org.wisdom.api.http.Negotiation Maven / Gradle / Ivy
/*
* #%L
* Wisdom-Framework
* %%
* Copyright (C) 2013 - 2014 Wisdom Framework
* %%
* 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.
* #L%
*/
package org.wisdom.api.http;
import com.google.common.net.MediaType;
import java.util.Collection;
import java.util.Map;
/**
* A class providing methods to ease the selection of negotiated content.
*/
public final class Negotiation {
private Negotiation() {
// Avoid direct instantiation.
}
/**
* 'Accept' based negotiation.
* This method determines the result to send to the client based on the 'Accept' header of the request.
* The returned result is enhanced with the 'Vary' header set to {@literal Accept}.
*
* This methods retrieves the accepted media type in their preference order and check,
* one-by-one if the given results match one of them. So, it ensures we get the most acceptable result.
*
* @param results the set of result structured as follows: mime-type -> result. The mime-type (keys) must be
* valid mime type such as 'application/json' or 'text/html'.
* @return the selected result, or a result with the status {@link org.wisdom.api.http.Status#NOT_ACCEPTABLE} if
* none of the given results match the request.
*/
public static Result accept(Map results) {
Context context = Context.CONTEXT.get();
if (context == null) {
throw new IllegalStateException("Negotiation cannot be achieved outside of a request");
}
Collection accepted = context.request().mediaTypes();
// accepted cannot be empty, if the header is missing text/* is added.
for (MediaType media : accepted) {
// Do we have a matching key.
for (Map.Entry entry : results.entrySet()) {
MediaType input = MediaType.parse(entry.getKey());
if (input.is(media)) {
return entry.getValue().with(HeaderNames.VARY, HeaderNames.ACCEPT);
}
}
}
return Results.status(Status.NOT_ACCEPTABLE);
}
//TODO Negotiation based on the Languages, Content-Type...
}