Springcloud的版本是Greenwich.SR2,Springboot版本是2.1.6.release.
需求是这样的,Zuul不想返回下游服务返回部分header字段到前端。如下List-1所示,这个ZuulFilter要在SendResponseFilter之前执行,filterType是POST类型,重要的是run()中重新设置了RequestContext中zuulResponseHeaders的值。List-1中所示,zuul将不会返回xxx这个header。
List-1
public class ResponseHeaderFilter extends ZuulFilter {
private static final String XXX = "xxx";
@Override
public String filterType() {
return FilterConstants.POST_TYPE;
}
@Override
public int filterOrder() {
//要在SendResponseFilter之前执行
return FilterConstants.SEND_RESPONSE_FILTER_ORDER - 10;
}
@Override
public boolean shouldFilter() {
return true;
}
@Override
public Object run() throws ZuulException {
RequestContext context = RequestContext.getCurrentContext();
List<Pair<String, String>> filteredResponseHeaders = new ArrayList<>();
List<Pair<String, String>> zuulResponseHeaders = context.getZuulResponseHeaders();
if (zuulResponseHeaders != null) {
for (Pair<String, String> it : zuulResponseHeaders) {
if (!it.first().contains(XXX)) {
Pair<String, String> pair = new Pair<>(it.first(), it.second());
filteredResponseHeaders.add(pair);
}
}
}
context.put("zuulResponseHeaders", filteredResponseHeaders);
return null;
}
}
难点在于,JSR的Servlet规范中,resposne只有addHeader和setHeader,没有removeHeader,而且setHeader并不是看上的覆盖值,而是追加,这与它的底层实现有关。看了下Zuul的github issue,看到了这个:https://github.com/Netflix/zuul/issues/326 ,测试有效。