fetch doesn't follow redirects

[bartlomieju]

Currently fetch doesn't support redirects - eg:

// current behavior
const response = await fetch("https://deno.land/std/colors/mod.ts")
response.status // 302
response.redirected // false
await Deno.readAll(response.body) // Uint8Array [] - empty!

// expected behavior
const response = await fetch("https://deno.land/std/colors/mod.ts")
response.status // 200
response.redirected // true
await Deno.readAll(response.body) // Uint8Array [...snip...] - should be filled with data

I did quick research and it seems that hyper client doesn't support redirects. I found this extension: https://github.com/srijs/rust-follow-redirects, but it's not very popular so I guess we'll need to handle that ourselves.

This feature is needed for installer denoland/std#471.

[Fenzland]

As I see, check response.status and refetch manually is better than auto follow.

[bartlomieju]

My bad - of course you can configure fetch to either follow redirects or not with fetch(url, {redirect: "follow"}); - but still Deno does not support this option now.

[TonyLianLong]

The redirected is unimplemented as in https://github.com/denoland/deno/blob/master/js/fetch.ts#L246. I can have a try at implementing this these two weeks when I'm free. This is a huge workload since redirected depends on unimplemented feature such as type and implementing redirected also requires the implementation of these features.