[voice] Add length limit to TTS handled by cache

We can safely assume that long TTS are generated for report (meteo, chatGPT ?), probably not meant to be repeated, and so not cached.

Signed-off-by: Gwendal Roulleau <[email protected]>

bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/cache/TTSLRUCacheImpl.java

@@ -56,6 +56,7 @@ public class TTSLRUCacheImpl implements TTSCache {
 
     static final String CONFIG_CACHE_SIZE_TTS = "cacheSizeTTS";
     static final String CONFIG_ENABLE_CACHE_TTS = "enableCacheTTS";
+    static final String CONFIG_MAX_TEXTLENGTH_CACHE_TTS = "maxTextLengthCacheTTS";
 
     static final String VOICE_TTS_CACHE_PID = "org.openhab.voice.tts";
 
@@ -66,6 +67,11 @@ public class TTSLRUCacheImpl implements TTSCache {
      * current request is not known and may or may not exceed the limit.
      */
     protected long cacheSizeTTS = DEFAULT_CACHE_SIZE_TTS * 1024;
+    /**
+     * Length text limit. If exceeded, the cache will passthrough the request without storing it.
+     * (One can safely assume that long TTS are generated for report, probably not meant to be repeated)
+     */
+    private long maxTextLengthCacheTTS = 150;
     protected boolean enableCacheTTS = true;
 
     private StorageService storageService;
@@ -89,6 +95,8 @@ protected void modified(Map<String, Object> config) {
         this.enableCacheTTS = ConfigParser.valueAsOrElse(config.get(CONFIG_ENABLE_CACHE_TTS), Boolean.class, true);
         this.cacheSizeTTS = ConfigParser.valueAsOrElse(config.get(CONFIG_CACHE_SIZE_TTS), Long.class,
                 DEFAULT_CACHE_SIZE_TTS) * 1024;
+        this.maxTextLengthCacheTTS = ConfigParser.valueAsOrElse(config.get(CONFIG_MAX_TEXTLENGTH_CACHE_TTS),
+                Integer.class, 150);
 
         if (enableCacheTTS) {
             this.lruMediaCache = new LRUMediaCache<>(storageService, cacheSizeTTS, VOICE_TTS_CACHE_PID,
@@ -100,7 +108,8 @@ protected void modified(Map<String, Object> config) {
     public AudioStream get(CachedTTSService tts, String text, Voice voice, AudioFormat requestedFormat)
             throws TTSException {
         LRUMediaCache<AudioFormatInfo> lruMediaCacheLocal = lruMediaCache;
-        if (!enableCacheTTS || lruMediaCacheLocal == null) {
+        if (!enableCacheTTS || lruMediaCacheLocal == null
+                || (maxTextLengthCacheTTS > 0 && text.length() > maxTextLengthCacheTTS)) {
             return tts.synthesizeForCache(text, voice, requestedFormat);
         }
 

bundles/org.openhab.core.voice/src/main/resources/OH-INF/config/voice.xml

@@ -59,6 +59,12 @@
 			<description>The limit size of the TTS cache (in kB).</description>
 			<default>10240</default>
 		</parameter>
+		<parameter name="maxTextLengthCacheTTS" type="integer">
+			<label>TTS Cache Maximum Text Length</label>
+			<description>The limit length of a text handled by the TTS cache. If exceeded, will passthrough to the TTS without
+				storing it. 0 for no limit.</description>
+			<default>150</default>
+		</parameter>
 	</config-description>
 
 </config-description:config-descriptions>

bundles/org.openhab.core.voice/src/main/resources/OH-INF/i18n/voice.properties

@@ -17,6 +17,12 @@ system.config.voice.listeningMelody.description = A melody to be played to adver
 system.config.voice.listeningMelody.option.Bb = Bb
 system.config.voice.listeningMelody.option.F# = F#
 system.config.voice.listeningMelody.option.E = E
+system.config.voice.enableCacheTTS.label = Enable TTS caching
+system.config.voice.enableCacheTTS.description = true to allow TTS services to cache audio files on disk.
+system.config.voice.cacheSizeTTS.label = TTS Cache Size
+system.config.voice.cacheSizeTTS.description = The limit size of the TTS cache (in kB).
+system.config.voice.maxTextLengthCacheTTS.label = TTS Cache Maximum Text Length
+system.config.voice.maxTextLengthCacheTTS.description = The limit length of a text handled by the TTS cache. If exceeded, will passthrough to the TTS without storing it. 0 for no limit.
 
 error.ks-error = Encountered error while spotting keywords, {0}
 error.stt-error = Encountered error while recognizing text, {0}