feat(transcription): add Microsoft Translator service

README.md

@@ -263,6 +263,27 @@ before starting to listen to requests. You may refer to the
 [documentation](https://github.com/LibreTranslate/LibreTranslate/blob/main/README.md)
 to set up a volume or set the available languages to reduce download time.
 
+Microsoft Translator configuration for translation
+==================
+
+To use [Microsoft Translator](https://learn.microsoft.com/azure/ai-services/translator/)
+for translation, configure the following properties in `/etc/jitsi/jigasi/sip-communicator.properties`:
+
+```
+org.jitsi.jigasi.transcription.translationService=org.jitsi.jigasi.transcription.BingTranslationService
+org.jitsi.jigasi.transcription.bing.subscription_key=<your-translator-key>
+org.jitsi.jigasi.transcription.bing.subscription_region=<your-resource-region>
+```
+
+The default endpoint is `https://api.cognitive.microsofttranslator.com` and
+the default API version is `3.0`. Override them only when using a custom
+Translator endpoint or API version:
+
+```
+org.jitsi.jigasi.transcription.bing.endpoint=https://api.cognitive.microsofttranslator.com
+org.jitsi.jigasi.transcription.bing.api_version=3.0
+```
+
 Transcription options
 =====================
 

jigasi-home/sip-communicator.properties

@@ -239,6 +239,13 @@ org.jitsi.jigasi.xmpp.acc.USE_DEFAULT_STUN_SERVER=false
 # org.jitsi.jigasi.transcription.translationService=org.jitsi.jigasi.transcription.LibreTranslateTranslationService
 # org.jitsi.jigasi.transcription.libreTranslate.api_url=http://localhost:5000/translate
 
+# Bing (Microsoft Translator Text API v3) server
+# org.jitsi.jigasi.transcription.translationService=org.jitsi.jigasi.transcription.BingTranslationService
+# org.jitsi.jigasi.transcription.bing.subscription_key=
+# org.jitsi.jigasi.transcription.bing.subscription_region=
+# org.jitsi.jigasi.transcription.bing.endpoint=https://api.cognitive.microsofttranslator.com
+# org.jitsi.jigasi.transcription.bing.api_version=3.0
+
 # translation
 # org.jitsi.jigasi.transcription.ENABLE_TRANSLATION=false
 

src/main/java/org/jitsi/jigasi/transcription/BingTranslationService.java

@@ -0,0 +1,237 @@
+/*
+ * Jigasi, the JItsi GAteway to SIP.
+ *
+ * Copyright @ 2018 - present 8x8, Inc.
+ *
+ * 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.jitsi.jigasi.transcription;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.StringEntity;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.util.EntityUtils;
+import org.jitsi.jigasi.JigasiBundleActivator;
+import org.jitsi.utils.logging.Logger;
+
+import java.io.IOException;
+import java.util.List;
+
+
+/**
+ * Implements a {@link TranslationService} which uses the Microsoft Translator
+ * Text API (v3) to translate a given text from one language to another.
+ * <p>
+ * The service requires a valid Azure Cognitive Services subscription key,
+ * passed through the configuration property
+ * {@code org.jitsi.jigasi.transcription.bing.subscription_key}. For
+ * multi-service or regional resources the region must additionally be set via
+ * {@code org.jitsi.jigasi.transcription.bing.subscription_region}.
+ * <p>
+ * <a href="https://learn.microsoft.com/azure/ai-services/translator/reference/v3-0-translate">
+ * Microsoft Translator v3 reference</a> for request / response details.
+ */
+public class BingTranslationService
+        implements TranslationService
+{
+    /**
+     * Property name for the Azure subscription key used to authenticate
+     * against the Translator API. Required; without it every call returns
+     * an empty string.
+     */
+    public final static String SUBSCRIPTION_KEY
+        = "org.jitsi.jigasi.transcription.bing.subscription_key";
+
+    /**
+     * Property name for the Azure region of the Translator resource.
+     * Required for multi-service and regional resources.
+     */
+    public final static String SUBSCRIPTION_REGION
+        = "org.jitsi.jigasi.transcription.bing.subscription_region";
+
+    /**
+     * Property name for the Translator endpoint. Defaults to the global
+     * endpoint; a custom-domain resource would use its own hostname.
+     */
+    public final static String ENDPOINT
+        = "org.jitsi.jigasi.transcription.bing.endpoint";
+
+    /**
+     * Property name for the Translator API version. Defaults to {@code 3.0}.
+     */
+    public final static String API_VERSION
+        = "org.jitsi.jigasi.transcription.bing.api_version";
+
+    public final static String DEFAULT_ENDPOINT
+        = "https://api.cognitive.microsofttranslator.com";
+
+    public final static String DEFAULT_API_VERSION = "3.0";
+
+    private final String subscriptionKey;
+
+    private final String subscriptionRegion;
+
+    private final String endpoint;
+
+    private final String apiVersion;
+
+    private final Logger logger
+        = Logger.getLogger(BingTranslationService.class);
+
+    public BingTranslationService()
+    {
+        subscriptionKey = JigasiBundleActivator.getConfigurationService()
+            .getString(SUBSCRIPTION_KEY, "");
+        subscriptionRegion = JigasiBundleActivator.getConfigurationService()
+            .getString(SUBSCRIPTION_REGION, "");
+        endpoint = JigasiBundleActivator.getConfigurationService()
+            .getString(ENDPOINT, DEFAULT_ENDPOINT);
+        apiVersion = JigasiBundleActivator.getConfigurationService()
+            .getString(API_VERSION, DEFAULT_API_VERSION);
+    }
+
+    /**
+     * Utility function to extract the primary language code like:
+     * 'en-GB', 'en_GB', 'enGB', 'zh-CN', 'zh-TW'
+     * <p>
+     * Behaves equivalent to the function "_getPrimaryLanguageCode"
+     * in jitsi-meet/blob/master/react/features/subtitles/middleware.ts,
+     * matching {@link LibreTranslateTranslationService}.
+     *
+     * @param language The language to use for translation or user requested.
+     * @return Primary language code
+     */
+    private static String getPrimaryLanguageCode(String language)
+    {
+        if (language == null)
+        {
+            return "auto";
+        }
+
+        return language.replaceAll("[-_A-Z].*", "");
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public String translate(String sourceText, String sourceLang,
+                            String targetLang)
+    {
+        if (subscriptionKey == null || subscriptionKey.isEmpty())
+        {
+            logger.error("Bing translation requested but "
+                + SUBSCRIPTION_KEY + " is not set.");
+            return "";
+        }
+
+        String from = getPrimaryLanguageCode(sourceLang);
+        String to = getPrimaryLanguageCode(targetLang);
+
+        StringBuilder url = new StringBuilder(endpoint);
+        if (!endpoint.endsWith("/"))
+        {
+            url.append('/');
+        }
+        url.append("translate?api-version=").append(apiVersion);
+        if (!"auto".equals(from))
+        {
+            url.append("&from=").append(from);
+        }
+        url.append("&to=").append(to);
+
+        Gson gson = new GsonBuilder().disableHtmlEscaping().create();
+        JsonArray body = new JsonArray();
+        JsonObject item = new JsonObject();
+        item.addProperty("Text", sourceText);
+        body.add(item);
+
+        StringEntity entity = new StringEntity(
+            gson.toJson(body), ContentType.APPLICATION_JSON);
+
+        HttpResponse response;
+        try (CloseableHttpClient httpClient
+                = HttpClientBuilder.create().build())
+        {
+            HttpPost request = new HttpPost(url.toString());
+            request.setEntity(entity);
+            request.setHeader("Accept", "application/json");
+            request.setHeader("Content-type", "application/json");
+            request.setHeader(
+                "Ocp-Apim-Subscription-Key", subscriptionKey);
+            if (subscriptionRegion != null && !subscriptionRegion.isEmpty())
+            {
+                request.setHeader(
+                    "Ocp-Apim-Subscription-Region", subscriptionRegion);
+            }
+
+            response = httpClient.execute(request);
+            String jsonBody = EntityUtils.toString(response.getEntity());
+            int statusCode = response.getStatusLine().getStatusCode();
+            if (statusCode != 200)
+            {
+                logger.error("Microsoft Translator responded with status code "
+                    + statusCode + ".");
+                logger.error(jsonBody);
+                return "";
+            }
+
+            BingResponse[] parsed
+                = gson.fromJson(jsonBody, BingResponse[].class);
+            if (parsed == null || parsed.length == 0
+                || parsed[0].translations == null
+                || parsed[0].translations.isEmpty())
+            {
+                logger.error(
+                    "Microsoft Translator returned an empty translation set: "
+                        + jsonBody);
+                return "";
+            }
+            String text = parsed[0].translations.get(0).text;
+            return text == null ? "" : text;
+        }
+        catch (IOException e)
+        {
+            logger.error("Error during request to Microsoft Translator.");
+            logger.error(e.toString());
+            return "";
+        }
+    }
+
+    /**
+     * Class representing the top-level JSON response objects returned by the
+     * Microsoft Translator v3 {@code /translate} endpoint. Used for
+     * JSON-to-POJO conversion with Gson.
+     */
+    static class BingResponse
+    {
+        List<BingTranslation> translations;
+    }
+
+    /**
+     * Class representing each element inside the {@code translations} array
+     * of a Microsoft Translator v3 response.
+     */
+    static class BingTranslation
+    {
+        String text;
+        String to;
+    }
+}