Merged with https://github.com/restify/plugins/pull/10

package.json

@@ -23,8 +23,11 @@
   },
   "devDependencies": {
     "mocha": "~3.2.0",
-    "should": "~11.2.1",
     "restify": "~4.3.0",
+    "should": "~11.2.1",
     "supertest": "~3.0.0"
+  },
+  "dependencies": {
+    "assert-plus": "^1.0.0"
   }
 }

src/actual.js

@@ -1,20 +1,27 @@
-var restify = require('restify');
-
-//
-// For now, delegate to restify.CORS
-//
-// Although there's a few things we could fix
-// around Access-Control-Expose-Headers
-//
-// It would also break the cyclic dependency with Restify :)
-//
+var origin = require('./origin.js');
+var constants = require('./constants.js');
 
 exports.handler = function(options) {
 
-  return restify.CORS({
-    credentials: options.credentials,
-    origins: options.origins,
-    headers: options.exposeHeaders
-  });
+  return function(req, res, next) {
+    var originHeader = req.headers['origin'];
+
+    // If either no origin was set, or the origin isn't supported, continue
+    // without setting any headers
+    if (!originHeader || !origin.match(originHeader, options.origins)) {
+      return next();
+    }
+
+    // if match was found, let's set some headers.
+    res.setHeader(constants['AC_ALLOW_ORIGIN'], originHeader);
+    res.setHeader(constants['STR_VARY'], constants['STR_ORIGIN']);
+    if(options.credentials) {
+      res.setHeader(constants['AC_ALLOW_CREDS'], 'true');
+    }
+    res.setHeader(constants['AC_EXPOSE_HEADERS'],
+      options.exposeHeaders.join(', '));
+
+    return next();
+  };
 
 };

src/constants.js

@@ -0,0 +1,32 @@
+module.exports = {
+  ALLOW_HEADERS: [
+    'accept',
+    'accept-version',
+    'content-type',
+    'request-id',
+    'origin',
+    'x-api-version',
+    'x-request-id',
+    'x-requested-with'
+  ],
+  EXPOSE_HEADERS: [
+    'api-version',
+    'content-length',
+    'content-md5',
+    'content-type',
+    'date',
+    'request-id',
+    'response-time'
+  ],
+  AC_REQ_METHOD: 'access-control-request-method',
+  AC_REQ_HEADERS: 'access-control-request-headers',
+  AC_ALLOW_CREDS: 'access-control-allow-credentials',
+  AC_ALLOW_ORIGIN: 'access-control-allow-origin',
+  AC_ALLOW_HEADERS: 'access-control-allow-headers',
+  AC_ALLOW_METHODS: 'access-control-allow-methods',
+  AC_EXPOSE_HEADERS: 'access-control-expose-headers',
+  AC_MAX_AGE: 'access-control-max-age',
+  STR_VARY: 'vary',
+  STR_ORIGIN: 'origin',
+  HTTP_NO_CONTENT: 204
+}

src/index.js

@@ -1,17 +1,79 @@
-var util       = require('util');
+var assert = require('assert-plus');
 var preflight = require('./preflight');
 var actual = require('./actual');
+var constants = require('./constants.js');
 
+/**
+ * From http://www.w3.org/TR/cors/#resource-processing-model
+ *
+ * If "simple" request (paraphrased):
+ *
+ * 1. If the Origin header is not set, or if the value of Origin is not a
+ *    case-sensitive match to any values listed in `opts.origins`, do not
+ *    send any CORS headers
+ *
+ * 2. If the resource supports credentials add a single
+ *    'Access-Control-Allow-Credentials' header with the value as "true", and
+ *    ensure 'AC-Allow-Origin' is not '*', but is the request header value,
+ *    otherwise add a single Access-Control-Allow-Origin header, with either the
+ *    value of the Origin header or the string "*" as value
+ *
+ * 3. Add Access-Control-Expose-Headers as appropriate
+ *
+ * @public
+ * @function createCorsContext
+ * @param    {Object} options an options object
+ * @param    {Array} [options.origins] an array of whitelisted origins, can be
+ * both strings and regular expressions
+ * @param    {Boolean} [options.credentials] if true, uses creds
+ * @param    {Array} [options.allowHeaders] user defined headers to allow
+ * @param    {Array} [options.exposeHeaders] user defined headers to expose
+ * @param    {Number} [options.preflightMaxAge] ms to cache preflight requests
+ * @param    {Object | Function} [options.preflightStrategy]
+ * customize preflight request handling
+ * @returns  {Object} returns an object with actual and preflight handlers
+ */
 module.exports = function(options) {
 
-  if (! util.isArray(options.origins))       options.origins = ['*'];
-  if (! util.isArray(options.allowHeaders))  options.allowHeaders = [];
-  if (! util.isArray(options.exposeHeaders)) options.exposeHeaders = [];
-  if (options.origins[0] === '*')            options.credentials = false;
+  assert.object(options, 'options');
+  assert.optionalArray(options.origins, 'options.origins');
+  options.origins.forEach(function (o) {
+      assert.ok(typeof o === 'string' || o instanceof RegExp, o +
+                ' is not a valid origin');
+  });
+  assert.optionalBool(options.credentials, 'options.credentials');
+  assert.optionalArrayOfString(options.allowHeaders, 'options.allowHeaders');
+  assert.optionalArrayOfString(options.exposeHeaders,
+                                 'options.exposeHeaders');
+  assert.optionalNumber(options.preflightMaxAge, 'options.preflightMaxAge');
+  assert.optionalObject(options.preflightStrategy,
+                          'options.preflightStrategy');
+
+  var opts = options;
+  opts.origins = options.origins || ['*']
+  opts.credentials = options.credentials || false;
+  opts.allowHeaders = options.allowHeaders || [];
+  opts.exposeHeaders = options.exposeHeaders || [];
+
+  assert.ok(options.origins.indexOf('*') === -1 ||
+              options.credentials === false,
+              'credentials not supported with wildcard');
+
+  constants['EXPOSE_HEADERS'].forEach(function (h) {
+      if (opts.exposeHeaders.indexOf(h) === -1) {
+          opts.exposeHeaders.push(h);
+      }
+  });
+
+  constants['ALLOW_HEADERS'].forEach(function (h) {
+      if (opts.allowHeaders.indexOf(h) === -1) {
+          opts.allowHeaders.push(h);
+      }
+  });
 
   return {
-    actual: actual.handler(options),
-    preflight: preflight.handler(options)
+    actual: actual.handler(opts),
+    preflight: preflight.handler(opts)
   };
 
 };

src/origin.js

@@ -1,11 +1,16 @@
+exports.match = function(incomingOrigin, origins) {
+    if(!incomingOrigin) {
+      return null;
+    }
 
-exports.match = function(origin, list) {
-  function belongs(o) {
-    return (origin === o || o === "*");
+    for(var i = 0; i < origins.length; i++) {
+        var origin = origins[i];
+        if( (origin instanceof RegExp && origin.test(incomingOrigin)) ||
+            (typeof origin === 'string' && origin === incomingOrigin) ||
+            (origin === '*')) {
+            return incomingOrigin;
         }
-  if (origin && list.some(belongs)) {
-    return origin;
-  } else {
-    return false;
     }
+
+    return null;
 };

src/preflight.js

@@ -1,19 +1,5 @@
-var restify   = require('restify');
 var origin = require('./origin');
-
-//
-// For now we use the "default headers" from restify.CORS
-// Maybe this should just be a global setting on this module
-// (ie. list of extra Access-Control-Expose-Headers, regardless of what the middleware config says)
-//
-
-//
-// TODO:
-// Handle the spec better around "simple methods" and "simple headers".
-//
-
-var DEFAULT_ALLOW_HEADERS = restify.CORS.ALLOW_HEADERS;
-var HTTP_NO_CONTENT = 204;
+var constants = require('./constants.js');
 
 exports.handler = function(options) {
 
@@ -25,37 +11,36 @@ exports.handler = function(options) {
     if (origin.match(originHeader, options.origins) === false) return next();
 
     // 6.2.3
-    var requestedMethod = req.headers['access-control-request-method'];
+    var requestedMethod = req.headers[constants['AC_REQ_METHOD']];
     if (!requestedMethod) return next();
 
     // 6.2.4
-    var requestedHeaders = req.headers['access-control-request-headers'];
+    var requestedHeaders = req.headers[constants['AC_REQ_HEADERS']];
     requestedHeaders = requestedHeaders ? requestedHeaders.split(', ') : [];
 
     var allowedMethods = [requestedMethod, 'OPTIONS'];
-    var allowedHeaders = DEFAULT_ALLOW_HEADERS.concat(['x-requested-with'])
+    var allowedHeaders = constants['ALLOW_HEADERS']
                             .concat(options.allowHeaders);
 
     res.once('header', function() {
-
       // 6.2.7
-      res.header('Access-Control-Allow-Origin', originHeader);
-      res.header('Access-Control-Allow-Credentials', true);
+      res.header(constants['AC_ALLOW_ORIGIN'], originHeader);
+      res.header(constants['AC_ALLOW_CREDS'], true);
 
       // 6.2.8
       if (options.preflightMaxAge) {
-        res.header('Access-Control-Max-Age', options.preflightMaxAge);
+        res.header(constants['AC_MAX_AGE'], options.preflightMaxAge);
       }
 
       // 6.2.9
-      res.header('Access-Control-Allow-Methods', allowedMethods.join(', '));
+      res.header(constants['AC_ALLOW_METHODS'], allowedMethods.join(', '));
 
       // 6.2.10
-      res.header('Access-Control-Allow-Headers', allowedHeaders.join(', '));
+      res.header(constants['AC_ALLOW_HEADERS'], allowedHeaders.join(', '));
 
     });
 
-    res.send(HTTP_NO_CONTENT);
+    res.send(constants['HTTP_NO_CONTENT']);
   };
 
 };

test/cors.actual.spec.js

@@ -45,16 +45,13 @@ describe('CORS: simple / actual requests', function() {
    });
 
    it('6.1.3 Does not set Access-Control-Allow-Credentials header if Origin is *', function(done) {
+     should.throws(function() {
        var server = test.corsServer({
          origins: ['*'],
          credentials: true
        });
-      request(server)
-        .get('/test')
-        .set('Origin', 'http://api.myapp.com')
-        .expect(test.noHeader('access-control-allow-credentials'))
-        .expect(200)
-        .end(done);
+     });
+     done();
     });
 
    it('6.1.3 Sets Access-Control-Allow-Credentials header if configured', function(done) {

test/origin.spec.js

@@ -10,12 +10,12 @@ describe('Origin list', function() {
 
   it('returns null if the origin is not in the list', function() {
     var o = origin.match('http://random-website.com', list);
-    o.should.eql(false);
+    (o === null).should.eql(true);
   });
 
   it('does not do partial matches', function() {
     var o = origin.match('api.myapp.com', list);
-    o.should.eql(false);
+    (o === null).should.eql(true);
   });
 
   it('returns the origin if it matched', function() {