Feign调用服务丢失Cookie和Header信息
今天在使用Feign调用其他微服务的接口时，发现了一个问题：因为我的项目采用了无状态登录，token信息是存放在cookie中的，所以调用接口时，因为cookie中没有token信息，我的请求被拦截器拦截了。
参考几篇文章，靠谱的解决方法是： 将cookie信息放到请求头中，再进行调用接口时，拦截器中可以对请求头进行解析，获取cookie信息
服务调用方
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package top.codekiller.manager.upload.config; import feign.RequestInterceptor; import lombok.extern.slf4j.Slf4j; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import java.util.Enumeration; /** * @author codekiller * @date 2020/5/26 14:22 * * 自定义的请求头处理类，处理服务发送时的请求头； * 将服务接收到的请求头中的uniqueId和token字段取出来，并设置到新的请求头里面去转发给下游服务 * 比如A服务收到一个请求，请求头里面包含uniqueId和token字段，A处理时会使用Feign客户端调用B服务 * 那么uniqueId和token这两个字段就会添加到请求头中一并发给B服务； */ @Configuration @Slf4j public class FeignHeaderConfiguration { @Bean public RequestInterceptor requestInterceptor() { return requestTemplate -> { ServletRequestAttributes attrs = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); if (attrs != null ) { HttpServletRequest request = attrs.getRequest(); // 如果在Cookie内通过如下方式取 Cookie[] cookies = request.getCookies(); if (cookies != null && cookies.length > 0 ) { for (Cookie cookie : cookies) { requestTemplate.header(cookie.getName(), cookie.getValue()); System.out.println( "信息" +cookie.getName()+cookie.getValue()); } } else { log.warn( "FeignHeadConfiguration" , "获取Cookie失败！" ); }
// 如果放在header内通过如下方式取 Enumeration<String> headerNames = request.getHeaderNames(); if (headerNames != null ) { while (headerNames.hasMoreElements()) { String name = headerNames.nextElement(); String value = request.getHeader(name); /** * 遍历请求头里面的属性字段，将jsessionid添加到新的请求头中转发到下游服务 * */ if ( "jsessionid" .equalsIgnoreCase(name)) { log.debug( "添加自定义请求头key:" + name + ",value:" + value); requestTemplate.header(name, value); } else { log.debug( "FeignHeadConfiguration" , "非自定义请求头key:" + name + ",value:" + value + "不需要添加!" ); } } } else { log.warn( "FeignHeadConfiguration" , "获取请求头失败！" ); } } }; } } |
服务接受方
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//有些请求时从通过feign进行请求的，这一部分请求时不包含cookie信息的，因此我们要从请求头中获取 Enumeration<String> headerNames = request.getHeaderNames(); if (headerNames != null ) { while (headerNames.hasMoreElements()) { String name = headerNames.nextElement(); String value = request.getHeader(name); System.out.println( "header的信息" +name+ "::::" +value); if (name.equalsIgnoreCase( "MC_TOKEN" )){ //注意这里变成了小写 token=value; } } } |
运行的时候，我发现请求还是被拦截了，看了下打印信息，发现我的MC_TOKEN变成了小写，所以在字符串进行比较的时候要忽略大小写。
以下为扩展，仅仅记录一下
这样仍然有个问题：
在开启熔断器之后，方法里的attrs是null，因为熔断器默认的隔离策略是thread，也就是线程隔离，实际上接收到的对象和这个在发送给B不是一个线程，怎么办？
有一个办法，修改隔离策略hystrix测试数据mand.default.execution.isolation.strategy=SEMAPHORE，改为信号量的隔离模式，但是不推荐，因为thread是默认的，而且要命的是信号量模式，熔断器不生效，比如设置了熔断时间。
另一个办法：重写Feign的隔离策略
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import com.netflix.hystrix.HystrixThreadPoolKey; import com.netflix.hystrix.HystrixThreadPoolProperties; import com.netflix.hystrix.strategy.HystrixPlugins; import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy; import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariable; import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableLifecycle; import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier; import com.netflix.hystrix.strategy.executionhook.HystrixCommandExecutionHook; import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher; import com.netflix.hystrix.strategy.properties.HystrixPropertiesStrategy; import com.netflix.hystrix.strategy.properties.HystrixProperty; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; import org.springframework.web.context.request.RequestAttributes; import org.springframework.web.context.request.RequestContextHolder;
import java.util.concurrent.BlockingQueue; import java.util.concurrent.Callable; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit;
/** * 自定义Feign的隔离策略; * 在转发Feign的请求头的时候，如果开启了Hystrix，Hystrix的默认隔离策略是Thread(线程隔离策略)，因此转发拦截器内是无法获取到请求的请求头信息的，可以修改默认隔离策略为信号量模式：hystrix测试数据mand.default.execution.isolation.strategy=SEMAPHORE，这样的话转发线程和请求线程实际上是一个线程，这并不是最好的解决方法，信号量模式也不是官方最为推荐的隔离策略；另一个解决方法就是自定义Hystrix的隔离策略，思路是将现有的并发策略作为新并发策略的成员变量,在新并发策略中，返回现有并发策略的线程池、Queue；将策略加到Spring容器即可； * */ @Component public class FeignHystrixConcurrencyStrategyIntellif extends HystrixConcurrencyStrategy {
private static final Logger log = LoggerFactory.getLogger(FeignHystrixConcurrencyStrategyIntellif. class ); private HystrixConcurrencyStrategy delegate;
public FeignHystrixConcurrencyStrategyIntellif() { try { this .delegate = HystrixPlugins.getInstance().getConcurrencyStrategy(); if ( this .delegate instanceof FeignHystrixConcurrencyStrategyIntellif) { // Welcome to singleton hell... return ; } HystrixCommandExecutionHook commandExecutionHook = HystrixPlugins.getInstance().getCommandExecutionHook(); HystrixEventNotifier eventNotifier = HystrixPlugins.getInstance().getEventNotifier(); HystrixMetricsPublisher metricsPublisher = HystrixPlugins.getInstance().getMetricsPublisher(); HystrixPropertiesStrategy propertiesStrategy = HystrixPlugins.getInstance().getPropertiesStrategy(); this .logCurrentStateOfHystrixPlugins(eventNotifier, metricsPublisher, propertiesStrategy); HystrixPlugins.reset(); HystrixPlugins.getInstance().registerConcurrencyStrategy( this ); HystrixPlugins.getInstance().registerCommandExecutionHook(commandExecutionHook); HystrixPlugins.getInstance().registerEventNotifier(eventNotifier); HystrixPlugins.getInstance().registerMetricsPublisher(metricsPublisher); HystrixPlugins.getInstance().registerPropertiesStrategy(propertiesStrategy); } catch (Exception e) { log.error( "Failed to register Sleuth Hystrix Concurrency Strategy" , e); } }
private void logCurrentStateOfHystrixPlugins(HystrixEventNotifier eventNotifier, HystrixMetricsPublisher metricsPublisher, HystrixPropertiesStrategy propertiesStrategy) { if (log.isDebugEnabled()) { log.debug( "Current Hystrix plugins configuration is [" + "concurrencyStrategy [" + this .delegate + "]," + "eventNotifier [" + eventNotifier + "]," + "metricPublisher [" + metricsPublisher + "]," + "propertiesStrategy [" + propertiesStrategy + "]," + "]" ); log.debug( "Registering Sleuth Hystrix Concurrency Strategy." ); } }
@Override public <T> Callable<T> wrapCallable(Callable<T> callable) { RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes(); return new WrappedCallable<>(callable, requestAttributes); }
@Override public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey, HystrixProperty<Integer> corePoolSize, HystrixProperty<Integer> maximumPoolSize, HystrixProperty<Integer> keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) { return this .delegate.getThreadPool(threadPoolKey, corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); }
@Override public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolProperties threadPoolProperties) { return this .delegate.getThreadPool(threadPoolKey, threadPoolProperties); }
@Override public BlockingQueue<Runnable> getBlockingQueue( int maxQueueSize) { return this .delegate.getBlockingQueue(maxQueueSize); }
@Override public <T> HystrixRequestVariable<T> getRequestVariable(HystrixRequestVariableLifecycle<T> rv) { return this .delegate.getRequestVariable(rv); }
static class WrappedCallable<T> implements Callable<T> { private final Callable<T> target; private final RequestAttributes requestAttributes;
public WrappedCallable(Callable<T> target, RequestAttributes requestAttributes) { this .target = target; this .requestAttributes = requestAttributes; }
@Override public T call() throws Exception { try { RequestContextHolder.setRequestAttributes(requestAttributes); return target.call(); } finally { RequestContextHolder.resetRequestAttributes(); } } } } |
然后使用默认的熔断器隔离策略，也可以在拦截器内获取到上游服务的请求头信息了；
Feign调用存在的问题
① feign远程调用丢失请求头
问题描述：
当远程调用其他服务时，设置了拦截器判断用户是否登录，但是结果是即使用户登录了，也会显示用户没登录，原因在于远程调用时，发送的请求是一个新的情求，请求中并不存在cookie，而原始请求中是携带cookie的。
解决方案如下：
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@Configuration public class MallFeignConfig { @Bean ( "requestInterceptor" ) public RequestInterceptor requestInterceptor() { RequestInterceptor requestInterceptor = template -> { //1、使用RequestContextHolder拿到刚进来的请求数据 ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); if (requestAttributes != null ) { //老请求 HttpServletRequest request = requestAttributes.getRequest(); if (request != null ) { //2、同步请求头的数据（主要是cookie） //把老请求的cookie值放到新请求上来，进行一个同步 String cookie = request.getHeader( "Cookie" ); template.header( "Cookie" , cookie); } } }; return requestInterceptor; } } |
② 异步调用Feign丢失上下文问题
问题描述：
由于feign请求拦截器为新的request设置请求头底层是使用ThreadLocal保存刚进来的请求，所以在异步情况下，其他线程并不能获取到主线程的ThreadLocal，所以也拿不到请求。
解决：
先获取主线程的requestAttributes，再分别向其他线程中设置
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RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes(); CompletableFuture.runAsync(() ->{ RequestContextHolder.setRequestAttributes(requestAttributes); }); |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
原文链接：https://blog.csdn.net/qq_44766883/article/details/106358839
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