OverviewResource.java

package com.mediture.truchart.rest.resources;

import java.util.*;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.jboss.resteasy.core.Dispatcher;
import org.jboss.resteasy.core.ResourceInvoker;
import org.jboss.resteasy.core.ResourceMethodInvoker;
import org.jboss.resteasy.core.ResourceMethodRegistry;
import org.jboss.resteasy.util.WeightedMediaType;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

/**
 * A resource that displays a list of available
 * endpoints (which is helpful to see for debugging purposes).
 *
 * @author Patrick Stegmann
 * http://stackoverflow.com/questions/19795391/list-all-exposed-available-endpoints-of-resteasy-service
 * https://gist.github.com/wonderb0lt/10731371
 */
@Path("/api/v1/routes")
public class OverviewResource {
    private static final class MethodDescription {
        private String method;
        private String fullPath;
        private MediaType[] produces;
        private MediaType[] consumes;

        public MethodDescription(String method, String fullPath, MediaType[] produces, MediaType[] consumes) {
            super();
            this.method = method;
            this.fullPath = fullPath;
            this.produces = produces;
            this.consumes = consumes;
        }

    }

    private static final class ResourceDescription {
        private String basePath;
        private List<MethodDescription> calls;

        public ResourceDescription(String basePath) {
            this.basePath = basePath;
            this.calls = Lists.newArrayList();
        }

        public void addMethod(String path, ResourceMethodInvoker method) {
            for (String verb : method.getHttpMethods()) {
                calls.add(new MethodDescription(verb, path, method.getProduces(), method.getConsumes()));
            }
        }

        private static String mostPreferredOrNull(List<WeightedMediaType> preferred) {
            if (preferred.isEmpty()) {
                return null;
            }
            else {
                return preferred.get(0).toString();
            }
        }

        public static List<ResourceDescription> fromBoundResourceInvokers(Set<Map.Entry<String, List<ResourceInvoker>>> bound) {
            Map<String, ResourceDescription> descriptions = Maps.newHashMap();

            for (Map.Entry<String, List<ResourceInvoker>> entry : bound) {
                ResourceMethodInvoker aMethod = (ResourceMethodInvoker) entry.getValue().get(0);
                String basePath = aMethod.getMethod().getDeclaringClass().getAnnotation(Path.class).value();
                String thisPath = Optional.ofNullable(aMethod.getMethod()
                        .getAnnotation(Path.class))
                        .map(a -> basePath + a.value())
                        .orElse(basePath);

                if (!descriptions.containsKey(thisPath)) {
                    descriptions.put(thisPath, new ResourceDescription(thisPath));
                }

                for (ResourceInvoker invoker : entry.getValue()) {
                    ResourceMethodInvoker methodinvoker = (ResourceMethodInvoker) invoker;
                    descriptions.get(thisPath).addMethod(basePath, methodinvoker);
                }
            }

            return Lists.newLinkedList(descriptions.values());
        }
    }

    @GET
    @Path("/")
    @Produces(MediaType.APPLICATION_JSON)
    public List<ResourceDescription> getAvailableEndpoints(@Context Dispatcher dispatcher) {
        return ResourceDescription.fromBoundResourceInvokers(getResoureDescriptions((ResourceMethodRegistry) dispatcher.getRegistry()));
    }

    @GET
    @Path("/")
    @Produces(MediaType.TEXT_HTML)
    public Response getAvailableEndpointsHtml(@Context Dispatcher dispatcher) {
        // Yeah, yeah, HTML per StringBuilder. I can't be bovvered to make a JSP :D
        StringBuilder sb = new StringBuilder();
        List<ResourceDescription> descriptions = getAvailableEndpoints(dispatcher);

        sb.append("<h1>").append("REST interface overview").append("</h1>");

        for (ResourceDescription resource : descriptions) {
            sb.append("<h2>").append(resource.basePath).append("</h2>");
            sb.append("<ul>");

            for (MethodDescription method : resource.calls) {
                sb.append("<li> ").append(method.method).append(" ");
                sb.append("<strong>").append(method.fullPath).append("</strong>");

                sb.append("<ul>");

                if (method.consumes != null) {
                    sb.append("<li>").append("Consumes: ").append(Arrays.asList(method.consumes)).append("</li>");
                }

                if (method.produces != null) {
                    sb.append("<li>").append("Produces: ").append(Arrays.asList(method.produces)).append("</li>");
                }

                sb.append("</ul>");
            }

            sb.append("</ul>");
        }

        return Response.ok(sb.toString()).build();

    }

    private Set<Map.Entry<String, List<ResourceInvoker>>> getResoureDescriptions(ResourceMethodRegistry registry) {
        return registry.getBounded().entrySet();
    }
}