New method to build a valid consumer name for a web client (openhab#3359

)

Signed-off-by: Laurent Garnier <lg.hc@free.fr>

bundles/org.openhab.core.thing/src/main/java/org/openhab/core/thing/util/ThingWebClientUtil.java

@@ -0,0 +1,67 @@
+/**
+ * Copyright (c) 2010-2023 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.thing.util;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+import org.openhab.core.thing.ThingUID;
+
+/**
+ * {@link ThingWebClientUtil} provides an utility method to create a valid consumer name for web clients.
+ *
+ * @author Laurent Garnier - Initial contribution
+ */
+@NonNullByDefault
+public class ThingWebClientUtil {
+
+    private static final int MAX_CONSUMER_NAME_LENGTH = 20;
+
+    /**
+     * Build a valid consumer name for HTTP or WebSocket client.
+     *
+     * @param uid thing UID for which to associate HTTP or WebSocket client
+     * @param prefix a prefix to consider for the name; can be null
+     * @return a valid consumer name
+     */
+    public static String buildWebClientConsumerName(ThingUID uid, @Nullable String prefix) {
+        String pref = prefix == null ? "" : prefix;
+        String name = pref + uid.getAsString().replace(':', '-');
+        if (name.length() > MAX_CONSUMER_NAME_LENGTH) {
+            // Try to use only prefix + binding ID + thing ID
+            name = pref + uid.getBindingId();
+            if (name.length() > (MAX_CONSUMER_NAME_LENGTH / 2)) {
+                // Truncate the binding ID to keep enough place for thing ID
+                name = name.substring(0, MAX_CONSUMER_NAME_LENGTH / 2);
+            }
+            // Add the thing ID
+            String id = uid.getId();
+            int maxIdLength = MAX_CONSUMER_NAME_LENGTH - 1 - name.length();
+            if (id.length() > maxIdLength) {
+                // If thing ID is too big, use a hash code of the thing UID instead of thing id
+                // and truncate it if necessary
+                id = buildHashCode(uid, maxIdLength);
+            }
+            name += "-" + id;
+        }
+        return name;
+    }
+
+    // Make the method public just to be able to call it inside the tests
+    static String buildHashCode(ThingUID uid, int maxLength) {
+        String result = Integer.toHexString(uid.hashCode());
+        if (result.length() > maxLength) {
+            result = result.substring(result.length() - maxLength);
+        }
+        return result;
+    }
+}

bundles/org.openhab.core.thing/src/test/java/org/openhab/core/thing/util/ThingWebClientUtilTest.java

@@ -0,0 +1,69 @@
+/**
+ * Copyright (c) 2010-2023 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.thing.util;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.junit.jupiter.api.Test;
+import org.openhab.core.thing.ThingUID;
+
+/**
+ * @author Laurent Garnier - Initial contribution
+ */
+@NonNullByDefault
+public class ThingWebClientUtilTest {
+
+    private ThingUID uid1 = new ThingUID("mycroft", "mycroft", "yy");
+    private ThingUID uid2 = new ThingUID("mycroft", "mycroft", "myInstance");
+    private ThingUID uid3 = new ThingUID("mycroft", "mycroft", "myPersonalInstance");
+    private ThingUID uid4 = new ThingUID("amazonechocontrol", "account", "myAccount");
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenThingUidSizeIsOk() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid1, null);
+        assertThat(name, is("mycroft-mycroft-yy"));
+    }
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenPrefixAndThingUidSizeIsOk() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid1, "x-");
+        assertThat(name, is("x-mycroft-mycroft-yy"));
+    }
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenPrefixIsTooBig() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid1, "xxxx-");
+        assertThat(name, is("xxxx-mycro-yy"));
+    }
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenThingUidIsTooBig() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid2, null);
+        assertThat(name, is("mycroft-myInstance"));
+    }
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenThingIdIsTooBig() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid3, null);
+        String hashCode = ThingWebClientUtil.buildHashCode(uid3, 12);
+        assertThat(name, is("mycroft-" + hashCode));
+    }
+
+    @Test
+    public void testBuildWebClientConsumerNameWhenBindingIdIsTooBig() {
+        String name = ThingWebClientUtil.buildWebClientConsumerName(uid4, null);
+        assertThat(name, is("amazonecho-myAccount"));
+    }
+}