Java: introducing websocket support.

1 files changed, 177 insertions, 0 deletions

diff --git a/src/java/nginx/unit/websocket/server/UriTemplate.java b/src/java/nginx/unit/websocket/server/UriTemplate.java
new file mode 100644
index 00000000..7877fac9
--- /dev/null
+++ b/src/java/nginx/unit/websocket/server/UriTemplate.java
@@ -0,0 +1,177 @@
+/*
+ *  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.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import javax.websocket.DeploymentException;
+
+import org.apache.tomcat.util.res.StringManager;
+
+/**
+ * Extracts path parameters from URIs used to create web socket connections
+ * using the URI template defined for the associated Endpoint.
+ */
+public class UriTemplate {
+
+    private static final StringManager sm = StringManager.getManager(UriTemplate.class);
+
+    private final String normalized;
+    private final List<Segment> segments = new ArrayList<>();
+    private final boolean hasParameters;
+
+
+    public UriTemplate(String path) throws DeploymentException {
+
+        if (path == null || path.length() ==0 || !path.startsWith("/")) {
+            throw new DeploymentException(
+                    sm.getString("uriTemplate.invalidPath", path));
+        }
+
+        StringBuilder normalized = new StringBuilder(path.length());
+        Set<String> paramNames = new HashSet<>();
+
+        // Include empty segments.
+        String[] segments = path.split("/", -1);
+        int paramCount = 0;
+        int segmentCount = 0;
+
+        for (int i = 0; i < segments.length; i++) {
+            String segment = segments[i];
+            if (segment.length() == 0) {
+                if (i == 0 || (i == segments.length - 1 && paramCount == 0)) {
+                    // Ignore the first empty segment as the path must always
+                    // start with '/'
+                    // Ending with a '/' is also OK for instances used for
+                    // matches but not for parameterised templates.
+                    continue;
+                } else {
+                    // As per EG discussion, all other empty segments are
+                    // invalid
+                    throw new IllegalArgumentException(sm.getString(
+                            "uriTemplate.emptySegment", path));
+                }
+            }
+            normalized.append('/');
+            int index = -1;
+            if (segment.startsWith("{") && segment.endsWith("}")) {
+                index = segmentCount;
+                segment = segment.substring(1, segment.length() - 1);
+                normalized.append('{');
+                normalized.append(paramCount++);
+                normalized.append('}');
+                if (!paramNames.add(segment)) {
+                    throw new IllegalArgumentException(sm.getString(
+                            "uriTemplate.duplicateParameter", segment));
+                }
+            } else {
+                if (segment.contains("{") || segment.contains("}")) {
+                    throw new IllegalArgumentException(sm.getString(
+                            "uriTemplate.invalidSegment", segment, path));
+                }
+                normalized.append(segment);
+            }
+            this.segments.add(new Segment(index, segment));
+            segmentCount++;
+        }
+
+        this.normalized = normalized.toString();
+        this.hasParameters = paramCount > 0;
+    }
+
+
+    public Map<String,String> match(UriTemplate candidate) {
+
+        Map<String,String> result = new HashMap<>();
+
+        // Should not happen but for safety
+        if (candidate.getSegmentCount() != getSegmentCount()) {
+            return null;
+        }
+
+        Iterator<Segment> candidateSegments =
+                candidate.getSegments().iterator();
+        Iterator<Segment> targetSegments = segments.iterator();
+
+        while (candidateSegments.hasNext()) {
+            Segment candidateSegment = candidateSegments.next();
+            Segment targetSegment = targetSegments.next();
+
+            if (targetSegment.getParameterIndex() == -1) {
+                // Not a parameter - values must match
+                if (!targetSegment.getValue().equals(
+                        candidateSegment.getValue())) {
+                    // Not a match. Stop here
+                    return null;
+                }
+            } else {
+                // Parameter
+                result.put(targetSegment.getValue(),
+                        candidateSegment.getValue());
+            }
+        }
+
+        return result;
+    }
+
+
+    public boolean hasParameters() {
+        return hasParameters;
+    }
+
+
+    public int getSegmentCount() {
+        return segments.size();
+    }
+
+
+    public String getNormalizedPath() {
+        return normalized;
+    }
+
+
+    private List<Segment> getSegments() {
+        return segments;
+    }
+
+
+    private static class Segment {
+        private final int parameterIndex;
+        private final String value;
+
+        public Segment(int parameterIndex, String value) {
+            this.parameterIndex = parameterIndex;
+            this.value = value;
+        }
+
+
+        public int getParameterIndex() {
+            return parameterIndex;
+        }
+
+
+        public String getValue() {
+            return value;
+        }
+    }
+}