在我们的rest服务中,需要暴露一个中间件的接口给用户,但是需要经过rest服务的认证,这是典型的网关使用场景。可以引入网关组件来搞定,但是引入zuul等中间件会增加系统复杂性,这里实现一个超轻量级的网关,只实现请求转发,认证等由rest服务的spring security来搞定。
如何进行请求转发呢? 熟悉网络请求的同学应该很清楚,请求无非就是请求方式、HTTP header,以及请求body,我们将这些信息取出来,透传给转发的url即可。
举例:
/graphdb/ 转发到 Graph_Server/
获取转发目的地址:
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private String createRedictUrl(HttpServletRequest request, String routeUrl, String prefix) {
String queryString = request.getQueryString();
return routeUrl + request.getRequestURI().replace(prefix, "") +
(queryString != null ? "?" + queryString : "");
}
解析请求头和内容
然后从request中提取出header、body等内容,构造一个 RequestEntity
,后续可以用 RestTemplate
来请求。
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private RequestEntity createRequestEntity(HttpServletRequest request, String url) throws URISyntaxException, IOException {
String method = request.getMethod();
HttpMethod httpMethod = HttpMethod.resolve(method);
MultiValueMap headers = parseRequestHeader(request);
byte[] body = parseRequestBody(request);
return new RequestEntity<>(body, headers, httpMethod, new URI(url));
}
private byte[] parseRequestBody(HttpServletRequest request) throws IOException {
InputStream inputStream = request.getInputStream();
return StreamUtils.copyToByteArray(inputStream);
}
private MultiValueMap parseRequestHeader(HttpServletRequest request) {
HttpHeaders headers = new HttpHeaders();
List headerNames = Collections.list(request.getHeaderNames());
for (String headerName : headerNames) {
List headerValues = Collections.list(request.getHeaders(headerName));
for (String headerValue : headerValues) {
headers.add(headerName, headerValue);
}
}
return headers;
}
透明转发
最后用 RestTemplate
来实现请求:
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private ResponseEntity route(RequestEntity requestEntity) {
RestTemplate restTemplate = new RestTemplate();
return restTemplate.exchange(requestEntity, String.class);
}
全部代码
以下是轻量级转发全部代码:
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import org.springframework.http.*;
import org.springframework.stereotype.Service;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StreamUtils;
import org.springframework.web.client.RestTemplate;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Collections;
import java.util.List;
Spring 集成
Spring Controller,RequestMapping里把GET \ POST\PUT\DELETE 支持的请求带上,就能实现转发了。
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https://www.cnblogs.com/xiaoqi/p/spring-boot-route.html
Original: https://www.cnblogs.com/softidea/p/14000457.html
Author: 沧海一滴
Title: spring boot实现超轻量级网关(反向代理、转发)
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