Spring Cloud Gateway:在路径中使用查询参数值

Question

在Spring Cloud Gateway中，有没有一种方法可以获取查询参数的值并在目标的路径中使用它？

例如

/inbound/path?someId=123

导致呼叫

/outbound/123/detail

我试过以下几种：

predicates:
- Path=/inbound/path
- Query=someId, (?<theId>/?.*)
filters:
- SetPath=/outbound/{theId}/detail

predicates:
- Path=/inbound/path
- Query=someId, {theId}
filters:
- SetPath=/outbound/{theId}/detail

predicates:
- Path=/inbound/path
filters:
- RewritePath=/inbound/path?someId=(?<theId>/?.*) /outbound/${theId}/detail

Answer 1

我为此编写了一个自定义路由谓词。

配置：

predicates:
- Path=/inbound/path
- QueryParam=someId
filters:
- SetPath=/outbound/{someId}/detail

自定义代码：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.gateway.handler.predicate.AbstractRoutePredicateFactory;
import org.springframework.cloud.gateway.handler.predicate.GatewayPredicate;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.server.ServerWebExchange;
import javax.validation.constraints.NotEmpty;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
/**
* Shamelessly inspired by QueryRoutePredicateFactory
* This will store the first value of the query parameter as a template variable under the same name
*/
public class QueryParamRoutePredicateFactory extends AbstractRoutePredicateFactory<QueryParamRoutePredicateFactory.Config> {
public static final String PARAM_KEY = "param";
private final Logger logger = LoggerFactory.getLogger(getClass());
public QueryParamRoutePredicateFactory() {
super(QueryParamRoutePredicateFactory.Config.class);
}
@Override
public List<String> shortcutFieldOrder() {
return Arrays.asList(PARAM_KEY);
}
@Override
public Predicate<ServerWebExchange> apply(QueryParamRoutePredicateFactory.Config config) {
return new GatewayPredicate() {
@Override
public boolean test(ServerWebExchange exchange) {
if (exchange.getRequest().getQueryParams().containsKey(config.param)) {
String value = exchange.getRequest().getQueryParams().getFirst(config.param);
logger.debug("Saving {}={}", config.param, value);
ServerWebExchangeUtils.putUriTemplateVariables(exchange, Map.of(config.param, value));
return true;
}
logger.debug("Query parameter {} not found.", config.param);
return false;
}
@Override
public String toString() {
return String.format("Query: param=%s", config.getParam());
}
};
}
@Validated
public static class Config {
@NotEmpty
private String param;
public String getParam() {
return param;
}
public QueryParamRoutePredicateFactory.Config setParam(String param) {
this.param = param;
return this;
}
}
}