fix(proxy): preserve cross-origin redirects - #34
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ModifyResponse stripped the scheme and host from every 302 Location header, without checking where the redirect pointed. An absolute cross-origin redirect, such as the auth filter sending an unauthenticated browser to the identity provider, was reduced to a bare path that the browser resolved against the proxy, so the OIDC flow never started. Compare the redirect target with the upstream origin and rewrite only when they match. Relative Location headers are left alone, as are redirects to any other origin. Refs OKDP#33
abir-oumghar
approved these changes
Sep 1, 2026
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Description
ModifyResponsestripped the scheme and host from every302 Locationheader without checking where the redirect pointed.As a result, any absolute cross-origin redirect could be reduced to a relative path and incorrectly resolved by the browser against
spark-web-proxy.For example, when the Spark authentication filter redirects an unauthenticated browser to an OIDC identity provider:
the proxy rewrote the
Locationto:The browser then resolved that relative path against
spark-web-proxy:resulting in a
404instead of continuing the OIDC authentication flow.This change:
Locationheaders unchanged;This preserves the existing Spark redirect behavior while allowing redirects to external origins, including identity providers, to pass through correctly.
Related Issue
Refs #33
Type of Change
How to Test
Run the project test suite:
make testThe issue can be reproduced using the Spark authentication filter with PKCE disabled, causing it to emit an HTTP
302redirect to Keycloak:Then access the Spark History UI through
spark-web-proxy.Before
The external OIDC redirect is rewritten and resolved against the proxy:
and returns
404.After
The original cross-origin
Locationis preserved:and the browser is correctly redirected to the identity provider.
Internal Spark redirects continue to be rewritten through the proxy, while relative redirects remain unchanged.
Checklist