Cypress: Return conditional data based an XHR's request details

[sarahgracesmith]

Often a server will respond conditionally to a request based on information in the POST data. Would be helpful to be able to do this using cy.route() - currently if a function is passed in it is called immediately, not at the point of requesting.

[bahmutov]

@sarahgracesmith can you give me a little code snippet of what you would like to see ideally here?

[sarahgracesmith]

for example, the following commentsResponse would check the request variables and dynamically return different results. Similar to how a server might behave. This would allow returning different results for the same route in a single test even if there's no logical point to re-route() in the test.

const commentsResponse = (routeData) => {
  //routeData is a reference to the current route's information
  if ( ... request contains some field ... )
    return {
      data: foo
    }
  } else {
    return {
      data: bar
    }
  }
}

cy.route('POST', '/comments/**', commentsResponse)

[bahmutov]

👍 I have this test passing

it('returns data based on response', () => {
    let req
    cy
      .route({
        url: '/users?_limit=3',
        response: r => {
          req = r
          return [1, 2, 3]
        },
        headers: {
          'access-control-allow-origin': '*'
        }
      })
      .as('users')
    cy.visit('has-fetch.html')
    cy.wait('@users').then(() => {
      expect(req).to.deep.equal({
        method: 'GET',
        url: '/users?_limit=3'
      })
    })
  })

which confirms the right logic

[SaladFork]

While the xhr object passed to the response function includes method and url of the request, it seems to be missing the request body.

Example desired usage:

let users = { 1: { id: 1, name: 'Foo', usesCypress: true } };
cy.route('GET', '/users/1', users[1]);

cy.route('PATCH', '/users/1', ({ request: { body } }) => {
  return { ...users[1], ...body };
});

// App code calls `patch('/users/1', { name: 'Bar' })` and expects
// to get back `{ id: 1, name: 'Bar', usesCypress: true }`

The above would mirror the data that gets passed to a then handler on cy.wait('@someStubbedRoute').

I am hard-coding in the responses in my tests today, but this would be useful for creating generic reusable routes.

[jennifer-shehane]

Closing as duplicate of https://github.com/cypress-io/cypress/issues/521