# IndieAuth Endpoint Discovery Hotfix - Implementation Report

**Date:** 2025-12-17
**Type:** Production Hotfix
**Priority:** Critical
**Status:** Implementation Complete

## Summary

Successfully implemented the IndieAuth endpoint discovery hotfix as specified in the design document. The authentication flow now correctly discovers endpoints from the user's profile URL per the W3C IndieAuth specification, instead of hardcoding the indielogin.com service.

## Implementation Steps

All implementation steps were completed successfully:

### Step 1: Update starpunk/config.py - Remove INDIELOGIN_URL
- Removed `INDIELOGIN_URL` config line (previously line 37)
- Added deprecation warning for users still setting `INDIELOGIN_URL` in environment
- Warning directs users to remove the deprecated config

### Step 2: Update starpunk/auth.py - Add imports and use endpoint discovery
- Added imports: `discover_endpoints`, `DiscoveryError`, `normalize_url` from `starpunk.auth_external`
- Rewrote `initiate_login()`:
  - Now discovers authorization_endpoint from the user's profile URL
  - Uses discovered endpoint instead of hardcoded INDIELOGIN_URL
  - Raises DiscoveryError if endpoint discovery fails or no authorization_endpoint found
- Rewrote `handle_callback()`:
  - Discovers authorization_endpoint from ADMIN_ME profile
  - Uses authorization_endpoint for authentication-only flow (per IndieAuth spec)
  - Does NOT include `grant_type` parameter (not needed for auth-only flows)
  - Uses `normalize_url()` for URL comparison to handle trailing slashes and case differences

### Step 3: Update starpunk/auth_external.py - Relax endpoint validation
- Changed endpoint validation in `_fetch_and_parse()`:
  - Now requires at least one endpoint (authorization_endpoint OR token_endpoint)
  - Previously required token_endpoint to be present
  - This allows profiles with only authorization_endpoint to work for login
  - Micropub will still require token_endpoint and fail gracefully with 401

### Step 4: Update starpunk/routes/auth.py - Import and handle DiscoveryError
- Added import for `DiscoveryError` from `starpunk.auth_external`
- Added exception handler in `login_initiate()`:
  - Catches DiscoveryError
  - Logs technical details at ERROR level
  - Shows user-friendly message: "Unable to verify your profile URL. Please check that it's correct and try again."
  - Redirects back to login form

### Step 5: Update tests/test_auth.py - Mock discover_endpoints()
- Removed `INDIELOGIN_URL` from test app fixture
- Updated all tests that call `initiate_login()` or `handle_callback()`:
  - Added `@patch("starpunk.auth.discover_endpoints")` decorator
  - Mock returns both authorization_endpoint and token_endpoint
  - Updated assertions to check for discovered endpoint instead of indielogin.com
- Tests updated:
  - `TestInitiateLogin.test_initiate_login_success`
  - `TestInitiateLogin.test_initiate_login_stores_state`
  - `TestHandleCallback.test_handle_callback_success`
  - `TestHandleCallback.test_handle_callback_unauthorized_user`
  - `TestHandleCallback.test_handle_callback_indielogin_error`
  - `TestHandleCallback.test_handle_callback_no_identity`
  - `TestLoggingIntegration.test_initiate_login_logs_at_debug`
  - `TestLoggingIntegration.test_initiate_login_info_level`
  - `TestLoggingIntegration.test_handle_callback_logs_http_details`

### Step 6: Update tests/test_auth_external.py - Fix error message
- Updated `test_discover_endpoints_no_token_endpoint`:
  - Changed assertion from "No token endpoint found" to "No IndieAuth endpoints found"
  - Matches new relaxed validation error message

### Step 7: Run tests to verify implementation
- All 51 tests in `tests/test_auth.py` pass
- All 35 tests in `tests/test_auth_external.py` pass
- All 32 tests in `tests/test_routes_admin.py` pass
- No regressions detected

## Files Modified

| File | Lines Changed | Description |
|------|--------------|-------------|
| `starpunk/config.py` | 9 added, 1 removed | Removed INDIELOGIN_URL, added deprecation warning |
| `starpunk/auth.py` | 1 added, 84 replaced | Added imports, rewrote initiate_login() and handle_callback() |
| `starpunk/auth_external.py` | 6 replaced | Relaxed endpoint validation |
| `starpunk/routes/auth.py` | 5 added | Added DiscoveryError import and exception handling |
| `tests/test_auth.py` | 1 removed, 43 modified | Removed INDIELOGIN_URL from fixture, added mocks |
| `tests/test_auth_external.py` | 2 modified | Updated error message assertion |

## Key Implementation Details

### Authorization Endpoint Usage
Per IndieAuth spec and architect clarifications:
- Authentication-only flows POST to the **authorization_endpoint** (not token_endpoint)
- The `grant_type` parameter is NOT included (only for access token flows)
- This differs from the previous implementation which incorrectly used indielogin.com's endpoints

### URL Normalization
The implementation now uses `normalize_url()` when comparing the returned 'me' URL with ADMIN_ME:
- Handles trailing slash differences (https://example.com vs https://example.com/)
- Handles case differences (https://Example.com vs https://example.com)
- This is spec-compliant behavior that was previously missing

### Error Handling
- Discovery failures are caught and logged at ERROR level
- User-facing error message is simplified and friendly
- Technical details remain in logs for debugging

### Backward Compatibility
- Deprecation warning added for INDIELOGIN_URL environment variable
- Existing .env files with INDIELOGIN_URL will log a warning but continue to work
- Users are instructed to remove the deprecated config

## Testing Results

### Unit Tests
- `tests/test_auth.py`: 51/51 passed
- `tests/test_auth_external.py`: 35/35 passed
- `tests/test_routes_admin.py`: 32/32 passed

### Integration
All modified tests now correctly mock endpoint discovery and validate the new behavior.

## Issues Encountered

No significant issues encountered during implementation. The design document was thorough and all architect clarifications were addressed:

1. Import placement - Moved to top-level as specified
2. URL normalization - Included as intentional bugfix
3. Endpoint selection - Used authorization_endpoint for auth-only flows
4. Validation relaxation - Allowed profiles with only authorization_endpoint
5. Test strategy - Mocked discover_endpoints() and removed INDIELOGIN_URL
6. grant_type parameter - Correctly omitted for auth-only flows
7. Error messages - Simplified user-facing messages

## Next Steps

1. Manual testing recommended:
   - Test login flow with actual IndieAuth profile
   - Verify endpoint discovery logs appear
   - Test with profiles that have custom endpoints
   - Verify error message appears for profiles without endpoints

2. Deployment:
   - Update production .env to remove INDIELOGIN_URL (optional - will show warning)
   - Deploy changes
   - Monitor logs for "Discovered authorization_endpoint" messages
   - Verify login works for admin user

3. Documentation:
   - Update CHANGELOG.md with hotfix entry
   - Consider adding migration guide if needed

## Verification Checklist

- [x] All specified files modified
- [x] All code changes follow architect's design exactly
- [x] Tests updated and passing
- [x] Error messages user-friendly
- [x] Logging appropriate for debugging
- [x] URL normalization implemented
- [x] Endpoint validation relaxed correctly
- [x] No regressions in existing tests
- [x] Implementation report created

## Conclusion

The hotfix has been successfully implemented according to the architect's design. The authentication flow now correctly implements the W3C IndieAuth specification for endpoint discovery. All tests pass and no regressions were detected.

The critical production bug preventing user login should be resolved once this code is deployed.

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**Developer:** Claude (Fullstack Developer Subagent)
**Date Completed:** 2025-12-17
**Ready for Review:** Yes
