io.undertow.server.handlers.cache.CacheHandler Maven / Gradle / Ivy
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* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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,
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* See the License for the specific language governing permissions and
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*/
package io.undertow.server.handlers.cache;
import io.undertow.Handlers;
import io.undertow.server.ConduitWrapper;
import io.undertow.server.HttpHandler;
import io.undertow.server.HttpServerExchange;
import io.undertow.server.handlers.ResponseCodeHandler;
import io.undertow.server.handlers.encoding.AllowedContentEncodings;
import io.undertow.util.ConduitFactory;
import org.xnio.conduits.StreamSinkConduit;
import static io.undertow.util.Headers.CONTENT_LENGTH;
/**
*
* Handler that attaches a cache to the exchange, a handler can query this cache to see if the
* cache has a cached copy of the content, and if so have the cache serve this content automatically.
*
*
* @author Stuart Douglas
*/
public class CacheHandler implements HttpHandler {
private final DirectBufferCache cache;
private volatile HttpHandler next = ResponseCodeHandler.HANDLE_404;
public CacheHandler(final DirectBufferCache cache, final HttpHandler next) {
this.cache = cache;
this.next = next;
}
public CacheHandler(final DirectBufferCache cache) {
this.cache = cache;
}
@Override
public void handleRequest(final HttpServerExchange exchange) throws Exception {
final ResponseCache responseCache = new ResponseCache(cache, exchange);
exchange.putAttachment(ResponseCache.ATTACHMENT_KEY, responseCache);
exchange.addResponseWrapper(new ConduitWrapper() {
@Override
public StreamSinkConduit wrap(final ConduitFactory factory, final HttpServerExchange exchange) {
if(!responseCache.isResponseCachable()) {
return factory.create();
}
final AllowedContentEncodings contentEncodings = exchange.getAttachment(AllowedContentEncodings.ATTACHMENT_KEY);
if(contentEncodings != null) {
if(!contentEncodings.isIdentity()) {
//we can't cache content encoded responses, as we have no idea how big they will end up being
return factory.create();
}
}
String lengthString = exchange.getResponseHeaders().getFirst(CONTENT_LENGTH);
if(lengthString == null) {
//we don't cache chunked requests
return factory.create();
}
int length = Integer.parseInt(lengthString);
final CachedHttpRequest key = new CachedHttpRequest(exchange);
final DirectBufferCache.CacheEntry entry = cache.add(key, length);
if (entry == null || entry.buffers().length == 0 || !entry.claimEnable()) {
return factory.create();
}
if (!entry.reference()) {
entry.disable();
return factory.create();
}
return new ResponseCachingStreamSinkConduit(factory.create(), entry, length);
}
});
next.handleRequest(exchange);
}
public HttpHandler getNext() {
return next;
}
public CacheHandler setNext(final HttpHandler next) {
Handlers.handlerNotNull(next);
this.next = next;
return this;
}
}