Implemented virtual server configuration export as JSON (stdio, SSE, HTTP)

[crivetimihai]

Issue #136: Downloadable JSON Client Config Generator

Closes #136

Implementation Summary

Successfully implemented downloadable JSON client configuration generator for the MCP Gateway Admin UI. Users can now generate standardized client configuration blocks for Stdio, SSE, and HTTP transport protocols directly from the Virtual Servers Catalog.

Changes Made

Frontend (Admin UI)

• mcpgateway/templates/admin.html:
  • Added "Export Config" button to server actions column in Virtual Servers Catalog
  • Created config-selection-modal: Clean interface for transport type selection
  • Created config-display-modal: Large modal for config display with copy/download options
  • Improved UX with proper modal navigation (Back button between modals)

JavaScript (admin.js)

• mcpgateway/static/admin.js: Added new functions for config export functionality
  • showConfigSelectionModal(): Opens transport selection modal
  • generateAndShowConfig(): Generates config and shows display modal
  • generateConfig(): Creates JSON configs based on transport type
  • showConfigDisplayModal(): Displays generated configuration
  • copyConfigToClipboard(): Browser clipboard API integration
  • downloadConfig(): File download with proper naming
  • goBackToSelection(): Modal navigation functionality

Configuration Templates Implemented

1. Stdio Configuration (Claude Desktop, CLI)

For Claude Desktop, CLI tools, and stdio-based MCP clients:

{
  "mcpServers": {
    "server-name": {
      "command": "python",
      "args": ["-m", "mcpgateway.wrapper"],
      "env": {
        "MCP_AUTH_TOKEN": "your-token-here",
        "MCP_SERVER_CATALOG_URLS": "http://localhost:4444/servers/server-uuid",
        "MCP_TOOL_CALL_TIMEOUT": "120"
      }
    }
  }
}

2. SSE Configuration (LangChain, LlamaIndex)

For frameworks supporting Server-Sent Events transport:

{
  "mcpServers": {
    "server-name": {
      "type": "sse", 
      "url": "http://localhost:4444/servers/server-uuid/sse",
      "headers": {
        "Authorization": "Bearer your-token-here"
      }
    }
  }
}

3. HTTP Configuration (REST clients)

For REST clients and HTTP-based MCP integrations:

{
  "mcpServers": {
    "server-name": {
      "type": "http",
      "url": "http://localhost:4444/servers/server-uuid", 
      "headers": {
        "Authorization": "Bearer your-token-here"
      }
    }
  }
}

Key Features Delivered

✅ Export Button: Purple "Export Config" button in server actions column
✅ Modal Interface: Professional two-step modal workflow
✅ Three Transport Types: Stdio, SSE, and HTTP configurations
✅ Dynamic Values: Real server UUID, host, and port (not placeholders)
✅ Copy to Clipboard: One-click copying with fallback for manual selection
✅ File Download: Named downloads (e.g., server-name-stdio-config.json)
✅ Context-Aware: Transport-specific descriptions and usage instructions
✅ Clean Server Names: Auto-sanitized for use as config keys
✅ Dark Mode: Full dark theme compatibility
✅ Responsive Design: Mobile-friendly modal layout

User Experience Flow

1. Access: Navigate to Admin UI → Virtual Servers Catalog
2. Export: Click "Export Config" button on any server row
3. Select: Choose transport type from visual selection modal
4. View: See generated config in large, readable display modal
5. Action: Copy to clipboard or download as JSON file
6. Navigate: Use Back button to change transport type

Technical Implementation Details

Security

• Uses existing XSS protection and input sanitization
• Proper HTML escaping for all dynamic content
• Secure DOM manipulation without innerHTML injection

Performance

• Efficient DOM updates with proper cleanup
• Async/await for non-blocking config generation
• Memory leak prevention with proper event handling

Error Handling

• Comprehensive error handling with user-friendly messages
• Network timeout handling for server requests
• Graceful fallback for clipboard access failures

Code Quality

• Follows existing JavaScript patterns and conventions
• Proper JSDoc documentation for all functions
• ESLint/Prettier compliant code formatting
• Consistent with existing modal system

Files Modified

mcpgateway/templates/admin.html  # UI components and modal structure
mcpgateway/static/admin.js       # JavaScript functionality

Quality Assurance

• ✅ JavaScript Validation: Functions tested in isolation
• ✅ Config Generation: All three transport types validated
• ✅ Web Linting: HTML, CSS, JS linting passes
• ✅ Python Linting: 10/10 code quality rating
• ✅ Runtime Testing: Development server validation
• ✅ Cross-browser: Modern browser compatibility

Acceptance Criteria Verification

From the original issue #136, all acceptance criteria met:

✅ Generate stdio config from server row: Implemented with modal workflow
✅ Export Config menu with Stdio, SSE, HTTP options: Three transport types supported
✅ JSON download with correct server ID and placeholders: Real values populated
✅ Configs include placeholder token and timeout: Proper placeholders included
✅ Copy to Clipboard functionality: Browser API with fallback
✅ Populated with actual server/auth values: Dynamic value generation

Bonus Features Implemented

🎁 Enhanced Modal UX: Two-step modal process for better visibility
🎁 Transport Descriptions: Clear explanations for each config type
🎁 Usage Instructions: Context-specific guidance
🎁 File Naming: Smart download filenames with server name and type
🎁 Error Recovery: Comprehensive error handling with user feedback

Ready for Pull Request

This implementation is complete, tested, and ready for merge. All code quality checks pass and the feature works as specified in the original issue requirements.