ratpack.http.internal.ContentNegotiationHandler.java Source code

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Here is the source code for ratpack.http.internal.ContentNegotiationHandler.java

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/*
 * Copyright 2014 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 ratpack.http.internal;

import com.google.common.base.Strings;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import io.netty.handler.codec.http.HttpHeaderNames;
import ratpack.handling.Context;
import ratpack.handling.Handler;

import java.util.Collections;
import java.util.List;
import java.util.Map;

public class ContentNegotiationHandler implements Handler {

    private final ImmutableMap<String, Handler> handlers;
    private final Handler noMatchHandler;

    public ContentNegotiationHandler(Map<String, Handler> handlers, Handler noMatchHandler) {
        this.handlers = ImmutableMap.copyOf(handlers);
        this.noMatchHandler = noMatchHandler;
    }

    @Override
    public void handle(Context context) throws Exception {
        if (handlers.isEmpty()) {
            noMatchHandler.handle(context);
            return;
        }

        List<String> types = Lists.newArrayList(handlers.keySet());
        String winner = types.get(0);
        Collections.reverse(types);

        String acceptHeader = context.getRequest().getHeaders().get(HttpHeaderNames.ACCEPT);
        if (!Strings.isNullOrEmpty(acceptHeader)) {
            winner = MimeParse.bestMatch(types, acceptHeader);
        }

        if (Strings.isNullOrEmpty(winner)) {
            noMatchHandler.handle(context);
        } else {
            context.getResponse().contentType(winner);
            handlers.get(winner).handle(context);
        }
    }
}