Merge pull request jaredwray#65 from philippeauriach/feature/dynamic-cache-ttl

Feature/dynamic cache ttl

Author: BryanDonovan

lib/caching.js

@@ -113,6 +113,10 @@ var caching = function(args) {
                         return;
                     }
 
+                    if (options && typeof options.ttl === 'function') {
+                        options.ttl = options.ttl(data);
+                    }
+
                     self.store.set(key, data, options, function(err) {
                         if (err && (!self.ignoreCacheErrors)) {
                             callbackFiller.fill(key, err);

test/caching.unit.js

@@ -360,6 +360,33 @@ describe("caching", function() {
                 });
             });
 
+            context("ttl function", function() {
+                beforeEach(function() {
+                    sinon.spy(memoryStoreStub, 'set');
+                });
+
+                afterEach(function() {
+                    memoryStoreStub.set.restore();
+                });
+
+                it("when a ttl function is passed in", function(done) {
+                    opts = {
+                        ttl: function(widget) {
+                            assert.deepEqual(widget, {name: name});
+                            return 0.2;
+                        }
+                    };
+                    cache.wrap(key, function(cb) {
+                        methods.getWidget(name, cb);
+                    }, opts, function(err, widget) {
+                        checkErr(err);
+                        assert.deepEqual(widget, {name: name});
+                        sinon.assert.calledWith(memoryStoreStub.set, key, {name: name}, {ttl: 0.2});
+                        done();
+                    });
+                });
+            });
+
             context("when result is already cached", function() {
                 function getCachedWidget(name, cb) {
                     cache.wrap(key, function(cacheCb) {