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 * as indicated by the @author tags.
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 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package io.undertow.server.handlers.encoding;

import io.undertow.Handlers;
import io.undertow.server.HandlerWrapper;
import io.undertow.server.HttpHandler;
import io.undertow.server.HttpServerExchange;
import io.undertow.server.handlers.ResponseCodeHandler;
import io.undertow.server.handlers.builder.HandlerBuilder;

import java.util.Collections;
import java.util.Map;
import java.util.Set;

Handler that serves as the basis for content encoding implementations.

Encoding handlers are added as delegates to this handler, with a specified server side priority.

If a request comes in with no q value then then server will pick the handler with the highest priority as the encoding to use, otherwise the q value will be used to determine the correct handler.

If no handler matches then the identity encoding is assumed. If the identity encoding has been specifically disallowed due to a q value of 0 then the handler will set the response code 406 (Not Acceptable) and return.

Author:Stuart Douglas
/** * Handler that serves as the basis for content encoding implementations. * <p> * Encoding handlers are added as delegates to this handler, with a specified server side priority. * <p> * If a request comes in with no q value then then server will pick the handler with the highest priority * as the encoding to use, otherwise the q value will be used to determine the correct handler. * <p> * If no handler matches then the identity encoding is assumed. If the identity encoding has been * specifically disallowed due to a q value of 0 then the handler will set the response code * 406 (Not Acceptable) and return. * * @author Stuart Douglas */
public class EncodingHandler implements HttpHandler { private volatile HttpHandler next = ResponseCodeHandler.HANDLE_404; private volatile HttpHandler noEncodingHandler = ResponseCodeHandler.HANDLE_406; private final ContentEncodingRepository contentEncodingRepository; public EncodingHandler(final HttpHandler next, ContentEncodingRepository contentEncodingRepository) { this.next = next; this.contentEncodingRepository = contentEncodingRepository; } public EncodingHandler(ContentEncodingRepository contentEncodingRepository) { this.contentEncodingRepository = contentEncodingRepository; } @Override public void handleRequest(final HttpServerExchange exchange) throws Exception { AllowedContentEncodings encodings = contentEncodingRepository.getContentEncodings(exchange); if (encodings == null || !exchange.isResponseChannelAvailable()) { next.handleRequest(exchange); } else if (encodings.isNoEncodingsAllowed()) { noEncodingHandler.handleRequest(exchange); } else { exchange.addResponseWrapper(encodings); exchange.putAttachment(AllowedContentEncodings.ATTACHMENT_KEY, encodings); next.handleRequest(exchange); } } public HttpHandler getNext() { return next; } public EncodingHandler setNext(final HttpHandler next) { Handlers.handlerNotNull(next); this.next = next; return this; } public HttpHandler getNoEncodingHandler() { return noEncodingHandler; } public EncodingHandler setNoEncodingHandler(HttpHandler noEncodingHandler) { Handlers.handlerNotNull(noEncodingHandler); this.noEncodingHandler = noEncodingHandler; return this; } public static class Builder implements HandlerBuilder { @Override public String name() { return "compress"; } @Override public Map<String, Class<?>> parameters() { return Collections.emptyMap(); } @Override public Set<String> requiredParameters() { return Collections.emptySet(); } @Override public String defaultParameter() { return null; } @Override public HandlerWrapper build(Map<String, Object> config) { return new HandlerWrapper() { @Override public HttpHandler wrap(HttpHandler handler) { return new EncodingHandler(handler, new ContentEncodingRepository() .addEncodingHandler("gzip", new GzipEncodingProvider(), 100) .addEncodingHandler("deflate", new DeflateEncodingProvider(), 10)); } }; } } }