edu.amherst.acdc.exts.ore.OreRouter Maven / Gradle / Ivy

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/*
 * Copyright Amherst College
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.amherst.acdc.exts.ore;

import static edu.amherst.acdc.exts.ore.OreHeaders.ORE_ACCEPT;
import static edu.amherst.acdc.exts.ore.OreHeaders.ORE_SUBJECT;
import static java.util.Optional.ofNullable;
import static org.apache.camel.Exchange.CONTENT_TYPE;
import static org.apache.camel.Exchange.HTTP_METHOD;
import static org.apache.camel.Exchange.HTTP_RESPONSE_CODE;
import static org.apache.camel.Exchange.HTTP_URI;

import java.util.Optional;

import org.apache.camel.builder.RouteBuilder;
import org.apache.jena.riot.Lang;
import org.apache.jena.riot.RDFLanguages;

/**
 * A content router for handling ORE extension requests.
 *
 * @author Aaron Coburn
 */
public class OreRouter extends RouteBuilder {

    private static final String DEFAULT_CONTENT_TYPE = "text/turtle";
    private static final String HTTP_QUERY_CONTEXT = "context";
    private static final String FCREPO_URI = "CamelFcrepoUri";
    private static final String FCREPO_BASE_URL = "CamelFcrepoBaseUrl";

    /**
     * Configure the message route workflow.
     */
    public void configure() throws Exception {

        from("jetty:http://{{rest.host}}:{{rest.port}}{{rest.prefix}}?" +
              "sendServerVersion=false&optionsEnabled=true&httpMethodRestrict=GET,OPTIONS")
          .routeId("OreRouter")
          .removeHeader("User-Agent")
          .process(e -> e.getIn().setHeader(FCREPO_URI,
                      e.getIn().getHeader(HTTP_QUERY_CONTEXT,
                          e.getIn().getHeader("Apix-Ldp-Resource"))))
          .setHeader(FCREPO_BASE_URL).simple("{{fcrepo.baseUrl}}")
          .choice()
            .when(header(HTTP_METHOD).isEqualTo("OPTIONS"))
              .setHeader(CONTENT_TYPE).constant("text/turtle")
              .setHeader("Allow").constant("GET,OPTIONS")
              .to("language:simple:resource:classpath:options.ttl")
            .when(header(HTTP_QUERY_CONTEXT).startsWith(header(FCREPO_BASE_URL)))
              .to("direct:get");

        from("direct:get").routeId("OreGet")
          .setHeader(ORE_ACCEPT, header("Accept"))
          .log("Building ORE Object ${body}")
          .setBody().header(FCREPO_URI)
          .to("seda:recurse?timeout={{ore.timeout}}")
          .removeHeader("breadcrumbId")
          .process(exchange -> {
              final String contentType = exchange.getIn().getHeader(ORE_ACCEPT, String.class);
              final Optional rdfLang = ofNullable(contentType).map(RDFLanguages::contentTypeToLang)
                                .map(Lang::getName);
              exchange.getIn().setHeader(CONTENT_TYPE, rdfLang.isPresent() ? contentType : DEFAULT_CONTENT_TYPE);
          })
          .to("direct:serialize");

        from("seda:recurse?concurrentConsumers={{ore.concurrency}}")
          .routeId("OreBuildRecursive")
          .setHeader(FCREPO_URI, body())
          .to("direct:getResource")
          .filter(header(HTTP_RESPONSE_CODE).isEqualTo(200))
            .log("Getting related resources for ${headers[CamelFcrepoUri]}")
            .to("direct:parse")
            .setHeader(ORE_SUBJECT).header(FCREPO_URI)
            .to("direct:members")
            .split(body(), new ModelAggregator())
            .to("seda:recurse?timeout={{ore.timeout}}");

        from("direct:getResource").routeId("OreResource")
          .removeHeader("breadcrumbId")
          .removeHeader("Accept")
          .removeHeaders("CamelHttp*")
          .setHeader("Accept").header(ORE_ACCEPT)
          .setHeader(HTTP_URI).header(FCREPO_URI)
          .to("http4://localhost?username={{fcrepo.authUsername}}"
                  + "&password={{fcrepo.authPassword}}&throwExceptionOnFailure=false");
    }
}