add cache hits/misses to posts cache

src/controllers/admin/cache.js

@@ -23,6 +23,9 @@ cacheController.get = function (req, res) {
 			itemCount: postCache.itemCount,
 			percentFull: percentFull,
 			avgPostSize: avgPostSize,
+			hits: utils.addCommas(String(postCache.hits)),
+			misses: utils.addCommas(String(postCache.misses)),
+			hitRatio: ((postCache.hits / (postCache.hits + postCache.misses) || 0)).toFixed(4),
 		},
 		groupCache: {
 			length: groupCache.length,

src/posts/cache.js

@@ -8,5 +8,7 @@ var cache = LRU({
 	length: function (n) { return n.length; },
 	maxAge: 0,
 });
+cache.hits = 0;
+cache.misses = 0;
 
 module.exports = cache;

src/posts/parse.js

@@ -27,8 +27,10 @@ module.exports = function (Posts) {
 
 		if (postData.pid && cache.has(String(postData.pid))) {
 			postData.content = cache.get(String(postData.pid));
+			cache.hits += 1;
 			return callback(null, postData);
 		}
+		cache.misses += 1;
 
 		async.waterfall([
 			function (next) {

src/views/admin/advanced/cache.tpl

@@ -19,6 +19,11 @@
 						[[admin/advanced/cache:percent-full, {postCache.percentFull}]]
 					</div>
 				</div>
+
+				<label>Hits:</label> <span>{postCache.hits}</span><br/>
+				<label>Misses:</label> <span>{postCache.misses}</span><br/>
+				<label>Hit Ratio:</label> <span>{postCache.hitRatio}</span><br/>
+
 				<div class="form-group">
 					<label for="postCacheSize">[[admin/advanced/cache:post-cache-size]]</label>
 					<input id="postCacheSize" type="text" class="form-control" value="" data-field="postCacheSize">