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Core Knot.x module consisting of Server, Repositories, Splitter, Assembler and Gateway.
There is a newer version: 1.6.0
/*
 * Copyright (C) 2016 Cognifide Limited
 *
 * 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 io.knotx.server;

import io.knotx.dataobjects.KnotContext;
import io.knotx.reactivex.proxy.KnotProxy;
import io.knotx.server.configuration.KnotxServerOptions;
import io.knotx.server.configuration.RoutingEntry;
import io.vertx.core.Handler;
import io.vertx.core.logging.Logger;
import io.vertx.core.logging.LoggerFactory;
import io.vertx.reactivex.core.Vertx;
import io.vertx.reactivex.ext.web.RoutingContext;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;

class KnotxEngineHandler implements Handler {

  private static final Logger LOGGER = LoggerFactory.getLogger(KnotxEngineHandler.class);

  private Vertx vertx;
  private KnotxServerOptions configuration;
  private String address;
  private Map routing;
  private Map proxies;

  private KnotxEngineHandler(Vertx vertx, KnotxServerOptions configuration, String address,
      Map routing) {
    this.vertx = vertx;
    this.configuration = configuration;
    this.address = address;
    this.routing = routing;
    this.proxies = new HashMap<>();
  }

  static KnotxEngineHandler create(Vertx vertx, KnotxServerOptions configuration,
      String address,
      Map routing) {
    return new KnotxEngineHandler(vertx, configuration, address, routing);
  }

  @Override
  public void handle(RoutingContext context) {
    try {
      handleRoute(context, address, routing);
    } catch (Exception ex) {
      LOGGER.error("Something very unexpected happened", ex);
      context.fail(ex);
    }
  }

  private void handleRoute(final RoutingContext context, final String address,
      final Map routing) {
    KnotContext knotContext = context.get(KnotContext.KEY);

    proxies.computeIfAbsent(address,
        adr -> KnotProxy.createProxyWithOptions(vertx, adr, configuration.getDeliveryOptions()))
        .rxProcess(knotContext)
        .doOnSuccess(ctx -> context.put(KnotContext.KEY, ctx))
        .subscribe(ctx -> {
              if (StringUtils.isNotBlank(ctx.getTransition())) {
                doTransition(context, ctx, routing);
              } else {
                doEndProcessing(context, ctx);
              }
            },
            error -> {
              LOGGER.error("Error happened while communicating with {} engine", error, address);
              context.fail(error);
            }
        );
  }
  private void doTransition(RoutingContext context, KnotContext ctx,
      final Map routing) {
    RoutingEntry entry = routing.get(ctx.getTransition());
    if (entry != null) {
      handleRoute(context, entry.getAddress(), entry.getOnTransition());
    } else {
      LOGGER.debug(
          "Received transition '{}' from '{}'. No further routing available for the transition. Go to the response generation.",
          ctx.getTransition(), address);
      // last knot can return default transition
      context.put(KnotContext.KEY, ctx);
      context.next();
    }
  }

  private void doEndProcessing(RoutingContext context, KnotContext ctx) {
    LOGGER.debug("Request processing finished by {} Knot. Go to the response generation",
        address);
    context.put(KnotContext.KEY, ctx);
    context.next();
  }

  ;

}