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# Which Problems Are Solved
When deploying the login application behind proxies or using Vercel
rewrites (e.g., `zitadel.com/login` → `login-zitadel-qa.vercel.app`),
the application was using the internal rewritten host instead of the
original user-facing host. This caused several issues:
1. **Broken Password Reset Emails**: Email links contained internal
hosts like `login-zitadel-qa.vercel.app` instead of `zitadel.com`
2. **Inconsistent User Experience**: Users would see different domains
in various parts of the flow
3. **Security Concerns**: Internal infrastructure details were exposed
to end users
4. **Scattered Logic**: Host detection logic was duplicated across
multiple files with inconsistent error handling
# How the Problems Are Solved
Created comprehensive host detection utilities in `/lib/server/host.ts`
and `/lib/client/host.ts`:
**Server-side utilities:**
- `getOriginalHost()` - Returns the original user-facing host
- `getOriginalHostWithProtocol()` - Returns host with proper protocol
(http/https)
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
Safari was not creating session cookies during local development,
causing authentication failures. This was due to nextjs default setting
of SameSite cookie property.
We explicitly set "strict" for session cookies now.
Closes#10473
# Which Problems Are Solved
Authentication Issues with Safari in local development
# How the Problems Are Solved
- Cleaner API: Replaced confusing sameSite boolean/string parameters
with iFrameEnabled boolean
- Better logic flow:
iFrameEnabled: true → sameSite: "none" (for iframe embedding)
Production → sameSite: "strict" (maximum security)
# Which Problems Are Solved
- The previous monorepo in monorepo structure for the login app and its
related packages was fragmented, complicated and buggy.
- The process for building and testing the login container was
inconsistent between local development and CI.
- Lack of clear documentation as well as easy and reliable ways for
non-frontend developers to reproduce and fix failing PR checks locally.
# How the Problems Are Solved
- Consolidated the login app and its related npm packages by moving the
main package to `apps/login/apps/login` and merging
`apps/login/packages/integration` and `apps/login/packages/acceptance`
into the main `apps/login` package.
- Migrated from Docker Compose-based test setups to dev container-based
setups, adding support for multiple dev container configurations:
- `.devcontainer/base`
- `.devcontainer/turbo-lint-unit`
- `.devcontainer/turbo-lint-unit-debug`
- `.devcontainer/login-integration`
- `.devcontainer/login-integration-debug`
- Added npm scripts to run the new dev container setups, enabling exact
reproduction of GitHub PR checks locally, and updated the pipeline to
use these containers.
- Cleaned up Dockerfiles and docker-bake.hcl files to only build the
production image for the login app.
- Cleaned up compose files to focus on dev environments in dev
containers.
- Updated `CONTRIBUTING.md` with guidance on running and debugging PR
checks locally using the new dev container approach.
- Introduced separate Dockerfiles for the login app to distinguish
between using published client packages and building clients from local
protos.
- Ensured the login container is always built in the pipeline for use in
integration and acceptance tests.
- Updated Makefile and GitHub Actions workflows to use
`--frozen-lockfile` for installing pnpm packages, ensuring reproducible
installs.
- Disabled GitHub release creation by the changeset action.
- Refactored the `/build` directory structure for clarity and
maintainability.
- Added a `clean` command to `docks/package.json`.
- Experimentally added `knip` to the `zitadel-client` package for
improved linting of dependencies and exports.
# Additional Changes
- Fixed Makefile commands for consistency and reliability.
- Improved the structure and clarity of the `/build` directory to
support seamless integration of the login build.
- Enhanced documentation and developer experience for running and
debugging CI checks locally.
# Additional Context
- See updated `CONTRIBUTING.md` for new local development and debugging
instructions.
- These changes are a prerequisite for further improvements to the CI
pipeline and local development workflow.
- Closes#10276
Max PeintnerandGitHub
Elio BischofandGitHub