adds addon module

addon/lib/cache.js

@@ -0,0 +1,52 @@
+const cacheManager = require('cache-manager');
+const mangodbStore = require('cache-manager-mongodb');
+
+const GLOBAL_KEY_PREFIX = 'torrentio-addon';
+const STREAM_KEY_PREFIX = `${GLOBAL_KEY_PREFIX}|stream`;
+
+const STREAM_TTL = process.env.STREAM_TTL || 24 * 60 * 60; // 24 hours
+const STREAM_EMPTY_TTL = process.env.STREAM_EMPTY_TTL || 30 * 60; // 30 minutes
+// When the streams are empty we want to cache it for less time in case of timeouts or failures
+
+const MONGO_URI = process.env.MONGODB_URI;
+const NO_CACHE = process.env.NO_CACHE || false;
+
+const cache = initiateCache();
+
+function initiateCache() {
+  if (NO_CACHE) {
+    return null;
+  } else if (MONGO_URI) {
+    return cacheManager.caching({
+      store: mangodbStore,
+      uri: MONGO_URI,
+      options: {
+        collection: 'torrentio-addon',
+        ttl: STREAM_TTL
+      },
+      ttl: STREAM_TTL,
+      ignoreCacheErrors: true
+    });
+  } else {
+    return cacheManager.caching({
+      store: 'memory',
+      ttl: STREAM_TTL
+    });
+  }
+}
+
+function cacheWrap(key, method, options) {
+  if (NO_CACHE || !cache) {
+    return method();
+  }
+  return cache.wrap(key, method, options);
+}
+
+function cacheWrapStream(id, method) {
+  return cacheWrap(`${STREAM_KEY_PREFIX}:${id}`, method, {
+    ttl: (streams) => streams.length ? STREAM_TTL : STREAM_EMPTY_TTL
+  });
+}
+
+module.exports = { cacheWrapStream };
+