Files
zitadel/apps/login
Max PeintnerandGitHub 637b370c17 chore(login): Extract auth flow utilities and eliminate RSC request interference (#10644)
The /login route was experiencing issues with React Server Component
(RSC) requests interfering with one-time authentication callbacks. When
users navigated to /login via client-side routing (router.push()),
Next.js automatically triggered _rsc requests that could consume
single-use createCallback tokens, breaking OIDC and SAML authentication
flows.

# Which Problems Are Solved

When users attempt to log in, Next.js automatically makes requests with
the `_rsc=1` query parameter for React Server Components. The current
implementation treats these as server errors:

```typescript
// Before
if (_rsc) {
  return NextResponse.json({ error: "No _rsc supported" }, { status: 500 });
}
```

This results in:
- Spurious 500 error logs polluting monitoring systems
- False alerts for server failures 
- Difficulty distinguishing real issues from benign RSC requests

# How the Problems Are Solved

This PR implements a comprehensive refactoring that:

- Eliminates RSC interference by providing server actions for internal
auth flow completion
- Separates concerns between external flow initiation and internal flow
completion
- Extracts shared utilities to improve code maintainability and
reusability
- Maintains full backward compatibility for external applications

# Additional Context

## New Architecture
- auth-flow.ts: Shared utilities for auth flow completion with RSC
protection
- flow-initiation.ts: Extracted OIDC/SAML flow initiation logic (~400
lines)
- auth.ts: Server actions for internal components

## Route Handler Simplification
- route.ts: Reduced from ~350 lines to ~75 lines
- External-only focus: Now handles only flow initiation for external
applications
- Removed completion logic: External apps use their own callback URLs
- Enhanced validation: Early RSC blocking and parameter validation

## Flow Logic Improvements
- Early return patterns: Guard clauses eliminate deep nesting
- Better error handling: Specific error messages for different failure
modes
- Fixed SAML flow: Addressed incomplete logic
- Consistent session handling: Unified approach across OIDC and SAML
2025-09-22 16:09:20 +00:00
..
2025-07-31 07:51:26 +00:00