response validation modify. Closes #1723

docs/Reference.md

@@ -538,6 +538,7 @@ The following options are available when adding a route:
         - `failAction` - defines what to do when a response fails validation. Options are:
             - `error` - return an Internal Server Error (500) error response. This is the default value.
             - `log` - log the error but send the response.
+        - `modify` - if `true`, applies the validation rule changes to the response. Defaults to `false`.
 
     - `cache` - if the route method is 'GET', the route can be configured to include caching directives in the response using the following options:
         - `privacy` - determines the privacy flag included in client-side caching using the 'Cache-Control' header. Values are:

lib/schema.js

@@ -221,8 +221,10 @@ internals.routeConfig = Joi.object({
     response: Joi.object({
         schema: Joi.alternatives(Joi.object(), Joi.func()).allow(true, false).required(),
         sample: Joi.number().min(0).max(100),
-        failAction: Joi.string().valid('error', 'log')
-    }),
+        failAction: Joi.string().valid('error', 'log'),
+        modify: Joi.boolean()
+    })
+        .without('modify', 'sample'),
     cache: Joi.object({
         privacy: Joi.string().valid('default', 'public', 'private'),
         expiresIn: Joi.number(),

lib/validation.js

@@ -137,6 +137,12 @@ exports.response = function (request, next) {
     var postValidate = function (err, value) {
 
         if (!err) {
+            if (value !== undefined &&
+                request.route.response.modify) {
+
+                request.response.source = value;
+            }
+
             return next();
         }
 

test/validation.js

@@ -614,6 +614,66 @@ describe('Validation', function () {
         });
     });
 
+    it('validates and modifies response', function (done) {
+
+        var handler = function (request, reply) {
+
+            return reply({ a: 1, b: 2 });
+        };
+
+        var server = new Hapi.Server({ debug: false });
+        server.connection();
+        server.route({
+            method: 'GET',
+            path: '/',
+            config: {
+                response: {
+                    schema: Joi.object({
+                        a: Joi.number()
+                    }).options({ stripUnknown: true }),
+                    modify: true
+                }
+            },
+            handler: handler
+        });
+
+        server.inject('/', function (res) {
+
+            expect(res.statusCode).to.equal(200);
+            expect(res.result).to.deep.equal({ a: 1 });
+            done();
+        });
+    });
+
+    it('throws on sample with response modify', function (done) {
+
+        var handler = function (request, reply) {
+
+            return reply({ a: 1, b: 2 });
+        };
+
+        var server = new Hapi.Server({ debug: false });
+        server.connection();
+        expect(function () {
+
+            server.route({
+                method: 'GET',
+                path: '/',
+                config: {
+                    response: {
+                        schema: Joi.object({
+                            a: Joi.number()
+                        }).options({ stripUnknown: true }),
+                        modify: true,
+                        sample: 90
+                    }
+                },
+                handler: handler
+            });
+        }).to.throw(/modify conflict with forbidden peer sample/);
+        done();
+    });
+
     it('validates response using custom validation function', function (done) {
 
         var i = 0;