Java tutorial
/* * Copyright (C) 2012 Roderick Baier * * 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 org.zlwima.emurgency.staticclientapp.websockets; import java.net.URI; import java.util.HashMap; import java.util.LinkedHashMap; import java.util.Map; import org.apache.commons.codec.binary.Base64; public class WebSocketHandshake { private URI url = null; private String protocol = null; private String nonce = null; private Map<String, String> extraHeaders = null; public WebSocketHandshake(URI url, String protocol, Map<String, String> extraHeaders) { this.url = url; this.protocol = protocol; this.extraHeaders = extraHeaders; this.nonce = this.createNonce(); } public byte[] getHandshake() { String path = url.getPath(); String host = url.getHost(); if (url.getPort() != -1) { host += ":" + url.getPort(); } LinkedHashMap<String, String> header = new LinkedHashMap<String, String>(); header.put("Host", host); header.put("Upgrade", "websocket"); header.put("Connection", "Upgrade"); header.put("Sec-WebSocket-Version", String.valueOf(WebSocket.getVersion())); header.put("Sec-WebSocket-Key", this.nonce); if (this.protocol != null) { header.put("Sec-WebSocket-Protocol", this.protocol); } if (this.extraHeaders != null) { for (String fieldName : this.extraHeaders.keySet()) { // Only checks for Field names with the exact same text, // but according to RFC 2616 (HTTP) field names are case-insensitive. if (!header.containsKey(fieldName)) { header.put(fieldName, this.extraHeaders.get(fieldName)); } } } String handshake = "GET " + path + " HTTP/1.1\r\n"; handshake += this.generateHeader(header); handshake += "\r\n"; byte[] handshakeBytes = new byte[handshake.getBytes().length]; System.arraycopy(handshake.getBytes(), 0, handshakeBytes, 0, handshake.getBytes().length); return handshakeBytes; } private String generateHeader(LinkedHashMap<String, String> headers) { String header = new String(); for (String fieldName : headers.keySet()) { header += fieldName + ": " + headers.get(fieldName) + "\r\n"; } return header; } private String createNonce() { byte[] nonce = new byte[16]; for (int i = 0; i < 16; i++) { nonce[i] = (byte) rand(0, 255); } return Base64.encodeBase64String(nonce); } public void verifyServerStatusLine(String statusLine) throws WebSocketException { int statusCode = Integer.valueOf(statusLine.substring(9, 12)); if (statusCode == 407) { throw new WebSocketException("connection failed: proxy authentication not supported"); } else if (statusCode == 404) { throw new WebSocketException("connection failed: 404 not found"); } else if (statusCode != 101) { throw new WebSocketException("connection failed: unknown status code " + statusCode); } } public void verifyServerHandshakeHeaders(HashMap<String, String> headers) throws WebSocketException { if (!headers.get("Upgrade").toLowerCase().equals("websocket")) { throw new WebSocketException("connection failed: missing header field in server handshake: Upgrade"); } else if (!headers.get("Connection").equals("Upgrade")) { throw new WebSocketException("connection failed: missing header field in server handshake: Connection"); } } private int rand(int min, int max) { int rand = (int) (Math.random() * max + min); return rand; } }