限制 Jersey 中的路径媒体类型映射

Question

我已经为我的 Jersey 应用程序配置 MEDIA_TYPE_MAPPINGS。不幸的是，这会导致我的应用程序中的通用上传服务出现一些问题。

@PUT
@Path("files/{filename}")
@Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
public Response uploadFile(
    @PathParam("filename") @NotNull @Size(max = 240) String filename, DataSource dataSource)

如果有人上传 .../files/file.xml 扩展名被删除。

有没有办法告诉 Jersey 跳过对该资源的过滤？

编辑：经过peeskillet的回答，我的假设得到了证实。我已提交改进请求：https://java.net/jira/browse/JERSEY-2780

Answer 1

首先，这绝不是一个错误。这是预期的行为。媒体类型映射的目的与处理文件无关，而是一种内容协商的替代形式，用于设置 headers 可能不可用的情况，例如在浏览器中。

虽然不在官方规范中，但此功能是规范最终发布之前的草案的一部分。大多数实现决定以一种或另一种方式包含它。 Jersey 恰好让你配置它。所以可以看到here in the spec in 3.7.1 Request Preprocessing

Set

M = {config.getMediaTypeMappings().keySet()}

L = {config.getLanguageMappings().keySet()}

m = null

l = null

Where config is an instance of the application-supplied subclass of ApplicationConfig.

For each extension (a . character followed by one or more alphanumeric characters) e in the final path segment scanning from right to left:

(a) Remove the leading ‘.’ character from e

(b) If m is null and e is a member of M then remove the corresponding extension from the effective request URI and set m = e.

(c) Else if l is null and e is a member of L then remove the corresponding extension from the effective request URI and set l = e. Else go to step 4

If m is not null then set the value of the Accept header to config.getExtensionMappings().get(m)

3(b) 基本上是说应该从请求的 URI 中删除扩展名，而 4 是说应该有一些扩展名映射可以将 json（扩展名）映射到 application/json 并将其设置为 Accept header。你可以从不同的测试中看到，这种行为

@POST
@Path("/files/{file}")
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
public Response doTest(@PathParam("file") String fileName, @Context HttpHeaders headers) {
    String accept = headers.getHeaderString(HttpHeaders.ACCEPT);
    return Response.ok(fileName + "; Accept: " + accept).build();
}
...

Map<String, MediaType> map = new HashMap<>();
map.put("xml", MediaType.APPLICATION_XML_TYPE);
resourceCnfig.property(ServerProperties.MEDIA_TYPE_MAPPINGS, map);

curl -v http://localhost:8080/api/mapping/files/file.xml -X POST
Result: file; Accept: application/xml

如果我们注释掉那个配置属性，你会看到 Accept header 还没有设置。

curl -v http://localhost:8080/api/mapping/files/file.xml -X POST
Result: file.xml; Accept: */**

话虽这么说...

当您配置 ServerProperties.MEDIA_TYPE_MAPPINGS、org.glassfish.jersey.server.filter.UriConnegFilter is the filter used for this feature. You can see in the source code in line 204 and 211 时，过滤器正在剥离扩展

path = new StringBuilder(path).delete(index, index + suffix.length() + 1).toString();
...
rc.setRequestUri(uriInfo.getRequestUriBuilder().replacePath(path).build(new Object[0]));

所以没有办法配置这个（至少我从查看源代码可以看出），所以我们必须扩展 class，覆盖 filter 方法和至少取出实际进行替换的最后一行，然后注册过滤器。这是我为使其正常工作所做的工作。我只是简单地复制并粘贴了过滤器中的代码，并注释掉了替换扩展名的那一行

import java.io.IOException;
import java.util.List;
import java.util.Map;
import javax.annotation.Priority;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.PreMatching;
import javax.ws.rs.core.Configuration;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.PathSegment;
import javax.ws.rs.core.UriInfo;
import org.glassfish.jersey.server.filter.UriConnegFilter;

@PreMatching
@Priority(3000)
public class MyUriConnegFilter extends UriConnegFilter {

    public MyUriConnegFilter(@Context Configuration config) {
        super(config);
    }

    public MyUriConnegFilter(Map<String, MediaType> mediaTypeMappings, 
                             Map<String, String> languageMappings) {
        super(mediaTypeMappings, languageMappings);
    }

    @Override
    public void filter(ContainerRequestContext rc)
            throws IOException {
        UriInfo uriInfo = rc.getUriInfo();

        String path = uriInfo.getRequestUri().getRawPath();
        if (path.indexOf('.') == -1) {
            return;
        }
        List<PathSegment> l = uriInfo.getPathSegments(false);
        if (l.isEmpty()) {
            return;
        }
        PathSegment segment = null;
        for (int i = l.size() - 1; i >= 0; i--) {
            segment = (PathSegment) l.get(i);
            if (segment.getPath().length() > 0) {
                break;
            }
        }
        if (segment == null) {
            return;
        }
        int length = path.length();

        String[] suffixes = segment.getPath().split("\.");
        for (int i = suffixes.length - 1; i >= 1; i--) {
            String suffix = suffixes[i];
            if (suffix.length() != 0) {
                MediaType accept = (MediaType) this.mediaTypeMappings.get(suffix);
                if (accept != null) {
                    rc.getHeaders().putSingle("Accept", accept.toString());

                    int index = path.lastIndexOf('.' + suffix);
                    path = new StringBuilder(path).delete(index, index + suffix.length() + 1).toString();
                    suffixes[i] = "";
                    break;
                }
            }
        }
        for (int i = suffixes.length - 1; i >= 1; i--) {
            String suffix = suffixes[i];
            if (suffix.length() != 0) {
                String acceptLanguage = (String) this.languageMappings.get(suffix);
                if (acceptLanguage != null) {
                    rc.getHeaders().putSingle("Accept-Language", acceptLanguage);

                    int index = path.lastIndexOf('.' + suffix);
                    path = new StringBuilder(path).delete(index, index + suffix.length() + 1).toString();
                    suffixes[i] = "";
                    break;
                }
            }
        }
        if (length != path.length()) {
            //rc.setRequestUri(uriInfo.getRequestUriBuilder().replacePath(path).build(new Object[0]));
        }
    }
}

然后配置它

Map<String, MediaType> map = new HashMap<>();
map.put("xml", MediaType.APPLICATION_XML_TYPE);
map.put("json", MediaType.APPLICATION_JSON_TYPE);
resourceConfig.register(new MyUriConnegFilter(map, null));

curl -v http://localhost:8080/api/mapping/files/file.xml -X POST
Result: file.xml; Accept: application/xml

curl -v http://localhost:8080/api/mapping/files/file.json -X POST
Result: file.json; Accept: application/json

限制 Jersey 中的路径媒体类型映射

Limit path media type mappings in Jersey

java

jersey

mapping

jersey-2.0

media-type

话虽这么说...