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v2.2.2 - CORS Support for Web Clients

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@PuroDelphi PuroDelphi released this 29 Jun 18:14
· 178 commits to main since this release
v2.2.2
0faa5ad

🌐 MCP Firebird v2.2.2 - CORS Support Release

🚀 Critical Enhancement: Web Client Support

This release adds CORS (Cross-Origin Resource Sharing) support to enable web-based MCP clients to connect to the Firebird server without browser security restrictions.

✅ What's New

🌐 CORS Configuration Added:

  • Fixed: Access-Control-Allow-Origin header missing error
  • Added: Complete CORS middleware to backwards compatible server
  • Configured: Proper headers for web client access from any origin
  • Supports: Web clients from localhost:3000 and other domains

🔧 CORS Headers Configured:

Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, DELETE, OPTIONS
Access-Control-Allow-Headers: Content-Type, mcp-session-id, Cache-Control, Accept
Access-Control-Allow-Credentials: false

🎯 Problem Solved:

Before v2.2.2:

Access to resource at 'http://localhost:3011/sse' from origin 'http://localhost:3000' 
has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present

After v2.2.2:
✅ Web clients can connect from any origin
✅ No more CORS policy blocking errors
✅ SSE connections work from browser applications
✅ OPTIONS preflight requests handled correctly

🔧 Technical Implementation

Server Enhancement:

  • Added cors middleware to startBackwardsCompatibleServer function
  • Maintains full backwards compatibility with existing clients
  • Applied to all SSE and HTTP endpoints
  • Zero impact on STDIO transport

Supported Scenarios:

  • ✅ Web Applications: Browser-based MCP clients
  • ✅ Development Servers: localhost with different ports
  • ✅ Cross-Domain Access: Any origin can connect
  • ✅ Existing Clients: No changes required for current users

📊 Version Progression

Version CORS Support Web Clients Status
v2.2.1 ❌ ❌ Blocked Previous
v2.2.2 ✅ ✅ Working Current

🚀 Usage Examples

Web Client Connection (Now Working):

// Browser JavaScript - now works without CORS errors
const eventSource = new EventSource('http://localhost:3003/sse');
eventSource.onmessage = function(event) {
    console.log('Received:', event.data);
};

NPX Commands (Unchanged):

# STDIO Mode (Claude Desktop)
npx mcp-firebird@latest --transport-type stdio \
  --database "F:\\Proyectos\\SAI\\AUTOSERVICIO_LA_PAZ.FDB" \
  --user SYSDBA --password masterkey

# SSE Mode (Web Clients + MCP Inspector)
npx mcp-firebird@latest --transport-type sse --sse-port 3003 \
  --database "F:\\Proyectos\\SAI\\AUTOSERVICIO_LA_PAZ.FDB" \
  --user SYSDBA --password masterkey

🎯 Who Benefits

  • Web Developers: Can now build browser-based MCP clients
  • Frontend Applications: Direct SSE connections without proxy servers
  • Development Teams: Cross-origin development setups work seamlessly
  • Existing Users: Zero impact, all current functionality preserved

📈 Migration from v2.2.1

No changes required! Simply update:

# Update global installation
npm install -g mcp-firebird@latest

# Or use npx (always gets latest)
npx mcp-firebird@latest --version  # Shows v2.2.2

🔄 Backwards Compatibility

  • ✅ STDIO Transport: Unchanged, works exactly as before
  • ✅ SSE Transport: Enhanced with CORS, existing clients unaffected
  • ✅ Configuration: Same parameters, same behavior
  • ✅ Performance: No performance impact

🌟 Key Features Maintained

  • 16 Database Tools: Complete Firebird operations
  • 10 Smart Prompts: SQL analysis and optimization
  • Dual Transport: STDIO + SSE protocols
  • Windows Compatible: Proper file path handling
  • Production Ready: Tested and stable

🚀 Next Steps

With CORS support now available, developers can:

  1. Build Web UIs: Create browser-based database management tools
  2. Integrate with Web Apps: Add MCP Firebird to existing web applications
  3. Develop Dashboards: Real-time database monitoring interfaces
  4. Create APIs: Web services that leverage MCP Firebird capabilities

🙏 Support the Project

If this CORS enhancement helps your web development:

PayPal

📞 Need Help?

  • 📖 Documentation: Check README and docs/ folder
  • 🐛 Issues: Report problems on GitHub Issues
  • 💬 Discussions: Join GitHub Discussions for questions
  • 🎥 Examples: See examples/sse-client.html for web client demo

Full Changelog: v2.2.1...v2.2.2

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