Cypress w/ Shopify - Error: Content-Length can't be present with chunked encoding

Current behavior

When locally testing Shopify themes whose storefronts are password-protected, Cypress tests fail almost immediately with the following error:

cy.visit() failed trying to load:

https://localhost:3000/?preview_theme_id=120240898208

We attempted to make an http request to this URL but the request failed without a response.

We received this error at the network level:

  > Error: Parse Error: Content-Length can't be present with chunked encoding

Common situations why this would fail:
  - you don't have internet access
  - you forgot to run / boot your web server
  - your web server isn't accessible
  - you have weird network configuration settings on your computer

Desired behavior

Cypress should load the storefront landing page normally when visiting: https://localhost:3000/?preview_theme_id=120240898208

Test code to reproduce

I have created a repo with instructions on how to set everything up to recreate the issue.

https://github.com/paxsolutions/cypress-shopify-issue

Versions

Cypress - v6.5.0 Chrome - v88.0.4324.192 Node - v14.4.0 macOS Big Sur

I understand there are several technologies in play here, still, any guidance is greatly appreciated.

[sirtawast]

This is a problem with the existing backend. For what it’s worth, NGINX setting chunked_transfer_encoding off; did the trick for me.

@paxsolutions not sure how you locally develop Shopify (used to be online only), but you might try proxying through NGINX or similar software and try and set the headers not to use chunked encoding.

#1185

This might be related.

I have similar issue with a certain webpack bundle / browser-sync configuration, wpack.io to be exact.

I can get the page to render by adding an additional header at NGINX, which servers the PHP upstream.

server {
  ...
  add_header transfer-encoding identity;
  ...
}

I might try using HTTPS and HTTP/2 so that transfer-encoding: chunked won’t be there anymore, as per HTTP/2 spec.

[Sawthis]

@sirtawast unfortunately it doesn’t help in my case which is described here: https://github.com/cypress-io/cypress/issues/1185#issuecomment-856745211