fix: prevent stubbed cy.intercepts from reaching server (#15942)

cypress-io · Apr 12, 2021 · dde2f22 · dde2f22 · cypress-bot · Apr 12, 2021
1 parent 86ffe20
commit dde2f22
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Showing 5 changed files with 46 additions and 5 deletions.
diff --git a/packages/driver/cypress/integration/commands/net_stubbing_spec.ts b/packages/driver/cypress/integration/commands/net_stubbing_spec.ts
@@ -984,6 +984,22 @@ describe('network stubbing', { retries: { runMode: 2, openMode: 0 } }, function
       }).wait('@getFoo').its('request.url').should('include', '/foo')
     })
 
+    // @see https://github.com/cypress-io/cypress/issues/15841
+    it('prevents requests from reaching destination server', function () {
+      const v = String(Date.now())
+
+      // this test creates server-side state via /set-var to test if requests are being sent or not
+      cy.then(async () => {
+        await $.get(`/set-var?v=${v}`)
+        expect(await $.get('/get-var')).to.eq(v)
+      })
+      .intercept('/set-var*', { statusCode: 200, body: 'else' })
+      .then(async () => {
+        await $.get(`/set-var?v=something`)
+        expect(await $.get('/get-var')).to.eq(v)
+      })
+    })
+
     // @see https://github.com/cypress-io/cypress/issues/8532
     context('can stub a response with an empty array', function () {
       const assertEmptyArray = (done) => {

diff --git a/packages/driver/cypress/plugins/server.js b/packages/driver/cypress/plugins/server.js
@@ -151,6 +151,17 @@ const createApp = (port) => {
     .send('<html><body>server error</body></html>')
   })
 
+  let _var = ''
+
+  app.get('/set-var', (req, res) => {
+    _var = req.query.v
+    res.sendStatus(200)
+  })
+
+  app.get('/get-var', (req, res) => {
+    res.send(_var)
+  })
+
   app.use(express.static(path.join(__dirname, '..')))
 
   app.use(require('errorhandler')())

diff --git a/packages/net-stubbing/lib/server/intercepted-request.ts b/packages/net-stubbing/lib/server/intercepted-request.ts
@@ -22,6 +22,7 @@ export class InterceptedRequest {
     subscriptions: Subscription[]
   }> = []
   includeBodyInAfterResponse: boolean = false
+  responseSent: boolean = false
   lastEvent?: string
   onError: (err: Error) => void
   /**
@@ -31,14 +32,13 @@ export class InterceptedRequest {
   /**
    * Finish the current request with a response.
    */
-  onResponse: (incomingRes: IncomingMessage, resStream: Readable) => void
+  _onResponse: (incomingRes: IncomingMessage, resStream: Readable) => void
   /**
    * A callback that can be used to send the response through the rest of the response proxy steps.
    */
   continueResponse?: (newResStream?: Readable) => void
   req: CypressIncomingRequest
   res: CypressOutgoingResponse
-  incomingRes?: IncomingMessage
   matchingRoutes: BackendRoute[]
   state: NetStubbingState
   socket: CyServer.Socket
@@ -49,14 +49,24 @@ export class InterceptedRequest {
     this.res = opts.res
     this.continueRequest = opts.continueRequest
     this.onError = opts.onError
-    this.onResponse = opts.onResponse
+    this._onResponse = opts.onResponse
     this.matchingRoutes = opts.matchingRoutes
     this.state = opts.state
     this.socket = opts.socket
 
     this.addDefaultSubscriptions()
   }
 
+  onResponse = (incomingRes: IncomingMessage, resStream: Readable) => {
+    if (this.responseSent) {
+      throw new Error('onResponse cannot be called twice')
+    }
+
+    this.responseSent = true
+
+    this._onResponse(incomingRes, resStream)
+  }
+
   private addDefaultSubscriptions () {
     if (this.subscriptionsByRoute.length) {
       throw new Error('cannot add default subscriptions to non-empty array')

diff --git a/packages/net-stubbing/lib/server/middleware/request.ts b/packages/net-stubbing/lib/server/middleware/request.ts
@@ -148,5 +148,11 @@ export const InterceptRequest: RequestMiddleware = async function () {
   // @ts-ignore
   mergeChanges(request.req, req)
 
+  if (request.responseSent) {
+    // request has been fulfilled with a response already, do not send the request outgoing
+    // @see https://github.com/cypress-io/cypress/issues/15841
+    return this.end()
+  }
+
   return request.continueRequest()
 }
diff --git a/packages/net-stubbing/lib/server/middleware/response.ts b/packages/net-stubbing/lib/server/middleware/response.ts
@@ -28,8 +28,6 @@ export const InterceptResponse: ResponseMiddleware = async function () {
     return this.next()
   }
 
-  request.incomingRes = this.incomingRes
-
   request.onResponse = (incomingRes, resStream) => {
     this.incomingRes = incomingRes