Adding support for etag and last-modified headers

lib/response/file.js

@@ -41,6 +41,7 @@ internals.File.prototype._prepare = function (callback) {
         self.headers['Content-Type'] = Mime.lookup(self._filePath) || 'application/octet-stream';
         self.headers['Content-Length'] = stat.size;
         self.headers['Last-Modified'] = new Date(stat.mtime).toUTCString();
+        self.headers.etag = JSON.stringify([stat.ino, stat.size, Date.parse(stat.mtime)].join('-'));
 
         return callback(self);
     });

lib/response/index.js

@@ -120,6 +120,20 @@ exports._respond = function (item, request, callback) {
             response = new internals.Error(errOptions);
         }
 
+        // Process ETag and If-Modified-Since headers
+
+        var ifModifiedSince = request.raw.req.headers['if-modified-since'] ? Date.parse(request.raw.req.headers['if-modified-since']) : null;
+        var lastModified = response.headers && response.headers['Last-Modified'] ? Date.parse(response.headers['Last-Modified']) : null;
+
+        if (response.headers && response.headers.etag && request.raw.req.headers['if-none-match'] === response.headers.etag) {
+            response = new internals.Empty();
+            response._code = 304;
+        }
+        else if (ifModifiedSince && lastModified && ifModifiedSince >= lastModified) {
+            response = new internals.Empty();
+            response._code = 304;
+        }
+
         // Set Cache, CORS, Location headers
 
         Headers.set(response, request);

test/integration/response.js

@@ -345,5 +345,41 @@ describe('Response', function () {
                 });
             });
         });
+
+        it('returns a 304 when the request has a matching etag', function (done) {
+
+            server.start(function () {
+
+                Request.post('http://localhost:17082/file', function (err, res1) {
+
+                    var headers = {
+                        'if-none-match': res1.headers.etag
+                    };
+
+                    Request.post({ url: 'http://localhost:17082/file', headers: headers }, function (err, res2) {
+
+                        expect(res2.statusCode).to.equal(304);
+                        done();
+                    });
+                });
+            });
+        });
+
+        it('returns a 304 when the request has a future modifed-since', function (done) {
+
+            server.start(function () {
+
+                var date =  new Date(Date.now());
+                var headers = {
+                    'if-modified-since': new Date(date.setFullYear(date.getFullYear() + 1)).toUTCString()
+                };
+
+                Request.post({ url: 'http://localhost:17082/file', headers: headers }, function (err, res) {
+
+                    expect(res.statusCode).to.equal(304);
+                    done();
+                });
+            });
+        });
     });
 });