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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * JBoss, Home of Professional Open Source.
 * 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,
 *  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.undertow.server.handlers;

import io.undertow.server.ExchangeCompletionListener;
import io.undertow.server.HandlerWrapper;
import io.undertow.server.HttpHandler;
import io.undertow.server.HttpServerExchange;
import io.undertow.server.handlers.builder.HandlerBuilder;
import io.undertow.server.handlers.cache.LRUCache;
import io.undertow.server.session.Session;
import io.undertow.server.session.SessionConfig;
import io.undertow.server.session.SessionManager;
import io.undertow.util.DateUtils;
import io.undertow.util.HeaderMap;
import io.undertow.util.Headers;
import io.undertow.util.Methods;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Handler that builds up a cache of resources that a browsers requests, and uses
 * server push to push them when supported.
 *
 * @author Stuart Douglas
 */
public class LearningPushHandler implements HttpHandler {

    private static final String SESSION_ATTRIBUTE = "io.undertow.PUSHED_RESOURCES";
    private static final int DEFAULT_MAX_CACHE_ENTRIES = Integer.getInteger("io.undertow.handlers.learning-push.default-max-entries", 200);
    private static final int DEFAULT_MAX_CACHE_AGE = Integer.getInteger("io.undertow.handlers.learning-push.default-max-age", LRUCache.MAX_AGE_NO_EXPIRY);

    private final LRUCache> cache;

    private final HttpHandler next;
    private int maxPushCacheEntries;
    private int maxPushCacheAge;

    public LearningPushHandler(final HttpHandler next) {
        this(DEFAULT_MAX_CACHE_ENTRIES, DEFAULT_MAX_CACHE_AGE, next);
    }

    public LearningPushHandler(int maxPathEtries, int maxPathAge, HttpHandler next) {
        this.next = next;
        this.maxPushCacheEntries = maxPathEtries;
        this.maxPushCacheAge = maxPathAge;
        cache = new LRUCache<>(maxPathEtries, maxPathAge);
    }

    public LearningPushHandler(int maxPathEtries, int maxPathAge, int maxPushEtries, int maxPushAge, HttpHandler next) {
        this.next = next;
        this.maxPushCacheEntries = maxPushEtries;
        this.maxPushCacheAge = maxPushAge;
        cache = new LRUCache<>(maxPathEtries, maxPathAge);
    }

    @Override
    public void handleRequest(HttpServerExchange exchange) throws Exception {
        String fullPath;
        String requestPath;
        if(exchange.getQueryString().isEmpty()) {
            fullPath = exchange.getRequestURL();
            requestPath = exchange.getRequestPath();
        } else{
            fullPath = exchange.getRequestURL() + "?" + exchange.getQueryString();
            requestPath = exchange.getRequestPath() + "?" + exchange.getQueryString();
        }

        doPush(exchange, fullPath);
        String referrer = exchange.getRequestHeaders().getFirst(Headers.REFERER);
        if (referrer != null) {
            String accept = exchange.getRequestHeaders().getFirst(Headers.ACCEPT);
            if (accept == null || !accept.contains("text/html")) {
                //if accept contains text/html it generally means the user has clicked
                //a link to move to a new page, and is not a resource load for the current page
                //we only care about resources for the current page

                exchange.addExchangeCompleteListener(new PushCompletionListener(fullPath, requestPath, referrer));
            }
        }
        next.handleRequest(exchange);
    }

    private void doPush(HttpServerExchange exchange, String fullPath) {
        if (exchange.getConnection().isPushSupported()) {
            LRUCache toPush = cache.get(fullPath);
            if (toPush != null) {
                Session session = getSession(exchange);
                if (session == null) {
                    return;
                }
                LRUCache pushed = (LRUCache) session.getAttribute(SESSION_ATTRIBUTE);
                if (pushed == null) {
                    pushed = new LRUCache<>(this.maxPushCacheEntries, this.maxPushCacheAge);
                }
                for (String entryKey : toPush.keySet()) {
                    PushedRequest request = toPush.get(entryKey);
                    if(request == null) {
                        continue;
                    }
                    Object pushedKey = pushed.get(request.getPath());
                    boolean doPush = pushedKey == null;
                    if (!doPush) {
                        if (pushedKey instanceof String && !pushedKey.equals(request.getEtag())) {
                            doPush = true;
                        } else if (pushedKey instanceof Long && ((Long) pushedKey) != request.getLastModified()) {
                            doPush = true;
                        }
                    }
                    if (doPush) {
                        //pushResource will fill request headers.
                        exchange.getConnection().pushResource(request.getPath(), Methods.GET, request.getRequestHeaders());
                        if(request.getEtag() != null) {
                            pushed.add(request.getPath(), request.getEtag());
                        } else {
                            pushed.add(request.getPath(), request.getLastModified());
                        }
                    }
                }
                session.setAttribute(SESSION_ATTRIBUTE, pushed);
            }

        }
    }

    protected Session getSession(HttpServerExchange exchange) {
        SessionConfig sc = exchange.getAttachment(SessionConfig.ATTACHMENT_KEY);
        SessionManager sm = exchange.getAttachment(SessionManager.ATTACHMENT_KEY);
        if (sc == null || sm == null) {
            return null;
        }
        Session session = sm.getSession(exchange, sc);
        if (session == null) {
            return sm.createSession(exchange, sc);
        }
        return session;
    }

    private final class PushCompletionListener implements ExchangeCompletionListener {

        private final String fullPath;
        private final String requestPath;
        private final String referer;

        private PushCompletionListener(String fullPath, String requestPath, String referer) {
            this.fullPath = fullPath;
            this.requestPath = requestPath;
            this.referer = referer;
        }

        @Override
        public void exchangeEvent(HttpServerExchange exchange, NextListener nextListener) {
            if (exchange.getStatusCode() == 200 && referer != null) {
                //for now only cache 200 response codes
                String lmString = exchange.getResponseHeaders().getFirst(Headers.LAST_MODIFIED);
                String etag = exchange.getResponseHeaders().getFirst(Headers.ETAG);
                long lastModified = -1;
                if(lmString != null) {
                    Date dt = DateUtils.parseDate(lmString);
                    if(dt != null) {
                        lastModified = dt.getTime();
                    }
                }
                LRUCache pushes = cache.get(referer);
                if(pushes == null) {
                    synchronized (cache) {
                        pushes = cache.get(referer);
                        if(pushes == null) {
                            cache.add(referer, pushes = new LRUCache(maxPushCacheEntries, maxPushCacheAge));
                        }
                    }
                }
                pushes.add(fullPath, new PushedRequest(new HeaderMap(), requestPath, etag, lastModified));
            }

            nextListener.proceed();
        }
    }

    private static class PushedRequest {
        private final HeaderMap requestHeaders;
        private final String path;
        private final String etag;
        private final long lastModified;

        private PushedRequest(HeaderMap requestHeaders, String path, String etag, long lastModified) {
            this.requestHeaders = requestHeaders;
            this.path = path;
            this.etag = etag;
            this.lastModified = lastModified;
        }

        public HeaderMap getRequestHeaders() {
            return requestHeaders;
        }

        public String getPath() {
            return path;
        }

        public String getEtag() {
            return etag;
        }

        public long getLastModified() {
            return lastModified;
        }
    }

    public static class Builder implements HandlerBuilder {

        @Override
        public String name() {
            return "learning-push";
        }

        @Override
        public Map> parameters() {
            Map> params = new HashMap<>();
            params.put("max-age", Integer.class);
            params.put("max-entries", Integer.class);
            params.put("max-push-age", Integer.class);
            params.put("max-push-entries", Integer.class);
            return params;
        }

        @Override
        public Set requiredParameters() {
            return null;
        }

        @Override
        public String defaultParameter() {
            return null;
        }

        @Override
        public HandlerWrapper build(Map config) {
            final int maxAge = config.containsKey("max-age") ? (Integer)config.get("max-age") : DEFAULT_MAX_CACHE_AGE;
            final int maxEntries = config.containsKey("max-entries") ? (Integer)config.get("max-entries") : DEFAULT_MAX_CACHE_ENTRIES;
            final int maxPushAge = config.containsKey("max-push-age") ? (Integer)config.get("max-push-age") : DEFAULT_MAX_CACHE_AGE;
            final int maxPushEntries = config.containsKey("max-push-entries") ? (Integer)config.get("max-push-entries") : DEFAULT_MAX_CACHE_ENTRIES;
            return new HandlerWrapper() {
                @Override
                public HttpHandler wrap(HttpHandler handler) {
                    return new LearningPushHandler(maxEntries, maxAge, maxPushEntries, maxPushAge, handler);
                }
            };
        }
    }
}




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