# OAuth 2.0 Implementation Status

## ✅ Completed (Task 1.1 - Partial)

### 1. OAuth Handler Module (`auth/oauth_handler.py`)
**Status:** ✅ Complete

**Features Implemented:**
- Client credentials grant flow
- Automatic token refresh with exponential backoff
- Encrypted token storage in memory (using Fernet)
- Thread-safe token access with async locks
- Retry logic for transient failures
- Token expiration monitoring (60-second buffer)
- Health status monitoring
- Comprehensive error handling

**Key Classes:**
- `OAuthToken`: Dataclass representing access tokens with expiration tracking
- `OAuthHandler`: Main OAuth manager with automatic refresh
- `OAuthError`, `TokenAcquisitionError`, `TokenRefreshError`: Exception hierarchy

**Usage Example:**
```python
from auth.oauth_handler import create_oauth_handler

handler = await create_oauth_handler(
    client_id="your-client-id",
    client_secret="your-secret",
    token_url="https://tenant.authentication.eu10.hana.ondemand.com/oauth/token"
)

# Get valid token (acquires or refreshes automatically)
token = await handler.get_token()
```

---

### 2. Authenticated Datasphere Connector (`auth/datasphere_auth_connector.py`)
**Status:** ✅ Complete

**Features Implemented:**
- OAuth-authenticated API wrapper for SAP Datasphere
- Automatic token refresh on 401 responses
- Context manager support for cleanup
- Async/await throughout

**Available Methods:**
- `get_spaces()` - List all spaces
- `get_space_details(space_id)` - Get space details
- `get_tables(space_id)` - List tables in space
- `get_table_schema(space_id, table_name)` - Get table schema
- `execute_query(space_id, query, limit)` - Execute SQL queries
- `get_connections()` - List data connections
- `get_tasks(space_id)` - List integration tasks
- `test_connection()` - Health check

**Usage Example:**
```python
from auth.datasphere_auth_connector import DatasphereAuthConnector, DatasphereConfig

config = DatasphereConfig(
    base_url="https://tenant.eu10.hcs.cloud.sap",
    client_id="client-id",
    client_secret="secret",
    token_url="https://tenant.authentication.eu10.hana.ondemand.com/oauth/token",
    tenant_id="tenant-id"
)

async with DatasphereAuthConnector(config) as connector:
    spaces = await connector.get_spaces()
    print(spaces)
```

---

### 3. Configuration Management (`config/settings.py`)
**Status:** ✅ Complete

**Features Implemented:**
- Pydantic-based settings with validation
- Environment variable loading from `.env` file
- Validation for URLs, ports, log levels
- Safe representation (no secret exposure in logs)
- Singleton pattern for global settings

**Configuration Fields:**
- `datasphere_base_url` - Tenant URL (validated)
- `datasphere_tenant_id` - Tenant identifier
- `datasphere_client_id` - OAuth client ID
- `datasphere_client_secret` - OAuth secret
- `datasphere_token_url` - Token endpoint (validated)
- `datasphere_scope` - Optional OAuth scope
- `log_level` - Logging level (validated)
- `server_port` - Server port (validated)
- `use_mock_data` - Development mode flag

**Usage Example:**
```python
from config import get_settings

settings = get_settings()
config = settings.get_datasphere_config()
```

---

### 4. Environment Template (`.env.example`)
**Status:** ✅ Complete

Provides template for users to configure their OAuth credentials.

---

### 5. Updated Dependencies (`requirements.txt`)
**Status:** ✅ Complete

**Added:**
- `aiohttp==3.9.1` - Async HTTP client
- `cryptography==41.0.7` - Token encryption

---

## 🚧 In Progress

### Next Steps (Task 1.1 Remaining):

1. **Remove Mock Data from MCP Server**
   - Remove hardcoded `MOCK_DATA` dictionary from `sap_datasphere_mcp_server.py`
   - Remove `use_mock_data` flag
   - Update tool handlers to use DatasphereAuthConnector

2. **Update `sap_datasphere_mcp_server.py`**
   - Load settings from environment
   - Initialize OAuth handler
   - Pass connector to MCP server

3. **Create OAuth Setup Documentation**
   - How to create Technical User in SAP Datasphere
   - How to configure OAuth app integration
   - How to get client credentials
   - Troubleshooting guide

---

## 📝 Files Created

```
auth/
├── __init__.py                      ✅ OAuth module exports
├── oauth_handler.py                 ✅ OAuth 2.0 token management
└── datasphere_auth_connector.py     ✅ Authenticated API connector

config/
├── __init__.py                      ✅ Config module exports
└── settings.py                      ✅ Environment-based settings

.env.example                         ✅ Configuration template
requirements.txt                     ✅ Updated with new dependencies
```

---

## 🎯 Success Criteria

- [x] OAuth handler with automatic token refresh
- [x] Encrypted token storage
- [x] Authenticated Datasphere connector
- [x] Configuration management with validation
- [x] Environment variable support
- [ ] Mock data removed from MCP server
- [ ] MCP server integrated with OAuth connector
- [ ] Documentation for OAuth setup
- [ ] Tested with real SAP Datasphere instance

---

## 🔐 Security Features

### Implemented:
✅ Client credentials flow (no user passwords)
✅ Token encryption in memory
✅ Automatic token refresh (60s before expiration)
✅ No credentials in source code
✅ Environment variable configuration
✅ Safe logging (no secret exposure)

### To Be Added (Later Tasks):
- Authorization flows for user consent
- SQL query validation
- Input sanitization
- Permission-based filtering

---

## 📊 Code Quality

- **Type Hints:** ✅ Comprehensive throughout
- **Async/Await:** ✅ Proper async patterns
- **Error Handling:** ✅ Custom exception hierarchy
- **Logging:** ✅ Structured logging at appropriate levels
- **Documentation:** ✅ Docstrings for all public methods
- **Tests:** ⚠️ Not yet implemented

---

## 🚀 Next Session Tasks

1. Update `sap_datasphere_mcp_server.py`:
   - Remove `MOCK_DATA` dictionary
   - Remove `DATASPHERE_CONFIG` hardcoded values
   - Integrate `DatasphereAuthConnector` in tool handlers

2. Update `sap_datasphere_mcp_server.py`:
   - Load settings from environment
   - Initialize OAuth handler
   - Pass to MCP server

3. Create `docs/OAUTH_SETUP.md`:
   - Step-by-step SAP Datasphere OAuth setup
   - Troubleshooting common issues
   - Security best practices

4. Test with real SAP Datasphere:
   - Verify OAuth flow
   - Test all connector methods
   - Validate error handling

---

## 📚 References

- [SAP Datasphere OAuth Documentation](https://help.sap.com/docs/SAP_DATASPHERE/9f804b8efa8043539289f42f372c4862/df7bbca2b73f4418881eeca39b9e0a3d.html)
- [MCP Specification 2025-03-26](https://modelcontextprotocol.io/specification/2025-03-26)
- [OAuth 2.0 Client Credentials](https://datatracker.ietf.org/doc/html/rfc6749#section-4.4)

---

**Last Updated:** 2025-10-29
**Completion:** ~60% of Task 1.1
**Time Spent:** ~2 hours
**Status:** Ready for integration with MCP server
