fix: request set headers

docs/Request.md

@@ -6,7 +6,7 @@ Request is a core Fastify object containing the following fields:
 - `query` - the parsed querystring
 - `body` - the body
 - `params` - the params matching the URL
-- `headers` - the headers
+- [`headers`](#headers) - the headers getter and setter
 - `raw` - the incoming HTTP request from Node core
 - `req` *(deprecated, use `.raw` instead)* - the incoming HTTP request from Node core
 - `server` - The Fastify server instance, scoped to the current [encapsulation context](Encapsulation.md)
@@ -24,6 +24,20 @@ Request is a core Fastify object containing the following fields:
 - `connection` - Deprecated, use `socket` instead. The underlying connection of the incoming request.
 - `socket` - the underlying connection of the incoming request
 
+### Headers
+
+The `request.headers` is a getter that return an Object with the headers of the incoming request.
+You can set custom headers like this:
+
+```js
+request.headers = {
+  'foo': 'bar',
+  'baz': 'qux'
+}
+```
+
+This operation will add to the request headers the new values that can be read calling `request.headers.bar`.  
+Moreover, you can still access the standard request's headers with the `request.raw.headers` property.
 
 ```js
 fastify.post('/:params', options, function (request, reply) {
@@ -38,6 +52,9 @@ fastify.post('/:params', options, function (request, reply) {
   console.log(request.ips)
   console.log(request.hostname)
   console.log(request.protocol)
+  console.log(request.url)
+  console.log(request.routerMethod)
+  console.log(request.routerPath)
   request.log.info('some info')
 })
 ```

lib/request.js

@@ -162,7 +162,13 @@ Object.defineProperties(Request.prototype, {
   },
   headers: {
     get () {
+      if (this.additionalHeaders) {
+        return Object.assign({}, this.raw.headers, this.additionalHeaders)
+      }
       return this.raw.headers
+    },
+    set (headers) {
+      this.additionalHeaders = headers
     }
   },
   server: {

test/schema-special-usage.test.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const { test } = require('tap')
+const Joi = require('@hapi/joi')
 const AJV = require('ajv')
 const S = require('fluent-json-schema')
 const Fastify = require('..')
@@ -748,3 +749,34 @@ test('multiple refs with the same ids', t => {
     t.same(res.json(), { hello: 'world' })
   })
 })
+
+test('JOI validation overwrite request headers', t => {
+  t.plan(3)
+  const schemaValidator = ({ schema }) => data => {
+    const validationResult = schema.validate(data)
+    return validationResult
+  }
+
+  const fastify = Fastify()
+  fastify.setValidatorCompiler(schemaValidator)
+
+  fastify.get('/', {
+    schema: {
+      headers: Joi.object({
+        'user-agent': Joi.string().required(),
+        host: Joi.string().required()
+      })
+    }
+  }, (request, reply) => {
+    reply.send(request.headers)
+  })
+
+  fastify.inject('/', (err, res) => {
+    t.error(err)
+    t.equal(res.statusCode, 200)
+    t.same(res.json(), {
+      'user-agent': 'lightMyRequest',
+      host: 'localhost:80'
+    })
+  })
+})