httpext: replace HTTP digest library

[Juneezee]

What?

This PR replaces our current HTTP digest library github.com/Soontao/goHttpDigestClient with github.com/icholy/digest.

Why?

The current HTTP Digest library,
github.com/Soontao/goHttpDigestClient, has not been updated since March 2017 and is known to be buggy.

github.com/icholy/digest is a newer library that provides an http.RoundTripper implementation, allowing digest challenges to be reused. This aligns well with our use case.

Checklist

• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have added tests for my changes.
• I have run linter and tests locally (make check) and all pass.

Checklist: Documentation (only for k6 maintainers and if relevant)

Please do not merge this PR until the following items are filled out.

• I have added the correct milestone and labels to the PR.
• I have updated the k6-documentation: grafana/k6-docs#PR-NUMBER
• I have updated the TypeScript definitions: grafana/k6-DefinitelyTyped#PR-NUMBER
• I have updated the release notes: link

Related PR(s)/Issue(s)

Closes #800.

[Juneezee]

I have performed a self-review of my changes.

/cc @na--, author of Issue #800

[Juneezee]

github.com/icholy/digest will handle the 401 response and cache the digest challenge for us.

https://github.com/icholy/digest/blob/v1.1.0/transport.go#L141-L188

[mstoykov]

Thank you for the PR @Juneezee 🙇

I think that we can drop the whole digest_transport.go file and not have one more transport wrapper.

I wonder if we can get some tests to see that we do not get 401 each time , as that is one of the consequences of the original issue that we want fixed.

[Juneezee]

I wonder if we can get some tests to see that we do not get 401 each time , as that is one of the consequences of the original issue that we want fixed.

@mstoykov I tried it, and it seems that the 401 Unauthorized case is unavoidable. The screenshot below shows the debugger attached to the TestRequest/Params/digest/auth/success test case, where we can see that the response status code is 401.

k6/js/modules/k6/http/request_test.go

Lines 956 to 957 in dafd7f8

	t.Run("digest", func(t *testing.T) {
	t.Run("success", func(t *testing.T) {

[kapsh]

Will it be possible to support custom digest header set by js Params.auth? I encountered service that sends challenge in non-standard x-something-authenticate and I'd like to use k6 to test it.