by overriding the isStaticFilter() property to false
*
* @return true by default
*/
public boolean isStaticFilter() {
return true;
}
/**
* The name of the Archaius property to disable this filter. by default it is zuul.[classname].[filtertype].disable
*
* @return
*/
public String disablePropertyName() {
return "zuul." + this.getClass().getSimpleName() + "." + filterType() + ".disable";
}
/**
* If true, the filter has been disabled by archaius and will not be run
*
* @return
*/
public boolean isFilterDisabled() {
filterDisabledRef.compareAndSet(null, DynamicPropertyFactory.getInstance().getBooleanProperty(disablePropertyName(), false));
return filterDisabledRef.get().get();
}
/**
* runFilter checks !isFilterDisabled() and shouldFilter(). The run() method is invoked if both are true.
*
* @return the return from ZuulFilterResult
*/
public ZuulFilterResult runFilter() {
ZuulFilterResult zr = new ZuulFilterResult();
if (!isFilterDisabled()) {
if (shouldFilter()) {
Tracer t = TracerFactory.instance().startMicroTracer("ZUUL::" + this.getClass().getSimpleName());
try {
Object res = run();
zr = new ZuulFilterResult(res, ExecutionStatus.SUCCESS);
} catch (Throwable e) {
t.setName("ZUUL::" + this.getClass().getSimpleName() + " failed");
zr = new ZuulFilterResult(ExecutionStatus.FAILED);
zr.setException(e);
} finally {
t.stopAndLog();
}
} else {
zr = new ZuulFilterResult(ExecutionStatus.SKIPPED);
}
}
return zr;
}
public int compareTo(ZuulFilter filter) {
return Integer.compare(this.filterOrder(), filter.filterOrder());
}
public static class TestUnit {
static Field field = null;
static {
try {
field = ZuulFilter.class.getDeclaredField("filterDisabledRef");
field.setAccessible(true);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
@Mock
private ZuulFilter f1;
@Mock
private ZuulFilter f2;
@Before
public void before() {
MockitoAnnotations.initMocks(this);
MonitoringHelper.initMocks();
}
@Test
public void testSort() {
when(f1.filterOrder()).thenReturn(1);
when(f2.filterOrder()).thenReturn(10);
when(f1.compareTo(any(ZuulFilter.class))).thenCallRealMethod();
when(f2.compareTo(any(ZuulFilter.class))).thenCallRealMethod();
ArrayList<ZuulFilter> list = new ArrayList<ZuulFilter>();
list.add(f2);
list.add(f1);
Collections.sort(list);
assertSame(f1, list.get(0));
}
@Test
public void testShouldFilter() {
class TestZuulFilter extends ZuulFilter {
@Override
public String filterType() {
return null;
}
@Override
public int filterOrder() {
return 0;
}
public boolean shouldFilter() {
return false;
}
public Object run() {
return null;
}
}
TestZuulFilter tf1 = spy(new TestZuulFilter());
TestZuulFilter tf2 = spy(new TestZuulFilter());
when(tf1.shouldFilter()).thenReturn(true);
when(tf2.shouldFilter()).thenReturn(false);
try {
tf1.runFilter();
tf2.runFilter();
verify(tf1, times(1)).run();
verify(tf2, times(0)).run();
} catch (Throwable throwable) {
throwable.printStackTrace();
}
}
@Test
public void testIsFilterDisabled() {
class TestZuulFilter extends ZuulFilter {
@Override
public String filterType() {
return null;
}
@Override
public int filterOrder() {
return 0;
}
public boolean isFilterDisabled() {
return false;
}
public boolean shouldFilter() {
return true;
}
public Object run() {
return null;
}
}
TestZuulFilter tf1 = spy(new TestZuulFilter());
TestZuulFilter tf2 = spy(new TestZuulFilter());
when(tf1.isFilterDisabled()).thenReturn(false);
when(tf2.isFilterDisabled()).thenReturn(true);
try {
tf1.runFilter();
tf2.runFilter();
verify(tf1, times(1)).run();
verify(tf2, times(0)).run();
} catch (Throwable throwable) {
throwable.printStackTrace();
}
}
@Test
public void testDisabledPropNameOnInit() throws Exception {
class TestZuulFilter extends ZuulFilter {
final String filterType;
public TestZuulFilter(String filterType) {
this.filterType = filterType;
}
@Override
public boolean shouldFilter() {
return false;
}
@Override
public Object run() {
return null;
}
@Override
public String filterType() {
return filterType;
}
@Override
public int filterOrder() {
return 0;
}
}
TestZuulFilter filter = new TestZuulFilter("pre");
assertFalse(filter.isFilterDisabled());
@SuppressWarnings("unchecked")
AtomicReference<DynamicBooleanProperty> filterDisabledRef = (AtomicReference<DynamicBooleanProperty>) field.get(filter);
String filterName = filterDisabledRef.get().getName();
assertEquals("zuul.TestZuulFilter.pre.disable", filterName);
}
}
}
filterType:这个函数需要返回一个字符串来代表过滤器的类型，而这个类型就是在HTTP请求过程中定义的各个阶段，在zuul中默认定义了4种不同生命周期的过滤器类型。分别是：
- pre： 可以在请求被路由之前调用
- routing：在路由时被调用
- post ：在routing和error过滤器之后被调用
- error ： 处理请求发生错误时被调用
filterOrder： 通过int 值来定义过滤器的执行顺序，数值越小优先级越高
shouldFilter：返回一个boolean值来判断该过滤器是否要执行。我们可以通过此方法来指定过滤器的有效范围
run ：过滤器的具体逻辑。在该函数中，我们可以实现自定义的过滤逻辑，来确定是否要拦截当前的请求，不对其进行后续的路由，或是在请求路由返回结果之后对处理结果进行加工。
第一步：自定义一个过滤器
package com.ssc.zuul_demo;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import javax.servlet.http.HttpServletRequest;
import java.util.Map;
import java.util.logging.Logger;
public class AccessFilter extends ZuulFilter {
Logger logger=Logger.getLogger("AccessFilter");
@Override
public String filterType() {
return "pre";
}
@Override
public int filterOrder() {
return 0;
}
@Override
public boolean shouldFilter() {
return true;
}
/**
*该过滤器主要是看请求是否存在accessToken参数，如果存在是正常访问，否则返回状态码401
*/
@Override
public Object run() throws ZuulException {
RequestContext ctx= RequestContext.getCurrentContext();
HttpServletRequest request=ctx.getRequest();
System.out.println(request.getMethod()+" "+request.getRequestURL().toString());
Object accessToken =request.getParameter("accessToken");
if(accessToken==null){
ctx.setSendZuulResponse(false);
ctx.setResponseStatusCode(401);
}
return null;
}
}
需要为其创建具体的Bean才能启动该过滤器，否则它并不会直接生效，当然也可以这样改
package com.ssc.zuul_demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;
@EnableZuulProxy
@SpringBootApplication
@EnableEurekaClient
public class ZuulDemoApplication {
public static void main(String[] args) {
SpringApplication.run(ZuulDemoApplication.class, args);
}
@Bean
public AccessFilter accessFilter(){
return new AccessFilter();
}
}
启动服务，校验
验证反例，不加 accessToken参数
将代码传到gitee:cloud_demo: springcloud样例 (gitee.com)