Feign调用服务时丢失Cookie和Header信息的解决方案
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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
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;
@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);
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
//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.command.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
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;
@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：
@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
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编程网。
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