io.pivotal.poc.dispatcher.MessageDispatcher.java Source code

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Here is the source code for io.pivotal.poc.dispatcher.MessageDispatcher.java

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/*
 * Copyright 2016 the original author or authors.
 *
 * 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.pivotal.poc.dispatcher;

import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.cloud.stream.binding.BinderAwareChannelResolver;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Controller;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;

/**
 * @author Mark Fisher
 */
@Controller
public class MessageDispatcher {

    private final BinderAwareChannelResolver resolver;

    private final Set<String> requestHeadersToMap;

    public MessageDispatcher(BinderAwareChannelResolver resolver, Set<String> requestHeadersToMap) {
        this.resolver = resolver;
        this.requestHeadersToMap = requestHeadersToMap;
    }

    @RequestMapping(path = "/{topic}", method = RequestMethod.POST, consumes = { "text/*", "application/json" })
    @ResponseStatus(HttpStatus.ACCEPTED)
    public ResponseEntity<?> handleRequest(@PathVariable String topic, @RequestBody String body,
            @RequestHeader HttpHeaders requestHeaders) {
        String id = sendMessage(topic, body, requestHeaders);
        return ResponseEntity.ok(id);
    }

    private String sendMessage(String topic, Object body, HttpHeaders requestHeaders) {
        MessageChannel channel = resolver.resolveDestination(topic + ".input");
        MessageBuilder<?> builder = MessageBuilder.withPayload(body);
        builder.setHeader(MessageHeaders.CONTENT_TYPE, requestHeaders.getContentType());
        for (Map.Entry<String, List<String>> entry : requestHeaders.entrySet()) {
            String headerName = entry.getKey();
            if (requestHeadersToMap.contains(headerName)) {
                builder.setHeaderIfAbsent(headerName,
                        StringUtils.collectionToCommaDelimitedString(entry.getValue()));
            }
        }
        Message<?> message = builder.build();
        channel.send(message);
        return message.getHeaders().getId().toString();
    }
}