Java tutorial
/* This class implements the W3C SPARQL 1.1 Protocol * * Author: Luca Roffia (luca.roffia@unibo.it) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ package it.unibo.arces.wot.sepa.engine.protocol; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.URLDecoder; import java.net.UnknownHostException; import java.util.List; import org.apache.commons.io.IOUtils; import com.google.gson.JsonObject; import com.google.gson.JsonParser; import com.google.gson.JsonPrimitive; import com.sun.net.httpserver.*; import org.apache.logging.log4j.Logger; import org.apache.logging.log4j.LogManager; import it.unibo.arces.wot.sepa.commons.request.QueryRequest; import it.unibo.arces.wot.sepa.commons.request.Request; import it.unibo.arces.wot.sepa.commons.request.UpdateRequest; import it.unibo.arces.wot.sepa.commons.response.ErrorResponse; import it.unibo.arces.wot.sepa.commons.response.QueryResponse; import it.unibo.arces.wot.sepa.commons.response.Response; import it.unibo.arces.wot.sepa.engine.beans.SEPABeans; import it.unibo.arces.wot.sepa.engine.core.EngineProperties; import it.unibo.arces.wot.sepa.engine.scheduling.SchedulerInterface; import it.unibo.arces.wot.sepa.engine.scheduling.RequestResponseHandler.ResponseAndNotificationListener; import it.unibo.arces.wot.sepa.engine.security.CORSManager; /** * This class implements the SPARQL 1.1 Protocol * * @author Luca Roffia (luca.roffia@unibo.it) * @version 0.1 */ public class HTTPGate extends Thread implements HTTPGateMBean { /** The scheduler of the SEPA engine. */ protected SchedulerInterface scheduler; /** The HTTP servers */ protected static HttpServer updateServer = null; protected static HttpServer queryServer = null; /** The logger */ protected Logger logger = LogManager.getLogger("HTTPGate"); /** The HTTP timeout */ private long timeout = 2000; /** The number of current transactions */ protected long transactions = 0; /** The number of update transactions */ private long updateTransactions = 0; /** The number of query transactions */ private long queryTransactions = 0; /** * The engine properties * * @see EngineProperties */ protected EngineProperties properties; protected String mBeanName = "SEPA:type=HTTPGate"; private int failedTransactions = 0; /** * Instantiates a new HTTP gate. * * @param properties * the properties * @param scheduler * the scheduler * * @see SchedulerInterface * @see EngineProperties */ public HTTPGate(EngineProperties properties, SchedulerInterface scheduler) throws IllegalArgumentException { if (properties == null) { logger.fatal("Properties are null"); throw new IllegalArgumentException("Properties are null"); } if (scheduler == null) { logger.fatal("Scheduler is null"); throw new IllegalArgumentException("Scheduler is null"); } this.properties = properties; this.scheduler = scheduler; } /* * (non-Javadoc) * * @see java.lang.Thread#run() */ @Override public void run() { try { updateServer.wait(); queryServer.wait(); } catch (InterruptedException e) { logger.info(e.getMessage()); } } /* * (non-Javadoc) * * @see java.lang.Thread#start() */ @Override public void start() { this.setName("Starting..."); SEPABeans.registerMBean(mBeanName, this); try { updateServer = HttpServer.create(new InetSocketAddress(properties.getUpdatePort()), 0); if (properties.getQueryPort() != properties.getUpdatePort()) queryServer = HttpServer.create(new InetSocketAddress(properties.getQueryPort()), 0); else queryServer = updateServer; } catch (IOException e) { logger.fatal(e.getMessage()); System.exit(1); } updateServer.createContext(properties.getUpdatePath(), new SPARQLHandler()); updateServer.createContext("/echo", new EchoHandler()); updateServer.setExecutor(null); updateServer.start(); if (queryServer != updateServer) { queryServer.createContext(properties.getQueryPath(), new SPARQLHandler()); queryServer.createContext("/echo", new EchoHandler()); queryServer.setExecutor(null); queryServer.start(); } logger.info("HTTP gate started"); String host = "localhost"; try { host = InetAddress.getLocalHost().getHostName(); } catch (UnknownHostException e) { logger.warn(e.getMessage()); } logger.info("Listening for SPARQL UPDATES on https://" + host + ":" + properties.getUpdatePort() + properties.getUpdatePath()); logger.info("Listening for SPARQL QUERIES on https://" + host + ":" + properties.getQueryPort() + properties.getQueryPath()); } /* * (non-Javadoc) * * @see java.lang.Thread#interrupt() */ @Override public void interrupt() { logger.info("Kill signal received...stopping HTTP servers..."); if (updateServer != null) updateServer.stop(0); if (queryServer != null) queryServer.stop(0); super.interrupt(); } /* * (non-Javadoc) * * @see arces.unibo.SEPA.beans.HTTPGateMBean#getTransactions() */ @Override public long getTotalTransactions() { return this.transactions; } /* * (non-Javadoc) * * @see arces.unibo.SEPA.beans.HTTPGateMBean#getQueryTransactions() */ @Override public long getQueryTransactions() { return this.queryTransactions; } /* * (non-Javadoc) * * @see arces.unibo.SEPA.beans.HTTPGateMBean#getUpdateTransactions() */ @Override public long getUpdateTransactions() { return this.updateTransactions; } /** * Builds the echo response. * * @param exchange * the exchange * @return the json object */ private JsonObject buildEchoResponse(HttpExchange exchange) { JsonObject json = new JsonObject(); json.add("method", new JsonPrimitive(exchange.getRequestMethod().toUpperCase())); json.add("protocol", new JsonPrimitive(exchange.getProtocol())); JsonObject headers = new JsonObject(); for (String header : exchange.getRequestHeaders().keySet()) { headers.add(header, new JsonPrimitive(exchange.getRequestHeaders().get(header).toString())); } json.add("headers", headers); String body = ""; try { body = IOUtils.toString(exchange.getRequestBody(), "UTF-8"); } catch (IOException e) { logger.error(e.getMessage()); body = e.getMessage(); } json.add("body", new JsonPrimitive(body)); json.add("contextPath", new JsonPrimitive(exchange.getHttpContext().getPath())); if (exchange.getRequestURI().getQuery() != null) json.add("query", new JsonPrimitive(exchange.getRequestURI().getQuery())); return json; } /** * Echo request. * * @param exchange * the HTTP exchange information */ private void echoRequest(HttpExchange exchange) { JsonObject json = buildEchoResponse(exchange); if (!CORSManager.processCORSRequest(exchange)) { failureResponse(exchange, ErrorResponse.UNAUTHORIZED, "CORS origin not allowed"); return; } if (CORSManager.isPreFlightRequest(exchange)) sendResponse(exchange, 204, null); else sendResponse(exchange, 200, json.toString()); } /** * Failure response. * * @param exchange * the exchange * @param httpResponseCode * the http response code * @param responseBody * the response body */ protected void failureResponse(HttpExchange exchange, int httpResponseCode, String responseBody) { failedTransactions++; JsonObject json = buildEchoResponse(exchange); json.add("body", new JsonPrimitive(responseBody)); json.add("code", new JsonPrimitive(httpResponseCode)); sendResponse(exchange, httpResponseCode, json.toString()); } /** * Send response. * * @param exchange * the exchange * @param httpResponseCode * the http response code * @param response * the response */ protected void sendResponse(HttpExchange exchange, int httpResponseCode, String response) { logger.info("<< HTTP response (" + httpResponseCode + ") " + response); // UTF-8 byte[] out = null; if (response != null) { try { out = response.getBytes("UTF-8"); } catch (UnsupportedEncodingException e) { logger.error(e.getMessage()); } } try { if (out != null) { String contentType = "application/json"; List<String> types; if ((types = exchange.getRequestHeaders().get("Accept")) != null) { if (!types.isEmpty()) contentType = types.get(0); } exchange.getResponseHeaders().add("Content-Type", contentType); exchange.sendResponseHeaders(httpResponseCode, out.length); } else exchange.sendResponseHeaders(httpResponseCode, -1); } catch (IOException e) { logger.error(e.getMessage()); } try { if (out != null) exchange.getResponseBody().write(out, 0, out.length); // else exchange.getResponseBody().write(new byte[]{0},0,1); } catch (IOException e) { logger.error(e.getMessage()); } try { exchange.getResponseBody().close(); } catch (IOException e) { logger.error(e.getMessage()); } } /** * The Class EchoHandler. */ public class EchoHandler implements HttpHandler { /* * (non-Javadoc) * * @see * com.sun.net.httpserver.HttpHandler#handle(com.sun.net.httpserver. * HttpExchange) */ @Override public void handle(HttpExchange exchange) throws IOException { echoRequest(exchange); } } /** * The Class SPARQLHandler. */ public class SPARQLHandler implements HttpHandler { /* * (non-Javadoc) * * @see * com.sun.net.httpserver.HttpHandler#handle(com.sun.net.httpserver. * HttpExchange) */ @Override public void handle(HttpExchange httpExchange) throws IOException { logger.info(">> HTTP request"); transactions += 1; //execute.submit(new HTTPRequestProcessor(httpExchange)); new HTTPRequestProcessor(httpExchange).start(); } /** * The Class Running. */ class HTTPRequestProcessor extends Thread implements ResponseAndNotificationListener { /** The HTTP exchange. */ private HttpExchange httpExchange; /** The response. */ private Response response = null; /** * Instantiates a new running. * * @param httpExchange * the http exchange */ public HTTPRequestProcessor(HttpExchange httpExchange) { this.httpExchange = httpExchange; } /** * This method parse the HTTP request according to * <a href="https://www.w3.org/TR/sparql11-protocol/"> SPARQL 1.1 * Protocol</a> * * * * * <pre> * HTTP Method Query String Parameters Request Content Type Request Message Body *---------------------------------------------------------------------------------------------------------------------------------------- * query via GET | GET query (exactly 1) None None * | default-graph-uri (0 or more) * | named-graph-uri (0 or more) *---------------------------------------------------------------------------------------------------------------------------------------- * query via URL-encoded POST | POST None application/x-www-form-urlencoded URL-encoded, ampersand-separated query parameters. * | query (exactly 1) * | default-graph-uri (0 or more) * | named-graph-uri (0 or more) *---------------------------------------------------------------------------------------------------------------------------------------- * query via POST directly | POST default-graph-uri (0 or more) * | named-graph-uri (0 or more) application/sparql-query Unencoded SPARQL query string *---------------------------------------------------------------------------------------------------------------------------------------- * update via URL-encoded POST| POST None application/x-www-form-urlencoded URL-encoded, ampersand-separated query parameters. * | update (exactly 1) * | using-graph-uri (0 or more) * | using-named-graph-uri (0 or more) *---------------------------------------------------------------------------------------------------------------------------------------- * update via POST directly | POST using-graph-uri (0 or more) application/sparql-update Unencoded SPARQL update request string * using-named-graph-uri (0 or more) * </pre> * * @param httpExchange * the HTTP exchange information * @return the corresponding request (update or query), otherwise * null * * @see QueryRequest * @see UpdateRequest */ private Request parseSPARQL11(HttpExchange httpExchange) { switch (httpExchange.getRequestMethod().toUpperCase()) { case "GET": logger.debug("query via GET"); if (httpExchange.getRequestURI().getQuery() == null) { failureResponse(httpExchange, 400, "query is null"); return null; } String[] query = httpExchange.getRequestURI().getQuery().split("&"); for (String param : query) { String[] value = param.split("="); if (value[0].equals("query")) { queryTransactions++; String sparql = ""; try { sparql = URLDecoder.decode(value[1], "UTF-8"); } catch (UnsupportedEncodingException e) { failureResponse(httpExchange, 400, e.getMessage()); return null; } Integer token = 0; if (scheduler != null) token = scheduler.getToken(); if (token == -1) { failureResponse(httpExchange, ErrorResponse.FORBIDDEN, "No more tokens"); return null; } return new QueryRequest(token, sparql); } } failureResponse(httpExchange, 400, "Wrong query format: " + httpExchange.getRequestURI().getQuery()); return null; case "POST": String body = null; try { body = IOUtils.toString(httpExchange.getRequestBody(), "UTF-8"); } catch (IOException e) { logger.error(e.getMessage()); failureResponse(httpExchange, 400, e.getMessage()); return null; } if (httpExchange.getRequestHeaders().get("Content-Type").contains("application/sparql-query")) { logger.debug("query via POST directly"); queryTransactions++; Integer token = 0; if (scheduler != null) token = scheduler.getToken(); if (token == -1) { failureResponse(httpExchange, ErrorResponse.FORBIDDEN, "No more tokens"); return null; } return new QueryRequest(token, body); } if (httpExchange.getRequestHeaders().get("Content-Type") .contains("application/sparql-update")) { logger.debug("update via POST directly"); updateTransactions++; Integer token = 0; if (scheduler != null) token = scheduler.getToken(); if (token == -1) { failureResponse(httpExchange, ErrorResponse.FORBIDDEN, "No more tokens"); return null; } return new UpdateRequest(token, body); } if (httpExchange.getRequestHeaders().get("Content-Type") .contains("application/x-www-form-urlencoded")) { String decodedBody; try { decodedBody = URLDecoder.decode(body, "UTF-8"); } catch (UnsupportedEncodingException e) { logger.error(e.getMessage()); failureResponse(httpExchange, 400, e.getMessage()); return null; } String[] parameters = decodedBody.split("&"); for (String param : parameters) { String[] value = param.split("="); if (value[0].equals("query")) { logger.debug("query via URL-encoded"); queryTransactions++; Integer token = 0; if (scheduler != null) token = scheduler.getToken(); if (token == -1) { failureResponse(httpExchange, ErrorResponse.FORBIDDEN, "No more tokens"); return null; } return new QueryRequest(token, value[1]); } if (value[0].equals("update")) { logger.debug("update via URL-encoded"); updateTransactions++; Integer token = 0; if (scheduler != null) token = scheduler.getToken(); if (token == -1) { failureResponse(httpExchange, ErrorResponse.FORBIDDEN, "No more tokens"); return null; } return new UpdateRequest(token, value[1]); } } } logger.error( "Request MUST conform to SPARQL 1.1 Protocol (https://www.w3.org/TR/sparql11-protocol/)"); failureResponse(httpExchange, 400, "Request MUST conform to SPARQL 1.1 Protocol (https://www.w3.org/TR/sparql11-protocol/)"); return null; } logger.error("UNSUPPORTED METHOD: " + httpExchange.getRequestMethod().toUpperCase()); failureResponse(httpExchange, 400, "Unsupported method: " + httpExchange.getRequestMethod()); return null; } /** * Validate. * * @param request * the request * @return true, if successful */ private boolean validate(Request request) { // TODO SPARQL validation to be implemented return true; } /* * (non-Javadoc) * * @see java.lang.Thread#run() */ public void run() { if (!CORSManager.processCORSRequest(httpExchange)) { failureResponse(httpExchange, ErrorResponse.UNAUTHORIZED, "CORS origin not allowed"); return; } if (CORSManager.isPreFlightRequest(httpExchange)) { sendResponse(httpExchange, 204, null); return; } // Parsing SPARQL 1.1 request and attach a token Request request = parseSPARQL11(httpExchange); // Parsing failed if (request == null) { logger.warn("SPARQL 1.1 SE parsing failed"); failureResponse(httpExchange, ErrorResponse.BAD_REQUEST, "SPARQL 1.1 SE parsing failed"); return; } // Timestamp long startTime = System.nanoTime(); // Validate if (!validate(request)) { logger.error("SPARQL 1.1 SE validation failed " + request.getSPARQL()); failureResponse(httpExchange, 400, "SPARQL 1.1 validation failed " + request.getSPARQL()); scheduler.releaseToken(request.getToken()); return; } // Timestamp long validatedTime = System.nanoTime(); // Add request if (scheduler != null) scheduler.addRequest(request, this); else { logger.error("Scheduler is null"); failureResponse(httpExchange, 500, "Scheduler is null"); scheduler.releaseToken(request.getToken()); return; } // Waiting response logger.debug("Waiting response in " + timeout + " ms..."); try { Thread.sleep(timeout); } catch (InterruptedException e) { } // Timestamp long processedTime = System.nanoTime(); // Logging logger.debug("Request validated in " + (startTime - validatedTime) + " and processed in " + (validatedTime - processedTime) + " ns"); // Send HTTP response if (response == null) sendResponse(httpExchange, 408, "Timeout"); else { // Check response status JsonObject json = new JsonParser().parse(response.toString()).getAsJsonObject(); // Query response if (response.getClass().equals(QueryResponse.class)) sendResponse(httpExchange, json.get("code").getAsInt(), json.get("body").toString()); else sendResponse(httpExchange, json.get("code").getAsInt(), json.toString()); } scheduler.releaseToken(request.getToken()); } /* * (non-Javadoc) * * @see arces.unibo.SEPA.scheduling.RequestResponseHandler. * ResponseAndNotificationListener#notify(arces.unibo.SEPA.commons. * response.Response) */ @Override public void notify(Response response) { logger.debug("Response #" + response.getToken()); this.response = response; interrupt(); } } } @Override public long getTimeout() { return timeout; } @Override public void setTimeout(long t) { timeout = t; } @Override public long getFailedTransactions() { return failedTransactions; } }