feign 源码解析 && RequestInterceptor

参考：Feign源码解析

2021-12-24 16:27:48

package com.amoros.pumpkin.scorecard.infrastructure.config;

import com.amoros.cloud.core.AgentId;
import com.amoros.pumpkin.scorecard.common.constants.BizConstants;
import feign.RequestInterceptor;
import feign.RequestTemplate;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

/**
 * feign 请求拦截器。可以添加 headers
 * 2021-12-09 16:36:05
 */
@Component
@Slf4j
public class FeignRequestInterceptor implements RequestInterceptor {

    @Override
    public void apply(RequestTemplate requestTemplate) {
        String agentUid = AgentId.getAgentUid();
        if (StringUtils.isNotEmpty(agentUid)) {
            log.info("FeignRequestInterceptor feign拦截器，请求 AgentId = " + agentUid);
            requestTemplate.header(BizConstants.X_CHANGE_DATA_SOURCE, agentUid);
            return;
        }

        log.warn("FeignRequestInterceptor feign拦截器，请求 AgentId 未设置");
    }
}

2022-08-15 11:03:46

package com.amoros.hawkeye.config;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.amoros.hawkeye.context.TenantIdHolder;
import com.amoros.hawkeye.context.UserIdHolder;
import com.amoros.hawkeye.util.MDCUtil;
import lombok.extern.slf4j.Slf4j;
import top.legendscloud.common.base.ComResp;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * Hawkeye 拦截器
 */
@Slf4j
@WebFilter(filterName = "com.amoros.hawkeye.config.HawkeyeFilter", urlPatterns = {
        "/bi/*",
        "/actionConfig/*",
        "/actionRelDetailConfig/*",
        "/ruleConfig/*",
        "/scheduleConfig/*",
        "/tenantConfig/*"
})
public class HawkeyeFilter implements Filter {

    /**
     * 租户ID
     */
    public static final String TENANT_ID = "X-Change-Data-Source";

    /**
     * 用户ID
     */
    public static final String USER_ID = "X-User-Id";

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;

        MDCUtil.set(req);
        log.info("=========================================== HawkeyeFilter 拦截了...");

        String tenantId = req.getHeader(TENANT_ID);

        // 所有请求租户ID必须有
        if (StrUtil.isBlank(tenantId)) {
            String errorMessage = StrUtil.format("请设置 header '{}'", TENANT_ID);
            log.error(errorMessage);

            ComResp comResp = new ComResp.Builder().fail().msg(errorMessage).build();

            resp.setContentType("application/json;charset=utf8");
            resp.getWriter().write(JSONUtil.toJsonStr(comResp));
            return;
        }
        TenantIdHolder.set(tenantId);
        UserIdHolder.set(req.getHeader(USER_ID));

        // 执行下一个拦截器
        chain.doFilter(request, response);
    }
}

package com.amoros.hawkeye.config;

import cn.hutool.core.lang.Assert;
import cn.hutool.core.util.StrUtil;
import com.amoros.hawkeye.context.JobContext;
import com.amoros.hawkeye.context.TenantIdHolder;
import com.amoros.hawkeye.context.UserIdHolder;
import com.amoros.hawkeye.exception.HawkeyeException;
import com.amoros.hawkeye.util.MDCUtil;
import datart.api.config.DatartProperties;
import feign.RequestInterceptor;
import feign.RequestTemplate;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.util.Enumeration;

/**
 * <pre>
 *     web -> me -> feign
 *     把别人调用我的 header 放入 我调用别人的 feign 请求中
 * </pre>
 */
@Slf4j
@Component
public class HawkeyeFeignRequestInterceptor implements RequestInterceptor {

    /**
     * 租户ID
     */
    public static final String TENANT_ID = "X-Change-Data-Source";

    /**
     * 用户ID
     */
    public static final String USER_ID = "X-User-Id";

    @Override
    public void apply(RequestTemplate template) {
        // datart 服务，直接跳过
        String serviceName = template.feignTarget().name();
        if (DatartProperties.SERVICE_NAME.equals(serviceName)) {
            return;
        }


        try {
            // 0、traceId
            MDCUtil.set(template);

            // 1、mvc.header => feign.header
            // headerCopy(template);

            // 2、Holder.get => headers.put
            String tenantId = TenantIdHolder.get();
            if (StrUtil.isNotBlank(tenantId)) {
                log.info("feign 拦截：TenantIdHolder 设置租户id=[{}]", tenantId);
                template.removeHeader(TENANT_ID);
                template.header(TENANT_ID, tenantId);
                template.header(USER_ID, UserIdHolder.get());
                return;
            }

            // 3、TENANT_ID 未设置 => throw
            Assert.notEmpty(template.headers().get(TENANT_ID), "请设置租户id");
        } catch (Exception e) {
            throw new HawkeyeException("设置feign请求头信息异常", e);
        }
    }

    /**
     * 当前上下文中的请求header 放入 feign请求header
     */
    private void headerCopy(RequestTemplate template) {
        // 1、Job => return
        if (JobContext.getJobExecutionContext() != null) {
            return;
        }

        // 2、Controller =>      mvc.headers => feign.headers 
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        Enumeration headerNames = request.getHeaderNames();
        if (headerNames != null) {
            while (headerNames.hasMoreElements()) {
                String name = (String) headerNames.nextElement();
                String values = request.getHeader(name);
                template.header(name, values);
            }
        }
    }
}