Merge pull request #9 from NREL/response-headers

Add the ability to modify response headers (can be used for CORS setup)

lib/gatekeeper/middleware.js

@@ -12,3 +12,4 @@ module.exports.rateLimit = require('./middleware/rate_limit');
 module.exports.bufferRequest = bufferedRequest.bufferRequest;
 module.exports.proxyBufferedRequest = bufferedRequest.proxyBufferedRequest;
 module.exports.rewriteRequest = require('./middleware/rewrite_request');
+module.exports.rewriteResponse = require('./middleware/rewrite_response');

lib/gatekeeper/middleware/rewrite_response.js

@@ -0,0 +1,57 @@
+'use strict';
+
+var _ = require('lodash');
+
+var RewriteResponse = function() {
+  this.initialize.apply(this, arguments);
+};
+
+_.extend(RewriteResponse.prototype, {
+  initialize: function() {
+  },
+
+  handleResponse: function(request, response, next) {
+    // Wait until response.writeHead() is called to modify the response so we
+    // can ensure that all the headers have been received, but not yet sent.
+    var origWriteHead = response.writeHead;
+    response.writeHead = function() {
+      this.setDefaultHeaders(request, response);
+      this.setOverrideHeaders(request, response);
+
+      return origWriteHead.apply(response, arguments);
+    }.bind(this);
+
+    next();
+  },
+
+  setDefaultHeaders: function(request, response) {
+    var headers = request.apiUmbrellaGatekeeper.settings.default_response_headers;
+    if(headers) {
+      for(var i = 0, len = headers.length; i < len; i++) {
+        var header = headers[i];
+        var existingValue = response.getHeader(header.key);
+        if(!existingValue) {
+          response.setHeader(header.key, header.value);
+        }
+      }
+    }
+  },
+
+  setOverrideHeaders: function(request, response) {
+    var headers = request.apiUmbrellaGatekeeper.settings.override_response_headers;
+    if(headers) {
+      for(var i = 0, len = headers.length; i < len; i++) {
+        var header = headers[i];
+        response.setHeader(header.key, header.value);
+      }
+    }
+  },
+});
+
+module.exports = function rewriteResponse() {
+  var middleware = new RewriteResponse();
+
+  return function(request, response, next) {
+    middleware.handleResponse(request, response, next);
+  };
+};

lib/gatekeeper/worker.js

@@ -99,6 +99,7 @@ _.extend(Worker.prototype, {
       middleware.rateLimit(this),
       middleware.rewriteRequest(),
       middleware.proxyBufferedRequest(this.server.proxy),
+      middleware.rewriteResponse(),
     ];
 
     this.stack = httpProxy.stack(this.middlewares, this.server.proxy);

test/server/api_matcher.js

@@ -311,7 +311,6 @@ describe('ApiUmbrellaGatekeper', function() {
         describe('mismatched case sensitivity', function() {
           shared.itBehavesLikeGatekeeperBlocked('/info/SPECIFIC/', 404, 'NOT_FOUND');
         });
-
       });
     });
 

test/server/response_rewriting.js

@@ -0,0 +1,157 @@
+'use strict';
+
+require('../test_helper');
+
+var request = require('request');
+
+describe('response rewriting', function() {
+  describe('setting default response headers', function() {
+    shared.runServer({
+      apis: [
+        {
+          frontend_host: 'localhost',
+          backend_host: 'example.com',
+          url_matches: [
+            {
+              frontend_prefix: '/',
+              backend_prefix: '/',
+            }
+          ],
+          settings: {
+            default_response_headers: [
+              { key: 'X-Add1', value: 'test1' },
+              { key: 'X-Add2', value: 'test2' },
+              { key: 'X-Existing1', value: 'test3' },
+              { key: 'X-EXISTING2', value: 'test4' },
+              { key: 'x-existing3', value: 'test5' },
+            ],
+          },
+          sub_settings: [
+            {
+              http_method: 'any',
+              regex: '^/headers/sub',
+              settings: {
+                default_response_headers: [
+                  { key: 'X-Add2', value: 'overridden' },
+                ],
+              },
+            },
+          ],
+        },
+      ],
+    });
+
+    describe('default', function() {
+      it('sets new header values', function(done) {
+        request.get('http://localhost:9333/headers/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          response.headers['x-add1'].should.eql('test1');
+          response.headers['x-add2'].should.eql('test2');
+          done();
+        });
+      });
+
+      it('leaves existing headers (case insensitive)', function(done) {
+        request.get('http://localhost:9333/headers/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          response.headers['x-existing1'].should.eql('existing1');
+          response.headers['x-existing2'].should.eql('existing2');
+          response.headers['x-existing3'].should.eql('existing3');
+          done();
+        });
+      });
+    });
+
+    describe('sub-url match', function() {
+      it('overrides the default header settings', function(done) {
+        request.get('http://localhost:9333/headers/sub/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          should.not.exist(response.headers['x-add1']);
+          response.headers['x-add2'].should.eql('overridden');
+          response.headers['x-existing1'].should.eql('existing1');
+          response.headers['x-existing2'].should.eql('existing2');
+          response.headers['x-existing3'].should.eql('existing3');
+          done();
+        });
+      });
+    });
+  });
+
+  describe('setting override response headers', function() {
+    shared.runServer({
+      apis: [
+        {
+          frontend_host: 'localhost',
+          backend_host: 'example.com',
+          url_matches: [
+            {
+              frontend_prefix: '/',
+              backend_prefix: '/',
+            }
+          ],
+          settings: {
+            override_response_headers: [
+              { key: 'X-Add1', value: 'test1' },
+              { key: 'X-Add2', value: 'test2' },
+              { key: 'X-Existing1', value: 'test3' },
+              { key: 'X-EXISTING2', value: 'test4' },
+              { key: 'x-existing3', value: 'test5' },
+            ],
+          },
+          sub_settings: [
+            {
+              http_method: 'any',
+              regex: '^/headers/sub',
+              settings: {
+                override_response_headers: [
+                  { key: 'X-Existing3', value: 'overridden' },
+                ],
+              },
+            },
+          ],
+        },
+      ],
+    });
+
+    describe('default', function() {
+      it('sets new header values', function(done) {
+        request.get('http://localhost:9333/headers/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          response.headers['x-add1'].should.eql('test1');
+          response.headers['x-add2'].should.eql('test2');
+          done();
+        });
+      });
+
+      it('overrides existing headers (case insensitive)', function(done) {
+        request.get('http://localhost:9333/headers/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          response.headers['x-existing1'].should.eql('test3');
+          response.headers['x-existing2'].should.eql('test4');
+          response.headers['x-existing3'].should.eql('test5');
+          done();
+        });
+      });
+    });
+
+    describe('sub-url match', function() {
+      it('overrides the default header settings', function(done) {
+        request.get('http://localhost:9333/headers/sub/?api_key=' + this.apiKey, function(error, response) {
+          should.not.exist(error);
+          response.statusCode.should.eql(200);
+          should.not.exist(response.headers['x-add1']);
+          should.not.exist(response.headers['x-add2']);
+          response.headers['x-existing1'].should.eql('existing1');
+          response.headers['x-existing2'].should.eql('existing2');
+          response.headers['x-existing3'].should.eql('overridden');
+          done();
+        });
+      });
+    });
+  });
+});

test/support/example_backend_app.js

@@ -82,6 +82,13 @@ app.get('/chunked', function(req, res) {
   }, 100);
 });
 
+app.get('/headers/*', function(req, res) {
+  res.set('X-Existing1', 'existing1');
+  res.set('x-existing2', 'existing2');
+  res.set('X-EXISTING3', 'existing3');
+  res.send('Hello World');
+});
+
 app.all('/info/*', function(req, res) {
   var rawUrl = req.protocol + '://' + req.hostname + req.url;
   res.json({