fix: added support for testing header modification with http-proxy

lib/request_overrider.js

@@ -227,6 +227,13 @@ function RequestOverrider(req, options, interceptors, remove, cb) {
     /// like to change request.path in mid-flight.
     options.path = req.path
 
+    // similarly, node-http-proxy will modify headers in flight, so we have to put the headers back
+    // into options
+    const reqHeaders = req.getHeaders ? req.getHeaders() : req._headers;
+    if (Object.keys(reqHeaders).length > 0) {
+      options.headers = req.getHeaders ? req.getHeaders() : req._headers;
+    }
+
     // fixes #976
     options.protocol = `${options.proto}:`
 

package.json

@@ -43,6 +43,7 @@
     "eslint-plugin-promise": "^4.0.1",
     "eslint-plugin-standard": "^4.0.0",
     "got": "^9.4.0",
+    "http-proxy": "^1.17.0",
     "hyperquest": "^2.1.3",
     "isomorphic-fetch": "^2.2.0",
     "lolex": "^3.0.0",

tests/test_intercept.js

@@ -11,6 +11,7 @@ const restify = require('restify-clients')
 const hyperquest = require('hyperquest')
 const got = require('got')
 const nock = require('..')
+const httpProxy = require('http-proxy')
 
 require('./cleanup_after_each')()
 
@@ -1711,3 +1712,43 @@ test('teardown', t => {
   t.deepEqual(leaks, [], 'No leaks')
   t.end()
 })
+
+test('works when headers removed by http-proxy', t => {
+  const serviceScope = nock('http://service', {
+    badheaders: ['authorization'],
+  })
+    .get('/endpoint')
+    .reply(200)
+
+  const proxy = httpProxy.createProxyServer({
+    prependUrl: false,
+  })
+
+  proxy.on('proxyReq', (proxyReq, req, res) => {
+    proxyReq.removeHeader('authorization')
+  })
+
+  const server = http.createServer((request, response) => {
+    proxy.web(request, response, { target: 'http://service' })
+  })
+
+  server.listen(() => {
+    const options = {
+      uri: `http://localhost:${server.address().port}/endpoint`,
+      method: 'GET',
+      headers: {
+        authorization: 'blah',
+      },
+    }
+
+    mikealRequest(options, (err, resp, body) => {
+      if (err) {
+        t.error(err)
+      } else {
+        t.equal(200, resp.statusCode)
+        serviceScope.done()
+        server.close(t.end)
+      }
+    })
+  })
+})