tango.git - Ulrich Hilger Code Repository

ulrich

2021-04-07 2442f9e5aabc718681795e9fba3e4aadaca460cd

commit \| author \| age
b379f5	1	/*
5f70da	2	Mediazentrale - Personal Media Center
U	3	Copyright (C) 2021 Ulrich Hilger
	4
	5	This program is free software: you can redistribute it and/or modify
	6	it under the terms of the GNU Affero General Public License as
	7	published by the Free Software Foundation, either version 3 of the
	8	License, or (at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU Affero General Public License for more details.
	14
	15	You should have received a copy of the GNU Affero General Public License
	16	along with this program. If not, see <https://www.gnu.org/licenses/>.
b379f5	17	*/
U	18	package de.uhilger.mediaz.api;
	19
	20	import com.google.gson.Gson;
	21	import com.sun.net.httpserver.HttpExchange;
	22	import com.sun.net.httpserver.HttpHandler;
	23	import de.uhilger.mediaz.App;
f45e20	24	import static de.uhilger.mediaz.App.RB_EP_LISTE;
b379f5	25	import de.uhilger.mediaz.Server;
2b5c60	26	import static de.uhilger.mediaz.Server.RB_SLASH;
081606	27	import de.uhilger.mediaz.store.FileStorage;
b1bf96	28	import de.uhilger.mediaz.entity.Entity;
b379f5	29	import java.io.BufferedReader;
081606	30	import java.io.File;
b379f5	31	import java.io.IOException;
U	32	import java.io.InputStream;
	33	import java.io.InputStreamReader;
	34	import java.io.OutputStream;
2b5c60	35	import java.util.List;
081606	36	import java.util.logging.Level;
b379f5	37	import java.util.logging.Logger;
U	38
	39	/**
2597cd	40	* HttpHandler fuer die Verwaltung von Entitaeten der Mediazentrale
5f70da	41	*
U	42	* @author Ulrich Hilger
	43	* @version 1, 5.4.2021
b379f5	44	*/
86bbf7	45	public class StorageHandler extends AbstractHandler implements HttpHandler {
b379f5	46
081606	47	private static final Logger logger = Logger.getLogger(StorageHandler.class.getName());
b379f5	48
U	49
	50	/*
2b5c60	51	Das REST-Muster sieht je Entitaet fuenf Faelle vor (Beispiel Ablageort):
U	52
	53	1. HTTP GET Ablageort/[Name]: Liefere den Ablageort als JSON
	54	2. HTTP GET Ablageort/: Liefere einer Liste von Ablageorten als JSON
	55	3. HTTP PUT: schreibe einen neuen Ablageort auf die Platte
	56	4. HTTP POST: schreibe Aenderungen auf die Platte
	57	5. HTTP DELETE: loesche den Ablageort
b379f5	58
U	59	Beispiele:
2b5c60	60
U	61	HTTP GET an /mz/api/store/Ablageort/
f45e20	62	liefert alle Ablageort-Objekte
U	63
	64	HTTP GET an /mz/api/store/Ablageort/liste/
2b5c60	65	liefert eine Liste der Namen vorhandener Ablageorte
b379f5	66
U	67	HTTP GET an /mz/api/store/Ablageort/Katalog
	68	liest den Ablageort namens "Katalog"
	69
	70	HTTP POST an /mz/api/store/Ablageort
081606	71	schreibt den neuen Ablageort im Body der Anfrage (Neu)
b379f5	72
U	73	HTTP PUT an /mz/api/store/Ablageort
	74	sucht den Ablageort mit dem Namen laut Body der Anfrage
081606	75	und schreibt den Inhalt aus der Anfrage in die Datei (Aenderung)
b379f5	76
U	77	HTTP DELETE an /mz/api/store/Ablageort/Katalog
	78	löscht den Ablageort namens "Katalog"
	79
	80	*/
	81
2b5c60	82	/** Name der HTTP Methode GET */
b379f5	83	public static final String HTTP_GET = "GET";
2b5c60	84
U	85	/** Name der HTTP Methode PUT */
b379f5	86	public static final String HTTP_PUT = "PUT";
2b5c60	87
U	88	/** Name der HTTP Methode POST */
b379f5	89	public static final String HTTP_POST = "POST";
2b5c60	90
U	91	/** Name der HTTP Methode DELETE */
b379f5	92	public static final String HTTP_DELETE = "DELETE";
f45e20	93
U	94	public static final String EP_LISTE = "liste/";
b379f5	95
U	96	@Override
	97	public void handle(HttpExchange e) throws IOException {
	98	String method = e.getRequestMethod();
5f70da	99	String response = "";
U	100	int code = 200;
b379f5	101	switch(method) {
U	102	case HTTP_GET:
5f70da	103	String json = lesen(e);
U	104	if(json != null) {
	105	response = json;
	106	} else {
	107	response = "nicht gefunden";
	108	code = 404;
	109	}
b379f5	110	break;
U	111
	112	case HTTP_PUT:
2b5c60	113	response = aendern(e);
b379f5	114	break;
U	115
	116	case HTTP_POST:
5f70da	117	response = neu(e);
b379f5	118	break;
U	119
	120	case HTTP_DELETE:
2b5c60	121	boolean geloescht = loeschen(e);
U	122	if(geloescht) {
	123	response = "geloescht";
	124	} else {
	125	response = "nicht geloescht";
	126	}
b379f5	127	break;
U	128	}
b29119	129	logger.fine(response);
5f70da	130	e.sendResponseHeaders(code, response.length());
b379f5	131	OutputStream os = e.getResponseBody();
U	132	os.write(response.getBytes());
	133	os.close();
b1bf96	134	}
U	135
5f70da	136	private String neu(HttpExchange e) throws IOException {
2597cd	137	return schreiben(e, false);
U	138	}
	139
	140	private String aendern(HttpExchange e) throws IOException {
	141	return schreiben(e, true);
	142	}
	143
	144	private String schreiben(HttpExchange e, boolean overwrite) throws IOException {
b1bf96	145	String path = e.getRequestURI().toString();
U	146	String[] elems = path.split(App.getRs(Server.RB_SLASH));
	147	String type = elems[elems.length - 1];
	148	String body = bodyLesen(e);
5f70da	149	String filename = "";
b1bf96	150	FileStorage fs = new FileStorage(App.getInitParameter(App.getRs(App.RB_AP_CONF)));
U	151	Gson gson = new Gson();
cf6509	152	logger.log(Level.FINE, "type: {0}, token: {1}", new Object[]{type, fs.typeFromName(type).getType().getTypeName()});
b1bf96	153	Object o = gson.fromJson(body, fs.typeFromName(type).getType());
U	154	if(o instanceof Entity) {
2597cd	155	Object antwortObjekt = fs.write((Entity) o, overwrite);
b1bf96	156	if(antwortObjekt instanceof File) {
U	157	File file = (File) antwortObjekt;
b29119	158	logger.log(Level.FINE, "Datei {0} geschrieben.", file.getAbsolutePath());
5f70da	159	filename = file.getName();
2597cd	160	return type + FileHandler.STR_BLANK + filename;
b1bf96	161	}
U	162	}
2597cd	163	return type + FileHandler.STR_BLANK + " Operation 'neu' fuer bereits existierende Entitaet.";
b1bf96	164	}
U	165
2597cd	166	/*
2b5c60	167	private String aendern(HttpExchange e) throws IOException {
U	168	return neu(e); // einstweilen wird einfach ueberschrieben
b1bf96	169	}
2597cd	170	*/
b1bf96	171
2b5c60	172	private boolean loeschen(HttpExchange e) {
5f70da	173	String path = e.getRequestURI().toString();
U	174	String[] elems = path.split(App.getRs(Server.RB_SLASH));
	175	String type = elems[elems.length - 2];
	176	String elemName = elems[elems.length - 1];
	177	FileStorage fs = new FileStorage(App.getInitParameter(App.getRs(App.RB_AP_CONF)));
2b5c60	178	return fs.delete(type, elemName);
U	179	}
	180
	181	private String lesen(HttpExchange e) {
	182	String path = e.getRequestURI().toString();
	183	String[] elems = path.split(App.getRs(Server.RB_SLASH));
	184	FileStorage fs = new FileStorage(App.getInitParameter(App.getRs(App.RB_AP_CONF)));
	185	if(path.endsWith(App.getRs(RB_SLASH))) {
f45e20	186	List list = null;
U	187	if(path.endsWith(App.getRs(RB_EP_LISTE))) {
	188	String type = elems[elems.length - 2];
	189	logger.fine(type);
	190	list = fs.list(type);
	191	} else {
	192	String type = elems[elems.length - 1];
	193	logger.fine(type);
	194	list = fs.listObjects(type);
	195	}
a43e1a	196	return jsonWithEnclosingType(list);
2b5c60	197	} else {
U	198	String type = elems[elems.length - 2];
	199	String elemName = elems[elems.length - 1];
	200	return fs.readJson(type, elemName);
	201	}
a43e1a	202	}
b379f5	203
U	204	private String bodyLesen(HttpExchange e) throws IOException {
	205	InputStream is = e.getRequestBody();
	206	BufferedReader r = new BufferedReader(new InputStreamReader(is));
	207	StringBuilder sb = new StringBuilder();
	208	String line = r.readLine();
	209	while(line != null) {
	210	sb.append(line);
	211	line = r.readLine();
	212	}
	213	r.close();
	214	String json = sb.toString();
b29119	215	logger.log(Level.FINE, "json: {0}", json);
b379f5	216	return json;
U	217	}
	218	}