Use cache for ttl if possible

Also fixes etag when compression enabled

src/utils/queryCacher.ts

@@ -143,6 +143,7 @@ async function getKeyLastModified(key: string): Promise<Date> {
     if (!config.redis?.enabled) return Promise.reject("ETag - Redis not enabled");
     return await redis.ttl(key)
         .then(ttl => {
+            if (ttl <= 0) return new Date();
             const sinceLive = config.redis?.expiryTime - ttl;
             const now = Math.floor(Date.now() / 1000);
             return new Date((now-sinceLive) * 1000);

src/utils/redis.ts

@@ -193,6 +193,15 @@ if (config.redis?.enabled) {
         }
     };
 
+    const ttl = client.ttl.bind(client);
+    exportClient.ttl = (key) => {
+        if (cache && cacheClient && cache.has(key)) {
+            return Promise.resolve(config.redis?.expiryTime - Math.floor((cache.ttl - cache.info(key).ttl) / 1000));
+        } else {
+            return ttl(createKeyName(key));
+        }
+    };
+
     const get = client.get.bind(client);
     const getRead = readClient?.get?.bind(readClient);
     exportClient.get = (key) => new Promise((resolve, reject) => {