Properly unpipe old pipes on request

Otherwise it feels like the scope is going wild because you'll end up
piping to the previous transformer

Scoop.test.js

@@ -45,7 +45,7 @@ await test('Scoop - capture of a web page.', async (t) => {
   await t.test('Scoop follows redirects', async (_t) => {
     const statusCode = 301
     const { exchanges: [redirect, html] } = await Scoop.capture(`${URL}/redirect?statusCode=${statusCode}&path=test.html`, options)
-    assert.equal(redirect.response.statusCode, statusCode)
+    assert.equal(redirect.response.startLine.split(' ')[1], statusCode.toString())
     assert.equal(html.response.body.toString(), testHtmlFixture.toString())
   })
 

intercepters/ScoopProxy.js

@@ -177,9 +177,8 @@ export class ScoopProxy extends ScoopIntercepter {
    * @returns {Buffer}
    */
   intercept (type, data, request) {
-    // Early exit if not recording exchanges or request is blocked
     const exchange = this.exchanges.find(ex => ex.requestParsed === request)
-    if (!exchange) return data
+    if (!exchange) return data // Early exit if not recording exchanges or request is blocked
 
     const prop = `${type}Raw` // `responseRaw` | `requestRaw`
     exchange[prop] = Buffer.concat([exchange[prop], data], exchange[prop].length + data.length)

utils/proxy.js

@@ -2,7 +2,7 @@ import * as http from 'http'
 import * as https from 'https'
 import { TLSSocket } from 'tls'
 import { URL } from 'url'
-import { Transform, PassThrough } from 'node:stream'
+import { PassThrough } from 'node:stream'
 
 const defaults = {
   requestTransformer: (_request) => new PassThrough(),
@@ -41,11 +41,7 @@ export function createProxy (options) {
   const proxy = http.createServer()
 
   proxy.on('connection', (socket) => {
-    socket.mirror = new Transform({
-      transform: (chunk, _encoding, callback) => {
-        process.nextTick(callback, null, chunk)
-      }
-    })
+    socket.mirror = new PassThrough()
     socket.pipe(socket.mirror)
   })
 
@@ -65,6 +61,10 @@ export function createProxy (options) {
   })
 
   proxy.on('request', (request) => {
+    // clear existing pipes from previous requests
+    // otherwise the previous request will be sent to the transformer
+    request.socket.mirror.unpipe()
+
     const urlString = request.url.startsWith('/')
       ? `${UNKNOWN_PROTOCOL}//${request.headers.host}${request.url}`
       : request.url
@@ -82,7 +82,7 @@ export function createProxy (options) {
     httpModule
       .request(options)
       .on('socket', (socket) => {
-        request.socket.mirror.pipe(requestTransformer(request)).pipe(socket, { end: false })
+        request.socket.mirror.pipe(requestTransformer(request)).pipe(socket)
         socket.mirror = new PassThrough()
         socket.pipe(socket.mirror)
       })