Add proxyPayloads option (#87)

Author: amiteshtoharya4

README.md

@@ -94,6 +94,19 @@ Rewrite the prefix to the specified string. Default: `''`.
 
 A `preHandler` to be applied on all routes. Useful for performing actions before the proxy is executed (e.g. check for authentication).
 
+### proxyPayloads
+
+When this option is `false`, you will be able to access the body but it will also disable direct pass through of the payload. As a result, it is left up to the implementation to properly parse and proxy the payload correctly.
+
+For example, if you are expecting a payload of type `application/xml`, then you would have to add a parser for it like so:
+
+```javascript
+fastify.addContentTypeParser('application/xml', (req, done) => {
+  const parsedBody = parsingCode(req)
+  done(null, parsedBody)
+})
+```
+
 ### config
 
 An object accessible within the `preHandler` via `reply.context.config`.

index.d.ts

@@ -23,6 +23,7 @@ declare const fastifyHttpProxy: Plugin<
     prefix?: string;
     rewritePrefix?: string;
     http2?: boolean;
+    proxyPayloads?: boolean;
     preHandler?: (
       request: FastifyRequest<
         HttpRequest,

index.js

@@ -22,8 +22,10 @@ module.exports = async function (fastify, opts) {
 
   fastify.register(From, fromOpts)
 
-  fastify.addContentTypeParser('application/json', bodyParser)
-  fastify.addContentTypeParser('*', bodyParser)
+  if (opts.proxyPayloads !== false) {
+    fastify.addContentTypeParser('application/json', bodyParser)
+    fastify.addContentTypeParser('*', bodyParser)
+  }
 
   function rewriteHeaders (headers) {
     const location = headers.location

test/test.js

@@ -111,6 +111,30 @@ async function run () {
     t.deepEqual(resultRoot.body, { something: 'posted' })
   })
 
+  test('skip proxying the incoming payload', async t => {
+    const server = Fastify()
+    server.register(proxy, {
+      upstream: `http://localhost:${origin.server.address().port}`,
+      proxyPayloads: false,
+      preHandler (request, reply, next) {
+        t.deepEqual(request.body, { hello: 'world' })
+        next()
+      }
+    })
+
+    await server.listen(0)
+    t.tearDown(server.close.bind(server))
+
+    await got(
+      `http://localhost:${server.server.address().port}/this-has-data`,
+      {
+        method: 'POST',
+        json: { hello: 'world' },
+        responseType: 'json'
+      }
+    )
+  })
+
   test('preHandler', async t => {
     const server = Fastify()
     server.register(proxy, {