Proxy buffers Transfer-Encoding: chunked responses and breaks streams

[nLight]

Hi friends!

We have a XmlHttpRequest that never finishes. We're using it as a stream parsing responseText on every onProgress event.

The problem is that we never get the last chunk as it would be sitting somewhere buffered. We can't really control the server behaviour here and I wonder if the buffer can be flushed after each chunk?

• Operating System: Linux
• Cypress Version: 3.1.3
• Browser Version: all of them

Is this a Feature or Bug?

bug

Current behavior:

cypress waits a request to complete

Desired behavior:

Cypress should propagate onProgress events and update responseText accordingly

How to reproduce:

• an endpoint with Transfer-Encoding: chunked that sends messages one after another and doesn't close throughout the session.
• browser connection that reads those messages listening to onProgress

[brian-mann]

I'm sure this is a bug and it'll be fixed by #687

[tdaniely]

Any ideas on how to workaround this currently? I have a big init call on most page loads that's chunked.
I'm trying to stub the route with the result of a cy.request(..), but I'm not getting there.
If I put the response in a fixture, then it goes through, but a static isn't enough in this situation.

Edit: Eventually opted to just change the app itself to disable chunked encoding during tests.

[nLight]

There are quite some issues that have one common thing among them: Transfer-Encoding: chunked. In our case we have a persistent connection that never closes. Looks like there's a some kind of buffer. We never get the last chunk of data. I assume there's a proxy that waits for another chunk or the connection to be closed by the server to flush the buffer.

[nLight]

@jennifer-shehane I wouldn't call it a feature though.

[nLight]

I updated description as I got some insights.