Merge branch 'release/0.2.0'

History.md

@@ -1,3 +1,6 @@
+- 0.2.0 2013-10-31
+  Better examples, version bump.
+
 - 0.1.3 2013-10-31
   Fixing unreleased connection in redis example.
 

README.md

@@ -27,6 +27,44 @@ priority cache(s) first.
 
 First, it includes a `wrap` function that lets you wrap any function in cache.
 (Note, this was inspired by [node-caching](https://github.com/mape/node-caching).)
+This is probably the feature you're looking for.  As an example, where you might have to do this
+
+```javascript
+function get_cached_user(id, cb) {
+    memory_cache.get(id, function (err, result) {
+        if (err) { return cb(err); }
+
+        if (result) {
+            return cb(null, result);
+        }
+
+        get_user(id, function (err, result) {
+            if (err) { return cb(err); }
+            memory_cache.set(id, result);
+            cb(null, result);
+        });
+    });
+}
+```
+... you can instead use the `wrap` function:
+
+```javascript
+function get_cached_user(id, cb) {
+    memory_cache.wrap(id, function (cache_callback) {
+        get_user(id, cache_callback);
+    }, cb);
+}
+
+get_cached_user(user_id, function (err, user) {
+    // First time fetches the user from the (fake) database:
+    console.log(user);
+
+    get_cached_user(user_id, function (err, user) {
+        // Second time fetches from cache.
+        console.log(user);
+    });
+});
+```
 
 Second, node-cache-manager features a built-in memory cache (using [node-lru-cache](https://github.com/isaacs/node-lru-cache)),
 with the standard functions you'd expect in most caches:
@@ -95,7 +133,27 @@ Redis cache store with connection pooling.
 // Returning user from slow database.
 // { id: 123, name: 'Bob' }
 // { id: 123, name: 'Bob' }
+```
+
+Here's a very basic example of how you could use this in an Express app:
 
+```javascript
+function respond(res, err, data) {
+    if (err) { 
+        res.json(500, err);
+    } else {
+        res.json(200, data);
+    }
+}
+
+app.get('/foo/bar', function(req, res) {
+    var cache_key = 'foo-bar:' + JSON.stringify(req.query);
+    memory_cache.wrap(cache_key, function(cache_cb) {
+        DB.find(req.query, cache_cb);
+    }, function(err, result) {
+        respond(res, err, result);
+    });
+});
 ```
 
 #### Custom Stores

examples/example.js

@@ -1,3 +1,4 @@
+/*jshint unused:false*/
 var cache_manager = require('../');
 var memory_cache = cache_manager.caching({store: 'memory', max: 100, ttl: 10/*seconds*/});
 var memory_cache2 = cache_manager.caching({store: 'memory', max: 100, ttl: 100/*seconds*/});
@@ -5,19 +6,23 @@ var memory_cache2 = cache_manager.caching({store: 'memory', max: 100, ttl: 100/*
 //
 // Basic usage
 //
-memory_cache2.set('foo', 'bar', function (err) {
+memory_cache.set('foo', 'bar', function (err) {
     if (err) { throw err; }
 
-    memory_cache2.get('foo', function (err, result) {
+    memory_cache.get('foo', function (err, result) {
         console.log(result);
         // >> 'bar'
-        memory_cache2.del('foo', function (err) { console.log(err); });
+        memory_cache.del('foo', function (err) {
+            if (err) {
+                console.log(err);
+            }
+        });
     });
 });
 
 function get_user(id, cb) {
     setTimeout(function () {
-        console.log("Returning user from slow database.");
+        console.log("Fetching user from slow database.");
         cb(null, {id: id, name: 'Bob'});
     }, 100);
 }
@@ -28,15 +33,37 @@ var key = 'user_' + user_id;
 //
 // wrap() example 
 //
-memory_cache2.wrap(key, function (cb) {
-    get_user(user_id, cb);
-}, function (err, user) {
+
+// Instead of manually managing the cache like this:
+function get_cached_user_manually(id, cb) {
+    memory_cache.get(id, function (err, result) {
+        if (err) { return cb(err); }
+
+        if (result) {
+            return cb(null, result);
+        }
+
+        get_user(id, function (err, result) {
+            if (err) { return cb(err); }
+            memory_cache.set(id, result);
+            cb(null, result);
+        });
+    });
+}
+
+// ... you can instead use the `wrap` function:
+function get_cached_user(id, cb) {
+    memory_cache.wrap(id, function (cache_callback) {
+        get_user(id, cache_callback);
+    }, cb);
+}
+
+get_cached_user(user_id, function (err, user) {
+    // First time fetches the user from the (fake) database:
     console.log(user);
 
-    // Second time fetches user from memory_cache2 
-    memory_cache2.wrap(key, function (cb) {
-        get_user(user_id, cb);
-    }, function (err, user) {
+    get_cached_user(user_id, function (err, user) {
+        // Second time fetches from cache.
         console.log(user);
     });
 });
@@ -47,6 +74,23 @@ memory_cache2.wrap(key, function (cb) {
 // { id: 123, name: 'Bob' }
 
 
+// Same as above, but written differently:
+memory_cache.wrap(key, function (cb) {
+    get_user(user_id, cb);
+}, function (err, user) {
+    console.log(user);
+
+    // Second time fetches user from memory_cache
+    memory_cache.wrap(key, function (cb) {
+        get_user(user_id, cb);
+    }, function (err, user) {
+        console.log(user);
+    });
+});
+
+//
+// multi-cache example
+//
 var multi_cache = cache_manager.multi_caching([memory_cache, memory_cache2]);
 var user_id2 = 456;
 var key2 = 'user_' + user_id;
@@ -76,7 +120,9 @@ multi_cache.wrap(key2, function (cb) {
 
             // Delete from all caches
             multi_cache.del('foo2', function (err) {
+                if (err) {
                     console.log(err);
+                }
                 process.exit();
             });
         });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "cache-manager",
-  "version": "0.1.3",
+  "version": "0.2.0",
   "description": "Cache module for Node.js",
   "main": "index.js",
   "scripts": {