骆驼在响应原始呼叫者时丢失 HTTP headers

Question

我已经创建了一个允许我转发 REST 呼叫的路由。一切进展顺利，除了我无法修改响应的 HTTP headers（实际上我什至无法在响应中保持不变）。

// My processor
private void remplacerLiensDansHeader(final Exchange exchange, final String rootUrlPivotJoram, final String rootUrlRemplacement) {
    // That is OK, I get the values just fine
    ArrayList<String> oldLinks = exchange.getIn().getHeader(HEADER_LINK, ArrayList.class);

    // This is also OK
    final List<String> newLinks = anciensLiens.stream().map(lien -> lien.replace(rootUrlPivotJoram, rootUrlRemplacement)).collect(toList());

    // No error, but apparently doesn't work
    exchange.getMessage().setHeader(HEADER_LINK, newLinks);
    exchange.getMessage().setHeader("test", "test");
}

// Route configuration
@Override
public void configure() throws Exception {
    this.from(RestRouteBuilder.endPoint(createProducerJoramConfiguration))
        .setExchangePattern(InOut)
        .removeHeader(Exchange.HTTP_URI)
        .toD(createProducerJoramConfiguration.getUrlDestination())
        .setHeader("test", () -> "test") // that doesn't work either
        .process(createProducerJoramConfiguration.getProcessor()); // this is the processor with the code above
}

这是我得到的响应（请注意，响应代码是 200，我认为这很奇怪，因为原始代码是 201）

curl -v -XPost --user "xxx:yyyy" http://localhost:10015/zzzz/webservices/xxxxx

*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 10015 (#0)
* Server auth using Basic with user 'xxx'
> Post /zzzzz/webservices/eeee HTTP/1.1
> Host: localhost:10015
> Authorization: Basic pppppppppppppppppp==
> User-Agent: curl/7.55.1
> Accept: */*
>
< HTTP/1.1 200
< Date: Tue, 31 Aug 2021 11:17:49 GMT
< Content-Type: application/octet-stream
< Content-Length: 0
<
* Connection #0 to host localhost left intact

我注意到两件事：

如果我在处理器中添加 body，那么 body 会出现在响应中，
如果我移除处理器，“原始响应”中的 headers 也不存在。

Answer 1

我不知道 header 你究竟失去了什么，但请注意 Camel HTTP component 有一个 默认 header 过滤器 （因为很多 Camel 组件都有）。

如果您不指定自己的 HeaderFilterStrategy, the default HttpHeaderFilterStrategy，则使用。

此默认筛选以下 headers：

content-length
content-type
主机
cache-control
连接
日期
语用
预告片
transfer-encoding
升级
通过
警告
驼色*
org.apache.camel*

使用这个过滤器，Camel 希望避免旧的 HTTP headers 仍然出现在传出请求中（可能有错误的数据）。

Camel headers 的过滤只是为了删除与 HTTP 无关的 Camel 特定内容。

Answer 2

实际上，问题出在 cxfrs 组件上。

我们设法在这里找到答案：请参阅：Response to REST client from Camel CXFRS route?

这是最终的解决方案。

感谢所有看过或回答的人，我希望这会对其他人有所帮助。

public class ModificationHeaderLinkProcessor implements Processor {

  private static final String HEADER_LINK = "Link";

  @Override
  public void process(final Exchange exchange) {
    List<String> newLinks= getNewLinks(exchange, oldUrl, newUrl);
    ResponseBuilder builder = createHttpResponse(exchange);
    builder.header(HEADER_LINK, newLinks);
    exchange.getIn().setBody(builder.build());
  }

  private List<String> getNewLinks(final Exchange exchange, final String oldUrl, final String newUrl) {
    ArrayList<String> oldLinks= exchange.getIn().getHeader(HEADER_LINK, ArrayList.class);
    return oldLinks.stream().map(link-> link.replace(oldUrl, newUrl)).collect(toList());
  }

  private ResponseBuilder createHttpResponse(final Exchange exchange) {
    ResponseBuilder builder = Response.status(getHttpStatusCode(exchange))
                                      .entity(exchange.getIn().getBody());
    clearUselessHeader(exchange);
    exchange.getIn().getHeaders().forEach(builder::header);
    return builder;
  }

  private void clearUselessHeader(final Exchange exchange) {
    exchange.getIn().removeHeader(HEADER_LINK);
    exchange.getIn().removeHeaders("Camel*");
  }

  private Integer getHttpStatusCode(final Exchange exchange) {
    return exchange.getIn().getHeader(exchange.HTTP_RESPONSE_CODE, Integer.class);
  }

  private final String getPropertiesValue(CamelContext camelContext, String key) {
    return camelContext.getPropertiesComponent().resolveProperty(key).orElseThrow();
  }
}

骆驼在响应原始呼叫者时丢失 HTTP headers

Camel loosing HTTP headers on response to original caller

java

routes

http-headers

apache-camel

esb