/*
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neon - Embeddable HTTP Server based on jdk.httpserver
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Copyright (C) 2024 Ulrich Hilger
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package de.uhilger.neon;
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import com.sun.net.httpserver.HttpExchange;
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import com.sun.net.httpserver.HttpHandler;
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import de.uhilger.neon.Action.Type;
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import de.uhilger.neon.entity.ActionDescriptor;
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import java.io.IOException;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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import java.lang.reflect.Parameter;
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import java.util.EnumMap;
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import java.util.HashMap;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Map;
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/**
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* Objekte der Klasse Handler nehmen Objekte entgegen die die Annotationen NeonActor enthalten.
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* Deren mit NeonMethod annotierten Methoden stellt der Handler via HTTP bereit.
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*
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* Wird ein Neon-Server mit der Klasse NeonFactory erzeugt, kann mit der Verwendung dieses Handlers
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* die NeonFactory den Server selbsttaetig erstellen, ohne zusaetzlichen Boilerplate Code, den eine
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* eigene Anwendung mitbringen muesste.
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*
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* @author Ulrich Hilger
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* @version 1, 6.2.2024
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*/
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public class Handler implements HttpHandler {
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private final Map<Type, Map> dispatcher;
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/**
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* Ein Objekt der Klasse Handler erzeugen
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*/
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public Handler() {
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dispatcher = new EnumMap<>(Type.class);
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//dispatcher.put(Type.GET, new HashMap<String, String>());
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//dispatcher.put(Type.PUT, new HashMap<String, String>());
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//dispatcher.put(Type.POST, new HashMap<String, String>());
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//dispatcher.put(Type.DELETE, new HashMap<String, String>());
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dispatcher.put(Type.GET, new HashMap<String, ActionDescriptor>());
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dispatcher.put(Type.PUT, new HashMap<String, ActionDescriptor>());
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dispatcher.put(Type.POST, new HashMap<String, ActionDescriptor>());
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dispatcher.put(Type.DELETE, new HashMap<String, ActionDescriptor>());
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}
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/**
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* Diesem Handler einen Actor hinzufuegen
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*
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* @param methodType HTTP Methode
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* @param route die Route, ueber die der Actor aufgerufen werden soll
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* @param className die Klasse, die die Methode enthaelt, die zur Verarbeitung der Route
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* ausgefuehrt werden soll
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*/
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public void setActor(Type methodType, String route, String className) {
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ActionDescriptor ad = new ActionDescriptor();
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ad.className = className;
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ad.routeParams = new HashMap<>();
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int pos = route.indexOf("{");
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if (pos > -1) {
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String paramStr = route.substring(pos);
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String[] params = paramStr
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.replaceAll("\\{", "")
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.replaceAll("\\}", "")
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.split("/");
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for (int i = 0; i < params.length; i++) {
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ad.routeParams.put(params[i], i);
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}
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ad.route = route.substring(0, pos - 1);
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} else {
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// Map kann leer bleiben
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ad.route = route;
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}
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//Logger.getLogger(Handler.class.getName())
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// .log(Level.INFO, "{0} {1} {2}", new Object[]{methodType, route, className});
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dispatcher.get(methodType).put(ad.route, ad);
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}
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/**
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* Eine Antwort senden
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*
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* Diese Methode kann ueberschrieben werden, falls die Antwort vor dem Senden noch weiter
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* bearbeiten werden soll.
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*
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* @param exchange das Objekt mit Informationen zu HTTP Anfrage und -Antwort
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* @param response das Ergebnisobjekt, das als Antwort gesendet werden soll
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* @throws IOException wenn die Antwort nicht gesendet werden kann
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*/
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public void respond(HttpExchange exchange, Object response) throws IOException {
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new HttpResponder().antwortSenden(exchange, HttpResponder.SC_OK, response.toString());
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}
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/**
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* Das Objekt abrufen, das auf die Routen verweist, die von diesem Handler beantwortet werden.
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*
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* eine Map<Type, Map<String, String>> GET - route1 - Klassenname GET - route2 - Klassenname PUT -
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* route1 - Klassenname PUT - route2 - Klassenname usw.
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*
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* @return das Dispatcher-Objekt dieses Handlers
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*/
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public Map<Type, Map> getDispatcher() {
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return dispatcher;
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}
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/**
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* Eine HTTP-Anfrage ausfuehren
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*
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* @param exchange das Objekt mit Informationen zu HTTP Anfrage und -Antwort
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* @throws IOException
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*/
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@Override
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public void handle(HttpExchange exchange) throws IOException {
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HttpHelper hh = new HttpHelper();
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String route = hh.getRouteString(exchange);
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Type requestMethod = Type.valueOf(exchange.getRequestMethod());
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/*
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Es wird erst geprueft, ob zu einer bestimmten Route
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ein Actor registriert wurde. Wenn kein Actor mit dieser
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Route existiert, wird geprueft, ob ein Actor
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mit der Route '/' vorhanden ist.
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*/
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boolean found = false;
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Object md = dispatcher.get(requestMethod);
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if (md instanceof Map) {
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int pos = route.lastIndexOf("/");
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Object o = ((Map) md).get(route);
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if (!(o instanceof ActionDescriptor)) {
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while (!found && (pos > -1)) {
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String routeRest = route.substring(0, pos);
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o = ((Map) md).get(routeRest);
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if (o instanceof ActionDescriptor) {
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found = true;
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handleRequest(exchange, o, routeRest, route.substring(routeRest.length()));
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}
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pos = routeRest.lastIndexOf("/");
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}
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} else {
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found = true;
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handleRequest(exchange, o, route, route);
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}
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if (!found) {
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o = dispatcher.get(requestMethod).get("/");
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if (o instanceof ActionDescriptor) {
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handleRequest(exchange, o, route, route);
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}
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}
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}
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}
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private void handleRequest(HttpExchange exchange, Object o, String route, String subroute) throws IOException {
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ActionDescriptor ad = (ActionDescriptor) o;
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String actorClassName = ad.className;
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try {
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Class actorClass = Class.forName(actorClassName);
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Method[] methods = actorClass.getMethods();
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for (Method method : methods) {
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Action action = method.getAnnotation(Action.class);
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if (action != null) {
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if (action.route().equals("/") || action.route().startsWith(route)) {
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Object[] actionArgs = getActionArgs(exchange, method, ad, subroute);
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Object actorObj = actorClass.getDeclaredConstructor().newInstance();
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addDataProvider(exchange, actorObj);
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Object antwort = method.invoke(actorObj, actionArgs);
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if (!action.handlesResponse()) {
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respond(exchange, antwort);
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}
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}
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}
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}
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} catch (ClassNotFoundException | NoSuchMethodException | SecurityException |
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InstantiationException | IllegalAccessException | IllegalArgumentException |
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InvocationTargetException ex) {
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// Klasse nicht gefunden. Muss das geloggt oder sonstwie behandel werden?
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}
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//}
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}
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private Object[] getActionArgs(HttpExchange exchange, Method method, ActionDescriptor ad, String subroute) {
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int count = method.getParameterCount();
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Parameter[] methodParams = method.getParameters();
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Object[] actionArgs = new Object[count];
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String[] routeParams = subroute.split("/");
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Map queryParams = new HashMap();
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if ((count > 1 && count > routeParams.length)
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|| (methodParams.length > 0 && !methodParams[0].getType().equals(HttpExchange.class))) {
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queryParams = new HttpHelper().getQueryMap(exchange);
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}
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int k = 0;
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for (Parameter methodParam : methodParams) {
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if (methodParam.getType().equals(HttpExchange.class)) {
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actionArgs[k] = exchange;
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} else {
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Integer i = ad.routeParams.getOrDefault(methodParam.getName(), -1);
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if (i < 0) {
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actionArgs[k] = queryParams.get(methodParam.getName());
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} else {
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actionArgs[k] = routeParams[i + 1];
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}
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}
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++k;
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}
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return actionArgs;
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}
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private void addDataProvider(HttpExchange exchange, Object actorObj) {
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if (actorObj instanceof DataConsumer) {
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DataConsumer consumer = (DataConsumer) actorObj;
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Object sdpListObj = exchange.getHttpContext().getAttributes().get("serverDataProviderList");
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if (sdpListObj instanceof List) {
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List sdpList = (List) sdpListObj;
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Iterator i = sdpList.iterator();
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while (i.hasNext()) {
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Object value = i.next();
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if (value instanceof DataProvider) {
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consumer.addDataProvider((DataProvider) value);
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}
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}
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}
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}
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}
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}
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