Java: introducing websocket support.

1 files changed, 285 insertions, 0 deletions

diff --git a/src/java/nginx/unit/websocket/server/UpgradeUtil.java b/src/java/nginx/unit/websocket/server/UpgradeUtil.java
new file mode 100644
index 00000000..162f01c7
--- /dev/null
+++ b/src/java/nginx/unit/websocket/server/UpgradeUtil.java
@@ -0,0 +1,285 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 nginx.unit.websocket.server;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.websocket.Endpoint;
+import javax.websocket.Extension;
+import javax.websocket.HandshakeResponse;
+import javax.websocket.server.ServerEndpointConfig;
+
+import nginx.unit.Request;
+
+import org.apache.tomcat.util.codec.binary.Base64;
+import org.apache.tomcat.util.res.StringManager;
+import org.apache.tomcat.util.security.ConcurrentMessageDigest;
+import nginx.unit.websocket.Constants;
+import nginx.unit.websocket.Transformation;
+import nginx.unit.websocket.TransformationFactory;
+import nginx.unit.websocket.Util;
+import nginx.unit.websocket.WsHandshakeResponse;
+import nginx.unit.websocket.pojo.PojoEndpointServer;
+
+public class UpgradeUtil {
+
+    private static final StringManager sm =
+            StringManager.getManager(UpgradeUtil.class.getPackage().getName());
+    private static final byte[] WS_ACCEPT =
+            "258EAFA5-E914-47DA-95CA-C5AB0DC85B11".getBytes(
+                    StandardCharsets.ISO_8859_1);
+
+    private UpgradeUtil() {
+        // Utility class. Hide default constructor.
+    }
+
+    /**
+     * Checks to see if this is an HTTP request that includes a valid upgrade
+     * request to web socket.
+     * <p>
+     * Note: RFC 2616 does not limit HTTP upgrade to GET requests but the Java
+     *       WebSocket spec 1.0, section 8.2 implies such a limitation and RFC
+     *       6455 section 4.1 requires that a WebSocket Upgrade uses GET.
+     * @param request  The request to check if it is an HTTP upgrade request for
+     *                 a WebSocket connection
+     * @param response The response associated with the request
+     * @return <code>true</code> if the request includes a HTTP Upgrade request
+     *         for the WebSocket protocol, otherwise <code>false</code>
+     */
+    public static boolean isWebSocketUpgradeRequest(ServletRequest request,
+            ServletResponse response) {
+
+        Request r = (Request) request.getAttribute(Request.BARE);
+
+        return ((request instanceof HttpServletRequest) &&
+                (response instanceof HttpServletResponse) &&
+                (r != null) &&
+                (r.isUpgrade()));
+    }
+
+
+    public static void doUpgrade(WsServerContainer sc, HttpServletRequest req,
+            HttpServletResponse resp, ServerEndpointConfig sec,
+            Map<String,String> pathParams)
+            throws ServletException, IOException {
+
+
+        // Origin check
+        String origin = req.getHeader(Constants.ORIGIN_HEADER_NAME);
+
+        if (!sec.getConfigurator().checkOrigin(origin)) {
+            resp.sendError(HttpServletResponse.SC_FORBIDDEN);
+            return;
+        }
+        // Sub-protocols
+        List<String> subProtocols = getTokensFromHeader(req,
+                Constants.WS_PROTOCOL_HEADER_NAME);
+        String subProtocol = sec.getConfigurator().getNegotiatedSubprotocol(
+                sec.getSubprotocols(), subProtocols);
+
+        // Extensions
+        // Should normally only be one header but handle the case of multiple
+        // headers
+        List<Extension> extensionsRequested = new ArrayList<>();
+        Enumeration<String> extHeaders = req.getHeaders(Constants.WS_EXTENSIONS_HEADER_NAME);
+        while (extHeaders.hasMoreElements()) {
+            Util.parseExtensionHeader(extensionsRequested, extHeaders.nextElement());
+        }
+
+        // Negotiation phase 1. By default this simply filters out the
+        // extensions that the server does not support but applications could
+        // use a custom configurator to do more than this.
+        List<Extension> installedExtensions = null;
+        if (sec.getExtensions().size() == 0) {
+            installedExtensions = Constants.INSTALLED_EXTENSIONS;
+        } else {
+            installedExtensions = new ArrayList<>();
+            installedExtensions.addAll(sec.getExtensions());
+            installedExtensions.addAll(Constants.INSTALLED_EXTENSIONS);
+        }
+        List<Extension> negotiatedExtensionsPhase1 = sec.getConfigurator().getNegotiatedExtensions(
+                installedExtensions, extensionsRequested);
+
+        // Negotiation phase 2. Create the Transformations that will be applied
+        // to this connection. Note than an extension may be dropped at this
+        // point if the client has requested a configuration that the server is
+        // unable to support.
+        List<Transformation> transformations = createTransformations(negotiatedExtensionsPhase1);
+
+        List<Extension> negotiatedExtensionsPhase2;
+        if (transformations.isEmpty()) {
+            negotiatedExtensionsPhase2 = Collections.emptyList();
+        } else {
+            negotiatedExtensionsPhase2 = new ArrayList<>(transformations.size());
+            for (Transformation t : transformations) {
+                negotiatedExtensionsPhase2.add(t.getExtensionResponse());
+            }
+        }
+
+        WsHttpUpgradeHandler wsHandler =
+                req.upgrade(WsHttpUpgradeHandler.class);
+
+        WsHandshakeRequest wsRequest = new WsHandshakeRequest(req, pathParams);
+        WsHandshakeResponse wsResponse = new WsHandshakeResponse();
+        WsPerSessionServerEndpointConfig perSessionServerEndpointConfig =
+                new WsPerSessionServerEndpointConfig(sec);
+        sec.getConfigurator().modifyHandshake(perSessionServerEndpointConfig,
+                wsRequest, wsResponse);
+        //wsRequest.finished();
+
+        // Add any additional headers
+        for (Entry<String,List<String>> entry :
+                wsResponse.getHeaders().entrySet()) {
+            for (String headerValue: entry.getValue()) {
+                resp.addHeader(entry.getKey(), headerValue);
+            }
+        }
+
+        Endpoint ep;
+        try {
+            Class<?> clazz = sec.getEndpointClass();
+            if (Endpoint.class.isAssignableFrom(clazz)) {
+                ep = (Endpoint) sec.getConfigurator().getEndpointInstance(
+                        clazz);
+            } else {
+                ep = new PojoEndpointServer();
+                // Need to make path params available to POJO
+                perSessionServerEndpointConfig.getUserProperties().put(
+                        nginx.unit.websocket.pojo.Constants.POJO_PATH_PARAM_KEY, pathParams);
+            }
+        } catch (InstantiationException e) {
+            throw new ServletException(e);
+        }
+
+        wsHandler.preInit(ep, perSessionServerEndpointConfig, sc, wsRequest,
+                negotiatedExtensionsPhase2, subProtocol, null, pathParams,
+                req.isSecure());
+
+        wsHandler.init(null);
+    }
+
+
+    private static List<Transformation> createTransformations(
+            List<Extension> negotiatedExtensions) {
+
+        TransformationFactory factory = TransformationFactory.getInstance();
+
+        LinkedHashMap<String,List<List<Extension.Parameter>>> extensionPreferences =
+                new LinkedHashMap<>();
+
+        // Result will likely be smaller than this
+        List<Transformation> result = new ArrayList<>(negotiatedExtensions.size());
+
+        for (Extension extension : negotiatedExtensions) {
+            List<List<Extension.Parameter>> preferences =
+                    extensionPreferences.get(extension.getName());
+
+            if (preferences == null) {
+                preferences = new ArrayList<>();
+                extensionPreferences.put(extension.getName(), preferences);
+            }
+
+            preferences.add(extension.getParameters());
+        }
+
+        for (Map.Entry<String,List<List<Extension.Parameter>>> entry :
+            extensionPreferences.entrySet()) {
+            Transformation transformation = factory.create(entry.getKey(), entry.getValue(), true);
+            if (transformation != null) {
+                result.add(transformation);
+            }
+        }
+        return result;
+    }
+
+
+    private static void append(StringBuilder sb, Extension extension) {
+        if (extension == null || extension.getName() == null || extension.getName().length() == 0) {
+            return;
+        }
+
+        sb.append(extension.getName());
+
+        for (Extension.Parameter p : extension.getParameters()) {
+            sb.append(';');
+            sb.append(p.getName());
+            if (p.getValue() != null) {
+                sb.append('=');
+                sb.append(p.getValue());
+            }
+        }
+    }
+
+
+    /*
+     * This only works for tokens. Quoted strings need more sophisticated
+     * parsing.
+     */
+    private static boolean headerContainsToken(HttpServletRequest req,
+            String headerName, String target) {
+        Enumeration<String> headers = req.getHeaders(headerName);
+        while (headers.hasMoreElements()) {
+            String header = headers.nextElement();
+            String[] tokens = header.split(",");
+            for (String token : tokens) {
+                if (target.equalsIgnoreCase(token.trim())) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+
+    /*
+     * This only works for tokens. Quoted strings need more sophisticated
+     * parsing.
+     */
+    private static List<String> getTokensFromHeader(HttpServletRequest req,
+            String headerName) {
+        List<String> result = new ArrayList<>();
+        Enumeration<String> headers = req.getHeaders(headerName);
+        while (headers.hasMoreElements()) {
+            String header = headers.nextElement();
+            String[] tokens = header.split(",");
+            for (String token : tokens) {
+                result.add(token.trim());
+            }
+        }
+        return result;
+    }
+
+
+    private static String getWebSocketAccept(String key) {
+        byte[] digest = ConcurrentMessageDigest.digestSHA1(
+                key.getBytes(StandardCharsets.ISO_8859_1), WS_ACCEPT);
+        return Base64.encodeBase64String(digest);
+    }
+}