added test for multipart/form-data request with text and file (#121)

* added test for multipart/form-data request with text and file

* added to test to check compatibility with fastify-multipart

* added warn message when fastify-reply-from is registered with fastify-multipart

* added documentation for incompatibility between fastify-reply-from and fastify-multipart

* removed unecessary async in test

* briefly explained why fastify-reply-from is incompatible with fastify-multipart

Co-authored-by: Luca Marzi <luca.marzi@mia-platform.eu>

Author: theliuk

README.md

@@ -12,6 +12,10 @@ HTTP2 to HTTP is supported too.
 npm i fastify-reply-from
 ```
 
+## Compatibility with fastify-multipart
+`fastify-reply-from` and [`fastify-multipart`](https://github.com/fastify/fastify-multipart) should not be registered as sibling plugins nor shold be registered in plugins which have a parent-child relationship.<br> The two plugins are incompatible, in the sense that the behavior of `fastify-reply-from` might not be the expected one when the above-mentioned conditions are not respected.<br> This is due to the fact that `fastify-multipart` consumes the multipart content by parsing it, hence this content is not forwarded to the target service by `fastify-reply-from`.<br>
+However, the two plugins may be used within the same fastify instance, at the condition that they belong to disjoint branches of the fastify plugins hierarchy tree. 
+
 ## Usage
 
 The following example set up two fastify servers and forward the request

index.js

@@ -133,6 +133,13 @@ module.exports = fp(function from (fastify, opts, next) {
     return this
   })
 
+  fastify.addHook('onReady', (done) => {
+    if (isFastifyMultipartRegistered(fastify)) {
+      fastify.log.warn('fastify-reply-from might not behave as expected when used with fastify-multipart')
+    }
+    done()
+  })
+
   fastify.onClose((fastify, next) => {
     close()
     // let the event loop do a full run so that it can
@@ -172,3 +179,7 @@ function requestHeadersNoOp (originalReq, headers) {
 function onErrorDefault (reply, { error }) {
   reply.send(error)
 }
+
+function isFastifyMultipartRegistered (fastify) {
+  return fastify.hasContentTypeParser('multipart') && fastify.hasRequestDecorator('multipart')
+}

package.json

@@ -34,6 +34,8 @@
     "@types/node": "^14.14.2",
     "@types/tap": "^14.10.1",
     "fastify": "^3.7.0",
+    "fastify-multipart": "^3.3.1",
+    "form-data": "^2.3.3",
     "got": "^11.8.0",
     "h2url": "^0.2.0",
     "msgpack5": "^4.2.1",
@@ -42,6 +44,7 @@
     "proxyquire": "^2.1.3",
     "simple-get": "^4.0.0",
     "snazzy": "^9.0.0",
+    "split2": "^3.2.2",
     "standard": "^16.0.3",
     "tap": "^14.10.7",
     "tsd": "^0.14.0",

test/fastify-multipart-incompatibility.js

@@ -0,0 +1,90 @@
+'use strict'
+
+const fs = require('fs')
+const path = require('path')
+const t = require('tap')
+const Fastify = require('fastify')
+const From = require('..')
+const Multipart = require('fastify-multipart')
+const http = require('http')
+const get = require('simple-get').concat
+const FormData = require('form-data')
+
+const split = require('split2')
+const logStream = split(JSON.parse)
+
+const instance = Fastify({
+  logger: {
+    level: 'warn',
+    stream: logStream
+  }
+})
+
+instance.register(Multipart)
+instance.register(From)
+
+t.plan(12)
+
+t.tearDown(instance.close.bind(instance))
+
+const filetPath = path.join(__dirname, 'fixtures', 'file.txt')
+const fileContent = fs.readFileSync(filetPath, { encoding: 'utf-8' })
+
+const target = http.createServer((req, res) => {
+  t.pass('request proxied')
+  t.equal(req.method, 'POST')
+  t.match(req.headers['content-type'], /^multipart\/form-data/)
+  let data = ''
+  req.setEncoding('utf8')
+  req.on('data', (d) => {
+    data += d
+  })
+  req.on('end', () => {
+    t.notMatch(data, 'Content-Disposition: form-data; name="key"')
+    t.notMatch(data, 'value')
+    t.notMatch(data, 'Content-Disposition: form-data; name="file"')
+    t.notMatch(data, fileContent)
+    res.setHeader('content-type', 'application/json')
+    res.statusCode = 200
+    res.end(JSON.stringify({ something: 'else' }))
+  })
+})
+
+instance.post('/', (request, reply) => {
+  reply.from(`http://localhost:${target.address().port}`)
+})
+
+t.tearDown(target.close.bind(target))
+
+instance.listen(0, (err) => {
+  t.error(err)
+
+  logStream.on('data', (log) => {
+    if (
+      log.level === 40 &&
+      log.msg.match(/fastify-reply-from might not behave as expected when used with fastify-multipart/)
+    ) {
+      t.pass('incompatibility warn message logged')
+    }
+  })
+
+  target.listen(0, (err) => {
+    t.error(err)
+
+    const form = new FormData()
+    form.append('key', 'value')
+    form.append('file', fs.createReadStream(filetPath, { encoding: 'utf-8' }))
+
+    get({
+      url: `http://localhost:${instance.server.address().port}`,
+      method: 'POST',
+      headers: {
+        ...form.getHeaders()
+      },
+      body: form
+    }, (err, res, data) => {
+      t.error(err)
+      t.deepEqual(JSON.parse(data), { something: 'else' })
+    })
+  })
+})

test/fixtures/file.txt

@@ -0,0 +1 @@
+file content