nextcloud-mcp-server

brandon/nextcloud-mcp-server

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Author	SHA1	Message	Date
Chris Coutinho	e331544cee	feat: Implement RFC 8693 token exchange for Keycloak (ADR-002 Tier 2) Implements OAuth 2.0 Token Exchange (RFC 8693) enabling the MCP server to exchange service account tokens for user-scoped tokens. This provides an alternative to refresh tokens for background operations. Core Implementation: - Added `get_service_account_token()` method to KeycloakOAuthClient for client_credentials grant - Added `exchange_token_for_user()` method implementing RFC 8693 token exchange - Fixed Fernet encryption key handling in RefreshTokenStorage (was incorrectly base64 decoding already-encoded keys) - Updated OAuth configuration to support offline_access scope and refresh token storage infrastructure Keycloak Configuration: - Enabled `serviceAccountsEnabled` in realm-export.json - Added `token.exchange.grant.enabled` attribute - Added `client.token.exchange.standard.enabled` attribute (required for Keycloak 26.2+ Standard Token Exchange V2) - Fresh Keycloak imports now correctly enable token exchange Docker Compose: - Added TOKEN_ENCRYPTION_KEY and ENABLE_OFFLINE_ACCESS environment variables - Created oauth-tokens volume for refresh token storage - Configured both mcp-oauth and mcp-keycloak services Testing & Documentation: - Added tests/manual/test_token_exchange.py - Validates complete RFC 8693 flow - Added tests/manual/test_nextcloud_impersonate.py - Documents session-based impersonation limitations - Added docs/oauth-impersonation-findings.md - Comprehensive investigation findings and resolution documentation Verified Working: ✅ Service account token acquisition (client_credentials grant) ✅ RFC 8693 token exchange for internal-to-internal tokens ✅ Exchanged tokens validate with Nextcloud APIs ✅ Keycloak 26.4.2 Standard Token Exchange V2 support Known Limitations: - User impersonation (requested_subject) requires Keycloak Legacy V1 with preview features - Cross-client token exchange limited to same realm - Refresh token storage infrastructure ready but unused (MCP protocol limitation) Dependencies: aiosqlite>=0.20.0 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>	2025-11-02 22:03:19 +01:00
Chris Coutinho	529dc4616b	docs: Implement separate clients architecture for Keycloak integration Implements proper OAuth 2.0 separation following RFC 8707 best practices with distinct resource server and OAuth client configurations. ## Architecture Changes - Create separate "nextcloud" bearer-only client (resource server) - Configure "nextcloud-mcp-server" OAuth client with audience mapper - Audience mapper targets "nextcloud" resource server - Token flow: aud="nextcloud", azp="nextcloud-mcp-server" ## Benefits - Proper OAuth client vs resource server separation - Support for future multi-resource tokens: aud=["nextcloud", "other-service"] - RFC 8707 Resource Indicators compliance - Clear requester identification via azp claim ## Documentation Updates - Correct OAuth flow: MCP Client initiates, handles redirect, shares tokens - Explain MCP Server as protected resource architecture - Document offline_access with refresh tokens (Tier 1, current) - Document token exchange with delegation (Tier 2, future when Keycloak adds support) - Reference Keycloak issue #38279 for delegation status ## Files - keycloak/realm-export.json: Add separate clients configuration - app-hooks/post-installation/15-setup-keycloak-provider.sh: Setup user_oidc with "nextcloud" client - docs/audience-validation-setup.md: Comprehensive documentation with corrected OAuth flow and delegation comparison - docker-compose.yml: Fix Keycloak healthcheck (bash TCP instead of curl) - scripts/test_separate_clients.sh: Verification script for architecture 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>	2025-11-02 22:03:19 +01:00

Author

SHA1

Message

Date

Chris Coutinho

e331544cee

feat: Implement RFC 8693 token exchange for Keycloak (ADR-002 Tier 2)

Implements OAuth 2.0 Token Exchange (RFC 8693) enabling the MCP server to
exchange service account tokens for user-scoped tokens. This provides an
alternative to refresh tokens for background operations.

**Core Implementation:**
- Added `get_service_account_token()` method to KeycloakOAuthClient for
  client_credentials grant
- Added `exchange_token_for_user()` method implementing RFC 8693 token exchange
- Fixed Fernet encryption key handling in RefreshTokenStorage (was incorrectly
  base64 decoding already-encoded keys)
- Updated OAuth configuration to support offline_access scope and refresh token
  storage infrastructure

**Keycloak Configuration:**
- Enabled `serviceAccountsEnabled` in realm-export.json
- Added `token.exchange.grant.enabled` attribute
- Added `client.token.exchange.standard.enabled` attribute (required for
  Keycloak 26.2+ Standard Token Exchange V2)
- Fresh Keycloak imports now correctly enable token exchange

**Docker Compose:**
- Added TOKEN_ENCRYPTION_KEY and ENABLE_OFFLINE_ACCESS environment variables
- Created oauth-tokens volume for refresh token storage
- Configured both mcp-oauth and mcp-keycloak services

**Testing & Documentation:**
- Added tests/manual/test_token_exchange.py - Validates complete RFC 8693 flow
- Added tests/manual/test_nextcloud_impersonate.py - Documents session-based
  impersonation limitations
- Added docs/oauth-impersonation-findings.md - Comprehensive investigation
  findings and resolution documentation

**Verified Working:**
✅ Service account token acquisition (client_credentials grant)
✅ RFC 8693 token exchange for internal-to-internal tokens
✅ Exchanged tokens validate with Nextcloud APIs
✅ Keycloak 26.4.2 Standard Token Exchange V2 support

**Known Limitations:**
- User impersonation (requested_subject) requires Keycloak Legacy V1 with
  preview features
- Cross-client token exchange limited to same realm
- Refresh token storage infrastructure ready but unused (MCP protocol limitation)

Dependencies: aiosqlite>=0.20.0

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

2025-11-02 22:03:19 +01:00

Chris Coutinho

529dc4616b

docs: Implement separate clients architecture for Keycloak integration

Implements proper OAuth 2.0 separation following RFC 8707 best practices
with distinct resource server and OAuth client configurations.

## Architecture Changes

- Create separate "nextcloud" bearer-only client (resource server)
- Configure "nextcloud-mcp-server" OAuth client with audience mapper
- Audience mapper targets "nextcloud" resource server
- Token flow: aud="nextcloud", azp="nextcloud-mcp-server"

## Benefits

- Proper OAuth client vs resource server separation
- Support for future multi-resource tokens: aud=["nextcloud", "other-service"]
- RFC 8707 Resource Indicators compliance
- Clear requester identification via azp claim

## Documentation Updates

- Correct OAuth flow: MCP Client initiates, handles redirect, shares tokens
- Explain MCP Server as protected resource architecture
- Document offline_access with refresh tokens (Tier 1, current)
- Document token exchange with delegation (Tier 2, future when Keycloak adds support)
- Reference Keycloak issue #38279 for delegation status

## Files

- keycloak/realm-export.json: Add separate clients configuration
- app-hooks/post-installation/15-setup-keycloak-provider.sh: Setup user_oidc with "nextcloud" client
- docs/audience-validation-setup.md: Comprehensive documentation with corrected OAuth flow and delegation comparison
- docker-compose.yml: Fix Keycloak healthcheck (bash TCP instead of curl)
- scripts/test_separate_clients.sh: Verification script for architecture

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

2025-11-02 22:03:19 +01:00

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