fix: properly handle Express.js send payload (#221)

Co-authored-by: extern-chalkin-andrey <Andrey.Chalkin@Solveva.com>

index.js

@@ -45,6 +45,12 @@ function doInject (dispatchFunc, options, callback) {
     ? Request.CustomRequest
     : Request
 
+  // Express.js detection
+  if (dispatchFunc.request && dispatchFunc.request.app === dispatchFunc) {
+    Object.setPrototypeOf(Object.getPrototypeOf(dispatchFunc.request), RequestConstructor.prototype)
+    Object.setPrototypeOf(Object.getPrototypeOf(dispatchFunc.response), Response.prototype)
+  }
+
   if (typeof callback === 'function') {
     const req = new RequestConstructor(options)
     const res = new Response(req, callback)

lib/response.js

@@ -62,7 +62,16 @@ Response.prototype.setTimeout = function (msecs, callback) {
 Response.prototype.writeHead = function () {
   const result = http.ServerResponse.prototype.writeHead.apply(this, arguments)
 
-  copyHeaders(this)
+  this._lightMyRequest.headers = Object.assign({}, this.getHeaders())
+
+  // Add raw headers
+  ;['Date', 'Connection', 'Transfer-Encoding'].forEach((name) => {
+    const regex = new RegExp('\\r\\n' + name + ': ([^\\r]*)\\r\\n')
+    const field = this._header.match(regex)
+    if (field) {
+      this._lightMyRequest.headers[name.toLowerCase()] = field[1]
+    }
+  })
 
   return result
 }
@@ -109,9 +118,6 @@ Response.prototype.addTrailers = function (trailers) {
 }
 
 function generatePayload (response) {
-  if (response._lightMyRequest.headers === null) {
-    copyHeaders(response)
-  }
   // Prepare response object
   const res = {
     raw: {
@@ -155,17 +161,4 @@ function getNullSocket () {
   })
 }
 
-function copyHeaders (response) {
-  response._lightMyRequest.headers = Object.assign({}, response.getHeaders())
-
-  // Add raw headers
-  ;['Date', 'Connection', 'Transfer-Encoding'].forEach((name) => {
-    const regex = new RegExp('\\r\\n' + name + ': ([^\\r]*)\\r\\n')
-    const field = response._header.match(regex)
-    if (field) {
-      response._lightMyRequest.headers[name.toLowerCase()] = field[1]
-    }
-  })
-}
-
 module.exports = Response

test/test.js

@@ -1949,3 +1949,19 @@ test('should leave the headers user-agent and content-type undefined when the he
     t.error(err)
   })
 })
+
+test("passes payload when using express' send", (t) => {
+  t.plan(3)
+
+  const app = express()
+
+  app.get('/hello', (req, res) => {
+    res.send('some text')
+  })
+
+  inject(app, { method: 'GET', url: 'http://example.com:8080/hello' }, (err, res) => {
+    t.error(err)
+    t.equal(res.headers['content-length'], '9')
+    t.equal(res.payload, 'some text')
+  })
+})