/*
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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.Headers;
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import com.sun.net.httpserver.HttpExchange;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.OutputStream;
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import java.nio.file.Files;
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import java.text.SimpleDateFormat;
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import java.util.Date;
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/**
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* Helfer zur Beantwortung von HTTP-Anfragen
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*
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* @author Ulrich Hilger
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* @version 1, 03.06.2021
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*/
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public class HttpResponder {
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/* Headernamen */
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public static final String ACCEPT_RANGES_HEADER = "Accept-Ranges";
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public static final String CONTENT_LENGTH = "Content-Length";
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public static final String CONTENT_TYPE = "Content-Type";
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public static final String LAST_MODIFIED_DATE_HEADER = "Last-Modified";
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/* Statuscodes */
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public static final int SC_OK = 200;
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public static final int SC_NOT_FOUND = 404;
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public static final int SC_METHOD_NOT_ALLOWED = 405;
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public static final int SC_UNPROCESSABLE_ENTITY = 422;
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public static final int SC_INTERNAL_SERVER_ERROR = 500;
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/* String Konstanten */
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public static final String STR_BYTES = "bytes";
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public static final String STR_NOT_FOUND = " not found.";
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public static final String LM_PATTERN = "EEE, dd MMM yyyy HH:mm:ss zzz";
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/**
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* Den Inhalt einer Datei ausliefern
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*
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* @param e das Objekt mit Methoden zur Untersuchung der Anfrage sowie zum
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* Anfertigen und Senden der Antwort
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* @param file die Datei, deren Inhalt ausgeliefert werden soll
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* @throws IOException falls etwas schief geht entsteht dieser Fehler
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*/
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public void serveFile(HttpExchange e, File file) throws IOException {
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if (file.exists()) {
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setHeaders(e, file);
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e.getResponseHeaders().set(CONTENT_LENGTH, Long.toString(file.length()));
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e.sendResponseHeaders(SC_OK, file.length());
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if(HttpHelper.HTTP_GET.equalsIgnoreCase(e.getRequestMethod())) {
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InputStream in = new FileInputStream(file);
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OutputStream os = e.getResponseBody();
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write(in, os);
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finish(in, os);
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}
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} else {
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sendNotFound(e, file.getName());
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}
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}
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public void write(InputStream in, OutputStream out) throws IOException {
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byte[] b = new byte[4096];
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int bytesRead = in.read(b);
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while (bytesRead > -1) {
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out.write(b, 0, bytesRead);
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bytesRead = in.read(b);
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}
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}
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public void finish(InputStream in, OutputStream out) throws IOException {
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in.close();
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finish(out);
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}
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public void finish(OutputStream out) throws IOException {
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out.flush();
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out.close();
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}
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/**
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* Die Header erzeugen, die unabhängig davon, ob der ganze
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* Inhalt oder nur Teile davon ausgeliefert werden sollen, in der
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* Antwort stehen sollen
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*
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* @param e das Objekt mit Methoden zur Untersuchung der Anfrage sowie zum
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* Anfertigen und Senden der Antwort
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* @param file die Datei, für die die Header gelten
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* @throws IOException falls etwas schief geht entsteht dieser Fehler
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*/
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public void setHeaders(HttpExchange e, File file) throws IOException {
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Headers resHeaders = e.getResponseHeaders();
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resHeaders.add(ACCEPT_RANGES_HEADER, STR_BYTES);
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String mimeType = Files.probeContentType(file.toPath());
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if (mimeType != null) {
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resHeaders.add(CONTENT_TYPE, mimeType);
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}
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SimpleDateFormat sdf = new SimpleDateFormat(LM_PATTERN);
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Date date = new Date(file.lastModified());
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resHeaders.add(LAST_MODIFIED_DATE_HEADER, sdf.format(date));
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}
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/**
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* Eine nicht gefunden Antwort senden
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*
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* @param e das Objekt mit Methoden zur Untersuchung der Anfrage sowie zum
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* Anfertigen und Senden der Antwort
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* @param fname Name der Datei, die nicht gefunden wurde
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* @throws IOException falls etwas schief geht entsteht dieser Fehler
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*/
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public void sendNotFound(HttpExchange e, String fname) throws IOException {
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antwortSenden(e, SC_NOT_FOUND, fname + STR_NOT_FOUND);
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}
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public void antwortSenden(HttpExchange exchange, int code, String antwort) throws IOException {
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byte[] bytes = antwort.getBytes();
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exchange.sendResponseHeaders(code, bytes.length);
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OutputStream os = exchange.getResponseBody();
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os.write(bytes);
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finish(os);
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}
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}
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