# Code Refactoring: Modular Structure
## Overview
The codebase has been successfully refactored from a single monolithic `index.js` file into a modular structure for better organization, maintainability, and testing.
## New Structure
```
n8n-ai-bridge/
├── index.js # Main server and HTTP transport logic
├── index.js.backup # Backup of original monolithic code
└── tools/ # Modular tool implementations
├── utils.js # Shared utilities and authentication
├── workflow-tools.js # All workflow-related operations
├── execution-tools.js # Execution-related operations
├── credential-tools.js # Credential-related operations
├── node-tools.js # Node type operations
└── test-tools.js # Self-test functionality
```
## Modular Organization
### `tools/utils.js`
- **Purpose**: Shared utility functions and authentication helpers
- **Exports**:
- `n8nApi` - Configured axios instance
- `extractApiKeyFromHeaders()` - Extract API keys from headers
- `getApiKey()` - Get API key from session/headers/environment
- `getAuthenticatedConfig()` - Create authenticated request config
- `validateAuthentication()` - Validate authentication for tools
### `tools/workflow-tools.js`
- **Purpose**: All workflow-related operations
- **Exports**:
- `listWorkflows()` - List workflows
- `getWorkflow()` - Get workflow details
- `createWorkflow()` - Create new workflow
- `updateWorkflow()` - Update existing workflow
- `activateWorkflow()` - Activate workflow
- `deactivateWorkflow()` - Deactivate workflow
- `deleteWorkflow()` - Delete workflow
### `tools/execution-tools.js`
- **Purpose**: Execution-related operations
- **Exports**:
- `listExecutions()` - List workflow executions
### `tools/credential-tools.js`
- **Purpose**: Credential-related operations
- **Exports**:
- `listCredentials()` - List credentials
- `createCredential()` - Create new credential
### `tools/node-tools.js`
- **Purpose**: Node type operations
- **Exports**:
- `listNodes()` - List available node types
### `tools/test-tools.js`
- **Purpose**: Self-test functionality
- **Exports**:
- `selfTest()` - Basic connectivity test
### `index.js` (Main Server)
- **Purpose**: MCP server, HTTP transport, and tool orchestration
- **Responsibilities**:
- HTTP server setup
- MCP protocol handling
- Tool registration and dispatch
- Session management
- Authentication middleware
## Benefits of Refactoring
### 1. **Separation of Concerns**
- Each module has a single, well-defined purpose
- Tool logic is separated from server infrastructure
- Authentication and utilities are centralized
### 2. **Maintainability**
- Easier to locate and modify specific functionality
- Reduced complexity in individual files
- Clear dependencies between modules
### 3. **Testability**
- Individual tools can be tested in isolation
- Mock dependencies can be easily injected
- Smaller, focused test suites
### 4. **Reusability**
- Tool functions can be reused in other contexts
- Utility functions are centralized and shared
- Consistent patterns across all tools
### 5. **Extensibility**
- New tools can be added easily by creating new modules
- Existing tools can be enhanced without affecting others
- Plugin-like architecture for future enhancements
## Migration Notes
### Original Structure
- **Before**: Single 1744-line `index.js` file with all functionality
- **Issues**:
- Hard to navigate and maintain
- Tight coupling between server logic and tool implementations
- Difficult to test individual components
### Refactored Structure
- **After**: Modular structure with clear separation
- **Benefits**:
- Each file focuses on specific functionality
- Loose coupling through well-defined interfaces
- Easy to test and maintain individual components
## Testing
The refactored code has been tested and verified to work correctly:
✅ **Server Startup**: Successfully starts on port 3001
✅ **Health Check**: Responds correctly to `/health` endpoint
✅ **MCP Protocol**: Properly handles MCP JSON-RPC messages
✅ **Tool Registration**: All 12 tools are correctly registered
✅ **Authentication**: Session-based and header-based auth working
✅ **Module Loading**: All ES6 imports resolve correctly
## Usage
The server works exactly the same as before from a client perspective:
```bash
# Start the server
node index.js
# Test with MCP client
npx -p mcp-remote mcp-remote-client http://localhost:3001/mcp
# Health check
curl http://localhost:3001/health
```
## Future Enhancements
With this modular structure, future enhancements become much easier:
1. **Add New Tools**: Create new tool modules in the `tools/` directory
2. **Enhanced Testing**: Add unit tests for individual tool modules
3. **Configuration**: Add tool-specific configuration files
4. **Plugins**: Implement a plugin system for external tools
5. **Documentation**: Generate API documentation from tool schemas
