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On localhost fetch headers.get comes up null for everything

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  • Last reply by tbednarczyk

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I've been having this issue ever since the latest release of firefox.

Essentially it will be fine for a while and then all of a sudden firefox is unable to retrieve any headers from the fetch response. If I refresh firefox this fixes the issue, but only for a small amount of time. The same bug doesn't happen on chrome and I haven't had it happen to me yet on firefox developer edition. It happens if I use this browser on private browsing with no plugins as well.

Note that we do use a fetch wrapper but it essentially returns the entire response object in the screenshots below.

Also note that it doesn't seem to happen anywhere but localhost. Is there anything I can do here?

Attached screenshots

Chosen solution

Turns out this is an error with Rack::Cors for Rails not firefox.

It seems that for firefox 83 Rack is not sending any `Access-Control-*` headers.

And if you don't have Access-Control-Expose-Headers: Content-Disposition you can't access that header.

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Capitalized version doesn't work either.

Helpful?

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Chosen Solution

Turns out this is an error with Rack::Cors for Rails not firefox.

It seems that for firefox 83 Rack is not sending any `Access-Control-*` headers.

And if you don't have Access-Control-Expose-Headers: Content-Disposition you can't access that header.

Helpful?

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