capture websocket request in cypress

Question

I'm trying to capture all the requests that occur during the test. My application uses WebSocket and with the intercept command I can't catch wss requests. Is there any way to do this?

Answer 1

I don't think web sockets can be caught directly by the intercept command.

One approach is to observe the results of ws communication, as shown here Testing a websocket application with Cypress between two instance of Cypress runner.

If your app talks between app and server, then start the server in /cypress/plugins/index.js and use cy.task() to get the server end of the communication.

---

There is also a library cypress-websocket-testing which uses rxjs, which is quite powerful but takes some getting used to.

cy.streamRequest(config, options).then(results => {
        expect(results).to.not.be.undefined;
})
// When in need of a bit more flexibility
cy.stream(config).then(subject => {
      subject
        .pipe(
          takeUntil(timer(1000)),
          reduce((acc , val) => acc.concat([val]), [])
        )
        .subscribe({
          next: (results) => {
            expect(results).to.not.be.undefined;
          },
          error: (err) => {},
          complete: done
        });
    });

Answer 2

Not supported in Cypress as of now only xhr requests are supported by cy.intercept, you need to create wesbsocket server and listen at a port and it needed to be started in another process and then using fixtures send the required response data